From the Guidelines
Fluconazole 450 mg per week for at least 6 months is a useful alternative for treating onychomycosis in patients who cannot tolerate terbinafine or itraconazole. This recommendation is based on the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1. The guidelines suggest that fluconazole has some activity against dermatophytes and some Candida species, and its long half-life allows for once-weekly dosing.
Key points to consider when using fluconazole for onychomycosis include:
- The treatment duration should be at least 6 months for toenail infections and 3 months for fingernail infections 1
- Higher doses (450 mg per week) and longer treatment durations are associated with higher cure rates 1
- Fluconazole appears to be less effective than itraconazole or terbinafine, but may be a useful alternative in patients who cannot tolerate these medications 1
- Common adverse effects of fluconazole include headache, skin rash, gastrointestinal complaints, and insomnia, and adverse effects leading to treatment discontinuation occur in up to 58% of patients receiving higher weekly doses 1
It is essential to monitor patients for potential side effects and drug interactions, as fluconazole inhibits several cytochrome P450 enzymes 1. Treatment success rates with fluconazole range from 47% to 62% in toenail infections and from 89% to 100% in fingernail infections, which is somewhat lower than terbinafine but still significant 1. Patients should be advised that visible improvement may take several months as healthy nail grows in to replace infected nail.
From the Research
Efficacy of Fluconazole for Onychomycosis
- Fluconazole has been evaluated as a treatment option for onychomycosis, with studies showing varying degrees of efficacy 2, 3, 4.
- A review of seven studies on fluconazole treatment for onychomycosis found that the drug was superior to placebo, with mycologic eradication rates ranging from 36% to 100% in placebo-controlled studies 2.
- However, fluconazole was found to be less effective than terbinafine and itraconazole in the treatment of onychomycosis, with a mycologic cure rate of 31.2% compared to 75% and 61.1%, respectively 2, 4.
Optimal Dosing Regimen
- A study analyzing the relationship between fluconazole doses, cure rates, and duration of therapy found that longer treatments, but not higher weekly doses, resulted in better cure rates for toenail onychomycosis 3.
- The study recommended a dose of 150 mg weekly for more than 6 months for the treatment of onychomycosis 3.
Comparison with Other Antifungal Agents
- A comparative study of fluconazole, itraconazole, and terbinafine found that terbinafine was the most effective treatment for onychomycosis, with a clinical cure rate of 81.3% compared to 77.8% and 37.5% for itraconazole and fluconazole, respectively 4.
- Another study found that itraconazole and terbinafine were effective against Scopulariopsis brevicaulis, a non-dermatophyte mold that can cause onychomycosis, while fluconazole was less effective 5.