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Non-steroidal anti-inflammatory drugs (NSAID) are members of a
therapeutic A therapy or medical treatment (often abbreviated tx, Tx, or Tx) is the attempted remediation of a health problem, usually following a medical diagnosis. As a rule, each therapy has indications and contraindications. There are many different ...
drug class A drug class is a set of medications and other compounds that have a similar chemical structures, the same mechanism of action (i.e. binding to the same biological target), a related mode of action, and/or are used to treat the same disease. In ...
which reduces pain, decreases inflammation, decreases fever, and prevents blood clots. Side effects depend on the specific drug, its dose and duration of use, but largely include an increased risk of gastrointestinal ulcers and bleeds,
heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
, and kidney disease. The term ''non-steroidal'', common from around 1960, distinguishes these drugs from corticosteroids, which during the 1950s had acquired a bad reputation due to overuse and side-effect problems after their initial introduction in 1948. NSAIDs work by inhibiting the activity of
cyclooxygenase Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as pr ...
enzymes (the
COX-1 Cyclooxygenase 1 (COX-1), also known as prostaglandin G/H synthase 1, prostaglandin-endoperoxide synthase 1 or prostaglandin H2 synthase 1, is an enzyme that in humans is encoded by the ''PTGS1'' gene. In humans it is one of two cyclooxygenases. ...
and
COX-2 Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (The HUGO official symbol is PTGS2; HGNC ID, HGNC:9605), also known as cyclooxygenase-2 or COX-2, is an enzyme that in humans is encoded by the ''PTGS2'' gene ...
isoenzyme In biochemistry, isozymes (also known as isoenzymes or more generally as multiple forms of enzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters (e.g. dif ...
s). In cells, these enzymes are involved in the synthesis of key biological mediators, namely prostaglandins, which are involved in
inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...
, and
thromboxane Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for i ...
s, which are involved in blood clotting. There are two general types of NSAIDs available: non-selective, and COX-2 selective. Most NSAIDs are non-selective, and inhibit the activity of both COX-1 and COX-2. These NSAIDs, while reducing inflammation, also inhibit platelet aggregation and increase the risk of gastrointestinal ulcers and bleeds. COX-2 selective inhibitors have fewer gastrointestinal side effects, but promote
thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...
, and some of these agents substantially increase the risk of heart attack. As a result, certain older COX-2 selective inhibitors are no longer used due to the high risk of undiagnosed
vascular disease Vascular disease is a class of diseases of the blood vessels – the arteries and veins of the circulatory system of the body. Vascular disease is a subgroup of cardiovascular disease. Disorders in this vast network of blood vessels can cause ...
. These differential effects are due to the different roles and tissue localisations of each COX isoenzyme. By inhibiting physiological COX activity, all NSAIDs increase the risk of kidney disease and, through a related mechanism, heart attack. In addition, NSAIDs can blunt the production of erythropoietin, resulting in anaemia, since haemoglobin needs this hormone to be produced. The most prominent NSAIDs are
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
, ibuprofen, and
naproxen Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulat ...
; all available
over the counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...
(OTC) in most countries. Paracetamol (acetaminophen) is generally not considered an NSAID because it has only minor anti-inflammatory activity. Paracetamol treats pain mainly by blocking COX-2 and inhibiting
endocannabinoid Cannabinoids () are several structural classes of compounds found in the cannabis plant primarily and most animal organisms (although insects lack such receptors) or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tet ...
reuptake almost exclusively within the brain, and only minimally in the rest of the body.


Medical uses

NSAIDs are often suggested for the treatment of acute or chronic conditions where pain and inflammation are present. NSAIDs are generally used for the symptomatic relief of the following conditions: *
Osteoarthritis Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...
*
Rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are invol ...
*Mild-to-moderate pain due to inflammation and tissue injury *
Low back pain Low back pain (LBP) or lumbago is a common disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can vary from a dull constant ache to a sudden sharp feel ...
*Inflammatory arthropathies (e.g.,
ankylosing spondylitis Ankylosing spondylitis (AS) is a type of arthritis characterized by long-term inflammation of the joints of the spine typically where the spine joins the pelvis. Occasionally areas affected may include other joints such as the shoulders or hi ...
,
psoriatic arthritis Psoriatic arthritis is a long-term inflammatory arthritis that occurs in people affected by the autoimmune disease psoriasis. The classic feature of psoriatic arthritis is swelling of entire fingers and toes with a sausage-like appearance. Th ...
,
reactive arthritis Reactive arthritis, also known as Reiter's syndrome, is a form of inflammatory arthritis that develops in response to an infection in another part of the body (cross-reactivity). Coming into contact with bacteria and developing an infection can t ...
) * Tennis elbow * Headache * Migraine *Acute
gout Gout ( ) is a form of inflammatory arthritis characterized by recurrent attacks of a red, tender, hot and swollen joint, caused by deposition of monosodium urate monohydrate crystals. Pain typically comes on rapidly, reaching maximal intens ...
* Dysmenorrhea ( menstrual pain) *
Metastatic Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...
bone pain *Postoperative pain *Muscle stiffness and pain due to
Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
* Pyrexia (fever) *
Ileus Ileus is a disruption of the normal propulsive ability of the intestine. It can be caused by lack of peristalsis or by mechanical obstruction. The word 'ileus' is from Ancient Greek ''eileós'' (, "intestinal obstruction"). The term 'subileus' ref ...
*
Renal colic Renal colic is a type of abdominal pain commonly caused by obstruction of ureter from dislodged kidney stones. The most frequent site of obstruction is the vesico-ureteric junction (VUJ), the narrowest point of the upper urinary tract. Acute ob ...
* Macular edema *Traumatic injury


Chronic pain and cancer-related pain

The effectiveness of NSAIDs for treating non-cancer chronic pain and cancer-related pain in children and adolescents is not clear. There have not been sufficient numbers of high-quality randomised controlled trials conducted.


Inflammation

Differences in anti-inflammatory activity between the various individual NSAIDs are small, but there is considerable variation in individual patient response, and tolerance to these drugs. About 60% of patients will respond to any NSAID; of the others, those who do not respond to one may well respond to another. Pain relief starts soon after taking the first dose, and a full analgesic effect should normally be obtained within a week, whereas an anti-inflammatory effect may not be achieved (or may not be clinically assessable) for up to three weeks. If appropriate responses are not obtained within these times, another NSAID should be tried.


