Clarithromycin, sold under the brand name Biaxin among others, is an

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

used to treat various

bacterial Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were amon ...

infections. This includes

strep throat Streptococcal pharyngitis, also known as streptococcal sore throat (strep throat), is pharyngitis (an infection of the pharynx, the back of the throat) caused by ''Streptococcus pyogenes'' a gram-positive, group A streptococcus. Common sympto ...

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severit ...

, skin infections, '' H. pylori'' infection, and

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the '' Borrelia'' bacterium, which is spread by ticks in the genus '' Ixodes''. The most common sign of infection is an expanding red rash, known as erythema ...

, among others. Clarithromycin can be taken by mouth as a pill or liquid. Common side effects include nausea, vomiting, headaches, and diarrhea. Severe

allergic reaction 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 derm ...

s are rare. Liver problems have been reported. It may cause harm if taken during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

. It is in the

macrolide The Macrolides are a class of natural products that consist of a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. The lactone rings are usually 14-, 15-, or 16-membered. Ma ...

class and works by slowing down bacterial

protein synthesis Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside cells, balancing the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a number of critical ...

. Clarithromycin was developed in 1980 and approved for medical use in 1990. It is on the World Health Organization's List of Essential Medicines. Clarithromycin is available as a generic medication. It is made from

erythromycin Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used durin ...

and is chemically known as 6-O-methylerythromycin.

Medical uses

Clarithromycin is primarily used to treat a number of bacterial infections including

, '' Helicobacter pylori'', and as an alternative to

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from '' Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum usin ...

. Other uses include cat scratch disease and other infections due to bartonella,

cryptosporidiosis Cryptosporidiosis, sometimes informally called crypto, is a parasitic disease caused by '' Cryptosporidium'', a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tra ...

, as a second line agent in

and

toxoplasmosis Toxoplasmosis is a parasitic disease caused by '' Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis are associated with a variety of neuropsychiatric and behavioral conditions. Occasionally, people may have a few weeks or mont ...

. It may also be used to prevent bacterial endocarditis in those who cannot take penicillin. It is effective against upper and lower respiratory tract infections, skin and soft tissue infections and helicobacter pylori infections associated with duodenal ulcers.

Spectrum of bacterial susceptibility

Aerobic Gram-positive bacteria * ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

'' * ''

Streptococcus pneumoniae ''Streptococcus pneumoniae'', or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic (under aerobic conditions) or beta-hemolytic (under anaerobic conditions), aerotolerant anaerobic member of the genus Streptococcus. They ar ...

'' * ''

Streptococcus pyogenes ''Streptococcus pyogenes'' is a species of Gram-positive, aerotolerant bacteria in the genus '' Streptococcus''. These bacteria are extracellular, and made up of non-motile and non-sporing cocci (round cells) that tend to link in chains. They ...

'' Aerobic Gram-negative bacteria * Haemophilus parainfluenzae * ''

Haemophilus influenzae ''Haemophilus influenzae'' (formerly called Pfeiffer's bacillus or ''Bacillus influenzae'') is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bact ...

'' * '' Moraxella catarrhalis'' Helicobacter * Helicobacter pylori Mycobacteria

Mycobacterium avium complex ''Mycobacterium avium ''complex is a group of mycobacteria comprising ''Mycobacterium intracellulare'' and ''Mycobacterium avium'' that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontub ...

consisting of: * Mycobacterium avium avium * Mycobacterium intracellulare Other bacteria * '' Chlamydia pneumoniae'' * '' Mycoplasma pneumoniae'' Safety and effectiveness of clarithromycin in treating clinical infections due to the following bacteria have not been established in adequate and well-controlled clinical trials: Aerobic Gram-positive bacteria * Streptococcus agalactiae * Streptococcus (Groups C, F, G) * Viridans group streptococci Aerobic Gram-negative bacteria *

Bordetella pertussis ''Bordetella pertussis'' is a Gram-negative, aerobic, pathogenic, encapsulated coccobacillus of the genus ''Bordetella'', and the causative agent of pertussis or whooping cough. Like '' B. bronchiseptica'', ''B. pertussis'' is motile and exp ...

Legionella pneumophila ''Legionella pneumophila'' is a thin, aerobic, pleomorphic, flagellated, non-spore-forming, Gram-negative bacterium of the genus '' Legionella''. ''L. pneumophila'' is the primary human pathogenic bacterium in this group and is the causative ...

