Maximum Dose of Amoxicillin for Adults with Strep Infections
The maximum dose of amoxicillin for adults with streptococcal infections is 1,000 mg per day when given as a once-daily regimen, or 500 mg per dose when given twice daily for a total of 10 days. 1, 2
Recommended Dosing Regimens for Streptococcal Pharyngitis
Standard Treatment for Adults
- 500 mg twice daily for 10 days (total daily dose of 1,000 mg) 1, 2
- Alternative: 250 mg four times daily for 10 days (total daily dose of 1,000 mg) 1
Treatment for Children
- 50 mg/kg once daily (maximum = 1,000 mg) for 10 days 1, 2
- Alternative: 25 mg/kg twice daily (maximum = 500 mg per dose) for 10 days 1, 2
Importance of Complete Treatment Course
- A full 10-day course is essential to prevent acute rheumatic fever, even if symptoms resolve earlier 2
- Patients are generally considered non-contagious after 24 hours of antibiotic therapy 2
- Shorter courses (5-7 days) have been studied but are not currently recommended in guidelines 3
Special Situations
Chronic Carriers with Recurrent Symptoms
- Amoxicillin/clavulanate: 40 mg/kg/day of amoxicillin component in three divided doses (maximum = 2,000 mg amoxicillin per day) for 10 days 1, 2
Penicillin-Allergic Patients
- Cephalexin: 20 mg/kg twice daily (maximum = 500 mg per dose) for 10 days 1, 2
- Clindamycin: 7 mg/kg three times daily (maximum = 300 mg per dose) for 10 days 1, 2
- Azithromycin: 12 mg/kg once daily (maximum = 500 mg) for 5 days (note: resistance concerns) 1, 2
Clinical Considerations
- Amoxicillin is preferred over penicillin V for streptococcal pharyngitis due to better taste and twice-daily dosing option, which may improve compliance 2, 4
- Once-daily dosing of amoxicillin has shown effectiveness in studies, but once-daily dosing of penicillin is associated with decreased efficacy 4
- Twice-daily dosing of penicillin or amoxicillin is as effective as more frequent dosing regimens 4
Potential Adverse Effects
- Most common adverse reactions (>1%) include diarrhea, rash, vomiting, and nausea 5
- Serious but rare reactions include anaphylaxis and severe cutaneous adverse reactions 5
- Clostridioides difficile-associated diarrhea may occur 5
Important Caveats
- Amoxicillin should only be used for confirmed or strongly suspected bacterial infections to reduce the development of drug-resistant bacteria 5
- Dose adjustment is necessary for patients with severe renal impairment (GFR >30 mL/min) 5
- Drug interactions may occur with probenecid, oral anticoagulants, allopurinol, and oral contraceptives 5
Remember that the maximum dose recommendation of 1,000 mg per day for streptococcal pharyngitis carries a "Strong, high" recommendation based on quality evidence 1, 2.