Doubled dose of oral terbinafine is required for Microsporum canis tinea capitis

Fourteen children, ages 1-15 years, with Microsporum canis tinea capitis we re given oral terbinafine for 4 weeks at the recommended daily dose accordi ng to their weight: 10-20 kg, 62.5 mg; 20-40 kg, 125 mg; >40 kg, 250 mg. Be cause none of the patients had clinically responded to treatment by week 4 the dose of terbinafine was doubled (up to 250 mg) for an additional 4-8 we eks in six patients, and continued at the original dose in six patients. Tw o patients dropped out of the study. On final evaluation, four patients wer e cured after 8-12 weeks of treatment. All cured patients received the doub led dose of terbinafine, except for one who was on the usual adult dose of 250 mg from the onset. Oral terbinafine was well tolerated by all but one p atient, who experienced gastrointestinal disturbance and slightly raised tr ansaminase levels during the first 4 weeks of treatment. Terbinafine side e ffects were not correlated with dosage or duration of treatment. We conclud e that oral terbinafine should be dosed for M. canis tinea capitis at a rev ised schedule according to body weight: 10-25 kg, 125 mg/day and > 25 kg, 2 50 mg/day. The appropriate duration of terbinafine treatment remains to be determined.