Surgical pain

Pain following surgery can be significant, and many people require strong pain medications such as opioids. There is some low-certainty evidence that starting NSAID painkiller medications in adults early, before surgery, may help reduce post-operative pain, and also reduce the dose or quantity of opioid medications required after surgery. Any increase risk of surgical bleeding, bleeding in the gastrointestinal system, myocardial infarctions, or injury to the kidneys has not been well studied. When used in combination with paracetamol, the analgesic effect on post-operative pain may be improved.


Aspirin

Aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
, the only NSAID able to irreversibly inhibit
COX-1 Cyclooxygenase 1 (COX-1), also known as prostaglandin G/H synthase 1, prostaglandin-endoperoxide synthase 1 or prostaglandin H2 synthase 1, is an enzyme that in humans is encoded by the ''PTGS1'' gene. In humans it is one of two cyclooxygenases. ...
, is also indicated for antithrombosis through inhibition of platelet aggregation. This is useful for the management of arterial
thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...
, and prevention of adverse cardiovascular events like heart attacks. Aspirin inhibits platelet aggregation by inhibiting the action of thromboxane A2.


Dentistry

NSAIDs are useful in the management of post-operative
dental pain Toothache, also known as dental pain,Segen JC. (2002). ''McGraw-Hill Concise Dictionary of Modern Medicine''. The McGraw-Hill Companies. is pain in the teeth or their supporting structures, caused by dental diseases or pain referred to the te ...
following invasive dental procedures such as
dental extraction A dental extraction (also referred to as tooth extraction, exodontia, exodontics, or informally, tooth pulling) is the removal of teeth from the dental alveolus (socket) in the alveolar bone. Extractions are performed for a wide variety of reaso ...
. When not contra-indicated, they are favoured over the use of paracetamol alone due to the anti-inflammatory effect they provide. There is weak evidence suggesting that taking pre-operative analgesia can reduce the length of post operative pain associated with placing orthodontic spacers under local anaesthetic.


Contraindications

NSAIDs may be used with caution by people with the following conditions: *
Irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...
(IBS) *Persons who are over age 50, and who have a family history of gastrointestinal (GI) problems *Persons who have had previous gastrointestinal problems from NSAID use NSAIDs should usually be avoided by people with the following conditions: *
Peptic ulcer Peptic ulcer disease (PUD) is a break in the inner lining of the stomach, the first part of the small intestine, or sometimes the lower esophagus. An ulcer in the stomach is called a gastric ulcer, while one in the first part of the intestines ...
or stomach bleeding *Uncontrolled hypertension * Kidney disease *People with inflammatory bowel disease (Crohn's disease or ulcerative colitis) *Past
transient ischemic attack A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of ...
(excluding
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
) *Past stroke (excluding
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
) *Past
myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
(excluding
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
) * Coronary artery disease (excluding
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
) *Undergoing coronary artery bypass surgery * Congestive heart failure (excluding low-dose aspirin) *In third trimester of pregnancy *Persons who have undergone
gastric bypass surgery Gastric bypass surgery refers to a technique in which the stomach is divided into a small upper pouch and a much larger lower "remnant" pouch and then the small intestine is rearranged to connect to both. Surgeons have developed several differ ...
*Persons who have a history of allergic or allergic-type NSAID hypersensitivity reactions, e.g. aspirin-induced asthma


Adverse effects

The widespread use of NSAIDs has meant that the adverse effects of these drugs have become increasingly common. Use of NSAIDs increases risk of a range of
gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...
(GI) problems, kidney disease and adverse cardiovascular events. As commonly used for post-operative pain, there is evidence of increased risk of kidney complications. Their use following gastrointestinal surgery remains controversial, given mixed evidence of increased risk of leakage from any bowel anastomosis created. An estimated 10–20% of people taking NSAIDs experience indigestion. In the 1990s high doses of prescription NSAIDs were associated with serious upper gastrointestinal adverse events, including bleeding. NSAIDs, like all medications, may interact with other medications. For example, concurrent use of NSAIDs and quinolone antibiotics may increase the risk of quinolones' adverse
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
effects, including seizure. There is an argument over the benefits and risks of NSAIDs for treating chronic musculoskeletal pain. Each drug has a benefit-risk profile and balancing the risk of no treatment with the competing potential risks of various therapies should be considered. For people over the age of 65 years old, the balance between the benefits of pain-relief medications such as NSAIDS and the potential for adverse effects has not been well determined. There is some evidence suggesting that, for some people, use of NSAIDS (or other anti-inflammatories) may contribute to the initiation of chronic pain. In October 2020, the U.S.
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They are recommending avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.


Combinational risk

If a
COX-2 inhibitor COX-2 inhibitors are a type of nonsteroidal anti-inflammatory drug (NSAID) that directly targets cyclooxygenase-2, COX-2, an enzyme responsible for inflammation and pain. Targeting selectivity for COX-2 reduces the risk of peptic ulceration and i ...
is taken, a traditional NSAID (prescription or over-the-counter) should not be taken at the same time. Rofecoxib (Vioxx) was shown to produce significantly fewer gastrointestinal adverse drug reactions (
ADR ADR or adr may refer to: Computing * Asynchronous DRAM refresh, an approach for persistent memory found in some Intel Xeon processors * The adr microformat, part of the hCard microformat * Architectural decision record * Action–domain–respond ...
s) compared with naproxen. The study, the VIGOR trial, raised the issue of the cardiovascular safety of the coxibs (COX-2 inhibitors). A statistically significant increase in the incidence of
myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
s was observed in patients on rofecoxib. Further data, from the APPROVe trial, showed a statistically significant relative risk of cardiovascular events of 1.97 versus placebo—which caused a worldwide withdrawal of rofecoxib in October 2004. Use of methotrexate together with NSAIDs in
rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are invol ...
is safe, if adequate monitoring is done.


