Amoxicillin/clavulanic acid explained

Amoxicillin/clavulanic acid, also known as co-amoxiclav or amox-clav, sold under the brand name Augmentin, among others, is an antibiotic medication used 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, streptococcal pharyngitis, pneumonia, cellulitis, urinary tract infections, and animal bites. It is taken by mouth or by injection into a vein.^[1]

Common side effects include diarrhea, vomiting, and allergic reactions. It also increases the risk of yeast infections, headaches, and blood clotting problems.^{[1] [2]} It is not recommended in people with a history of a penicillin allergy.^[1] It is relatively safe for use during pregnancy.

Amoxicillin/clavulanic acid was approved for medical use in the United States in 1984.^[3] It is on the World Health Organization's List of Essential Medicines.^{[4] [5]} The World Health Organization classifies amoxicillin/clavulanic-acid as critically important for human medicine.^[6] It is available as a generic medication.^[3] In 2021, it was the 115th most commonly prescribed medication in the United States, with more than 5million prescriptions.^{[7] [8]}

Medical uses

Amoxicillin/clavulanic acid is widely used to treat or prevent many infections caused by susceptible bacteria, such as:

• urinary tract infections
• respiratory tract infections
• skin and soft tissue infections
• sinus infections
• tonsillitis
• cat scratches
• infections caused by the bacterial flora of the mouth, such as:
  • dental infections
  • infected animal bites
  • infected human bites (including uncomplicated "clenched-fist" or "reverse-bite" injuries)^[9]

It is also used for tuberculosis that is resistant to other treatments.^[3] The World Health Organization recommends giving amoxicillin-clavulanate along with meropenem as one of the therapeutic options in drug resistant tuberculosis.^[10] However, across the spectrum of dosage of amoxicillin-clavulanate combination, the dose of clavulanate is constant at 125 mg, whereas the dose of amoxicillin varies at 250 mg, 500 mg and 875 mg. Thus the use of low dose amoxicillin-clavulanate in combination with meropenem may be used in part of treatment regime for drug resistant TB and this has been demonstrated in a clinical setting also. Its efficacy is attributed not to the amoxicillin component, but to the protective action of clavulanic acid over meropenem against beta-lactamase produced by the mycobacteria. Therefore, the minimum dosage of amoxicillin (250 mg) is recommended.^[11]

Adverse effects

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.^[12]

History

British scientists working at Beecham (now part of GlaxoSmithKline), filed for patent protection for the drug combination in 1977, which was granted in 1982.^[13] It was sold under the brand name Augmentin.^{[14] [15]}

Preparations

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.^{[14] [16]}

An intravenous preparation has been available in the UK since 1985,^[17] 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.

Veterinary use

Amoxicillin/clavulanic acid is used in numerous animals for a variety of conditions:

• Dogs: Skin and soft tissue infections such as wounds, abscesses, cellulitis, superficial/juvenile and deep pyoderma due to susceptible strains of the following organisms: β-lactamase-producing Staphylococcus aureus, non-β-lactamase-producing Staphylococcus aureus, Staphylococcus spp., Streptococcus spp., and E. coli; and periodontal infections due to susceptible strains of both aerobic and anaerobic bacteria.^[18]
• Cats: Skin and soft tissue infections such as wounds, abscesses, and cellulitis/dermatitis due to susceptible strains of the following organisms: β-lactamase-producing Staphylococcus aureus, non-β-lactamase-producing Staphylococcus aureus, Staphylococcus spp., Streptococcus spp., E. coli, and Pasteurella spp; urinary tract infections (cystitis) due to susceptible strains of E. coli.

Bacterial resistance

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.^[19]

