What is the typical dose of amoxicillin (amoxicillin) for strep throat?

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 for adolescents and adults, always for a full 10-day course. 1, 2

Specific Dosing Regimens by Age

Children (≥3 months and <40 kg)

• Preferred: 50 mg/kg once daily (maximum 1000 mg) for 10 days 1, 2
• Alternative: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 2
• Once-daily dosing improves adherence and has equivalent efficacy to multiple daily doses 1, 3, 4

Adolescents and Adults (≥40 kg)

• Standard dose: 500 mg twice daily for 10 days 1, 2
• Alternative: 1000 mg once daily for 10 days 1, 2

Infants <3 months

• Maximum 30 mg/kg/day divided every 12 hours due to immature renal function 5
• Still requires full 10-day course 5

Critical Treatment Principles

The full 10-day course is absolutely essential—even if symptoms resolve in 3-4 days—to prevent acute rheumatic fever and achieve maximal bacterial eradication. 1, 2, 6 Therapy can be safely delayed up to 9 days after symptom onset and still prevent rheumatic fever, so waiting 24-48 hours for culture results does not increase risk 1

Patients become non-contagious after just 24 hours of antibiotic therapy and can return to school/work at that point if afebrile and improved. 1, 7 Research demonstrates that 91% of children have undetectable Group A Streptococcus by the morning after a single evening dose 7

Why Amoxicillin Over Penicillin V

Amoxicillin is preferred over penicillin V because: 1, 2

• Superior palatability in children (suspension tastes better)
• Once-daily dosing option enhances adherence
• Equivalent efficacy to penicillin V
• Narrow spectrum with proven safety
• Low cost compared to alternatives

Common Pitfalls to Avoid

Do not shorten the course below 10 days despite clinical improvement—this dramatically increases treatment failure rates and risk of acute rheumatic fever. 1, 2, 6 The only exception is azithromycin, which requires 5 days due to unique pharmacokinetics 8, 6

Do not prescribe broad-spectrum cephalosporins (cefdinir, cefixime, cefpodoxime) when amoxicillin can be used—these are more expensive and promote antibiotic resistance. 1, 8 Reserve these only for documented penicillin allergy 8

Do not perform routine follow-up throat cultures in asymptomatic patients who completed therapy—testing should only occur in special circumstances like history of rheumatic fever. 8, 6

Renal Impairment Dosing

For patients with severe renal impairment (GFR <30 mL/min): 5

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours
• Hemodialysis: 500 mg or 250 mg every 24 hours, with additional dose during and after dialysis

Administration Tips

• Take at the start of meals to minimize gastrointestinal intolerance 5
• Shake oral suspension well before each use 5
• Refrigeration of suspension is preferable but not required 5
• Discard unused suspension after 14 days 5

Evidence Quality

The once-daily amoxicillin regimen has strong, high-quality evidence supporting its efficacy, with multiple randomized controlled trials demonstrating non-inferiority to traditional multiple-daily-dose regimens. 3, 4 The American Heart Association recently endorsed once-daily dosing specifically for streptococcal pharyngitis. 2