Treatment of Recurrent Strep Throat After Recent Amoxicillin
For a patient with strep throat recurring 30 days after completing amoxicillin, you should treat with an alternative antibiotic regimen that has superior eradication rates, specifically clindamycin, amoxicillin-clavulanate, or a narrow-spectrum cephalosporin, rather than repeating the same amoxicillin course. 1
First-Line Options for This Recurrence
The IDSA 2012 guidelines provide strong evidence for specific regimens when initial penicillin/amoxicillin therapy fails 1:
- Clindamycin: 20-30 mg/kg/day divided into 3 doses for 10 days (max 300 mg/dose) - Strong recommendation, high-quality evidence 1
- Amoxicillin-clavulanate: 40 mg/kg/day (amoxicillin component) divided into 3 doses for 10 days (max 2000 mg/day) - Strong recommendation, moderate-quality evidence 1
- Benzathine penicillin G IM (if compliance is questionable): 600,000 U for <27 kg or 1,200,000 U for ≥27 kg as single dose - Strong recommendation, high-quality evidence 1
Why Not Simply Repeat Amoxicillin?
A single recurrence shortly after treatment can be retreated with the same agent, but the 30-day interval suggests either treatment failure, reinfection, or carrier state with intercurrent viral infection. 1 The guidelines distinguish between:
- True treatment failure: Requires alternative therapy with better eradication rates 1
- Carrier state with viral pharyngitis: Most common scenario, where the patient harbors GAS chronically but has viral symptoms 1
- Reinfection: New acquisition from contacts 1
Critical Decision Point: Is This True Infection or Carrier State?
Before treating, consider these clinical clues 1:
- Favor true GAS infection: Sudden onset, fever >100.4°F, tonsillar exudates, anterior cervical adenopathy, absence of cough/coryza 2
- Favor carrier with viral infection: Gradual onset, cough, rhinorrhea, conjunctivitis, diarrhea 1, 2
However, in clinical practice when the patient is symptomatic with positive testing, you cannot reliably distinguish these scenarios, so treatment is warranted. 1
Specific Regimen Selection
If Compliance Was Good with Initial Course:
Use one of the superior eradication regimens above, as these have demonstrated better bacteriologic cure rates than repeat penicillin/amoxicillin 1:
- Clindamycin has approximately 1% resistance in the US and excellent tissue penetration 3
- Amoxicillin-clavulanate overcomes beta-lactamase-producing co-pathogens that may protect GAS 1
If Compliance Was Questionable:
Benzathine penicillin G IM is preferred because it guarantees complete drug delivery 1. You can also add rifampin 20 mg/kg/day in 2 doses for the last 4 days (max 600 mg/day) to enhance eradication 1.
Important Caveats
Do NOT use macrolides (azithromycin, erythromycin) for treatment failures - they are not included in failure regimens due to insufficient data and resistance rates of 5-8% in the US 1. Macrolides are only appropriate for penicillin-allergic patients on initial treatment, not for failures 1.
Avoid routine post-treatment cultures unless the patient remains symptomatic or has special risk factors (history of rheumatic fever) 1. Asymptomatic carriers do not require treatment and are at very low risk for complications 1.
When Multiple Recurrences Occur
If this becomes a pattern over months with multiple positive cultures 1:
- Most likely chronic carrier experiencing repeated viral infections 1
- Consider carrier eradication regimens only in special circumstances: outbreak settings, family history of rheumatic fever, excessive family anxiety, or when tonsillectomy is being considered 1
- Tonsillectomy may be considered for rare patients with truly recurrent infections (not carriers), though benefit is limited and temporary 1
What NOT to Do
- Do NOT test or treat asymptomatic household contacts - this is not recommended and wastes resources 1, 4
- Do NOT use tetracyclines, sulfonamides, or older fluoroquinolones - these are ineffective against GAS 1
- Do NOT prescribe continuous prophylaxis except for patients with history of rheumatic fever 1