Overview
Amoxicillin/clavulanic acid is a combination antibiotic consisting of amoxicillin (a beta-lactam antibiotic) and clavulanic acid (a beta-lactamase inhibitor). This combination extends amoxicillin's spectrum of activity to include beta-lactamase-producing bacteria that are otherwise resistant to amoxicillin alone. It is widely used for treating various bacterial infections.
Mechanism of Action
Amoxicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to cell lysis and death. Clavulanic acid irreversibly inhibits beta-lactamase enzymes produced by resistant bacteria, protecting amoxicillin from degradation and restoring its antibacterial activity against beta-lactamase-producing strains.
Indications
- Acute bacterial sinusitis
- Acute otitis media
- Community-acquired pneumonia
- Skin and skin structure infections
- Urinary tract infections
- Chronic obstructive pulmonary disease exacerbations
- Animal/human bite wounds
Dosage
Dosage varies based on infection severity, patient age, and renal function. Common adult dosage: 500 mg amoxicillin/125 mg clavulanic acid every 8 hours or 875 mg/125 mg every 12 hours. Pediatric dosage based on weight. Extended-release formulation (Augmentin XR): 2 tablets (each containing 1000 mg amoxicillin/62.5 mg clavulanic acid) every 12 hours. Always follow specific product labeling and healthcare provider instructions.
Contraindications
- History of serious hypersensitivity reactions (e.g., anaphylaxis) to amoxicillin, clavulanic acid, other beta-lactam antibiotics
- History of cholestatic jaundice/hepatic dysfunction associated with amoxicillin/clavulanic acid
- Patients with mononucleosis due to high rash incidence
Side Effects
- Diarrhea
- Nausea
- Vomiting
- Skin rash
- Abdominal pain
- Headache
- Vaginal candidiasis
- Elevated liver enzymes
- Allergic reactions
- Antibiotic-associated colitis
Interactions
- Probenecid decreases renal tubular secretion of amoxicillin
- Allopurinol may increase incidence of skin rash
- Oral contraceptives: may reduce effectiveness
- Methotrexate: amoxicillin may increase methotrexate toxicity
- Warfarin: may enhance anticoagulant effect