to the editor: There are three points I would like to make regarding the article¹ on streptococcal pharyngitis.

First, the authors attribute azithromycin's “once daily dosing” and “shorter treatment course” to its “extended spectrum.” The duration of therapy and timing of doses are consequences of the pharmacokinetic properties of the compound, not the antimicrobial spectrum. Specifically, the half-life of azithromycin in many tissues is as long as two to four days, resulting in antimicrobial activity for five days or more after a typical five-day course.²

Second, I would take exception to the authors' inclusion of penicillin resistance among the theories for treatment failures. As Bromberg³ notes in the accompanying editorial, resistance to penicillin has not been documented in a clinical setting.^4,5

Third, in an era with increasing antibiotic resistance, I would support the authors' proposal of reserving cephalosporins and other, more broad-spectrum antibiotics for treatment failures. The authors cite a study showing a 92 percent bacteriologic cure rate with a cephalosporin compared to 84 percent with penicillin.¹ This 8 percent difference translates to needing to treat an average of 12.5 patients with cephalosporin to prevent one penicillin-associated treatment failure.

editor's note: This letter was sent to the authors of “Management of Group A Beta-Hemolytic Streptococcal Pharyngitis,” who did not reply.