A pilot evaluation of pulse itraconazole vs. terbinafine for treatment of Candida toenail onychomycosis.

摘要

Onychomycosis, a fungal infection of the nail bed, is responsible for approximately 50% of all nail dystrophies and is most commonly caused by dermatophytes. Onychomycosis due to yeasts, such as Candida, is relatively rare, ranging from 1.7% of toenail infections (15/1177) to 2.9.2.% of fingernail infections (14/62). In a Middle Eastern study of 151 individuals, Candida species accounted for 81% of isolates.While many studies have evaluated the efficacy of oral antifungal agents for treatment of onychomycosis caused by dermatophytes, few studies have evaluated the efficacy of oral antifungal agents for onychomycosis due to Candida. Itraconazole (Jonssen Pharmaceutica Products, Titusville, NJ), terbinafine (Novartis Pharmaceuticals Corporation, East Hanover, NJ), and fluconazole (PFIZER Inc., New York, NY) all have in vitro activity against Candida species; generally, the minimum inhibitory concentration (MIC) is lowest for itraconazole, followed by fluconazole and then terbinafine. In a recent open-label trial, 44 patients with Candida onychomycosis (fingernail and/or toenail involvement) were treated with itraconazole pulse therapy (400 mg/day for 1 week of each month for 3 months). Mycological cure was achieved in 29 of 32 patients with toenail disease (90.6%) and in 12 of 12 patients with fingernail involvement (100%). Complete cure or marked improvement (mycological curewith 75% or greater decrease in target nail involvement) was reported in 2.4 of 32 patients with toenail disease (75%) and in 11 of 12. patients with fingernail involvement (91.7%). Another study by Lebwohl and colleagues evaluated the use of terbinafine 250 mg daily for 12 or 24 weeks in individuals with toenail onychomycosis caused by nondermatophytes. Of the 23 individuals with Candida, 21 (91.3%) achieved mycological cure and 10 (43.5%) achieved complete cure (mycological cure plus 100% normal target toenail). Segal and colleagues evaluated 16 weeks of terbinafine (250 mg daily) in 20 patients with Candida toenail and fingernail infections. A toenail was chosen as the target nail in three patients; of these three patients, only one had a complete cure (33.3%). Complete cure was reported in 85 of the 126 (67.5%) infected toenails which were not designated as target toenails. Zaidi and colleagues reported a 33% complete cure rate in 15 patients with Candida onychomycosis when using a higher dose of terbinafine, 500 mg daily for 16 weeks.While in vitro studies support the use of azole antifungals, in the treatment of onychomycosis due to Candida, medication interactions with these agents often preclude their use. Terbinafine has fewer drug interactions. The purpose of this pilot study was to compare treatment with oral terbinafine and pulse itraconazole for toenail onychomycosis caused by Candida.