{{Unreferenced|date=July 2007}}
{{drugbox |
| IUPAC_name = 7-[2-amino-2-(4-hydroxyphenyl) -acetyl]amino-3,3-dimethyl-6-oxo -2-thia-5-azabicyclo[3.2.0]heptane -4-carboxylic acid
| image = Amoxicillin-2D-skeletal.png
| image2= Amoxicillin-3D-balls.png
| width = 218px
| CAS_number = 26787-78-0
| ATC_prefix = J01
| ATC_suffix = CA04
| PubChem = 33613
| DrugBank = APRD00248
| C = 16 | H = 19 | N = 3 | O = 5 | S = 1
| molecular_weight = 365.4 g/mol
| bioavailability = 95% oral
| metabolism = less than 30% biotransformed in [[liver]]
| elimination_half-life = 61.3 minutes
| excretion = [[renal]]
| pregnancy_AU = A
| pregnancy_US = B
| pregnancy_category =
| legal_AU =
| legal_UK = POM
| legal_US =
| routes_of_administration = [[Wiktionary:oral|Oral]], [[intravenous therapy|intravenous]]
}}
'''Amoxicillin''' ([[International Nonproprietary Name|INN]]) or '''amoxycillin''' (former [[British Approved Name|BAN]]) is a moderate-spectrum [[beta-lactam antibiotic|β-lactam antibiotic]] used to treat [[bacterial]] [[infection]]s caused by susceptible [[microorganism]]s. It is usually the drug of choice within the class because it is better absorbed, following oral administration, than other beta-lactam antibiotics. Amoxicillin is susceptible to degradation by [[beta-lactamase|β-lactamase]]-producing bacteria, and so may be given with [[clavulanic acid]] to decrease its susceptibility (see below). It was developed by [[Beecham (pharmaceutical company)|Beecham]] in 1972 and is currently marketed by [[GlaxoSmithKline]] (the inheritor company) under the original trade name '''Amoxil'''.

==Mode of action==
{{main|Beta-lactam antibiotic}}
Amoxicillin 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 wall]] of [[Gram-positive]] bacteria.

==Microbiology==
Amoxicillin is a moderate-spectrum antibiotic active against a wide range of [[Gram-positive]], and a limited range of [[Gram-negative]] organisms. Some examples of susceptible and resistant organisms, from the Amoxil® Approved Product Information (GSK, 2003), are listed below.
===Susceptible Gram-positive organisms===
''[[Streptococcus]]'' spp., penicillin-susceptible ''[[Streptococcus]] pneumoniae'', non [[beta-lactamase|β-lactamase]]-producing ''[[Staphylococcus]]'' spp., and ''[[Enterococcus]] faecalis.''

===Susceptible Gram-negative organisms===
Non-[[beta-lactamase|β-lactamase]] producing strains of the following bacteria: ''[[Haemophilus]] influenzae'', ''[[Neisseria]] gonorrhoeae'', ''[[Neisseria]] meningitidis'', ''[[Escherichia coli]]'', ''[[Proteus (bacterium)|Proteus]] mirabilis'' and ''[[Salmonella]] spp.''

===Resistant organisms===
Penicillinase-producing organisms, particularly penicillinase-producing ''[[Staphylococcus]]'' spp. Penicillinase-producing ''N. gonorrhoeae'' and ''H. influenzae'' are also resistant.

All strains of ''[[Pseudomonas]]'' spp., ''[[Klebsiella]]'' spp., ''[[Enterobacter]]'' spp., [[indole]]-positive ''[[Proteus (bacterium)|Proteus]]'' spp., ''[[Serratia]]'' marcescens, and ''[[Citrobacter]]'' spp. are resistant.

The incidence of β-lactamase-producing resistant organisms, including ''[[Escherichia coli|E. coli]]'', appears to be increasing.

Doubling the routinely given concentration (in pediatrics) of amoxicillin has been shown to eradicate intermediately resistant ''Streptococcus pneumoniae'' in selected infections.<ref name=2003RedBook>{{cite book | title = 2003 Red Book: Report of the Committee on Infectious Diseases | publisher = [[American Academy of Pediatrics]] | location = Elk Grove Village, Illinois | year = 2003 | id = ISBN 11-58110-095-7}}</ref>

==Formulations==
Amoxicillin in trihydrate form is available as capsules, tablets, or syrup for oral use, and as the sodium salt for intravenous administration. It is one of the most common antibiotics issued to children. It has 3 ionizable groups.

== Amoxicillin and clavulanic acid ==
{{main|Co-amoxiclav}}
Amoxicillin (in either trihydrate or sodium salt forms) may be combined with [[Clavulanic acid]] (as [[potassium clavulanate]]), a β-lactamase inhibitor, to increase the spectrum of action against [[Gram-negative]] organisms, and to overcome bacterial antibiotic resistance mediated through β-lactamase production. This formulation is referred to as [[Co-amoxiclav]] ([[British Approved Name]]), but commonly by proprietary names such as Amoksiklav (×2 or SOLVO), Augmentin, Clamoxyl, Augclav, and Augmexx.

== Side effects ==
[[Adverse drug reaction|Side effect]]s are as those for other [[Beta-lactam antibiotic#Adverse effects|beta-lactam antibiotic]]s.
Side effects include [[nausea]], vomiting and easy fatigue.

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 onset 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.

== Proprietary preparations ==
[[Image:NOVAMOXIN.JPG|right|thumb|300px|Novamoxin Prescription Drug - 500 MG Amoxicillin Trihydrate]]
The patent for amoxicillin has expired. Thus amoxicillin is marketed under many trade names including: Actimoxi, Amoksibos, Amoxiclav Sandoz, Amoxil, Amoksiklav, Amoxibiotic, Amoxicilina, Apo-Amoxi, Bactox, Betalaktam, Cilamox, Curam, Dedoxil, Dispermox, Duomox, Isimoxin, Klavox, Lamoxy, Moxypen, Moxyvit, Novamoxin, Ospamox, Panklav, Pamoxicillin, Polymox, Samthongcillin, Senox, Sinacilin, Trimox, Tolodina, Wymox, Zerrsox and Zimox.

==See also==
* [[Clavulanic acid]]
* [[Co-amoxiclav]]

== References ==
* {{cite web | author=GlaxoSmithKline |authorlink=GlaxoSmithKline |title=Amoxil - Prescribing information |year=2006 | month=February | url=http://us.gsk.com/products/assets/us_amoxil.pdf | format=PDF}}
* Neal, MJ (2002). ''Medical Pharmacology at a Glance'' (4 ed.). Oxford: Blackwell Science. ISBN 0-632-05244-9
* [[British National Formulary]] ''45'' March 2003
* [http://www.amoxicillin.com Amoxicillin.com - Amoxicillin information]

==Footnotes==
{{reflist}}

==External links==

{{PenicillinAntiBiotics}}

[[Category:Beta-lactam antibiotics]]

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