What antibiotic is recommended for a male patient with strep throat and no known allergies?

First-Line Antibiotic for Strep Throat in Non-Allergic Males

For a male patient with strep throat and no allergies, prescribe either penicillin V 500 mg orally twice daily for 10 days or amoxicillin 500 mg orally twice daily (or 1000 mg once daily) for 10 days. 1, 2

Why Penicillin or Amoxicillin

• Penicillin and amoxicillin are the drugs of choice based on their narrow spectrum of activity, proven efficacy, excellent safety profile, and low cost (strong, high-quality evidence). 1, 2
• No documented penicillin resistance exists in Group A Streptococcus anywhere in the world, making these agents reliably effective. 3
• Amoxicillin is equally effective to penicillin V and may be preferred due to better palatability and the option for once-daily dosing (750-1000 mg once daily), which can improve compliance. 2, 4

Specific Dosing Regimens

Penicillin V:

• 500 mg orally twice daily for 10 days (or 250 mg three to four times daily) 2

Amoxicillin:

• 500 mg orally twice daily for 10 days, OR
• 1000 mg once daily for 10 days 2, 4

Critical Treatment Duration

• A full 10-day course is essential to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever. 1, 2
• Shortening the course by even a few days dramatically increases treatment failure rates and the risk of rheumatic fever. 3
• The patient becomes non-contagious after 24 hours of appropriate antibiotic therapy. 2

Common Pitfalls to Avoid

• Do not prescribe broader-spectrum antibiotics (such as cephalosporins, macrolides, or fluoroquinolones) when penicillin or amoxicillin can be used—this unnecessarily increases cost and selection pressure for antibiotic-resistant flora. 1, 3
• Do not shorten the treatment course below 10 days despite clinical improvement, as symptoms typically resolve within 3-4 days but bacterial eradication requires the full course. 3
• Do not use amoxicillin if concurrent infectious mononucleosis is suspected, as this can cause a characteristic rash; use a first-generation cephalosporin or macrolide instead. 2
• Do not use sulfonamides, tetracyclines, or trimethoprim-sulfamethoxazole due to high resistance rates (approximately 50% for TMP-SMX). 2

When to Consider Alternatives

Only deviate from penicillin/amoxicillin if:

• The patient has a documented penicillin allergy (use first-generation cephalosporins for non-anaphylactic allergy, or clindamycin/azithromycin for immediate/anaphylactic allergy) 1, 3
• The patient has concurrent infectious mononucleosis 2
• There is documented treatment failure after appropriate penicillin therapy (consider clindamycin for chronic carriers) 3