Pasteurella multocida ''Pasteurella multocida'' is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus of the family Pasteurellaceae. Strains of the species are currently classified into five serogroups (A, B, D, E, F) based on capsular composition and ...

Anaerobic Gram-positive bacteria * Clostridium perfringens * Peptococcus Niger * Cutibacterium acnes Anaerobic Gram-negative bacteria * Prevotella melaninogenica (formerly

Bacteroides melaninogenicus ''Prevotella melaninogenica'' is a species of bacterium in the normal microbiota of the upper respiratory tract. It is an important human pathogen in various anaerobic infections, often mixed with other aerobic and anaerobic bacteria. ''P. mel ...

)

Contraindications

* Clarithromycin should not be taken by people who are allergic to other macrolides or inactive ingredients in the tablets, including microcrystalline cellulose, croscarmelose sodium, magnesium stearate, and povidone * Clarithromycin should not be used by people with a history of

cholestatic jaundice Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme metab ...

and/or liver dysfunction associated with prior clarithromycin use. * Clarithromycin should not be used in the setting of

hypokalaemia Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an abnorm ...

(low blood potassium) * Use of clarithromycin with the following medications: cisapride,

pimozide Pimozide (sold under the brand name Orap) is an antipsychotic drug of the diphenylbutylpiperidine class. It was discovered at Janssen Pharmaceutica in 1963. It has a high potency compared to chlorpromazine (ratio 50-70:1). On a weight basis ...

, astemizole, terfenadine,

ergotamine Ergotamine, sold under the brand names Cafergot (with caffeine) and Ergomar among others, is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It possesses structural sim ...

ticagrelor Ticagrelor, sold under the brand name Brilinta among others, is a medication used for the prevention of stroke, heart attack and other events in people with acute coronary syndrome, meaning problems with blood supply in the coronary arteries. It ...

ranolazine Ranolazine, sold under the brand name Ranexa among others, is a medication used to treat heart related chest pain. Typically it is used together with other medications when those are insufficient. Benefits appear smaller in women than men. It ...

dihydroergotamine Dihydroergotamine (DHE), sold under the brand names D.H.E. 45 and Migranal among others, is an ergot alkaloid used to treat migraines. It is a derivative of ergotamine. It is administered as a nasal spray or injection and has an efficacy simi ...

is not recommended. * It should not be used with

colchicine Colchicine is a medication used to treat gout and Behçet's disease. In gout, it is less preferred to NSAIDs or steroids. Other uses for colchicine include the management of pericarditis and familial Mediterranean fever. Colchicine is taken b ...

in people with kidney or liver impairment. * Concomitant use with cholesterol medications such as lovastatin or

simvastatin Simvastatin, sold under the brand name Zocor among others, is a statin, a type of lipid-lowering medication. It is used along with exercise, diet, and weight loss to decrease elevated lipid levels. It is also used to decrease the risk of hear ...

. *

Hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune ...

to clarithromycin or any component of the product, erythromycin, or any

antibiotics. *

QT prolongation Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, ...

or ventricular cardiac arrhythmias, including

torsade de pointes ''Torsades de pointes, torsade de pointes'' or ''torsades des pointes'' (TdP) (, , translated as "twisting of peaks") is a specific type of abnormal heart rhythm that can lead to sudden cardiac death. It is a polymorphic ventricular tachycardia t ...

Side effects

The most common side effects are gastrointestinal:

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 ...

(3%),

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

(3%), abdominal pain (3%), and

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenter ...

(6%). It also can cause headaches,

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

, and abnormal

liver function tests Liver function tests (LFTs or LFs), also referred to as a hepatic panel, are groups of blood tests that provide information about the state of a patient's liver. These tests include prothrombin time (PT/INR), activated partial thromboplastin ti ...

. Allergic reactions include rashes 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 follo ...

. Less common side effects (<1%) include extreme irritability, hallucinations (auditory and visual), dizziness/motion sickness, and alteration in senses of smell and taste, including a metallic taste. Dry mouth, panic attacks, and nightmares have also been reported, albeit less frequently.

