Amoxicillin is an antibiotic medication belonging to the aminopenicillin class of the penicillin family. The drug is used to treat bacterial infections[ It is taken orally (swallowed by mouth), or less commonly by either intramuscular injection or by an IV bolus injection, which is a relatively quick intravenous injection lasting from a couple of seconds to a few minutes.]
Common adverse effects include nausea and rash.[ It may also increase the risk of candidiasis and, when used in combination with clavulanic acid, diarrhea.][ While usable in those with , the dose may need to be decreased.][ Its use in pregnancy and breastfeeding does not appear to be harmful.][ Amoxicillin is in the β-lactam family of antibiotics.][
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Amoxicillin was discovered in 1958 and came into medical use in 1972.[ In 2022, it was the 26th most commonly prescribed medication in the United States, with more than 20million prescriptions.]
Medical uses
Amoxicillin is used in the treatment of a number of infections, including acute otitis media, streptococcal pharyngitis, pneumonia, Cellulitis, urinary tract infections, Salmonella infections, Lyme disease, and chlamydia infections.
Acute otitis media
Children with acute otitis media who are younger than six months of age are generally treated with amoxicillin or other antibiotics. Although most children with acute otitis media who are older than two years old do not benefit from treatment with amoxicillin or other antibiotics, such treatment may be helpful in children younger than two years old with acute otitis media that is bilateral or accompanied by ear drainage.
Respiratory infections
Most sinusitis infections are caused by , for which amoxicillin and amoxicillin-clavulanate are ineffective,[
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H. pylori
It is effective as one part of a multi-drug regimen for the treatment of stomach infections of Helicobacter pylori. It is typically combined with a proton-pump inhibitor (such as omeprazole) and a macrolide antibiotic (such as clarithromycin); other drug combinations are also effective.
Lyme borreliosis
Amoxicillin is effective for the treatment of early cutaneous Lyme borreliosis; the effectiveness and safety of oral amoxicillin is neither better nor worse than common alternatively-used antibiotics.
Odontogenic infections
Amoxicillin is used to treat odontogenic infections, infections of the tongue, lips, and other oral tissues. It may be prescribed following a tooth extraction, particularly in those with compromised immune systems.
Skin infections
Amoxicillin is occasionally used for the treatment of skin infections,[ such as acne vulgaris.]
Infections in infants in resource-limited settings
Amoxicillin is recommended by the World Health Organization for the treatment of with signs and symptoms of pneumonia in resource-limited situations when the parents are unable or unwilling to accept hospitalization of the child. Amoxicillin in combination with gentamicin is recommended for the treatment of infants with signs of other severe infections when hospitalization is not an option.
Prevention of bacterial endocarditis
It is also used to prevent bacterial endocarditis and as a pain-reliever in high-risk people having dental work done, to prevent Streptococcus pneumoniae and other encapsulated bacterial infections in those without , 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.]
Combination treatment
Amoxicillin is susceptible to degradation by beta-lactamase-producing bacteria, which are resistant to most 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 Coamoxiclav.
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.
Adverse effects
Adverse effects are similar to those for other β-lactam antibiotics, including nausea, vomiting, , and antibiotic-associated colitis. Diarrhea (loose bowel movements) may also occur.
Rarer adverse effects include mental and behavioral changes, lightheadedness, insomnia, hyperactivity, agitation, mental confusion, anxiety, sensory overload, and unclear thinking.
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 the fingertips and around the 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 adverse effects can be fatal due to anaphylaxis.
Use of the amoxicillin/clavulanic acid combination for more than one week has caused a drug-induced immunoallergic-type hepatitis in some patients. Young children having ingested acute overdoses of amoxicillin manifested lethargy, vomiting, and Renal failure.
There is poor reporting of adverse effects of amoxicillin from clinical trials. For this reason, the severity and frequency of adverse effects from amoxicillin are probably higher than reported in clinical trials.
Nonallergic rash
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 and may rarely be a component of the DRESS syndrome.
The rash is described as maculopapular or morbilliform (Measles; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash".
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.
Image:Amoxicillin rash 3 hours after 17th dose.JPG|Nonallergic amoxicillin rash eight days after first dose: This photo was taken 24 hours after the rash began.
Image:Amoxicillin rash 11 hours after 17th dose.JPG|Eight hours after the first photo, individual spots have grown and begun to merge.
Image:Amoxicillin rash 26 hours after 17th dose.JPG|At 23 hours after the first photo, the color appears to be fading, and much of rash has spread to confluence.
Interactions
Amoxicillin may interact with these drugs:
When given intravenously or intramuscularly:[
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It should not be mixed with blood products, or proteinaceous fluids (including protein hydrolysates) or with intravenous lipid emulsions
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aminoglycoside should be injected at a separate site from amoxicillin if the patient is prescribed both medications at the same time. Neither drug should be mixed in a syringe. Neither should they be mixed in an intravenous fluid container or giving set because of loss of activity of the aminoglycoside under these conditions.
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ciprofloxacin should not be mixed with amoxicillin.
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Infusions containing dextran or bicarbonate should not be mixed with amoxicillin solutions.
Pharmacology
Amoxicillin (α-amino- p-hydroxybenzyl penicillin) is a semisynthetic derivative of penicillin with a structure similar to ampicillin but with better absorption when taken by mouth, thus yielding higher concentrations in blood and in urine.[
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Amoxicillin attaches to the cell wall of susceptible bacteria and results in their death. It is effective against streptococci, pneumococci, enterococci, Haemophilus influenzae, Escherichia coli, Proteus mirabilis, Neisseria meningitidis, Neisseria gonorrhoeae, Shigella, Chlamydia trachomatis, Salmonella, Borrelia burgdorferi, and Helicobacter pylori.[ As a derivative of ampicillin, amoxicillin is a member of the penicillin family and, like penicillins, is a β-lactam antibiotic.]
Chemistry
Amoxicillin is a β-lactam and aminopenicillin antibiotic in terms of chemical structure.
The experimental log P of amoxicillin is 0.87.
History
Amoxicillin was one of several semisynthesis derivatives of 6-aminopenicillanic acid (6-APA) developed by the Beecham Group in the 1960s. It was invented by Anthony Alfred Walter Long and John Herbert Charles Nayler, two British scientists.[
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Society and culture
Economics
Amoxicillin is relatively inexpensive.
Modes of delivery
Pharmaceutical manufacturers make amoxicillin in trihydrate form, for oral use available as capsules, regular, chewable and dispersible tablets, syrup and pediatric suspension for oral use, and as the sodium salt for intravenous administration.
An extended-release is available.
Research with mice indicated successful delivery using intraperitoneally injected amoxicillin-bearing microparticles.
Names
Amoxicillin is the international nonproprietary name (INN),
Amoxicillin is one of the semisynthetic penicillins discovered by the former pharmaceutical company Beecham Group. The patent for amoxicillin has expired, thus amoxicillin and co-amoxiclav preparations are marketed under various brand names across the world.
Veterinary uses
Amoxicillin is also sometimes used as an antibiotic for animals. The use of amoxicillin for animals intended for human consumption (, cattle, and swine for example) has been approved.
Further reading
