Augmentin (Co-amoxiclav)

Augmentin in Brief
  • Active ingredients: Amoxicillin and Clavulanic Acid
  • Brand names: Augmentin®, Clavamox®, Co-amoxiclav
  • Therapeutic class: Antibiotic
  • Pharmacologic class: Aminopenicillin, Beta-lactam (Beta-Lactam and Beta-Lactamase Inhibitor Combination)
  • Pregnancy Category: B
  • Originally discovered: 1977, Beecham Research Laboratories, United Kingdom UK

Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch


Augmentin is an antibacterial combination consisting of the semisynthetic antibiotic amoxicillin and the beta-lactamase inhibitor, clavulanate potassium (the potassium salt of clavulanic acid).

The presence of clavulanic acid in Augmentin protects amoxicillin from degradation by beta-lactamase enzymes and effectively extends the antibacterial spectrum to include many bacteria normally resistant to amoxicillin.



Co-amoxiclav was invented around 1977/78 by British scientists working at Beecham, which filed for US patent protection for the drug combination in 1979. U.S. Patents 4,441,609 was granted in 1984.

FDA approved uses

Co-amoxiclav is indicated for the treatment of the following infections due to susceptible strains of sensitive organisms:

  • Lower respiratory tract infections - bronchitis, pneumonia, bronchiolitis
  • Otitis media (middle ear infection)
  • Sinusitis
  • Skin and skin structure infections - cellulitis (infection of the dermis and subcutaneous tissue), erysipelas (infection of dermis or hypodermi), folliculitis (inflammation of the hair follicles), furuncles (boils), carbuncles, abscesses, impetigo (large vesicles or honey-crusted sores), infected ulcers, infected burns, and other.
  • Urinary tract infections (UTI) - infections of the kidneys, ureters, bladder and urethra (for more details read Augmentin for UTI treatment)

Off-label & Investigational uses

  • Antimicrobial prophylaxis in gynecologic surgery4
  • Intra-abdominal and pelvic sepsis
  • Peritonitis5
  • Pelvic inflammatory disease7
  • Chlamydial infections - Co-amoxiclav may have potential for the treatment of polymicrobial infections involving Chlamydia trachomatis6.
  • Exacerbations of mild-to-moderate chronic obstructive pulmonary disease (COPD) -- amoxicillin/clavulanate significantly prolongs the time to the next exacerbation9.
  • Uncomplicated appendicitis8. A complicated appendicitis, where the appendix is perforated, requires surgery, and it is difficult to distinguish complicated disease from uncomplicated.


"Pros" and "Cons"


  • The main advantage of Augmentin over Amoxicillin is a broader antimicrobial spectrum. Augmentin provides an additional coverage of beta-lactamase producing B. catarrhalis, H. influenzae, N. gonorrhoeae, and S. aureus (not MRSA). The expanded coverage makes it a useful alternative in cases of amoxicillin resistant infections for patients who cannot tolerate alternative antibiotics.
  • Can be given without regard to meals. The absorption is not affected by food.
  • Excellent tissue penetration. Diffuses readily into most body tissues and fluids, with the exception of brain and spinal fluid.
  • Long-established track record in scientific studies and in practice.
  • Very effective for middle ear infection (otitis media). Augmentin is among the preferred beta-lactam antibiotics for the treatment of acute otitis media2.
  • Animal and human bites. Because of its anaerobic coverage, Co-amoxiclav is an excellent drug for treating infections caused by human and animal bites.
  • In situations of increased emergence of beta-lactamase producing organisms, it may be the first choice for the treatment of otitis media, sinusitis, bronchitis, urinary tract infections and skin and soft tissue infections.


  • Higher rate of diarrhea and other gastrointestinal problems, than with amoxicillin alone1. Diarrhea or loose stools occurs in approximately 20-30% people taking Augmentin.
  • Liver injury. Amoxicillin-clavulanic acid can produce a wide range of liver injury including intrahepatic cholestasis without hepatitis, acute hepatocellular injury, and cholestatic hepatitis with hepatocellular necrosis. It can produce cholecystitis-like symptoms. Normalization of liver enzymes usually occurs between 11.5-18 weeks after discontinuation of drug. Rarely the liver enzymes remain elevated with resulting chronic liver disease and progression to cirrhosis.
    The most important predisposing factors are age more than 65, and concomitant use of hepatotoxic drugs 10.
    The reporting rate of hepatitis is on average 9-fold higher for Augmentin than for amoxicillin1.
  • Prolonged use may result in C. difficile-associated diarrhea and pseudomembranous colitis.
  • Lacks activity against atypical microbes.
  • Frequently causes hypersensitivity reactions and rash.
  • Broad spectrum of antimicrobial activity increases the risk of evolving resistance.
  • Expensive.