Cardiovascular

NSAIDs, aside from aspirin, increase the risk of
myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
and stroke. This occurs at least within a week of use. They are not recommended in those who have had a previous heart attack as they increase the risk of death or recurrent MI. Evidence indicates that
naproxen Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulat ...
may be the least harmful out of these. NSAIDs aside from (low-dose) aspirin are associated with a doubled risk of heart failure in people without a history of cardiac disease. In people with such a history, use of NSAIDs (aside from low-dose aspirin) was associated with a more than 10-fold increase in heart failure. If this link is proven causal, researchers estimate that NSAIDs would be responsible for up to 20 percent of hospital admissions for congestive heart failure. In people with heart failure, NSAIDs increase mortality risk (
hazard ratio In survival analysis, the hazard ratio (HR) is the ratio of the hazard rates corresponding to the conditions characterised by two distinct levels of a treatment variable of interest. For example, in a clinical study of a drug, the treated populati ...
) by approximately 1.2–1.3 for naproxen and ibuprofen, 1.7 for rofecoxib and celecoxib, and 2.1 for diclofenac. On 9 July 2015, the
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) toughened warnings of increased
heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
and stroke risk associated with nonsteroidal anti-inflammatory drugs (NSAIDs) ''other than
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
''.


Possible erectile dysfunction risk

A 2005 Finnish survey study found an association between long term (over 3 months) use of NSAIDs and erectile dysfunction. A 2011 publication in ''
The Journal of Urology ''The Journal of Urology'' is a peer-reviewed medical journal covering urology published by Elsevier on behalf of the American Urological Association. It was established in 1917. A special centenary issue was released in 2017 to celebrate 100 years ...
'' received widespread publicity. According to the study, men who used NSAIDs regularly were at significantly increased risk of erectile dysfunction. A link between NSAID use and erectile dysfunction still existed after controlling for several conditions. However, the study was observational and not controlled, with low original participation rate, potential participation bias, and other uncontrolled factors. The authors warned against drawing any conclusion regarding cause.


Gastrointestinal

The main
adverse drug reaction An adverse drug reaction (ADR) is a harmful, unintended result caused by taking medication. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs. The meaning of this term ...
s (ADRs) associated with NSAID use relate to direct and indirect irritation of the gastrointestinal (GI) tract. NSAIDs cause a dual assault on the GI tract: the acidic molecules directly irritate the
gastric mucosa The gastric mucosa is the mucous membrane layer of the stomach, which contains the glands and the gastric pits. In humans, it is about 1 mm thick, and its surface is smooth, soft, and velvety. It consists of simple columnar epithelium, lamina ...
, and inhibition of COX-1 and COX-2 reduces the levels of protective prostaglandins. Inhibition of prostaglandin synthesis in the GI tract causes increased gastric acid secretion, diminished bicarbonate secretion, diminished mucus secretion and diminished trophic effects on the epithelial mucosa. Common gastrointestinal side effects include: * Nausea or vomiting * Indigestion * Gastric ulceration or bleeding *
Diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...
Clinical NSAID ulcers are related to the systemic effects of NSAID administration. Such damage occurs irrespective of the route of administration of the NSAID (e.g., oral, rectal, or parenteral) and can occur even in people who have
achlorhydria Achlorhydria and hypochlorhydria refer to states where the production of hydrochloric acid in gastric secretions of the stomach and other digestive organs is absent or low, respectively. It is associated with various other medical problems. Sig ...
. Ulceration risk increases with therapy duration, and with higher doses. To minimize GI side effects, it is prudent to use the lowest effective dose for the shortest period of time—a practice that studies show is often not followed. Over 50% of patients who take NSAIDs have sustained some mucosal damage to their small intestine. The risk and rate of gastric adverse effects is different depending on the type of NSAID medication a person is taking. Indomethacin,
ketoprofen Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAID) with analgesic and antipyretic effects. It acts by inhibiting the body's production of prostaglandin. It was patented in 1967 and approved for medica ...
, and
piroxicam Piroxicam is a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class used to relieve the symptoms of painful inflammatory conditions like arthritis. Piroxicam works by preventing the production of endogenous prostaglandins which are in ...
use appear to lead to the highest rate of gastric adverse effects, while ibuprofen (lower doses) and
diclofenac Diclofenac, sold under the brand name Voltaren, among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth or rectally in a suppository, used by injection, or ...
appear to have lower rates. Certain NSAIDs, such as aspirin, have been marketed in enteric-coated formulations that manufacturers claim reduce the incidence of gastrointestinal ADRs. Similarly, some believe that rectal formulations may reduce gastrointestinal ADRs. However, consistent with the systemic mechanism of such ADRs, and in clinical practice, these formulations have not demonstrated a reduced risk of GI ulceration. Numerous "gastro-protective" drugs have been developed with the goal of preventing gastrointestinal toxicity in people who need to take NSAIDs on a regular basis. Gastric adverse effects may be reduced by taking medications that suppress acid production such as
proton pump inhibitor Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase proton pump. They are the most potent inhibitor ...
s (e.g.:
omeprazole Omeprazole, sold under the brand names Prilosec and Losec, among others, is a medication used in the treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger–Ellison syndrome. It is also used to prevent upp ...
and
esomeprazole Esomeprazole, sold under the brand name Nexium among others, is a medication which reduces stomach acid. It is used to treat gastroesophageal reflux disease, peptic ulcer disease, and Zollinger–Ellison syndrome. Effectiveness is similar to ...
), or by treatment with a drug that mimics prostaglandin in order to restore the lining of the GI tract (e.g.: a prostaglandin analog
misoprostol Misoprostol is a synthetic prostaglandin medication used to prevent and treat stomach and duodenal ulcers, induce labor, cause an abortion, and treat postpartum bleeding due to poor contraction of the uterus. Misoprostol is taken by mouth w ...
). Diarrhea is a common side effect of misoprostol, however, higher doses of misoprostol have been shown to reduce the risk of a person having a complication related to a gastric ulcer while taking NSAIDs. While these techniques may be effective, they are expensive for maintenance therapy. Hydrogen sulfide NSAID hybrids prevent the gastric ulceration/bleeding associated with taking the NSAIDs alone. Hydrogen sulfide is known to have a protective effect on the cardiovascular and gastrointestinal system.


Inflammatory bowel disease

NSAIDs should be used with caution in individuals with inflammatory bowel disease (e.g., Crohn's disease or
ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...
) due to their tendency to cause gastric bleeding and form ulceration in the gastric lining.


