Amoxicillin/clavulanic acid, also known as co-amoxiclav, is an antibiotic useful for the treatment of a number of bacterial infections. It is a combination consisting of amoxicillin, a β-lactam antibiotic, and potassium clavulanate, a β-lactamase inhibitor. It is specifically used for otitis media, strep throat, pneumonia, cellulitis, urinary tract infections, animal bites, and tuberculosis. It is taken by mouth or by injection into a vein.
Common side effects include diarrhea, vomiting, and allergic reactions. It also increases the risk of yeast infections, headaches, and blood clotting problems. It is not recommended in people with a history of a penicillin allergy. It is relatively safe for use during pregnancy.
Amoxicillin/clavulanic acid was approved for medical use in the United States in 1984. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication. The wholesale cost in the developing world is about US$0.18–1.14 per day. In the United States a course of treatment costs $50–100. In 2016 it was the 114th most prescribed medication in the United States with more than 6 million prescriptions.
Amoxicillin/clavulanic acid is widely used to treat or prevent many infections caused by susceptible bacteria, such as:
This combination results in an antibiotic with an increased spectrum of action and restored efficacy against amoxicillin-resistant bacteria that produce β-lactamase.
Possible side effects include diarrhea, vomiting, nausea, thrush, and skin rash. These do not usually require medical attention. As with all antimicrobial agents, antibiotic-associated diarrhea due to Clostridium difficile infection—sometimes leading to pseudomembranous colitis—may occur during or after treatment with amoxicillin/clavulanic acid.
Rarely, cholestatic jaundice (also referred to as cholestatic hepatitis, a form of liver toxicity) has been associated with amoxicillin/clavulanic acid. The reaction may occur up to several weeks after treatment has stopped, and usually takes weeks to resolve. It is more frequent in men, older people, and those who have taken long courses of treatment; the estimated overall incidence is one in 100,000 exposures. In the United Kingdom, co-amoxiclav carries a warning from the Committee on Safety of Medicines to this effect.
As all aminopenicillins, amoxicillin has been associated with Stevens–Johnson syndrome/toxic epidermal necrolysis, although these reactions are very rare.
British scientists working at Beecham (now part of GlaxoSmithKline), filed for US patent protection for the drug combination in 1979.
They marketed it under the trade name Augmentin
. A patent was granted in 1985.
Amoxicillin/clavulanic acid is the International Nonproprietary Name (INN) and co-amoxiclav is the British Approved Name (BAN).
Many branded products indicate their strengths as the quantity of amoxicillin. Augmentin
250, for example, contains 250 mg of amoxicillin and 125 mg of clavulanic acid.
An intravenous preparation has been available in the UK since 1985, but no parenteral preparation is available in the US; the nearest equivalent is ampicillin/sulbactam.
Suspensions of amoxicillin/clavulanic acid are available for use in children. They must be refrigerated to maintain effectiveness.
Amoxicillin/clavulanic acid is used in numerous animals for a variety of conditions:
In combination with prednisolone, it is used for intramammary infusion for the treatment of mastitis in lactating cows. Trade names include Clavaseptin, Clavamox, and Synulox.
Amoxicillin/clavulanic acid is banned from use in domestic-food animals (cattle, swine, etc.) in both the US and Europe; in the UK, Synulox can be used in domestic-food animals as long as a specified withdrawal period is observed.
Bacterial antibiotic resistance is a growing problem in veterinary medicine. Amoxicillin/clavulanic acid is reported to be effective against clinical Klebsiella infections, but is not efficacious against Pseudomonas infections.