1. Clinical Overview
A fixed-dose combination antibiotic consisting of Amoxycillin, a broad-spectrum beta-lactam antibiotic, and Clavulanic Acid, a beta-lactamase inhibitor. The 200mg/28.5mg ratio (7:1) is a standard pediatric and low-dose adult formulation in India. Clavulanic acid protects amoxycillin from degradation by beta-lactamase enzymes produced by resistant bacteria, thereby extending its spectrum of activity to include many beta-lactamase-producing strains.
| Onset | Duration | Bioavailability |
|---|---|---|
| 1-2 hours | Approximately 6-8 hours (dosing interval is typically 8-12 hours) | Amoxycillin: ~90% (oral); Clavulanic Acid: ~75% (oral) |
2. Mechanism of Action
Amoxycillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to inhibition of transpeptidation, activation of autolytic enzymes, and ultimately bacterial cell lysis and death. Clavulanic acid has weak intrinsic antibacterial activity but irreversibly inhibits a wide range of beta-lactamase enzymes (e.g., TEM-1, SHV-1) produced by resistant bacteria, thereby protecting amoxycillin from hydrolysis.
3. Indications & Uses
- Acute Bacterial Otitis Media
- Acute Bacterial Sinusitis
- Community-Acquired Pneumonia (mild to moderate)
- Acute Exacerbation of Chronic Bronchitis
- Skin and Skin Structure Infections (uncomplicated)
- Urinary Tract Infections (uncomplicated cystitis)
4. Dosage & Administration
Adult Dosage: One tablet (200mg/28.5mg) every 8 hours OR two tablets every 12 hours. For more severe infections, higher strength formulations (e.g., 500mg/125mg) are preferred.
Administration: Take at the start of a meal to enhance absorption and reduce gastrointestinal side effects (especially diarrhea). Swallow whole with a glass of water. Do not crush/chew unless it's a dispersible tablet. Complete the full prescribed course even if you feel better.
5. Side Effects
Common side effects may include:
- Diarrhea / Loose stools
- Nausea
- Vomiting
- Abdominal discomfort
- Candidiasis (oral/vaginal)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| 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 toxicity. | Major |
| Allopurinol | Increased incidence of non-allergic skin rash. | Moderate |
| Oral Contraceptives | Potential reduction in efficacy due to altered gut flora; advise backup non-hormonal contraception. | Moderate |
| Warfarin/Acenoocoumarol | May potentiate anticoagulant effect, increasing INR and bleeding risk. | Major |
| Mycophenolate Mofetil | Reduces plasma concentration of the active metabolite (MPA). | Moderate |
7. Patient Counselling
- DO complete the full course of medication as prescribed.
- DO take the medicine at the start of a meal.
- DO drink plenty of fluids.
- DO inform your doctor if you have a history of kidney, liver disease, or allergies.
- DONT skip doses.
- DONT share your antibiotics with others.
- DONT take it for viral infections like cold or flu.
8. Toxicology & Storage
Overdose: Primarily gastrointestinal: nausea, vomiting, diarrhea. Risk of electrolyte imbalance. Crystalluria may occur with very high doses, especially in dehydration. Central nervous system effects like hyperactivity, drowsiness, or seizures are possible with massive overdose, particularly in renal failure.
Storage: Store below 25°C, in a cool, dry place. Protect from light and moisture. Keep out of reach of children. For dispersible tablets: Store in the original blister pack until use. Do not use if the tablet is discolored or broken.