Renal

NSAIDs are also associated with a fairly high incidence of adverse drug reactions ( ADRs) on the kidney and over time can lead to chronic kidney disease. The mechanism of these kidney ADRs is due to changes in kidney blood flow. Prostaglandins normally dilate the
afferent arteriole The afferent arterioles are a group of blood vessels that supply the nephrons in many excretory systems. They play an important role in the regulation of blood pressure as a part of the tubuloglomerular feedback mechanism. The afferent arteriole ...
s of the
glomeruli ''Glomerulus'' () is a common term used in anatomy to describe globular structures of entwined vessels, fibers, or neurons. ''Glomerulus'' is the diminutive of the Latin ''glomus'', meaning "ball of yarn". ''Glomerulus'' may refer to: * the filter ...
. This helps maintain normal glomerular perfusion and
glomerular filtration rate Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearing toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pre ...
(GFR), an indicator of
kidney function Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging. Functions of a healthy kidney include maintaining a person's fluid ...
. This is particularly important in kidney failure where the kidney is trying to maintain renal perfusion pressure by elevated angiotensin II levels. At these elevated levels, angiotensin II also constricts the afferent arteriole into the glomerulus in addition to the efferent arteriole it normally constricts. Since NSAIDs block this prostaglandin-mediated effect of afferent arteriole dilation, particularly in kidney failure, NSAIDs cause unopposed constriction of the afferent arteriole and decreased RPF (renal perfusion flow) and GFR. Common ADRs associated with altered kidney function include: *
Sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
and fluid retention * Hypertension (high blood pressure) These agents may also cause kidney impairment, especially in combination with other nephrotoxic agents. Kidney failure is especially a risk if the patient is also concomitantly taking an ACE inhibitor (which removes angiotensin II's vasoconstriction of the efferent arteriole) and a diuretic (which drops plasma volume, and thereby RPF)—the so-called "triple whammy" effect. In rarer instances NSAIDs may also cause more severe kidney conditions: *
Interstitial nephritis Interstitial nephritis, also known as tubulointerstitial nephritis, is inflammation of the area of the kidney known as the renal interstitium, which consists of a collection of cells, extracellular matrix, and fluid surrounding the renal tubules ...
* Nephrotic syndrome *
Acute kidney injury Acute kidney injury (AKI), previously called acute renal failure (ARF), is a sudden decrease in kidney function that develops within 7 days, as shown by an increase in serum creatinine or a decrease in urine output, or both. Causes of AKI are c ...
*
Acute tubular necrosis Acute tubular necrosis (ATN) is a medical condition involving the death of tubular epithelial cells that form the renal tubules of the kidneys. Because necrosis is often not present, the term acute tubular injury (ATI) is preferred by pathologists ...
* Renal papillary necrosis NSAIDs in combination with excessive use of phenacetin or paracetamol (acetaminophen) may lead to analgesic nephropathy.


Photosensitivity

Photosensitivity Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicit ...
is a commonly overlooked adverse effect of many of the NSAIDs. The 2-arylpropionic acids are the most likely to produce photosensitivity reactions, but other NSAIDs have also been implicated including
piroxicam Piroxicam is a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class used to relieve the symptoms of painful inflammatory conditions like arthritis. Piroxicam works by preventing the production of endogenous prostaglandins which are in ...
,
diclofenac Diclofenac, sold under the brand name Voltaren, among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth or rectally in a suppository, used by injection, or ...
, and benzydamine. Benoxaprofen, since withdrawn due to its liver toxicity, was the most photoactive NSAID observed. The mechanism of photosensitivity, responsible for the high photoactivity of the 2-arylpropionic acids, is the ready decarboxylation of the carboxylic acid moiety. The specific absorbance characteristics of the different chromophoric 2-aryl substituents, affects the decarboxylation mechanism.


During pregnancy

While NSAIDs as a class are not direct teratogens, use of NSAIDs in late pregnancy can cause premature closure of the fetal
ductus arteriosus The ''ductus arteriosus'', also called the ''ductus Botalli'', named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta. It a ...
and kidney ADRs in the fetus. Thus, NSAIDs are not recommended during the third trimester of pregnancy because of the increased risk of premature constriction of the ductus arteriosus. Additionally, they are linked with
premature birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 2 ...
and miscarriage. Aspirin, however, is used together with heparin in pregnant women with
antiphospholipid syndrome Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS provokes blood clots (thrombosis) in both arteries and veins as well as pregnancy-r ...
. Additionally, indomethacin can be used in pregnancy to treat polyhydramnios by reducing fetal urine production via inhibiting fetal renal blood flow. In contrast, paracetamol (acetaminophen) is regarded as being safe and well tolerated during pregnancy, but Leffers et al. released a study in 2010, indicating that there may be associated male infertility in the unborn. Doses should be taken as prescribed, due to risk of liver toxicity with overdoses. In France, the country's health agency contraindicates the use of NSAIDs, including aspirin, after the sixth month of pregnancy. In October 2020, the U.S.
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
(FDA) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. They are recommending avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.


Allergy and allergy-like hypersensitivity reactions

A variety of allergic or allergic-like NSAID hypersensitivity reactions follow the ingestion of NSAIDs. These hypersensitivity reactions differ from the other adverse reactions listed here which are toxicity reactions, i.e. unwanted reactions that result from the pharmacological action of a drug, are dose-related, and can occur in any treated individual; hypersensitivity reactions are idiosyncratic reactions to a drug. Some NSAID hypersensitivity reactions are truly allergic in origin: 1) repetitive IgE-mediated
urticarial Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...
skin eruptions,
angioedema Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are ...
, and
anaphylaxis Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the foll ...
following immediately to hours after ingesting one structural type of NSAID but not after ingesting structurally unrelated NSAIDs; and 2) Comparatively mild to moderately severe
T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...
-mediated delayed onset (usually more than 24 hour), skin reactions such as
maculopapular rash A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. It may only appear red in lighter-skinned people. The term "maculopapular" is a compound: '' macules'' are small, flat ...
,
fixed drug eruption Fixed drug reactions, are common and so named because they recur at the same site with each exposure to a particular medication. Medications inducing fixed drug eruptions are usually those taken intermittently. Signs and symptoms A painful and it ...
s,
photosensitivity reaction Photodermatitis, sometimes referred to as sun poisoning or photoallergy, is a form of allergic contact dermatitis in which the allergen must be activated by light to sensitize the allergic response, and to cause a rash or other systemic effects o ...
s, delayed
urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-last ...
, and
contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are ...
; or 3) far more severe and potentially life-threatening t-cell-mediated delayed systemic reactions such as the
DRESS syndrome Drug reaction with eosinophilia and systemic symptoms (DRESS), also termed drug-induced hypersensitivity syndrome (DIHS), is a rare reaction to certain medications. It involves primarily a widespread skin rash, fever, swollen lymph nodes, and c ...
, acute generalized exanthematous pustulosis, the
Stevens–Johnson syndrome Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN), it forms a spectrum of disease, with SJS being less severe. Erythema ...
, and
toxic epidermal necrolysis Toxic epidermal necrolysis (TEN) is a type of severe skin reaction. Together with Stevens–Johnson syndrome (SJS) it forms a spectrum of disease, with TEN being more severe. Early symptoms include fever and flu-like symptoms. A few days later ...
. Other NSAID hypersensitivity reactions are allergy-like symptoms but do not involve true allergic mechanisms; rather, they appear due to the ability of NSAIDs to alter the metabolism of arachidonic acid in favor of forming metabolites that promote allergic symptoms. Affected individuals may be abnormally sensitive to these provocative metabolites or overproduce them and typically are susceptible to a wide range of structurally dissimilar NSAIDs, particularly those that inhibit COX1. Symptoms, which develop immediately to hours after ingesting any of various NSAIDs that inhibit COX-1, are: 1) exacerbations of asthmatic and rhinitis (see aspirin-induced asthma) symptoms in individuals with a history of
asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
or
rhinitis Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip. The inflammation is caused by viruses, bacteria, irrita ...
and 2) exacerbation or first-time development of
wheals A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this s ...
or
angioedema Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are ...
in individuals with or without a history of chronic
urticarial Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...
lesions or angioedema.


Possible effects on bone and soft tissue healing

It has been hypothesized that NSAIDs may delay healing from
bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
and soft-tissue injuries by inhibiting inflammation. On the other hand, it has also been hypothesized that NSAIDs might speed recovery from soft tissue injuries by preventing inflammatory processes from damaging adjacent, non-injured muscles. There is moderate evidence that they delay bone healing. Their overall effect on soft-tissue healing is unclear.


Ototoxicity

Long-term use of NSAID analgesics and paracetamol is associated with an increased risk of hearing loss.


Other

The use of NSAIDs for analgesia following gastrointestinal surgery remains controversial, given mixed evidence of an increased risk of leakage from any bowel anastomosis created. This risk may vary according to the class of NSAID prescribed. Common adverse drug reactions (ADR), other than listed above, include: raised liver enzymes, headache,
dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...
. Uncommon ADRs include an abnormally high level of potassium in the blood, confusion, spasm of the airways, and rash. Ibuprofen may also rarely cause
irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...
symptoms. NSAIDs are also implicated in some cases of
Stevens–Johnson syndrome Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN), it forms a spectrum of disease, with SJS being less severe. Erythema ...
. Most NSAIDs penetrate poorly into the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
(CNS). However, the COX enzymes are expressed constitutively in some areas of the CNS, meaning that even limited penetration may cause adverse effects such as somnolence and dizziness. NSAIDs may increase the risk of bleeding in patients with Dengue fever For this reason, NSAIDs are only available with a prescription in India. In very rare cases, ibuprofen can cause
aseptic meningitis Aseptic meningitis is the inflammation of the meninges, a membrane covering the brain and spinal cord, in patients whose cerebral spinal fluid test result is negative with routine bacterial cultures. Aseptic meningitis is caused by viruses, my ...
. As with other drugs,
allergies Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermat ...
to NSAIDs might exist. While many allergies are specific to one NSAID, up to 1 in 5 people may have unpredictable cross-reactive allergic responses to other NSAIDs as well.


Drug interactions

NSAIDs reduce kidney blood flow and thereby decrease the efficacy of diuretics, and inhibit the elimination of
lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ...
and methotrexate. NSAIDs cause decreased ability to form blood clots, which can increase the risk of bleeding when combined with other drugs that also decrease blood clotting, such as warfarin. NSAIDs may aggravate hypertension (high blood pressure) and thereby antagonize the effect of antihypertensives, such as ACE inhibitors. NSAIDs may interfere and reduce effectiveness of
SSRI Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs increase the extracellul ...
antidepressants. NSAIDs, when used in combination with SSRIs, increases the risk of adverse gastrointestinal effects. NSAIDs, when used in combination with SSRIs, increases the risk of internal bleeding and brain hemorrhages. Various widely used nonsteroidal anti-inflammatory drugs (NSAIDs) enhance
endocannabinoid Cannabinoids () are several structural classes of compounds found in the cannabis plant primarily and most animal organisms (although insects lack such receptors) or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tet ...
signaling by blocking the anandamide-degrading membrane enzyme
fatty acid amide hydrolase Fatty acid amide hydrolase or FAAH (, oleamide hydrolase, anandamide amidohydrolase) is a member of the serine hydrolase family of enzymes. It was first shown to break down anandamide in 1993. In humans, it is encoded by the gene ''FAAH''.; Fu ...
( FAAH). NSAIDs may reduce the effectiveness of antibiotics. Tests on cultured bacteria found that antibiotic effectiveness was reduced by 18-30% on average compared to tests which did not include NSAIDs.


Immune response

Although small doses generally have little to no effect on the immune system, large doses of NSAIDs significantly suppress the production of immune cells. As NSAIDs affect prostaglandins, they affect the production of most fast growing cells. This includes immune cells. Unlike corticosteroids, they do not directly suppress the immune system and so their effect on the immune system is not immediately obvious. They suppress the production of new immune cells, but leave existing immune cells functional. Large doses slowly reduce the immune response as the immune cells are renewed at a much lower rate. Causing a gradual reduction of the immune system, much slower and less noticeable than the immediate effect of Corticosteroids. The effect significantly increases with dosage, in a nearly exponential rate. Doubling of dose reduced cells by nearly four times. Increasing dose by five times reduced cell counts to only a few percent of normal levels. This is likely why the effect was not immediately obvious in low dose trials, as the effect is not apparent until much higher dosages are tested.


