Amoxycillin is a broad-spectrum, bactericidal, beta-lactam antibiotic belonging to the aminopenicillin class. It is a semi-synthetic derivative of ampicillin with enhanced oral bioavailability. It acts by inhibiting bacterial cell wall synthesis, leading to osmotic lysis and cell death. It is effective against a wide range of Gram-positive and some Gram-negative bacteria, but is susceptible to degradation by beta-lactamases. It is a first-line agent for many common infections in the Indian context.
Adult: 250-500 mg orally every 8 hours. For severe infections: 500-875 mg every 12 hours or 500 mg every 8 hours. Maximum daily dose: 3-4 grams.
Note: Can be taken with or without food. Taking with food may reduce GI upset. Capsule/Tablet: Swallow whole with a full glass of water. Do not crush or chew sustained-release formulations. Suspension: Shake the bottle well before each use. Use the measuring device provided. Complete the full prescribed course even if symptoms improve.
Amoxycillin is a bactericidal antibiotic. It binds to specific penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. This binding inhibits the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall, a critical component for cell wall structural integrity. The inhibition leads to the activation of autolytic enzymes (autolysins) in the cell wall, resulting in lysis and death of the bacterium.
Pregnancy: Pregnancy Category A (Australian categorization) / Category B (US FDA). Considered generally safe. Extensive human data shows no increased risk of malformations. Used for treating infections in pregnancy. However, use only if clearly needed and under medical supervision.
Driving: Amoxycillin is not known to impair the ability to drive or operate machinery. However, if dizziness or other CNS effects occur, caution is advised.
| Probenecid | Decreases renal tubular secretion of amoxycillin, increasing and prolonging its blood levels. | Moderate |
| Methotrexate | Amoxycillin may reduce renal clearance of methotrexate, increasing risk of methotrexate toxicity (bone marrow suppression, mucositis). | Major |
| Allopurinol | Concomitant use increases the incidence of non-allergic skin rash. | Moderate |
| Oral Contraceptives | Potential for reduced efficacy of oral contraceptives; advise use of a backup non-hormonal contraceptive method. | Moderate |
| Warfarin and other Coumarin Anticoagulants | May potentiate anticoagulant effect, increasing INR and risk of bleeding. Monitor INR closely. | Major |
| Other Bacteriostatic Antibiotics (e.g., Tetracyclines, Chloramphenicol) | Theoretically may reduce the bactericidal effect of amoxycillin (antagonism). | Moderate |
Same composition (Amoxycillin (500mg)), different brands: