What is the recommended antibiotic for strep throat in a patient with a penicillin allergy?

From the Guidelines

For patients with a penicillin allergy who have strep throat, the recommended antibiotic is typically azithromycin (Zithromax) at a dose of 12 mg/kg once daily (maximum = 500 mg) for 5 days, as it is effective against Group A Streptococcus and has a strong, moderate recommendation strength and quality of evidence 1. This recommendation is based on the most recent and highest quality study available, which prioritizes morbidity, mortality, and quality of life as the outcome. The use of azithromycin is supported by its ability to inhibit bacterial protein synthesis, making it an effective treatment for strep throat. Some key points to consider when prescribing azithromycin for strep throat in patients with a penicillin allergy include:

• Completing the full 5-day course of antibiotics, even if symptoms improve before completion, to ensure complete eradication of the bacteria and prevent complications like rheumatic fever or kidney inflammation.
• Monitoring for adverse reactions, such as severe diarrhea, and contacting the healthcare provider immediately if they occur.
• Using over-the-counter pain relievers like acetaminophen or ibuprofen and warm salt water gargles for symptom relief while the antibiotics take effect. Alternative options, such as clarithromycin (Biaxin) 7.5 mg/kg per dose twice daily (maximum = 250 mg per dose) for 10 days or clindamycin 7 mg/kg per dose three times daily (maximum = 300 mg per dose) for 10 days, may also be considered, but azithromycin is generally the preferred choice due to its shorter treatment duration and strong, moderate recommendation strength and quality of evidence 1.

From the FDA Drug Label

Pharyngitis/Tonsillitis In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS):

Three U. S. Streptococcal Pharyngitis Studies Azithromycin vs. Penicillin V EFFICACY RESULTS Day 14Day 30 Bacteriologic Eradication: Azithromycin323/340 (95%)255/330 (77%) Penicillin V242/332 (73%)206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin336/343 (98%)310/330 (94%) Penicillin V284/338 (84%)241/325 (74%)

The recommended antibiotic for strep throat in a patient with a penicillin allergy is azithromycin.

• Dosage: 12 mg/kg once a day for 5 days
• Key points:
  • Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30
  • Bacteriologic eradication rates were 95% for azithromycin and 73% for penicillin at Day 14
  • Clinical success rates were 98% for azithromycin and 84% for penicillin at Day 14 2

From the Research

Recommended Antibiotics for Strep Throat in Penicillin-Allergic Patients

• For patients allergic to penicillin, alternative antibiotics are required to treat strep throat, also known as streptococcal pharyngitis 3.
• Macrolides, such as clarithromycin and azithromycin, are rational alternatives to erythromycin for streptococcal pharyngitis/tonsillitis in penicillin-allergic patients 3.
• Azithromycin has been shown to be a safe and effective alternative treatment for streptococcal pharyngitis in adult outpatients 4.
• However, a study found that 10 days of clarithromycin therapy was more effective than 5 days of azithromycin therapy in eradicating group A streptococci from the throats of individuals with symptomatic pharyngitis 5.
• Another study found that azithromycin was as clinically effective and as safe as traditional penicillin in treating streptococcal pharyngitis in children, but appeared inferior in eliminating group A beta-hemolytic streptococci from the throat 6.
• It's worth noting that there is significant resistance to azithromycin and clarithromycin in some parts of the United States, and first-generation cephalosporins are recommended for patients with nonanaphylactic allergies to penicillin 7.

Key Considerations

• The choice of antibiotic should be based on the patient's allergy status, the severity of the infection, and the presence of any underlying medical conditions.
• Patients with worsening symptoms after appropriate antibiotic initiation or with symptoms lasting 5 days after the start of treatment should be reevaluated 7.
• Tonsillectomy is rarely recommended as a preventive measure, and is typically considered only for patients with recurrent episodes of streptococcal pharyngitis 7.