Mechanism of action

Most NSAIDs act as nonselective inhibitors of the
cyclooxygenase Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as pr ...
(COX)
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s, inhibiting both the cyclooxygenase-1 (
COX-1 Cyclooxygenase 1 (COX-1), also known as prostaglandin G/H synthase 1, prostaglandin-endoperoxide synthase 1 or prostaglandin H2 synthase 1, is an enzyme that in humans is encoded by the ''PTGS1'' gene. In humans it is one of two cyclooxygenases. ...
) and cyclooxygenase-2 (
COX-2 Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (The HUGO official symbol is PTGS2; HGNC ID, HGNC:9605), also known as cyclooxygenase-2 or COX-2, is an enzyme that in humans is encoded by the ''PTGS2'' gene ...
)
isoenzyme In biochemistry, isozymes (also known as isoenzymes or more generally as multiple forms of enzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters (e.g. dif ...
s. This inhibition is competitively reversible (albeit at varying degrees of reversibility), as opposed to the mechanism of
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
, which is irreversible inhibition. COX catalyzes the formation of prostaglandins and
thromboxane Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for i ...
from arachidonic acid (itself derived from the cellular phospholipid bilayer by phospholipase A2). Prostaglandins act (among other things) as messenger molecules in the process of
inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...
. This
mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targ ...
was elucidated in 1970 by John Vane (1927–2004), who received a
Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...
for his work (see Mechanism of action of aspirin). COX-1 is a constitutively expressed enzyme with a "house-keeping" role in regulating many normal physiological processes. One of these is in the
stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
lining, where prostaglandins serve a protective role, preventing the stomach mucosa from being eroded by its own acid. COX-2 is an enzyme facultatively expressed in inflammation, and it is inhibition of COX-2 that produces the desirable effects of NSAIDs. When nonselective COX-1/COX-2 inhibitors (such as aspirin, ibuprofen, and naproxen) lower stomach prostaglandin levels,
ulcers An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...
of the
stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
or duodenum and internal
bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...
can result. The discovery of COX-2 led to research to the development of selective COX-2 inhibiting drugs that do not cause gastric problems characteristic of older NSAIDs. NSAIDs have been studied in various assays to understand how they affect each of these enzymes. While the assays reveal differences, unfortunately, different assays provide differing ratios. Paracetamol (acetaminophen) is not considered an NSAID because it has little anti-inflammatory activity. It treats pain mainly by blocking COX-2 mostly in the central nervous system, but not much in the rest of the body. However, many aspects of the mechanism of action of NSAIDs remain unexplained, and for this reason, further COX pathways are hypothesized. The COX-3 pathway was believed to fill some of this gap but recent findings make it appear unlikely that it plays any significant role in humans and alternative explanation models are proposed. NSAIDs interact with the
endocannabinoid system The endocannabinoid system (ECS) is a biological system composed of endocannabinoids, which are endogenous lipid-based retrograde neurotransmitters that bind to cannabinoid receptors (CBRs), and cannabinoid receptor proteins that are expressed ...
and its
endocannabinoid Cannabinoids () are several structural classes of compounds found in the cannabis plant primarily and most animal organisms (although insects lack such receptors) or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tet ...
s, as COX2 have been shown to utilize endocannabinoids as substrates, and may have a key role in both the
therapeutic effect Therapeutic effect refers to the response(s) after a treatment of any kind, the results of which are judged to be useful or favorable. This is true whether the result was expected, unexpected, or even an unintended consequence. An adverse effect ( ...
s and
adverse effect An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a " side effect", when judged to be secondary to a main or therapeutic effect. The term compl ...
s of NSAIDs, as well as in NSAID-induced placebo responses. NSAIDs are also used in the acute pain caused by
gout Gout ( ) is a form of inflammatory arthritis characterized by recurrent attacks of a red, tender, hot and swollen joint, caused by deposition of monosodium urate monohydrate crystals. Pain typically comes on rapidly, reaching maximal intens ...
because they inhibit urate crystal
phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...
besides inhibition of prostaglandin synthase.


Antipyretic activity

NSAIDs have
antipyretic An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...
activity and can be used to treat fever. Fever is caused by elevated levels of prostaglandin E2, which alters the firing rate of neurons within the
hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...
that control thermoregulation. Antipyretics work by inhibiting the enzyme COX, which causes the general inhibition of prostanoid biosynthesis ( PGE2) within the
hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...
. PGE2 signals to the hypothalamus to increase the body's thermal setpoint. Ibuprofen has been shown more effective as an
antipyretic An antipyretic (, from ''anti-'' 'against' and ' 'feverish') is a substance that reduces fever. Antipyretics cause the hypothalamus to override a prostaglandin-induced increase in temperature. The body then works to lower the temperature, which r ...
than paracetamol (acetaminophen). Arachidonic acid is the precursor substrate for cyclooxygenase leading to the production of prostaglandins F, D, and E.


Classification

NSAIDs can be classified based on their chemical structure or mechanism of action. Older NSAIDs were known long before their mechanism of action was elucidated and were for this reason classified by chemical structure or origin. Newer substances are more often classified by mechanism of action.


Salicylates

*
Aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
(
acetylsalicylic acid Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat ...
) *
Diflunisal Diflunisal is a salicylic acid derivative with analgesic and anti-inflammatory activity. It was developed by Merck Sharp & Dohme in 1971, as MK647, after showing promise in a research project studying more potent chemical analogs of aspirin. It wa ...
(Dolobid) * Salicylic acid and its salts *
Salsalate Salsalate is a medication that belongs to the salicylate and nonsteroidal anti-inflammatory drug (NSAID) classes. Salsalate is the generic name of a prescription drug marketed under the brandnames Mono-Gesic, Salflex, Disalcid, and Salsitab. Oth ...
(Disalcid)


Propionic acid derivatives

* Ibuprofen * Dexibuprofen *
Naproxen Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulat ...
* Fenoprofen *
Ketoprofen Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAID) with analgesic and antipyretic effects. It acts by inhibiting the body's production of prostaglandin. It was patented in 1967 and approved for medica ...
* Dexketoprofen * Flurbiprofen * Oxaprozin * Loxoprofen * Pelubiprofen * Zaltoprofen


Acetic acid derivatives

* Indomethacin * Tolmetin *
Sulindac Sulindac is a nonsteroidal anti-inflammatory drug (NSAID) of the arylalkanoic acid class that is marketed as Clinoril. Imbaral (not to be confused with mebaral) is another name for this drug. Its name is derived from sul(finyl)+ ind(ene)+ ac(etic ...
* Etodolac * Ketorolac *
Diclofenac Diclofenac, sold under the brand name Voltaren, among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth or rectally in a suppository, used by injection, or ...
* Aceclofenac *
Bromfenac Bromfenac is a nonsteroidal anti-inflammatory drug (NSAID) marketed in the US as an ophthalmic solution (brand names Prolensa and Bromday, prior formulation brand name Xibrom, which has since been discontinued) by ISTA Pharmaceuticals for short ...
*
Nabumetone Nabumetone is a nonsteroidal anti-inflammatory drug (NSAID). Nabumetone was developed by Beecham and first received regulatory approval in 1991. It is available under numerous brand names, such as Relafen, Relifex, and Gambaran. Nabumetone is ...
(drug itself is non-acidic but the active, principal metabolite has a carboxylic acid group)