Mode of action

Augmentin is bactericidal and works by inhibiting the synthesis of bacterial cell walls.

Amoxicillin inhibits bacterial cell wall mucopeptide synthesis. Clavulanic acid inactivates a wide range of beta-lactam enzymes found in bacteria resistant to beta-lactam antibiotics.

Time to clear out the system

The half-life of amoxicillin after the oral administration of Augmentin is 1.3 hours and that of clavulanic acid is 1.0 hour.

Further reading


  • 1. Salvo F, Polimeni G, Moretti U, Conforti A, Leone R, Leoni O, Motola D, Dusi G, Caputi AP. Adverse drug reactions related to amoxicillin alone and in association with clavulanic acid: data from spontaneous reporting in Italy. Journal of Antimicrob Chemother April 21, 2007
  • 2. Beta-lactam Antibiotics Against S pneumoniae. Pharmacotherapy 19(11):1308-1314, 1999.
  • 3. Cormio G, Bettocchi S, Ceci O, Nappi L, Di Fazio F, Cacciapuoti C, Selvaggi L. Antimicrobial prophylaxis in laparoscopic gynecologic surgery. J Chemother. 2003 Dec;15(6):574-8.
  • 4. Cormio G, Vicino M, Loizzi V, Tangari D, Selvaggi L. Antimicrobial prophylaxis in vaginal gynecologic surgery. J Chemother. 2007 Apr;19(2):193-7. PubMed
  • 5. Grange JD, Amiot X, Grange V, Gutmann L, Biour M, Bodin F, Poupon R. Amoxicillin-clavulanic acid therapy of spontaneous bacterial peritonitis: a prospective study of twenty-seven cases in cirrhotic patients. Hepatology. 1990 Mar;11(3):360-4. PubMed
  • 6. Beale AS, Faulds E, Hurn SE, Tyler J, Slocombe B. Comparative activities of amoxycillin, amoxycillin/clavulanic acid and tetracycline against Chlamydia trachomatis in cell culture and in an experimental mouse pneumonitis. J Antimicrob Chemother. 1991 May;27(5):627-38.
  • 7. Uri FI, Sartawi SA, Dajani YF, Masoud AA, Barakat HF. Augmentin compared with triple drug therapy for pelvic inflammatory disease. Int J Gynaecol Obstet. 1992 May;38(1):41-3. PubMed
  • 8. Vons C, Barry C, Maitre S, Pautrat K, Leconte M, Costaglioli B, Karoui M, Alves A, Dousset B, Valleur P, Falissard B, Franco D. Amoxicillin plus clavulanic acid versus appendicectomy for treatment of acute uncomplicated appendicitis: an open-label, non-inferiority, randomised controlled trial. Lancet. 2011 May 7;377(9777) PubMed
  • 9. Llor C, Moragas A, Hernández S, Bayona C, Miravitlles M. Efficacy of antibiotic therapy for acute exacerbations of mild to moderate chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2012 Oct 15;186(8):716-23. PubMed
  • 10. Yazici C, Mutlu E, Bonkovsky HL, Russo MW. Risk factors for severe or fatal drug-induced liver injury from amoxicillin-clavulanic acid. Hepatol Res. 2015 Jun;45(6):676-82. PubMed

Published: July 01, 2008
Last updated: July 14, 2017

Interesting facts

Augmentin facts
  • Clavulanic acid is produced by the fermentation of Streptomyces clavuligerus. It possesses the ability to inactivate a wide range of beta-lactamase enzymes secreted by resistant microorganisms.
  • When used alone, beta-lactamase inhibitors (clavulanate, sulbactam and tazobactam) have weak intrinsic antibacterial activity, but their effectiveness increases when they are combined with a beta-lactam antibiotic.
  • Augmentin has a higher rate of diarrhea and liver damage than amoxicillin.

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