Cefaclor, sold under the trade name Ceclor among others, is a second-generation

cephalosporin The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus '' Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibio ...

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

used to treat certain

bacterial infection Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and many are beneficial but others can cause infectious diseases. The number of t ...

s such as

pneumonia Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...

and infections of the ear, lung, skin, throat, and urinary tract. It is also available from other manufacturers as a generic. It was patented in 1973 and approved for medical use in 1979.

Medical uses

Cefaclor belongs to the family of antibiotics known as the

cephalosporins The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibiotic ...

(cefalosporins). The cephalosporins are broad-spectrum

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

that are used for the treatment of

septicaemia Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...

, biliary tract infections,

peritonitis Peritonitis is inflammation of the localized or generalized peritoneum, the lining of the inner wall of the abdomen and covering of the abdominal organs. Symptoms may include severe pain, swelling of the abdomen, fever, or weight loss. One pa ...

, and urinary tract infections. The pharmacology of the cephalosporins is similar to that of the

penicillins 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'' ...

, excretion being principally renal. Cephalosporins penetrate the

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ven ...

poorly unless the meninges are inflamed;

cefotaxime Cefotaxime is an antibiotic used to treat several bacterial infections in humans, other animals, and plant tissue culture. Specifically in humans it is used to treat joint infections, pelvic inflammatory disease, meningitis, pneumonia, urin ...

is a more suitable cephalosporin than cefaclor for infections of the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

, e.g.

. Cefaclor is active against many

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, including both

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

and

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

organisms.

Spectrum of activity

Cefaclor is frequently used against bacteria responsible for causing skin infections, otitis media, urinary tract infections, and others. Cefaclor has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections: Gram positive aerobes - Staphylococci (including coagulase-positive, coagulase-negative, and penicillinase-producing strains), Streptococcus pneumoniae, and Streptococcus pyogenes (group A β-hemolytic streptococci). The following represents MIC susceptibility data for a few medically significant microorganisms. * ''Haemophilus influenzae'': 0.03 μg/mL - 128 μg/mL * ''Staphylcoccus aureus'': 0.6 μg/mL - 128 μg/mL * ''Streptococcus pyogenes'': 0.06 μg/mL - 4 μg/mL

Cautions and contraindications

Cautions include known sensitivity to beta-lactam antibacterials, such as penicillins (Cefaclor should be avoided if there is a history of immediate

hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes Imm ...

reaction); renal impairment (no dose adjustment required, although manufacturer advises caution);

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

and

breast-feeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a pump and then fed to the infant. The World Health Organization (WHO ...

(but appropriate to use); false positive urinary glucose (if tested for reducing substances) and false positive

Coombs test The direct and indirect Coombs tests, also known as antiglobulin test (AGT), are blood tests used in immunohematology. The direct Coombs test detects antibodies that are stuck to the surface of the red blood cells. Since these antibodies sometimes ...

. Cefaclor has also been reported to cause a serum sickness-like reaction in children. Cefaclor is contraindicated in case of hypersensitivity (i.e. allergy) to cephalosporins.

Side effects

The principal

side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...

of the cephalosporins is hypersensitivity. Penicillin-sensitive patients may also be allergic to the cephalosporins, depending on the side chain and it's relation to the penicillin allergy. Most patients with penicillin allergy can tolerate the majority of cephalosporins without allergic reactions. The previous percentage of 10% cross reactivity rates are a gross overestimation. Allergic reactions may present as, for example, rashes,

pruritus An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both ...

(itching),

urticaria Hives, also known as urticaria, is a kind of skin rash with red or flesh-colored, 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 typically ...

, serum sickness-like reactions with rashes, fever and

arthralgia Arthralgia () literally means ' joint pain'. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication Medication (also called medicament, medicine, pharmaceuti ...

, and

anaphylaxis Anaphylaxis (Greek: 'up' + 'guarding') is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of the use of emergency medication on site. It typicall ...

. The frequency and severity of

serum sickness Serum sickness in humans is a adverse drug reaction, reaction to proteins in antiserum derived from a non-human animal source, occurring 5–10 days after exposure. Symptoms often include a rash, Arthralgia, joint pain, fever, and lymphadenopathy. ...

-like reactions in children has led researchers to question its role in pediatric illness. Other side effects include gastrointestinal disturbances (e.g. diarrhea, nausea and vomiting, abdominal discomfort, disturbances in liver enzymes, transient

hepatitis Hepatitis is inflammation of the liver parenchyma, liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), Anorexia (symptom), poor appetite ...

and cholestatic jaundice),

headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...