Notes and References

1. Book: WHO Model Formulary 2008 . 2009 . 9789241547659 . ((World Health Organization)) . Stuart MC, Kouimtzi M, Hill SR . 10665/44053 . World Health Organization . World Health Organization . free . 102.
2. Gillies M, Ranakusuma A, Hoffmann T, Thorning S, McGuire T, Glasziou P, Del Mar C . Common harms from amoxicillin: a systematic review and meta-analysis of randomized placebo-controlled trials for any indication . CMAJ . 187 . 1 . E21–E31 . January 2015 . 25404399 . 4284189 . 10.1503/cmaj.140848 .
3. Web site: Amoxicillin and Clavulanate Potassium. The American Society of Health-System Pharmacists. 8 December 2016. live. https://web.archive.org/web/20161129000556/https://www.drugs.com/monograph/amoxicillin-and-clavulanate-potassium.html. 29 November 2016.
4. Book: ((World Health Organization)) . World Health Organization model list of essential medicines: 21st list 2019 . 2019 . 10665/325771 . World Health Organization . World Health Organization . Geneva . WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO . free .
5. Book: ((World Health Organization)) . World Health Organization model list of essential medicines: 22nd list (2021) . 2021 . 10665/345533 . World Health Organization . World Health Organization . Geneva . WHO/MHP/HPS/EML/2021.02 . free .
6. Book: ((World Health Organization)) . 2019 . Critically important antimicrobials for human medicine . 6th revision . World Health Organization . World Health Organization . Geneva . 10665/312266 . 9789241515528 . free .
7. Web site: The Top 300 of 2021 . ClinCalc . 14 January 2024 . 15 January 2024 . https://web.archive.org/web/20240115223848/https://clincalc.com/DrugStats/Top300Drugs.aspx . live .
8. Web site: Amoxicillin; Clavulanate - Drug Usage Statistics . ClinCalc . 14 January 2024 . 18 January 2024 . https://web.archive.org/web/20240118002530/https://clincalc.com/DrugStats/Drugs/AmoxicillinClavulanate . live .
9. Book: Gordon D . Amoxicillin–Clavulanic Acid (Co-Amoxiclav) . Grayson ML . etal . Kucers' the Use of Antibiotics: a Clinical Review of Antibacterial, Antifungal, Antiparasitic and Antiviral Drugs . Hodder Arnold/ASM Press . London . 2010 . 193–4 . 978-0-340-92767-0.
10. Book: ((World Health Organization)) . 2016 . WHO treatment guidelines for drug-resistant tuberculosis, 2016 update . World Health Organization . 10665/250125 . free . 9789241549639 .
11. Mishra G, Caminero J . First Successful Use of Low Dose Amoxicillin-Clavulanic Acid in Management of Drug Resistant Tuberculosis . Journal of Clinical and Diagnostic Research . 2018 . 12 . 10 . OD08–OD10 . 10.7860/JCDR/2018/37279.12145 . 7 May 2021 . free . doi . 7 May 2021 . https://web.archive.org/web/20210507170039/https://jcdr.net/article_fulltext.asp?issn=0973-709x&year=2018&volume=12&issue=10&page=OD08&issn=0973-709x&id=12145 . live .
12. Harr T, French LE . Toxic epidermal necrolysis and Stevens-Johnson syndrome . Orphanet Journal of Rare Diseases . 5 . 39 . December 2010 . 21162721 . 3018455 . 10.1186/1750-1172-5-39 . free .
13. GB. 2005538. 1982-05-26. Pharmaceutical compositsions. Beecham Group Ltd.. Crowley PJ .
14. Book: . 57th . March 2009.
15. Bryan J. 23 June 2011. Still going strong at 30: co-amoxiclav. The Pharmaceutical Journal. 286. 762. 20 December 2020. 22 August 2017. https://web.archive.org/web/20170822100525/http://www.pharmaceutical-journal.com/opinion/comment/still-going-strong-at-30-co-amoxiclav/11079379.article. dead.
16. Web site: Augmentin -- Prescribing Information . December 2006 . live . https://web.archive.org/web/20131220172200/http://www.accessdata.fda.gov/drugsatfda_docs/label/2008/050575s037550597s044050725s025050726s019lbl.pdf . 20 December 2013 .
17. Davies BE, Boon R, Horton R, Reubi FC, Descoeudres CE . Pharmacokinetics of amoxycillin and clavulanic acid in haemodialysis patients following intravenous administration of Augmentin . British Journal of Clinical Pharmacology . 26 . 4 . 385–390 . October 1988 . 3190988 . 1386558 . 10.1111/j.1365-2125.1988.tb03395.x .
18. Web site: Recent Animal Drug Approvals . U.S. Food and Drug Administration . 15 March 2024 . 5 April 2024 . 5 April 2024 . https://web.archive.org/web/20240405052111/https://www.fda.gov/animal-veterinary/approved-animal-drug-products-green-book/recent-animal-drug-approvals . live .
19. Federation of Veterinarians in Europe Position Paper: "Antibiotic Resistance & Prudent Use of Antibiotics in Veterinary Medicine"