Adult Amoxicillin Dosing for Strep Throat
For a healthy adult with strep throat and no penicillin allergy, prescribe amoxicillin 500 mg orally twice daily for 10 full days, or alternatively 1000 mg once daily for 10 days. 1, 2
Standard Adult Dosing Regimens
The preferred regimen is amoxicillin 500 mg orally twice daily (every 12 hours) for 10 days, which provides equivalent efficacy to penicillin V with simpler dosing and better palatability 1, 2
An alternative once-daily regimen of 1000 mg orally once daily for 10 days is equally effective and may improve compliance, with strong evidence supporting this approach from the American Academy of Pediatrics and American Heart Association 1, 2, 3
The FDA-approved adult dosing range is 750 to 1750 mg/day in divided doses every 8 to 12 hours, with the 500 mg twice daily regimen falling within this range 4
Critical Treatment Duration Requirement
A full 10-day course is mandatory to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever, even if symptoms resolve earlier 1, 2
Shortening the course below 10 days dramatically increases treatment failure rates and the risk of rheumatic fever, which can occur even when therapy is delayed up to 9 days after symptom onset 1, 2
Patients become non-contagious after 24 hours of appropriate antibiotic therapy but must complete the full 10-day course 1, 2
Why Amoxicillin Over Penicillin V
Amoxicillin has strong, high-quality evidence equivalent to penicillin V but offers the advantage of simpler dosing (1-2 times daily versus 3-4 times daily for penicillin V), which improves compliance 1, 2
Both medications have proven efficacy, narrow spectrum of activity, excellent safety profiles, and low cost, with no documented resistance among Group A Streptococcus anywhere in the world 1, 5
The once-daily amoxicillin regimen is particularly advantageous for compliance compared to penicillin V's 3-4 times daily dosing requirement 3
Common Pitfalls to Avoid
Do not prescribe amoxicillin-clavulanate (Augmentin) for acute strep throat - there is no additional benefit, it has a broader spectrum than necessary, and it increases the risk of side effects 2
Do not shorten the treatment duration below 10 days based on clinical improvement - this is the most common error and significantly increases treatment failure and rheumatic fever risk 1, 2
Do not prescribe shorter courses even though symptoms typically resolve within 3-4 days - bacterial eradication requires the full 10-day course 1
Adjunctive Therapy
Acetaminophen or NSAIDs (ibuprofen) can be used for moderate to severe symptoms or high fever to provide symptomatic relief 1
Corticosteroids should not be used as adjunctive therapy 1