, and

Stevens–Johnson syndrome Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and #Classification, Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN) overlap, they are considered febrile mucocutaneous d ...

. Rare side effects include

eosinophilia Eosinophilia is a condition in which the eosinophil count in the peripheral blood exceeds . Hypereosinophilia is an elevation in an individual's circulating blood eosinophil count above 1.5 billion/ L (1,500/ μL). The hypereosinophilic syndrome ...

and blood disorders (including

thrombocytopenia In hematology, thrombocytopenia is a condition characterized by abnormally low levels of platelets (also known as thrombocytes) in the blood. Low levels of platelets in turn may lead to prolonged or excessive bleeding. It is the most common coag ...

leucopenia Leukopenia () is a decrease in the number of white blood cells (leukocytes). It places individuals at increased risk of infection as white blood cells are the body's primary defense against infections. Signs and symptoms Symptoms may include: * sk ...

agranulocytosis Agranulocytosis, also known as agranulosis or granulopenia, is an acute condition involving a severe and dangerous lowered white blood cell count (leukopenia, most commonly of neutrophils) and thus causing neutropenia in the circulating blood. I ...

aplastic anaemia Aplastic anemia (AA) is a severe hematologic condition in which the body fails to make blood cells in sufficient numbers. Normally, blood cells are produced in the bone marrow by stem cells that reside there, but patients with aplastic anemia ...

and

haemolytic anaemia Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonl ...

); reversible

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 ...

;

hyperactivity Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple ...

nervousness Anxiety is an emotion characterised by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different from fear in that fear is defined as the emotional response to a present threat, where ...

, sleep disturbances,

hallucinations A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...

confusion In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion"

hypertonia Hypertonia is a term sometimes used synonymously with ''spasticity'' and ''rigidity'' in the literature surrounding damage to the central nervous system, namely upper motor neuron lesions. Impaired ability of damaged motor neurons to regulate ...

, and

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to Balance disorder, disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a ...

Toxic epidermal necrolysis Toxic epidermal necrolysis (TEN), also known as Lyell's syndrome, 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 f ...

has been reported. In the UK, The Committee on the Safety of Medicines (

CSM CSM may refer to: Arts and entertainment * ''Cantigas de Santa Maria'', a collection of medieval Galician-Portuguese vernacular songs and poems in praise of the Virgin Mary * Chaos Space Marines, in the ''Warhammer 40,000'' fictional universe * ...

) has warned that the risk of diarrhea and rarely antibiotic-associated colitis are more likely with higher doses.

Pregnancy and breastfeeding

Cefaclor is passed into the

breast milk Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by the mammary glands in the breasts of women. Breast milk is the primary source of nutrition for newborn infants, comprising fats, proteins, carbohydrates, and a var ...

in small quantities, but is generally accepted to be safe to take during

breastfeeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Orga ...

. Cefaclor is not known to be harmful in

Interactions

Coumarins

Cephalosporins The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibiotic ...

possibly enhance the

anticoagulant An anticoagulant, commonly known as a blood thinner, is a chemical substance that prevents or reduces the coagulation of blood, prolonging the clotting time. Some occur naturally in blood-eating animals, such as leeches and mosquitoes, which ...

effect of

coumarins Coumarin derivatives are derivatives of coumarin and are considered phenylpropanoids. Among the most important derivatives are the 4-hydroxycoumarins, which exhibit anticoagulant properties, a characteristic not present for coumarin itself. ...

(e.g.

Warfarin Warfarin, sold under the brand name Coumadin among others. It is used as an anticoagulant, anticoagulant medication. It is commonly used to prevent deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who ha ...

) - change in patient's clinical condition, particularly associated with liver disease, intercurrent illness, or drug administration, necessitates more frequent testing of INR, and dose adjustment as necessary.

Probenecid

Excretion of

is reduced by

probenecid Probenecid, also sold under the brand name Probalan, is a medication that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia. Probenecid was developed as an alternative to caronamide to competitive ...

(resulting in increased concentrations of drug in the

blood plasma Blood plasma is a light Amber (color), amber-colored liquid component of blood in which blood cells are absent, but which contains Blood protein, proteins and other constituents of whole blood in Suspension (chemistry), suspension. It makes up ...

Antacids

Absorption of cefaclor is reduced by

antacids An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts o ...

. Therefore antacids should not be taken right before or at the same time as cefaclor.

References

{{CephalosporinAntiBiotics Cephalosporin antibiotics Organochlorides Phenethylamines