What is a suitable alternative antibiotic for a 9-year-old child with an anaphylactic Penicillin (PCN) allergy for treating streptococcal pharyngitis, specifically considering azithromycin?

From the Guidelines

Azithromycin is a suitable alternative antibiotic for a 9-year-old child with an anaphylactic penicillin allergy who has streptococcal pharyngitis, with a recommended dosage of 12 mg/kg once daily (maximum 500 mg per day) for 5 days. For most 9-year-olds weighing between 25-35 kg, this typically means 250-400 mg once daily 1. Azithromycin is effective against Group A Streptococcus and has the advantage of a shorter treatment course compared to other alternatives. It also has good compliance due to once-daily dosing and fewer gastrointestinal side effects than some other macrolides. However, it's essential to note that macrolide resistance rates for Group A Streptococcus vary geographically, so local resistance patterns should be considered 1.

Some key points to consider when prescribing azithromycin for streptococcal pharyngitis in a penicillin-allergic child include:

• The importance of completing the full 5-day course of antibiotics, even if symptoms improve before completion, to ensure eradication of the bacteria and prevent complications like rheumatic fever 1.
• The potential for cross-reactivity between penicillins and cephalosporins, which may limit the use of cephalosporins as an alternative in patients with anaphylactic penicillin allergy 1.
• The availability of other alternative antibiotics, such as clindamycin, which may be considered in cases where azithromycin is not suitable or effective 1.
• The need for careful consideration of local resistance patterns and the potential for treatment failure when selecting an antibiotic for streptococcal pharyngitis 1.

In terms of the evidence, the Infectious Diseases Society of America (IDSA) guidelines recommend azithromycin as a suitable alternative for patients with penicillin allergy, with a strength of recommendation of "strong" and a quality of evidence of "moderate" 1. Overall, azithromycin is a reasonable choice for the treatment of streptococcal pharyngitis in a 9-year-old child with an anaphylactic penicillin allergy, but it's crucial to consider the individual patient's needs and circumstances, as well as local resistance patterns, when making treatment decisions.

From the FDA Drug Label

Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy Azithromycin is often effective in the eradication of susceptible strains of Streptococcus pyogenes from the nasopharynx 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 a suitable alternative antibiotic for a 9-year-old child with an anaphylactic Penicillin (PCN) allergy for treating streptococcal pharyngitis.

• The clinical success rate (i.e., cure and improvement) for azithromycin in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) was 98% at Day 14 and 94% at Day 30 in clinical trials 2.
• Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) 2.
• However, susceptibility tests should be performed when patients are treated with azithromycin, as some strains of Streptococcus pyogenes may be resistant to azithromycin 2.

From the Research

Alternative Antibiotics for Strep Throat in Children with PCN Allergy

For a 9-year-old child with an anaphylactic Penicillin (PCN) allergy, alternative antibiotics are necessary for treating streptococcal pharyngitis. Azithromycin is considered a viable option due to its efficacy against Streptococcus pyogenes, the primary cause of strep throat.

Efficacy and Dosage of Azithromycin

• Azithromycin has been shown to be effective in treating streptococcal pharyngitis in children, with a recommended dosage of 12 mg/kg/day for 5 days 3, 4.
• A total dose of 60 mg/kg azithromycin, given either as 12 mg/kg once daily for 5 days or 20 mg/kg once daily for 3 days, provides the best rate of GABHS eradication 4.
• However, studies have also indicated that azithromycin may result in more recurrence of infection than penicillin V, necessitating a higher dosage or longer treatment duration 3, 5.

Comparison with Other Antibiotics

• Azithromycin has been compared to penicillin V, erythromycin, and clarithromycin in the treatment of streptococcal pharyngitis, with varying results 5, 6, 7.
• Clarithromycin, another macrolide antibiotic, has demonstrated excellent in vitro activity against group A beta-hemolytic streptococcus (GABHS) and may be a suitable alternative to azithromycin 7.

Safety and Tolerability

• Azithromycin is generally well-tolerated in children, with mild to moderate gastrointestinal side effects being the most common adverse events 3, 5.
• The safety and efficacy of azithromycin have been established in children with streptococcal pharyngitis, making it a viable option for those with PCN allergies 3, 4, 5.