Cardiac

In February 2018, the FDA issued a Safety Communication warning with respect to an increased risk for heart problems or death with the use of clarithromycin, and has recommended that alternative antibiotics be considered in those with heart disease. Clarithromycin can lead to a prolonged

QT interval The QT interval is a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart. It is calculated as the time from the start of the Q wave to the end of the T wave, and approximates to the time taken ...

. In patients with

long QT syndrome Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, ...

, cardiac disease, or patients taking other QT-prolonging medications, this can increase risk for life-threatening

arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adult ...

s. In one trial, the use of short-term clarithromycin treatment was correlated with an increased incidence of deaths classified as sudden cardiac deaths in stable coronary heart disease patients not using statins. Some case reports suspect it of causing liver disease.

Liver and kidney

Clarithromycin has been known to cause

jaundice Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme meta ...

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue rep ...

, and kidney problems, including

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

Central nervous system

Common adverse effects of clarithromycin in the central nervous system include dizziness, headaches. Rarely, it can cause

ototoxicity Ototoxicity is the property of being toxic to the ear (''oto-''), specifically the cochlea or auditory nerve and sometimes the vestibular system, for example, as a side effect of a drug. The effects of ototoxicity can be reversible and temporary, ...

, delirium and mania.

Infection

A risk of

oral candidiasis Oral candidiasis, also known as oral thrush among other names, is candidiasis that occurs in the mouth. That is, oral candidiasis is a mycosis (yeast/fungal infection) of ''Candida'' species on the mucous membranes of the mouth. ''Candida albic ...

and

vaginal candidiasis Vaginal yeast infection, also known as candidal vulvovaginitis and vaginal thrush, is excessive growth of yeast in the vagina that results in irritation. The most common symptom is vaginal itching, which may be severe. Other symptoms include bu ...

, due to the elimination of the yeast's natural bacterial competitors by the antibiotic, has also been noted.

Pregnancy and breastfeeding

Clarithromycin should not be used in pregnant women except in situations where no alternative therapy is appropriate. Clarithromycin can cause potential hazard to the fetus hence should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. For lactating mothers it is not known whether clarithromycin is excreted in human milk.

Interactions

Clarithromycin inhibits a liver enzyme,

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules ( xenobiotics), such as toxins or drugs, so that they can be removed from ...

, involved in the metabolism of many other commonly prescribed drugs. Taking clarithromycin with other medications that are metabolized by CYP3A4 may lead to unexpected increases or decreases in

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhala ...

levels. A few of the common interactions are listed below.

Colchicine

Clarithromycin has been observed to have a dangerous interaction with

as the result of inhibition of CYP3A4 metabolism and

P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein ...

transport. Combining these two drugs may lead to fatal colchicine toxicity, particularly in people with

chronic kidney disease Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...

Statins

Taking clarithromycin concurrently with certain

statins Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low ...

(a class of drugs used to reduce blood serum

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell memb ...

levels) increases the risk of side effects, such as muscle aches and muscle break down (

rhabdomyolysis Rhabdomyolysis (also called rhabdo) is a condition in which damaged skeletal muscle breaks down rapidly. Symptoms may include muscle pains, weakness, vomiting, and confusion. There may be tea-colored urine or an irregular heartbeat. Some of ...

Calcium channel blockers

Concurrent therapy with

calcium channel blocker Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists are a group of medications that disrupt the movement of calcium () through calcium channels. Calcium channel blockers are used as antihypertensive drugs, i.e., as ...

may increase risk of low blood pressure,

, and death, compared to pairing calcium channel blockers with azithromycin, a drug similar to clarithromycin but without CYP3A4 inhibition. Administration of clarithromycin in combination with verapamil have been observed to cause low blood pressure, low heart rate, and

lactic acidosis Lactic acidosis is a medical condition characterized by a build-up of lactate (especially -lactate) in the body, with formation of an excessively low pH in the bloodstream. It is a form of metabolic acidosis, in which excessive acid accumulates d ...

Carbamazepine

Clarithromycin may double the level of

carbamazepine Carbamazepine (CBZ), sold under the trade name Tegretol among others, is an anticonvulsant medication used primarily in the treatment of epilepsy and neuropathic pain. It is used as an adjunctive treatment in schizophrenia along with other m ...

in the body by reducing its clearance, which may lead to toxic symptoms of carbamazepine, such as double vision, loss of voluntary body movement, and nausea, as well as hyponatremia.

