|Systematic (IUPAC) name|
|Trade names||Amoxil, Tycil, and Trimox, among others|
|Metabolism||less than 30% biotransformed in liver|
|Biological half-life||61.3 minutes|
|CAS Registry Number|
|ATC code||J01 QG51|
|Molecular mass||365.4 g/mol|
|(what is this?)|
Amoxicillin (amox), also spelled amoxycillin, is an antibiotic useful for the treatment of a number of bacterial infections. It is the first line treatment for middle ear infections. It may also be used for strep throat, pneumonia, skin infections, and urinary tract infections among others. It is taken by mouth.
Common side effects include a nausea and rash. It may also increase the risk of yeast infections and, when used in combination with clavulanic acid, diarrhea. It should not be used in those who are allergic to penicillin. While usable in those with kidney problems the dose may need to be decreased. It use in pregnancy and breastfeeding appear to be okay.
Amoxicillin first became available in 1972. It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. It is one of the most commonly prescribed antibiotics in children. Amoxicillin is available as a generic medication and costs between 0.02 and 0.05 USD per pill. In the United States ten days of treatment costs about 16 USD.
Amoxicillin is used in the treatment of a number of infections, including acute otitis media, streptococcal pharyngitis, pneumonia, skin infections, urinary tract infections, Salmonella infections, Lyme disease, and chlamydia infections. It is also used to prevent bacterial endocarditis in high-risk people having dental work done, to prevent Streptococcus pneumoniae and other encapsulated bacterial infections in those without spleens, such as people with sickle-cell disease, and for both the prevention and the treatment of anthrax. The United Kingdom recommends against its use for infectious endocarditis prophylaxis. These recommendations have not appeared to have changed the rates of infection for infectious endocarditis.
Amoxicillin and amoxicillin-clavulanate have been recommended by guidelines as the drug of choice for bacterial sinusitis, but most sinusitis is caused by viruses, for which amoxicillin and amoxicillin-clavulanate are ineffective,  and the small benefit gained by Amoxicillin may be overridden by the adverse effects.  Amoxicillin is occasionally used for the treatment of skin infections, such as acne vulgaris. It is often an effective treatment for cases of acne vulgaris that have responded poorly to other antibiotics, such as doxycycline and minocycline.
Amoxicillin is susceptible to degradation by β-lactamase-producing bacteria, which are resistant to a narrow spectrum of β-lactam antibiotics, such as penicillin. For this reason, it may be combined with clavulanic acid, a β-lactamase inhibitor. This drug combination is commonly called co-amoxiclav.
Spectrum of activity
It is a moderate-spectrum, bacteriolytic, β-Lactam antibiotic in the aminopenicillin family used to treat susceptible Gram-positive and Gram-negative bacteria. It is usually the drug of choice within the class because it is better-absorbed, following oral administration, than other β-lactam antibiotics. In general, Streptococcus, Bacillus subtilis, Enterococcus, Haemophilus, Helicobacter, and Moraxella are susceptible to amoxicillin, whereas Citrobacter, Klebsiella and Pseudomonas aeruginosa are resistant to it. Some E. coli and most clinical isolates of Staphylococcus aureus have developed resistance to amoxicillin to varying degrees.
Side effects are similar to those for other β-lactam antibiotics, including nausea, vomiting, rashes, and antibiotic-associated colitis. Loose bowel movements (diarrhea) may also occur. Rarer side effects include mental changes, lightheadedness, insomnia, confusion, anxiety, sensitivity to lights and sounds, and unclear thinking. Immediate medical care is required upon the first signs of these side effects.
The onset of an allergic reaction to amoxicillin can be very sudden and intense; emergency medical attention must be sought as quickly as possible. The initial phase of such a reaction often starts with a change in mental state, skin rash with intense itching (often beginning in fingertips and around groin area and rapidly spreading), and sensations of fever, nausea, and vomiting. Any other symptoms that seem even remotely suspicious must be taken very seriously. However, more mild allergy symptoms, such as a rash, can occur at any time during treatment, even up to a week after treatment has ceased. For some people allergic to amoxicillin, the side effects can be fatal due to anaphylaxis.
Use of the amoxicillin/clavulanic acid combination for more than one week has caused mild hepatitis in some patients. Young children having ingested acute overdoses of amoxicillin manifested lethargy, vomiting, and renal dysfunction.
Between 3 and 10% of children taking amoxicillin (or ampicillin) show a late-developing (>72 hours after beginning medication and having never taken penicillin-like medication previously) rash, which is sometimes referred to as the "amoxicillin rash". The rash can also occur in adults.
The rash is described as maculopapular or morbilliform (measles-like; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash".) It starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction, and is not a contraindication for future amoxicillin usage, nor should the current regimen necessarily be stopped. However, this common amoxicillin rash and a dangerous allergic reaction cannot easily be distinguished by inexperienced persons, so a healthcare professional is often required to distinguish between the two.
A nonallergic amoxicillin rash may also be an indicator of infectious mononucleosis. Some studies indicate about 80-90% of patients with acute Epstein Barr virus infection treated with amoxicillin or ampicillin develop such a rash.
Amoxicillin may interact with these drugs:
- Anticoagulants (e.g., warfarin, dabigatran)
- Allopurinol (gout treatment)
- Certain antibiotics
- Cancer treatment (methotrexate)
- Uricosuric drugs
- Typhoid vaccine
Mechanism of actions
This drug acts by inhibiting the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell walls of both Gram-positive and Gram-negative bacteria.
It has two ionizable groups in the physiological range (the amino group in alpha-position to the amide carbonyl group and the carboxyl group).
