Antifungal Medications: Oral & Topical Treatments for Nail Fungus, Yeast Infections, Ringworm & Systemic Fungal Infections

Antifungal medications treat infections caused by fungi, including skin conditions such as ringworm (tinea), nail fungus (onychomycosis), oral and vaginal thrush (Candida), and more serious systemic mycoses. They fall into several classes — azoles, allylamines, polyenes, and echinocandins — each with distinct mechanisms, spectra of activity, and safety profiles. Some antifungals are available over the counter for topical use; others are prescription-only oral agents requiring liver monitoring due to hepatotoxicity risk.

Classes of Antifungal Medications

• Allylamines (e.g., terbinafine) — inhibit ergosterol synthesis at the squalene epoxidase step; fungicidal against dermatophytes; preferred for nail fungus
• Azoles (e.g., ketoconazole, fluconazole, itraconazole) — inhibit CYP51 (lanosterol 14-demethylase) in the ergosterol pathway; broad spectrum including Candida and dermatophytes
• Polyenes (e.g., amphotericin B, nystatin) — bind directly to ergosterol in the fungal membrane; nystatin is used topically/orally for thrush; amphotericin B is IV-only for serious infections

Antifungal Medications at Lucas Clinic

• Lamisil (Terbinafine) 250 mg Tablets — prescription oral terbinafine for nail fungus (onychomycosis); OTC topical cream/gel/spray 1% for ringworm and athlete’s foot
• Nizoral (Ketoconazole) 200 mg Tablets — prescription oral ketoconazole for systemic fungal infections; FDA liver toxicity warning; OTC shampoo 1%; Rx shampoo 2%

OTC vs Prescription Antifungals

Many topical antifungal creams, gels, powders, and sprays are available over the counter for skin fungal infections: clotrimazole, miconazole, terbinafine 1%, and butenafine are all OTC options for athlete’s foot (tinea pedis), ringworm (tinea corporis), and jock itch (tinea cruris). However, oral antifungal tablets used for nail fungus, systemic infections, or resistant skin infections require a prescription. Oral ketoconazole in particular carries an FDA black box warning for serious hepatotoxicity and should only be prescribed when other treatments have failed.