Enolic acid (Oxicam) derivatives

*
Piroxicam Piroxicam is a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class used to relieve the symptoms of painful inflammatory conditions like arthritis. Piroxicam works by preventing the production of endogenous prostaglandins which are in ...
*
Meloxicam Meloxicam, sold under the brand name Mobic among others, is a nonsteroidal anti-inflammatory medication (NSAID) used to treat pain and inflammation in rheumatic diseases and osteoarthritis. It is used by mouth or by injection into a vein. It i ...
* Tenoxicam * Droxicam *
Lornoxicam Lornoxicam, also known as chlortenoxicam, is a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class with analgesic (pain relieving), anti-inflammatory and antipyretic (fever reducing) properties. It is available in oral administration, ...
*
Isoxicam Isoxicam is a nonsteroidal anti-inflammatory drug (NSAID) that was taken or applied to reduce inflammation and as an analgesic reducing pain in certain conditions. The drug was introduced in 1983 by the Warner-Lambert Company. Isoxicam is a chem ...
(withdrawn from market 1985) *
Phenylbutazone Phenylbutazone, often referred to as "bute", is a nonsteroidal anti-inflammatory drug (NSAID) for the short-term treatment of pain and fever in animals. In the United States and United Kingdom, it is no longer approved for human use (except in th ...
(Bute)


Anthranilic acid derivatives (Fenamates)

The following NSAIDs are derived from fenamic acid. which is a derivative of anthranilic acid,Sriram D, Yogeeswari P
Medicinal Chemistry, 2nd Edition
Pearson Education India, 2010.
which in turn is a nitrogen
isostere Classical Isosteres are molecules or ions with similar shape and often electronic properties. Many definitions are available. but the term is usually employed in the context of bioactivity and drug development. Such biologically-active compounds co ...
of salicylic acid, which is the active metabolite of
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
. * Mefenamic acid * Meclofenamic acid *
Flufenamic acid Flufenamic acid (FFA) is a member of the anthranilic acid derivatives (or fenamate) class of nonsteroidal anti-inflammatory drugs (NSAIDs). Like other members of the class, it is a cyclooxygenase (COX) inhibitor, preventing the formation of pr ...
* Tolfenamic acid


Selective

COX-2 inhibitor COX-2 inhibitors are a type of nonsteroidal anti-inflammatory drug (NSAID) that directly targets cyclooxygenase-2, COX-2, an enzyme responsible for inflammation and pain. Targeting selectivity for COX-2 reduces the risk of peptic ulceration and i ...
s (Coxibs)

*
Celecoxib Celecoxib, sold under the brand name Celebrex among others, is a COX-2 inhibitor and nonsteroidal anti-inflammatory drug (NSAID). It is used to treat the pain and inflammation in osteoarthritis, acute pain in adults, rheumatoid arthritis, ankyl ...
(FDA alert) * Rofecoxib (withdrawn from market) *
Valdecoxib Valdecoxib is a nonsteroidal anti-inflammatory drug (NSAID) used in the treatment of osteoarthritis, rheumatoid arthritis, and painful menstruation and menstrual symptoms. It is a selective cyclooxygenase-2 inhibitor. It was patented in 1995. V ...
(withdrawn from market) *
Parecoxib Parecoxib, sold under the brand name Dynastat among others, is a water-soluble and injectable prodrug of valdecoxib. Parecoxib is a COX2 selective inhibitor. It is injectable. It is approved through much of Europe for short term perioperative ...
FDA withdrawn, licensed in the EU * Lumiracoxib TGA cancelled registration *
Etoricoxib Etoricoxib, sold under the trade name Arcoxia, is a selective COX-2 inhibitor from McOLSON Research Laboratories. Currently it is approved in more than 80 countries worldwide but not in the US, where the Food and Drug Administration (FDA) has r ...
not FDA approved, licensed in the EU * Firocoxib used in dogs and horses


Sulfonanilides

* Nimesulide (systemic preparations are banned by several countries for the potential risk of hepatotoxicity)


Others

* Clonixin * Licofelone acts by inhibiting LOX (lipooxygenase) and COX and hence known as 5-LOX/COX inhibitor * H-harpagide in figwort or devil's claw


Chirality

Most NSAIDs are
chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from i ...
molecules;
diclofenac Diclofenac, sold under the brand name Voltaren, among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory diseases such as gout. It is taken by mouth or rectally in a suppository, used by injection, or ...
is a notable exception. However, the majority are prepared as racemic mixtures. Typically, only a single enantiomer is pharmacologically active. For some drugs (typically profens), an
isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
''in vivo'' converts the inactive enantiomer into the active form, although its activity varies widely in individuals. This phenomenon is likely responsible for the poor correlation between NSAID efficacy and plasma concentration observed in older studies when specific analysis of the active enantiomer was not performed. Ibuprofen and
ketoprofen Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAID) with analgesic and antipyretic effects. It acts by inhibiting the body's production of prostaglandin. It was patented in 1967 and approved for medica ...
are now available in single-enantiomer preparations (dexibuprofen and dexketoprofen), which purport to offer quicker onset and an improved side-effect profile.
Naproxen Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulat ...
has always been marketed as the single active enantiomer.


Main practical differences

NSAIDs within a group tend to have similar characteristics and tolerability. There is little difference in clinical efficacy among the NSAIDs when used at equivalent doses. Rather, differences among compounds usually relate to dosing regimens (related to the compound's elimination half-life), route of administration, and tolerability profile. Regarding adverse effects, selective
COX-2 inhibitor COX-2 inhibitors are a type of nonsteroidal anti-inflammatory drug (NSAID) that directly targets cyclooxygenase-2, COX-2, an enzyme responsible for inflammation and pain. Targeting selectivity for COX-2 reduces the risk of peptic ulceration and i ...
s have lower risk of gastrointestinal bleeding. With the exception of
naproxen Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulat ...
, nonselective NSAIDs increase the risk of having a heart attack. Some data also supports that the partially selective
nabumetone Nabumetone is a nonsteroidal anti-inflammatory drug (NSAID). Nabumetone was developed by Beecham and first received regulatory approval in 1991. It is available under numerous brand names, such as Relafen, Relifex, and Gambaran. Nabumetone is ...
is less likely to cause gastrointestinal events. A consumer report noted that ibuprofen, naproxen, and
salsalate Salsalate is a medication that belongs to the salicylate and nonsteroidal anti-inflammatory drug (NSAID) classes. Salsalate is the generic name of a prescription drug marketed under the brandnames Mono-Gesic, Salflex, Disalcid, and Salsitab. Oth ...
are less expensive than other NSAIDs, and essentially as effective and safe when used appropriately to treat osteoarthritis and pain.