Amoxicillin was one of several semisynthetic derivatives of 6-aminopenicillanic acid (6-APA) developed at Beecham, England in the 1960s. It became available in 1972, and was the second aminopenicillin to reach the market (after ampicillin in 1961). Co-amoxiclav became available in 1981.
Society and culture
Modes of delivery
Pharmaceutical manufacturers make amoxicillin in trihydrate form, for oral use available as capsules, chewable and dispersible tablets, syrup and pediatric suspension for oral use, and as the sodium salt for intravenous administration. Amoxicillin is most commonly taken orally. The liquid forms are helpful where the patient might find it difficult to take tablets or capsules. Intravenous form is not sold in USA
Amoxicillin is one of the semisynthetic penicillins discovered by Beecham scientists. The patent for amoxicillin has expired, thus amoxicillin and co-amoxiclav preparations are marketed under many trade names and/or have several synonyms across the world, such as:
- Amoxibactin (animal use)
- Amoxoral (animal use)
- Senox 
Names without individual reference are referenced on the drugs.com website.
- "Amoxicillin". The American Society of Health-System Pharmacists. Retrieved 1 Aug 2015.
- Gillies, M; Ranakusuma, A; Hoffmann, T; Thorning, S; McGuire, T; Glasziou, P; Del Mar, C (17 November 2014). "Common harms from amoxicillin: a systematic review and meta-analysis of randomized placebo-controlled trials for any indication.". CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne 187: E21–31. doi:10.1503/cmaj.140848. PMID 25404399.
- Roy, Jiben (2012). An introduction to pharmaceutical sciences production, chemistry, techniques and technology. Cambridge: Woodhead Pub. p. 239. ISBN 9781908818041.
- "WHO Model List of EssentialMedicines" (PDF). World Health Organization. October 2013. Retrieved 22 April 2014.
- Kelly, Deirdre (2008). Diseases of the liver and biliary system in children (3 ed.). Chichester, UK: Wiley-Blackwell. p. 217. ISBN 9781444300543.
- "Amoxicillin". International Drug Price Indicator Guide. Retrieved 1 August 2015.
- "CG64 Prophylaxis against infective endocarditis: Full guidance" (PDF). NICE. Retrieved 8 June 2011.
- Thornhill, MH; Dayer, MJ; Forde, JM; Corey, GR; Chu, VH; Couper, DJ; Lockhart, PB (2011-05-03). "Impact of the NICE guideline recommending cessation of antibiotic prophylaxis for prevention of infective endocarditis: before and after study". BMJ (Clinical research ed.) 342: d2392. doi:10.1136/bmj.d2392. PMC 3086390. PMID 21540258.
- American Academy of Allergy, Asthma, and Immunology. "Five Things Physicians and Patients Should Question" (PDF). Choosing Wisely: an initiative of the ABIM Foundation (American Academy of Allergy, Asthma, and Immunology). Retrieved August 14, 2012.
- Ahovuo-Saloranta, A.; Rautakorpi, U. M.; Borisenko, O. V.; Liira, H.; Williams Jr, J. W.; Mäkelä, M. (2014). Ahovuo-Saloranta, Anneli, ed. "Antibiotics for acute maxillary sinusitis". The Cochrane Library. doi:10.1002/14651858.CD000243.pub3.
- "Adolescent Acne: Management".
- "Amoxicillin and Acne Vulgaris". scienceofacne.com. 2012-09-05. Retrieved 2012-08-17.
- "Amoxicillin Susceptibility and Resistance Data" (PDF). Retrieved 20 July 2013.
- "Amoxicillin spectrum of bacterial susceptibility and Resistance" (PDF). Retrieved 8 April 2012.
- Cundiff j, Joe S.; Joe, S (2007). "Amoxicillin-clavulanic acid-induced hepatitis". Amer. J. Otolaryngol. 28 (1): 28–30. doi:10.1016/j.amjoto.2006.06.007. PMID 17162128.
- R. Baselt (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Publications. pp. 81–83.
- "Role of delayed cellular hypersensitivity and adhesion molecules in amoxicillin-induced morbilliform rashes". Cat.inist.fr. Retrieved 2010-11-13.
- Pichichero ME (April 2005). "A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients". Pediatrics 115 (4): 1048–57. doi:10.1542/peds.2004-1276. PMID 15805383.
- Schmitt, Barton D. (2005). Your child's health: the parents' one-stop reference guide to symptoms, emergencies, common illnesses, behavior problems, healthy development (2nd ed.). New York: Bantam Books. ISBN 0-553-38369-8.
- Kagan, B (1977). "Ampicillin rash". Western Journal of Medicine 126 (4): 333–335. PMC 1237570. PMID 855325.
- British National Formulary 57 March 2009
- Geddes, AM et al. (Dec 2007). "Introduction: historical perspective and development of amoxicillin/clavulanate". Int J Antimicrob Agents 30 (Suppl 2): S109–12. doi:10.1016/j.ijantimicag.2007.07.015. PMID 17900874.
- Raviña, E (2014). The Evolution of Drug Discovery. Weinheim: Wiley-VCH. p. 262. ISBN 9783527326693.
- Bruggink, A (2001). Synthesis of β-lactam antibiotics. Springer. p. 17. ISBN 0-7923-7060-0.
- Farazuddin, Mohammad; Chauhan, Arun; Khan, Raza M.M.; Owais, Mohammad (2011). "Amoxicillin-bearing microparticles: potential in the treatment of Listeria monocytogenes infection in Swiss albino mice". Bioscience Reports 31 (4): 265–72. doi:10.1042/BSR20100027. PMID 20687896.
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- Neal, M. J. (2002). Medical pharmacology at a glance (4th ed.). Oxford: Blackwell Science. ISBN 0-632-05244-9.
- British National Formulary 45 March 2003