Clinical and pharmacokinetic studies of continuous itraconazole for the treatment of onychomycosis

Itraconazole, a triazole antifungal agent, has been widely used for onychomycosis with high cure rates. Unchanged itraconazole and a major metabolite hydroxy-itraconazole reach the nail with a strong affinity for keratin. The aim of this study was to elucidate clinical effectiveness and pharmacokinetic profiles of a 6-month continuous itraconazole treatment at a daily dose of 100 mg. Nail growth, the decrease in nail turbidity, and the nail concentrations of unchanged- and hydroxy-itraconazole were investigated. The affected nails we examined demonstrated nail growth proportional to the decrease in turbidity and a quick increase in drug concentration with a long duration of a high concentration after cessation. Our results support the hypothesis that this continuous therapy is a good modality for onychomycosis.