HIV medications

Depending on the combination of medications, clarithromycin therapy could be contraindicated, require changing doses of some medications, or be acceptable without dose adjustments. For example, clarithromycin may lead to decreased

zidovudine Zidovudine (ZDV), also known as azidothymidine (AZT), is an antiretroviral medication used to prevent and treat HIV/AIDS. It is generally recommended for use in combination with other antiretrovirals. It may be used to prevent mother-to-child ...

concentrations.

Mechanism of action

Clarithromycin prevents

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

from multiplying by acting as a protein synthesis inhibitor. It binds to 23S rRNA, a component of the 50S subunit of the bacterial

ribosome Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to fo ...

, thus inhibiting the

translation Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transla ...

peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. ...

Pharmacokinetics

Unlike erythromycin, clarithromycin is acid-stable, so can be taken orally without having to be protected from gastric acids. It is readily absorbed, and diffuses into most tissues and

phagocyte Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s. Due to the high concentration in phagocytes, clarithromycin is actively transported to the site of infection. During active phagocytosis, large concentrations of clarithromycin are released; its concentration in the tissues can be over 10 times higher than in plasma. Highest concentrations are found in liver, lung tissue, and stool.

Metabolism

Clarithromycin has a fairly rapid first-pass metabolism in the liver. Its major metabolites include an inactive metabolite, N-desmethylclarithromycin, and an active metabolite, 14-(''R'')-hydroxyclarithromycin. Compared to clarithromycin, 14-(''R'')-hydroxyclarithromycin is less potent against mycobacterial tuberculosis and the ''Mycobacterium avium'' complex. Clarithromycin (20%-40%) and its active metabolite (10%-15%) are excreted in urine. Of all the drugs in its class, clarithromycin has the best bioavailability at 50%, which makes it amenable to oral administration. Its elimination half-life is about 3 to 4 hours with 250 mg administered every 12 h, but increased to 5 to 7 h with 500 mg administered every 8 to 12 h. With any of these dosing regimens, the steady-state concentration of this metabolite is generally attained within 3 to 4 days.

History

Clarithromycin was invented by researchers at the Japanese drug company

Taisho Pharmaceutical is a Japanese pharmaceutical company based in Tokyo. History Taisho was established in 1912 as Taisho Seiyakusho to produce over-the-counter drugs. In 1928 the company changed its name to Taisho Pharmaceutical Co., Ltd. and in 1955 moved in ...

in 1980. The product emerged through efforts to develop a version of the antibiotic

that did not experience acid instability in the digestive tract, causing side effects, such as nausea and stomachache. Taisho filed for patent protection for the drug around 1980 and subsequently introduced a branded version of its drug, called Clarith, to the Japanese market in 1991. In 1985, Taisho partnered with the American company

Abbott Laboratories Abbott Laboratories is an American multinational medical devices and health care company with headquarters in Abbott Park, Illinois, United States. The company was founded by Chicago physician Wallace Calvin Abbott in 1888 to formulate known dr ...

for the international rights, and Abbott also gained FDA approval for Biaxin in October 1991. The drug went

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

in Europe in 2004 and in the US in mid-2005.

Society and culture

image:Clarith-200.jpg, 150px, A pack of clarithromycin tablets manufactured by

Available forms

Clarithromycin is available as a generic medication. In the United States, clarithromycin is available as immediate-release tablets, extended-release tablets, and granules for oral suspension.

Brand names

Clarithromycin is available under several brand names in many different countries, including Biaxin, Crixan, Claritron, Clarihexal, Clacid, Claritt, Clacee, Clarac, Clariwin, Claripen, Clarem, Claridar, Cloff, Fromilid, Infex, Kalixocin, Karicin, Klaricid, Klaridex, Klacid, Klaram, Klabax, Klerimed, MegaKlar, Monoclar, Resclar, Rithmo, Truclar, Vikrol and Zeclar.

Manufacturers

In the UK the drug product is manufactured in generic form by a number of manufacturers including Somex Pharma, Ranbaxy, Aptil and Sandoz.

References

External links

* * * {{Authority control CYP3A4 inhibitors Macrolide antibiotics Wikipedia medicine articles ready to translate AbbVie brands World Health Organization essential medicines Dimethylamino compounds