Amoxicilline

Amoxicillin is a beta-lactam antibiotic used to treat a variety of bacterial infections. It is a penicillin derivative and is one of the most commonly prescribed antibiotics in the world.

Mechanism of Action

Amoxicillin works by inhibiting the synthesis of bacterial cell walls. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, which inhibits the final transpeptidation step of peptidoglycan synthesis. This action leads to the weakening of the cell wall and eventually causes the lysis and death of the bacterium.

Pharmacokinetics

Amoxicillin is well absorbed from the gastrointestinal tract after oral administration, with a bioavailability of approximately 95%. It is widely distributed throughout the body and penetrates well into most tissues and fluids, including sinuses, middle ear, and lungs. The drug is partially metabolized in the liver and is primarily excreted in the urine. The elimination half-life of amoxicillin is approximately 61.3 minutes.

Clinical Uses

Amoxicillin is used to treat a variety of infections caused by susceptible strains of bacteria. These include:

• Upper respiratory tract infections such as pharyngitis, tonsillitis, and sinusitis.
• Lower respiratory tract infections such as pneumonia and bronchitis.
• Urinary tract infections.
• Skin and soft tissue infections.
• Helicobacter pylori eradication in combination with other medications.

Side Effects

Common side effects of amoxicillin include:

• Nausea
• Vomiting
• Diarrhea
• Rash

Serious side effects, although rare, can include:

• Anaphylaxis
• Stevens-Johnson syndrome
• Clostridium difficile infection

Contraindications

Amoxicillin is contraindicated in patients with a known hypersensitivity to penicillins or any component of the formulation. Caution is advised in patients with a history of allergy to cephalosporins due to possible cross-reactivity.

Drug Interactions

Amoxicillin may interact with other medications, including:

• Methotrexate: Amoxicillin can increase the serum concentration of methotrexate.
• Warfarin: Amoxicillin may enhance the anticoagulant effect of warfarin.
• Allopurinol: Concurrent use may increase the risk of rash.

Special Populations

Pregnancy

Amoxicillin is classified as pregnancy category B in the United States, indicating that there is no evidence of harm to the fetus in animal studies, but there are no adequate and well-controlled studies in pregnant women.

Breastfeeding

Amoxicillin is excreted in breast milk in small amounts. It is generally considered safe for use during breastfeeding, but caution is advised.

History

Amoxicillin was discovered in 1972 and has since become one of the most widely used antibiotics. It is on the World Health Organization's List of Essential Medicines, which lists the most effective and safe medicines needed in a health system.

See Also

• Antibiotic resistance
• Beta-lactamase
• Penicillin