Reasons for failures in penicillin treatment of streptococcal tonsillitis and possible alternatives

Penicillin V has long been regarded as the treatment of choice in streptococcal tonsillitis. This is based on factors such as its good tolerability, generally mild side effects, sustained high activity against beta-hemolytic streptococci and low cost. Over the years the oral dosage prescribed has gradually increased; the recommended dosage in the treatment of streptococcal pharyngotonsillitis in Sweden is now 25 mg/kg body weight/day, divided into two doses and given for 10 days. 1,2 Despite this high dosage recurrence rates of 10 to 30% have been reported in Sweden as in other countries. 2-7 The reasons for this high failure rate have been attributed to several individual factors (Table I), but the multifactorial background should also be considered