From the Guidelines
Terbinafine is the preferred treatment option over clotrimazole for dermatophyte infections, including onychomycosis, due to its higher efficacy and tolerability. Clotrimazole and terbinafine are both effective antifungal medications, but they work differently and are often used for different types of fungal infections. Clotrimazole is an azole antifungal that works best for superficial yeast infections like candidiasis, while terbinafine (an allylamine) is typically more effective for dermatophyte infections like athlete's foot, ringworm, and nail fungus.
Key Differences
- Clotrimazole is often used for superficial yeast infections, whereas terbinafine is preferred for dermatophyte infections.
- Terbinafine has been shown to be more effective than itraconazole in treating dermatophyte onychomycosis, with higher efficacy rates and lower relapse rates 1.
- The recommended dosage for terbinafine is 250 mg per day for 6 weeks in fingernail and 12–16 weeks in toenail infection, with patients being re-evaluated 3–6 months after treatment initiation 1.
Treatment Options
- For dermatophyte infections, terbinafine cream 1% applied once or twice daily for 1-2 weeks (for skin infections) or oral terbinafine 250mg daily for 6 weeks (fingernails) to 12 weeks (toenails) for nail infections is typically more effective.
- Clotrimazole works by disrupting fungal cell membrane formation, while terbinafine blocks ergosterol synthesis by inhibiting the enzyme squalene epoxidase, making it particularly effective against dermatophytes.
Side Effects
- Side effects for topical formulations of both medications are minimal, typically limited to mild skin irritation, while oral terbinafine may cause headache, gastrointestinal upset, and rarely liver problems requiring monitoring 1.
From the Research
Comparison of Clotrimazole and Terbinafine
- Clotrimazole is compared to terbinafine in several studies, with terbinafine showing greater efficacy in treating dermatophyte infections 2, 3
- Terbinafine is more effective than clotrimazole 1% cream in achieving mycological cure in patients with tinea pedis, tinea corporis/cruris, cutaneous candidiasis, and pityriasis versicolor 2
- However, in a cost analysis, initial therapy with terbinafine 1% cream was more costly than initial therapy with clotrimazole in the management of tinea pedis 3
- In cost-effectiveness studies, terbinafine had a lower cost per disease-free day than clotrimazole in the treatment of dermatophyte skin infections 3
Efficacy of Terbinafine
- Terbinafine is effective in treating a wide range of superficial dermatophyte infections, including onychomycosis, tinea pedis, and tinea corporis/cruris 4, 2
- Terbinafine has fungicidal activity against dermatophytes, with a low minimal inhibitory concentration (MIC) and a high minimal fungicidal concentration (MFC) ratio of 1:1 4
- Terbinafine is also effective in treating pityriasis versicolor and vaginal candidosis, but only when used topically 4