Comparison between cephalexin two- and four-time per day regimens in group A streptococcal pharyngitis.

In previous studies, twice daily (bid) and four times daily (qid) administration of most antibiotics approved for group A streptococcus (GAS) pharyngitis therapy have been demonstrated to be equally effective. In this study, four investigators collaborated in a double-blind, randomized multicenter study assessing the efficacy of cephalexin given in doses of 1.0 g or 0.5 g daily on a bid or qid regimen for 10 to 14 days to 157 patients with GAS pharyngitis. The mean daily doses for patients on the bid and qid regimens were 30 mg/kg and 29 mg/kg, respectively. Pretreatment and two follow-up cultures, usually 2 to 6 and 12 to 16 days after the end of treatment, were taken on all patients. Failure, defined as recurrence of the original GAS M-precipitin and T-agglutination types on follow-up culture, occurred in 7.3 percent of 82 patients on the bid and 5.3 percent of 75 patients on the qid regimen. We conclude that cephalexin bid and qid regimens are equally effective, and that the bid regimen can be recommended for all antibiotics approved for GAS pharyngitis therapy.