Recommended Amoxicillin Dosage for Strep Throat
For strep throat (Group A Streptococcal pharyngitis), the recommended dose of amoxicillin is 50 mg/kg once daily (maximum 1,000 mg) or alternatively 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days. 1
Dosing Recommendations
For Children:
- First-line option: 50 mg/kg once daily (maximum 1,000 mg) for 10 days 1
- Alternative option: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
For Adults:
- Standard dosing: 875 mg twice daily or 500 mg three times daily for 10 days 1, 2
- Once-daily option: 1,000 mg once daily for 10 days 1
Duration of Therapy
A full 10-day course of therapy is strongly recommended to:
- Ensure complete eradication of Group A Streptococcus from the pharynx 1
- Prevent acute rheumatic fever, a serious complication of untreated strep throat 1, 2
While some studies have investigated shorter courses (5-7 days) 3, the 10-day regimen remains the standard of care with the strongest evidence base and recommendation strength (strong, high-quality evidence) 1.
Important Clinical Considerations
- Timing of administration: Take amoxicillin at the start of a meal to minimize gastrointestinal intolerance 2
- Compliance advantage: Once-daily dosing may improve adherence, especially in children 1, 4
- Palatability factor: Amoxicillin is often preferred over penicillin V for children due to better taste acceptance 1
- Efficacy equivalent to penicillin: Amoxicillin has comparable efficacy to penicillin V, which has traditionally been the gold standard 1
Special Populations
Penicillin-Allergic Patients:
Do not use amoxicillin; instead consider:
- Cephalexin: 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days (if no immediate hypersensitivity to penicillin) 1
- Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
Patients with Renal Impairment:
- GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 2
- GFR <10 mL/min: 500 mg or 250 mg every 24 hours 2
Common Pitfalls to Avoid
- Inadequate duration: Do not shorten therapy to less than 10 days, as this increases risk of treatment failure and complications 1
- Unnecessary follow-up cultures: Routine post-treatment throat cultures are not recommended unless there are special circumstances 1
- Testing/treating asymptomatic contacts: Routine testing or empiric treatment of asymptomatic household contacts is not recommended 1
- Macrolide resistance concerns: Be aware of potential resistance when using macrolides (like azithromycin) as alternatives 1, 5
Remember that complete adherence to the full 10-day course is essential even if symptoms resolve earlier, as premature discontinuation can lead to treatment failure and increased risk of complications such as rheumatic fever 1, 2.