What antibiotics are used to treat Streptococcus (Strep) A infections in patients with a penicillin allergy?

From the Guidelines

For patients with a penicillin allergy, alternative antibiotics for treating Strep A (Group A streptococcal) infections include clindamycin, azithromycin, or clarithromycin 1.

Recommended Dosages

• Clindamycin is recommended at a dose of 300-450 mg orally every 6-8 hours for 10 days 1.
• Azithromycin can be given at a dose of 500 mg orally on the first day, followed by 250 mg orally once daily for the next 4 days 1.
• Clarithromycin is dosed at 250-500 mg orally every 12 hours for 10 days 1.

Important Considerations

It's crucial to note that the severity of the penicillin allergy and the specific clinical scenario may influence the choice of antibiotic, and consultation with an infectious disease specialist or an allergist may be necessary in complex cases 1. Some key points to consider when choosing an antibiotic include:

• The patient's medical history and current health status
• The severity of the Strep A infection
• The potential for antibiotic resistance
• The patient's ability to tolerate the antibiotic
• The cost and availability of the antibiotic In general, first-generation cephalosporins are also acceptable for patients allergic to penicillin who do not manifest immediate-type hypersensitivity to β-lactam antibiotics 1. However, it's essential to weigh the benefits and risks of each antibiotic and consider the individual patient's needs when making a treatment decision.

From the FDA Drug Label

NOTE: Penicillin by the intramuscular route is the usual drug of choice in the treatment of Streptococcus pyogenes infection and the prophylaxis of rheumatic fever. Azithromycin is often effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx Its use should be reserved for penicillin-allergic patients or other patients for whom, in the judgment of the physician, a penicillin is inappropriate.

The antibiotics used to treat Streptococcus (Strep) A infections in patients with a penicillin allergy are:

• Azithromycin 2, 2
• Clindamycin 3

These antibiotics can be used as an alternative to first-line therapy in individuals who cannot use first-line therapy.

From the Research

Antibiotic Options for Streptococcus A Infections in Patients with Penicillin Allergy

• For patients allergic to penicillin, alternative antibiotics such as macrolides (e.g., erythromycin, clarithromycin, azithromycin) can be used to treat Streptococcus A infections 4.
• Clarithromycin and azithromycin are newer macrolides that offer lower rates of gastrointestinal complaints and more convenient dosing compared to erythromycin 4.
• A study comparing clarithromycin and penicillin in the treatment of streptococcal pharyngitis found that clarithromycin was as effective and well-tolerated as penicillin 5.
• Azithromycin has also been shown to be effective in treating acute group A streptococcal pharyngitis, with similar clinical efficacy to penicillin V, although with lower bacteriologic eradication rates 6.

Considerations for Patients with Penicillin Allergy

• Patients with a reported penicillin allergy should be evaluated to determine the likelihood of a clinically significant reaction 7.
• For patients with a low-risk allergy history, a direct amoxicillin challenge may be appropriate, while moderate-risk patients can be evaluated with penicillin skin testing 7.
• Desensitization therapy to penicillin can be performed for patients with an IgE-mediated allergy who require penicillin treatment 8.

Available Antibiotic Options

• Erythromycin: generally effective, but may have gastrointestinal side effects 4.
• Clarithromycin: recommended for twice-daily administration, with a 10-day treatment duration 4, 5.
• Azithromycin: recommended for once-daily administration, with a 5-day treatment duration for streptococcal pharyngitis/tonsillitis 4, and a 3-day treatment duration for acute group A streptococcal pharyngitis 6.