Itraconazole. A reappraisal of its pharmacological properties and therapeutic use in the management of superficial fungal infections.

Abstract

Itraconazole is an orally administered triazole antifungal agent. Its spectrum of activity includes dermatophyte, dimorphic and dematiaceous fungi, yeasts, and some moulds. In clinical trials, mycological cure was attained in approximately 70 to 80, > or = 70 and > or = 80% of patients with, respectively, fingernail and toenail onychomycosis (200 mg/day for 3 months), dermatophytosis (100 mg/day for 2 to 4 weeks) and vaginal candidiasis (400 mg/day for 1 day or 200 mg/day for 3 days). Approximately 20 to 30% of patients with onychomycosis may relapse after completion of therapy; relapse rate data are limited for the other indications. Recently developed intermittent regimens of itraconazole (400 mg/day for 1 week per month for 3 to 4 months) appear to have similar efficacy to standard regimens in the treatment of onychomycosis. Shorter, higher dosage itraconazole treatment regimens (200 or 400 mg/day for 1 week) are also beneficial in dermatomycoses. Discrepancies and limitations of study design hamper conclusions about efficacy relative to other antifungal drugs. Newer intermittent and short course higher dosage itraconazole regimens have also not been evaluated in comparative studies. Available studies show that the efficacy of itraconazole appears to be greater than that of griseofulvin, but similar to or lower than that of terbinafine in patients with dermatophyte onychomycosis or cutaneous fungal infections. Moreover, the efficacy of itraconazole may be similar to or lower than that of fluconazole in the treatment of cutaneous mycoses. Comparative data from patients with acute vaginal candidiasis suggest that itraconazole is at least as effective as intravaginal clotrimazole and oral fluconazole, and superior to intravaginal econazole. These results require confirmation. Prescription-event monitoring data indicate that itraconazole is generally well tolerated. Gastrointestinal disturbances, dizziness and headache occur most commonly; liver toxicity has been rarely described. Its usefulness in some clinical situations may be limited because of its ability to interact with various therapeutic agents. In conclusion, itraconazole along with other established agents should be considered a first-line treatment for patients with extensive or recalcitrant cutaneous fungal infections, mixed dermatophyte and Candida onychomycosis or vaginal candidiasis. It is currently considered a second-line drug for dermatophyte onychomycosis; the use of newer intermittent itraconazole treatment regimens may, however, extend its role in the management of this condition. Although itraconazole offers greater benefit than conventional therapies (griseofulvin and ketoconazole) in terms of efficacy and tolerability, wider clinical experience is required to determine its merits relative to the newer agents, terbinafine and fluconazole.