A patient receiving amoxicillin/clavulanate (Augmentin) for a skin infection develops a streptococcal infection with only one dose of the current antibiotic remaining; what is the appropriate treatment for the streptococcal infection?

Treatment of Streptococcal Pharyngitis in a Patient Currently on Augmentin

Complete the remaining dose of Augmentin and then start a full 10-day course of penicillin V (250 mg twice or three times daily for children <27 kg; 500 mg twice daily for adolescents/adults ≥27 kg) or amoxicillin (50 mg/kg once daily, max 1000 mg) to treat the streptococcal pharyngitis. 1

Rationale and Clinical Approach

The key issue here is that while Augmentin (amoxicillin-clavulanate) contains amoxicillin—which is effective against Group A Streptococcus (GAS)—the patient has only one dose remaining, which is insufficient to treat streptococcal pharyngitis adequately.

Why a Full Course is Essential

• GAS pharyngitis requires 10 days of beta-lactam therapy to eradicate the organism from the pharynx and prevent complications, particularly acute rheumatic fever 2, 1
• The IDSA guidelines explicitly state that patients with acute GAS pharyngitis should receive "an appropriate antibiotic at an appropriate dose for a duration likely to eradicate the organism from the pharynx (usually 10 days)" 1
• One remaining dose of Augmentin provides inadequate duration of therapy

Antibiotic Selection

First-line options (strong, high-quality evidence):

• Penicillin V remains the treatment of choice due to proven efficacy, safety, narrow spectrum, and low cost 1
• Amoxicillin is equally effective and often preferred in children due to better palatability and once-daily dosing option, which may enhance adherence 1

Key point: While the patient is already on amoxicillin-clavulanate, the amoxicillin component is appropriate for strep throat. However, you must ensure a complete 10-day course from the start of strep treatment, not just finishing the skin infection regimen.

Alternative Approach if Penicillin Allergy

If the patient has a penicillin allergy:

• First-generation cephalosporin (cephalexin 20 mg/kg/dose twice daily, max 500 mg/dose) for 10 days—avoid in immediate hypersensitivity 1
• Clindamycin (7 mg/kg/dose three times daily, max 300 mg/dose) for 10 days 1
• Azithromycin (12 mg/kg once daily, max 500 mg) for 5 days or clarithromycin (7.5 mg/kg/dose twice daily, max 250 mg/dose) for 10 days—though macrolide resistance is a concern 1

Critical Pitfalls to Avoid

1. Do not assume the remaining Augmentin course is sufficient for strep pharyngitis treatment—it was prescribed for a skin infection with a different duration requirement
2. Do not count the days already on Augmentin toward the 10-day strep treatment unless you can confirm the patient has already received adequate dosing for at least 10 days total
3. Penicillin resistance in GAS has never been documented, so there is no concern about treatment failure due to resistance when using penicillin or amoxicillin 1

Practical Implementation

• Have the patient finish the last Augmentin dose for the skin infection
• Start a fresh 10-day course of penicillin V or amoxicillin specifically for the streptococcal pharyngitis
• Counsel the patient that clinical response typically occurs within 24-48 hours 1
• Emphasize completing the full 10-day course even when feeling better to prevent complications and reduce transmission 1
• No follow-up throat culture is needed after treatment in routine cases 1