Clinical and pharmacokinetic investigations of oral terbinafine in patients with tinea unguium.

A clinical trial of once-daily administration of a 125-mg tablet of terbinafine, an oral antimycotic agent, was performed on patients with tinea unguium to evaluate its efficacy, safety, possible side-effects and its incorporation into nails and hair. Thirty-four patients were recruited into the study. For the statistical analysis, one of these patients was used only for the safety rating. Accordingly, 33 patients were used for the efficacy rating, and all 34 patients were employed for the safety rating. The efficacy rating in the overall efficacy evaluation was 90.9% (30/33). No adverse effects, including abnormal changes in laboratory test values, were observed. A pharmacokinetic study revealed that terbinafine was detected in the nail tissue at and after week 2. It reached 0.78 ng mg-1 at the end of week 12 and remained at almost the same level thereafter. Terbinafine was also detected in hair at and after week 23. The average value was 3.14 ng mg-1. The plasma concentration of the drug reached a steady state (280.3 ng ml-1) at approximately week 10, and no tendency to further accumulation was noted. These results confirm the favourable incorporation of terbinafine into nail and hair. On the basis of these results, it was concluded that the drug demonstrates excellent efficacy and satisfactory safety in patients with tinea unguium. The pharmacokinetic investigation also demonstrated its excellent treatment efficacy.