Pharmacokinetics

Most nonsteroidal anti-inflammatory drugs are weak acids, with a pKa of 3–5. They are absorbed well from the
stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
and intestinal mucosa. They are highly protein-bound in plasma (typically >95%), usually to
albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...
, so that their
volume of distribution In pharmacology, the volume of distribution (VD, also known as apparent volume of distribution, literally, ''volume of dilution'') is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same c ...
typically approximates to plasma volume. Most NSAIDs are metabolized in the
liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...
by
oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
and conjugation to inactive metabolites that typically are excreted in the
urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...
, though some drugs are partially excreted in bile. Metabolism may be abnormal in certain disease states, and accumulation may occur even with normal dosage. Ibuprofen and diclofenac have short half-lives (2–3 hours). Some NSAIDs (typically oxicams) have very long half-lives (e.g. 20–60 hours).


History

It is widely believed that naturally occurring salicin in
willow Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist so ...
trees and other plants was used by the ancients as a form of analgesic or anti-inflammatory drug, but this story, although compelling, is not entirely true. Hippocrates does not mention willow at all.
Dioscorides Pedanius Dioscorides ( grc-gre, Πεδάνιος Διοσκουρίδης, ; 40–90 AD), “the father of pharmacognosy”, was a Greek physician, pharmacologist, botanist, and author of '' De materia medica'' (, On Medical Material) —a 5-vo ...
's
De materia medica (Latin name for the Greek work , , both meaning "On Medical Material") is a pharmacopoeia of medicinal plants and the medicines that can be obtained from them. The five-volume work was written between 50 and 70 CE by Pedanius Dioscorides, ...
was arguably the most influential herbal from Roman to Medieval times but, if he mentions willow at all (there is doubt about the identity of 'Itea'), then he used the ashes, steeped in vinegar, as a treatment for corns, which corresponds well with modern uses of salicylic acid. However, there is still some truth in this claim. Willow bark (from trees of the
salix Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
genus) was widely known to be used as a medicine by multiple First Nations communities. The bark would be chewed or steeped in water for its pain relieving and antipyretic effects. The effects are a result of the bark's salicin content. Meadowsweet, another plant to contain salicin, has strong roots in British folk medicine for the same maladies. These effects were first recorded in Western science by Reverend Edward Stone, who accidentally tried willow bark in 1757. He then went on to give it to 50 patients, where he reported a decrease in fever and pain. In the body, salicin is turned into salicylic acid, which produces the antipyretic and analgesic effects that the plants are known for. Salicin was first isolated by
Johann Andreas Buchner Johann Andreas Buchner (6 April 1783, Munich – 5 June 1852, Munich) was a German pharmacologist working in the area of alkaloids. He was the father of pharmacologist Ludwig Andreas Buchner (1813–1897). He studied at Johann Bartholomäus Trom ...
in 1827. By 1829, French chemist Henri Leroux had improved the extraction process to obtain about 30g of purified salicin from 1.5kg of willow bark. By
hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolys ...
, salicin releases
glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
and
salicyl alcohol Salicyl alcohol (saligenin) is an organic compound with the formula C6H4(OH)(CH2OH). It is a white solid that is used as a precursor in organic synthesis. Chemical synthesis Salicyl alcohol can be prepared through the reduction of salicylald ...
which can be converted into salicylic acid, both
in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...
and through chemical methods.John McMurry
Química Orgánica
(in Spanish). Published by Cengage Learning Editores, 2005.
In 1869, Hermann Kolbe synthesised salicylate, although it was too acidic for the
gastric mucosa The gastric mucosa is the mucous membrane layer of the stomach, which contains the glands and the gastric pits. In humans, it is about 1 mm thick, and its surface is smooth, soft, and velvety. It consists of simple columnar epithelium, lamina ...
. The reaction used to synthesise
aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...
acid from a
phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it ...
in the presence of is known as the Kolbe-Schmitt reaction. By 1897 the German chemist Felix Hoffmann and the Bayer company prompted a new age of pharmacology by converting salicylic acid into acetylsalicylic acid—named
aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
by Heinrich Dreser. Other NSAIDs like ibuprofen were developed from the 1950s forward. In 2001, NSAIDs accounted for 70,000,000 prescriptions and 30billion over-the-counter doses sold annually in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
.


Research

While studies have been conducted to see if various NSAIDs can improve behavior in transgenic mouse models of Alzheimer's disease and observational studies in humans have shown promise, there is no good evidence from randomized clinical trials that NSAIDs can treat or prevent Alzheimer's in humans; clinical trials of NSAIDs for treatment of Alzheimer's have found more harm than benefit. NSAIDs coordinate with metal ions affecting cellular function.


Veterinary use

Research supports the use of NSAIDs for the control of pain associated with veterinary procedures such as dehorning and castration of calves. The best effect is obtained by combining a short-term local anesthetic such as lidocaine with an NSAID acting as a longer term analgesic. However, as different species have varying reactions to different medications in the NSAID family, little of the existing research data can be extrapolated to animal species other than those specifically studied, and the relevant government agency in one area sometimes prohibits uses approved in other jurisdictions. In the United States,
meloxicam Meloxicam, sold under the brand name Mobic among others, is a nonsteroidal anti-inflammatory medication (NSAID) used to treat pain and inflammation in rheumatic diseases and osteoarthritis. It is used by mouth or by injection into a vein. It i ...
is approved for use only in canines, whereas (due to concerns about liver damage) it carries warnings against its use in catsMetaca
Client Information Sheet
, product description: "Non-steroidal anti-inflammatory drug for oral use in dogs only", and in the "What Is Metacam" section in bold-face type: "Do not use in cats.", January 2005.
except for one-time use during surgery. In spite of these warnings, meloxicam is frequently prescribed "off-label" for non-canine animals including cats and livestock species. In other countries, for example The European Union (EU), there is a label claim for use in cats.


See also

* Discovery and development of cyclooxygenase 2 inhibitors


References


External links

* {{Authority control Hepatotoxins