Cephalexin for Bacterial Pharyngitis
First-Line Treatment
- The American Academy of Pediatrics and the Infectious Diseases Society of America recommend penicillin or amoxicillin as the treatment of choice for Group A Streptococcus (GAS) pharyngitis due to proven efficacy, safety, narrow spectrum, and low cost 1, 3
Alternative Treatment Options
- For patients with non-immediate (non-anaphylactic) penicillin allergy, the American College of Allergy, Asthma, and Immunology suggests first-generation cephalosporins like cephalexin as a preferred alternative 2, 4
- The Centers for Disease Control and Prevention recommend dosing of 500 mg orally every 12 hours for adults (or 20 mg/kg per dose twice daily in children, maximum 500 mg/dose) for a full 10 days 2
Critical Safety Considerations
- Up to 10% of patients with immediate/anaphylactic penicillin reactions have cross-reactivity with cephalosporins, according to the American Academy of Allergy, Asthma, and Immunology 2, 4
- The FDA and the World Health Organization note that all beta-lactams, including cephalexin, must be avoided in patients with immediate hypersensitivity to penicillin 2, 4
Treatment of Penicillin Allergy
- For patients with immediate/anaphylactic penicillin allergy who cannot use any cephalosporins, the Infectious Diseases Society of America recommends clindamycin as the preferred choice: 300 mg orally three times daily for 10 days in adults (or 7 mg/kg per dose three times daily in children, maximum 300 mg/dose) 2
- The American Academy of Pediatrics notes that clindamycin has approximately 1% resistance rate among GAS in the United States 2
Macrolide Treatment
- Azithromycin is acceptable but less reliable: 500 mg once daily for 5 days (or 12 mg/kg once daily in children, maximum 500 mg) 2
- Clarithromycin: 250 mg twice daily for 10 days (or 7.5 mg/kg per dose twice daily in children, maximum 250 mg/dose) 2
- Macrolide resistance rates are 5-8% in the United States and vary geographically, according to the Centers for Disease Control and Prevention 2