Onychomycosis
Fungal infection of the nail plate, most often on the feet. Caused by dermatophytes (Trichophyton rubrum), less often by yeasts and moulds. The nail thickens, turns yellow and crumbles. Mild forms are treated with antifungal lacquer (amorolfine, ciclopirox); matrix involvement and more than 50% plate involvement require systemic therapy (terbinafine, itraconazole) for 6–12 weeks.
ICD-10 B35.12 drugs
Also known as: Nail fungus, Tinea unguium
Drugs used for this condition
- AAmorolfineFirst line · Topical antifungal (morpholine class)Amorolfine 5% nail lacquer is first-line for mild onychomycosis: distal and lateral involvement of less than 50% of the nail plate, no matrix involvement and few affected nails. AEDV and NICE CKS Fungal nail infection 2023 recommend application 1–2 times per week for 6–12 months. Cochrane CD012093 (Iorizzo 2020): complete cure rates 17–54% depending on disease severity. Matrix involvement, more than 50% plate disease or multiple affected nails do not respond to lacquer monotherapy – systemic terbinafine or itraconazole is needed, sometimes combined with lacquer. If amorolfine was prescribed as monotherapy for severe nail disease, consider seeking a second opinion.
- ATerbinafineFirst line · Allylamine antifungal (systemic and topical)Oral terbinafine 250 mg/day is first-line therapy for onychomycosis with matrix involvement or more than 50% nail plate disease. NICE CKS Fungal nail infection 2023 and BAD 2018 recommend continuous courses: 6 weeks for fingernails and 12 weeks for toenails. Complete cure rates: toenails about 70%, fingernails about 80%. Pulse regimens (1 week on each month for 3–4 cycles) showed comparable efficacy in the Warshaw 2005 trial, but real-world adherence is lower and relapse rates higher; AEDV considers continuous therapy the standard. Topical forms (cream, spray, gel) do not penetrate the nail plate and are ineffective for onychomycosis. Monitor ALT and AST at 4–6 weeks because of drug-induced liver injury risk. If terbinafine was prescribed as a cream for nail fungus or as a short pulse course without discussion of continuous therapy, consider seeking a second opinion.
How to read tiers A–F
Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.
- AStrong evidence – first or second line in international guidelines
- BRecommended in selected cases
- CStudy data contradict each other
- DBenefit not proven, no documented harm
- FDocumented harm, or risk without benefit