Amoxicillin Dosing for Strep Throat
For strep throat, amoxicillin should be dosed at 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for children, and 500 mg twice daily or 875 mg twice daily for adults, always for a full 10-day course. 1, 2
Pediatric Dosing
- Children should receive 50 mg/kg once daily (maximum 1000 mg) or alternatively 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days. 1, 2
- Once-daily dosing improves adherence and has comparable efficacy to traditional penicillin V regimens. 2
- Amoxicillin is often preferred over penicillin V in children due to better palatability and taste acceptance. 2
- Research demonstrates that amoxicillin 40 mg/kg/day achieves superior clinical cure (87.9% vs 70.9%) and bacteriologic eradication (79.3% vs 54.5%) compared to standard-dose penicillin V. 3
Adult Dosing
- Adults should receive 500 mg twice daily or 875 mg twice daily for 10 days. 2, 4
- An alternative once-daily regimen of 1000 mg for 10 days may be used to improve adherence. 2
Critical Treatment Principles
- The full 10-day course must be completed even when symptoms resolve early to prevent acute rheumatic fever and ensure complete eradication of Group A Streptococcus. 1, 2, 4
- Patients become non-contagious after 24 hours of antibiotic therapy. 5, 2
- Treatment should be initiated at the start of a meal to minimize gastrointestinal intolerance. 4
Penicillin Allergy Alternatives
For patients with documented penicillin allergy, alternative regimens include:
- Cephalexin: 500 mg twice daily for 10 days (avoid in immediate-type hypersensitivity reactions). 1
- Clindamycin: 300 mg three times daily for 10 days. 1, 5
- Azithromycin: 500 mg once daily for 5 days (note: geographic variation in macrolide resistance exists). 1, 5
- Clarithromycin: 250 mg twice daily for 10 days (macrolide resistance is well-documented). 1, 5
Common Pitfalls to Avoid
- Inadequate treatment duration: Stopping antibiotics before 10 days increases risk of treatment failure, rheumatic fever, and persistent carriage. 1, 2
- Confusing amoxicillin with amoxicillin-clavulanate: Plain amoxicillin is first-line for uncomplicated strep throat; amoxicillin-clavulanate is reserved for recurrent infections or suspected resistance. 5
- Routine post-treatment cultures: These are not recommended unless special circumstances exist (recurrent infections, rheumatic fever history). 2
When to Consider Amoxicillin-Clavulanate
- Amoxicillin-clavulanate (40 mg/kg/day of amoxicillin component divided three times daily for children; 500 mg twice daily for adults) should be reserved for recurrent strep pharyngitis or suspected bacterial resistance, not as first-line therapy. 5