From the Guidelines
Yes, cephalexin (Keflex) can be used to treat Streptococcus pyogenes (Group A streptococcus) infections. The typical dose for children is 20 mg/kg/dose twice daily (max = 500 mg/dose) for 10 days, as recommended by the Infectious Diseases Society of America 1. For adults, the dose is not explicitly stated in the provided evidence, but it is generally recommended to consult a healthcare professional for proper diagnosis and treatment. Cephalexin is considered a suitable alternative for individuals with penicillin allergy, but it is essential to note that it should be avoided in individuals with immediate-type hypersensitivity to penicillin 1.
- The evidence suggests that cephalexin is effective against Streptococcus pyogenes, but it is not the first-line treatment 1.
- Other antibiotics like penicillin or amoxicillin are considered first-line treatments for strep throat, and cephalexin may be recommended as an alternative in cases of penicillin allergy 1.
- It is crucial to consult a healthcare professional for proper diagnosis and treatment, as they can recommend the most suitable antibiotic and dosage based on individual patient needs 1.
From the FDA Drug Label
Cephalexin is indicated for the treatment of the following infections when caused by susceptible strains of the designated microorganisms: Respiratory tract infections caused by Streptococcus pneumoniae and Streptococcus pyogenes Cephalexin has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section Aerobes, Gram-positive: ... Streptococcus pyogenes
Cephalexin can treat Streptococcus pyogenes (Group A streptococcus) infections when the strain is susceptible to the drug.
- The drug label indicates that cephalexin is effective against Streptococcus pyogenes in respiratory tract infections and other infections.
- However, culture and susceptibility tests should be performed to confirm the effectiveness of cephalexin against the specific strain of Streptococcus pyogenes causing the infection 2.
From the Research
Cephalexin Effectiveness Against Streptococcus pyogenes
- Cephalexin has been shown to be effective in treating Streptococcus pyogenes (Group A streptococcus) infections, with studies demonstrating its efficacy in pharyngitis and tonsillitis due to beta-haemolytic streptococci 3.
- A randomized, double-blind, crossover study found that cephalexin was more effective than penicillin in the treatment of group A beta-hemolytic streptococcal throat infections in children, with lower rates of symptomatic clinical failure and bacteriologic failure 4.
- Another study compared the efficacy of cephalexin given in doses of 1.0 g or 0.5 g daily on a twice-daily (bid) or four-times-daily (qid) regimen for 10 to 14 days in patients with group A streptococcal pharyngitis, and found that the bid and qid regimens were equally effective 5.
Comparison with Other Antibiotics
- A prospective open-label, observational cohort study compared the bacteriologic and clinical efficacy of oral cephalexin twice vs. three times daily vs. cefadroxil once daily as therapy for group A beta-hemolytic streptococcal tonsillopharyngitis, and found that all three regimens were equivalent in terms of bacteriologic and clinical cure 6.
- While penicillin is considered the treatment of choice for streptococcal pharyngitis due to its cost, narrow spectrum of activity, and effectiveness, first-generation cephalosporins like cephalexin are recommended as an alternative for patients with penicillin allergy, and some advocate for their use in all nonallergic patients due to better eradication of group A beta-hemolytic streptococcus 7.
Treatment Regimens
- Cephalexin can be administered in various dosages and regimens, including 1-2 g/day in adults and 20-100 mg/kg/day in children, with twice-daily or four-times-daily regimens being equally effective 3, 5.
- The duration of treatment is typically 10 days, although some studies have used shorter or longer treatment courses 4, 6.