What is the recommended treatment for an adult with a confirmed strep throat culture?

Treatment of Confirmed Strep Throat in Adults

For adults with culture-confirmed group A streptococcal pharyngitis, penicillin or amoxicillin remains the drug of choice, given for 10 days to ensure bacterial eradication and prevent acute rheumatic fever. 1, 2

First-Line Treatment Options

Penicillin V is the gold standard antibiotic due to its proven efficacy, narrow spectrum of activity, safety profile, and low cost 1. The recommended dosing is:

• 500 mg orally twice daily for 10 days (preferred for compliance) 1
• Alternative: 250 mg orally three to four times daily for 10 days 1

Amoxicillin is equally effective and often preferred due to better palatability and similar efficacy 1, 2:

• 500 mg orally twice daily for 10 days 2
• Alternative: 250 mg orally three times daily for 10 days 2

The full 10-day course is essential to achieve maximal pharyngeal eradication of group A streptococci and prevent acute rheumatic fever, even if symptoms resolve earlier 1, 2.

For Penicillin-Allergic Patients

The choice of alternative antibiotic depends on the type of allergic reaction 1:

Non-Anaphylactic Penicillin Allergy

First-generation cephalosporins are preferred for patients without immediate hypersensitivity reactions 1:

• Cephalexin 500 mg orally twice daily for 10 days 1
• Cefadroxil 1 gram orally once daily for 10 days 1

Immediate/Anaphylactic Penicillin Allergy

Avoid all beta-lactam antibiotics (including cephalosporins) due to up to 10% cross-reactivity risk 1. Use:

• Clindamycin 300 mg orally three times daily for 10 days (preferred due to ~1% resistance rate) 1
• Azithromycin 500 mg orally once daily for 5 days (acceptable alternative, but 5-8% macrolide resistance in the US) 1
• Clarithromycin 250 mg orally twice daily for 10 days 1

Critical Treatment Principles

Do not shorten the antibiotic course below 10 days (except azithromycin's 5-day regimen), as this increases treatment failure rates and risk of acute rheumatic fever 1, 2.

Routine post-treatment throat cultures are not recommended for asymptomatic patients who have completed therapy 1.

Do not test or treat asymptomatic household contacts prophylactically, as this has not been shown to reduce subsequent infection rates 1.

Symptomatic Management

Acetaminophen or NSAIDs (such as ibuprofen) should be offered for pain relief and fever control 1, 3.

Avoid aspirin in children due to the risk of Reye syndrome 1.

Corticosteroids are not recommended as adjunctive therapy 1.

Common Pitfalls to Avoid

Do not rely on clinical features alone without microbiological confirmation, as this leads to overtreatment of viral pharyngitis 1.

Do not use broad-spectrum antibiotics (such as fluoroquinolones or third-generation cephalosporins) when narrow-spectrum agents are appropriate 1.

Do not prescribe macrolides as first-line therapy in non-allergic patients, as resistance rates are increasing and they should be reserved for penicillin-allergic individuals 1.

Ensure patients take amoxicillin at the start of a meal to minimize gastrointestinal intolerance 2.