Amoxicillin is an antibiotic medication belonging to the aminopenicillin class of the penicillin family.
Trade names Amoxil, Trimox
Pregnancy category AU: A
Routes of administration By mouth, IV (bolus), intramuscular injection
Drug class β-Lactam antibiotic; Aminopenicillin
Bioavailability Oral: 60%
Protein binding 17%
Metabolism Hydroxylation, oxidative deamination, aliphatic chain oxidation, decarboxylation, glucuronidation
Metabolites Seven
Onset of action ≤1.3–1.5 hours
Elimination half-life 61.3 minutes
Excretion Urine: 70–78%
The drug is used to treat bacterial infections such as middle ear infection, strep throat, pneumonia, skin infections, odontogenic infections, and urinary tract infections.
It is taken orally 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 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.
Its use in pregnancy and breastfeeding does not appear to be harmful.
Amoxicillin is in the β-lactam family of antibiotics.
It is one of the most commonly prescribed antibiotics in children
Amoxicillin is used in the treatment of a number of infections: acute otitis media, streptococcal pharyngitis, pneumonia, skin infections, urinary tract infections, Salmonella infections, Lyme disease, and chlamydia infections.
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.
In the past, amoxicillin was dosed three times daily when used to treat acute otitis media, but there is now evidence that two-times daily dosing or once-daily dosing has similar effectiveness.
Amoxicillin is considered the first-line empirical treatment for most cases of uncomplicated bacterial sinusitis in children and adults when culture data is unavailable.
Amoxicillin is recommended as the preferred first-line treatment for community-acquired pneumonia in adults either alone in mild to moderate severity disease or in combination with a macrolide.
It is as effective as co-amoxiclav for people admitted to hospital with pneumonia, regardless of its severity.
The World Health Organization (WHO) recommends amoxicillin as first-line treatment for pneumonia that is not severe.
Amoxicillin is used in post-exposure inhalation of anthrax to prevent disease progression and for prophylaxis.
It is part of a multi-drug regimen for the treatment of stomach infections of Helicobacter pylori: It is typically combined with a proton-pump inhibitor and a macrolide antibiotic.
Amoxicillin is effective for the treatment of early cutaneous Lyme disease.
Amoxicillin is used to treat odontogenic infections, infections of the tongue, lips, and other oral tissues.
Amoxicillin may be prescribed following a tooth extraction, particularly in those with compromised immune systems.
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 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.
Amoxicillin is susceptible to degradation by β-lactamase-producing bacteria, which are resistant to most β-lactam antibiotics, such as penicillin.
It may be combined with clavulanic acid, a β-lactamase inhibitor.
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 strains of Staphylococcus aureus have developed resistance to amoxicillin to varying degrees.
Adverse effects are similar to those for other β-lactam antibiotics, including nausea, vomiting, rashes, and antibiotic-associated colitis. Diarrhea (loose bowel movements) may also occur.
Rarer adverse effects include mental and behavioral changes, lightheadedness, insomnia, hyperactivity, agitation, confusion, anxiety, sensitivity to lights and sounds, and unclear thinking.
Amoxicillin has been associated with an increased risk of seizures.
Amoxicillin-induced neurotoxicity has been especially associated with concentrations of greater than 110 mg/L.
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, intense itching, and sensations of fever, nausea, and vomiting.
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 dysfunction.
Between 3 and 10% of children taking amoxicillin (or ampicillin) show a late-developing 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.
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.
A nonallergic amoxicillin rash may also be an indicator of infectious mononucleosis.
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 (dabigatran, warfarin). Methotrexate (chemotherapy and immunosuppressant). Typhoid, Cholera and BCG vaccines. Probenecid reduces renal excretion and increases blood levels of amoxicillin. Oral contraceptives potentially become less effective. Allopurinol Mycophenolate
When given intravenously or intramuscularly: It should not be mixed with blood products, or proteinaceous fluids or with intravenous lipid emulsions, aminoglycoside should be injected at a separate site from amoxicillin if the patient is prescribed both medications at the same time.
Ciprofloxacin should not be mixed with amoxicillin.
Infusions containing dextran or bicarbonate should not be mixed with amoxicillin solutions.
Amoxicillin 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.
Amoxicillin diffuses easily into tissues and body fluids. It will cross the placenta and is excreted into breastmilk in small quantities.
Amoxicillin is metabolized by the liver and excreted into the urine.
It has an onset of 30 minutes and a half-life of 3.7 hours in newborns and 1.4 hours in adults.
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.
It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the bacterial cell wall.
Amoxicillin is a β-lactam and aminopenicillin antibiotic in terms of chemical structure.
It is structurally related to ampicillin.
The experimental log P of amoxicillin is 0.87.[62][63] It is described as an “ambiphilic”—between hydrophilic and lipophilic—antibiotic.[64]
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.
The intravenous form of amoxicillin is not sold in the United States.
When an intravenous aminopenicillin is required ampicillin is typically used.
When there is an adequate response to ampicillin, the course of antibiotic therapy may often be completed with oral amoxicillin.[74]