Terbinafine is an antifungal medication that inhibits squalene epoxidase, an enzyme in the ergosterol synthesis pathway. Terbinafine is used to treat tinea infections. Most notably, terbinafine can treat onychomycosis if used in an oral form. Side effects associated with oral use of terbinafine include GI upset, loss of sense of taste, headache, and hepatotoxicity.

Key Points

  • Terbinafine
    • Mechanism
      • Inhibits fungal enzyme squalene epoxidase
        • Inhibits synthesis of lanosterol, a precursor to ergosterol, which forms fungal cell membrane
      • Cleared via liver metabolism
    • Clinical Use
      • Dermatophytosis (tinea)
        • Especially onychomycosis - fungal infections of nails
      • Paracoccidioidomycosis
      • Seborrheic dermatitis
    • Adverse Effects
      • Headache
        • Seen in ~7-13% of patients
      • Loss of taste (dysgeusia)
        • Seen in ~3% of patients
        • May be severe and lead to weight loss, depression, anxiety
      • Hepatotoxicity
        • Seen in ~3% of patients
      • GI upset
        • Diarrhea and vomiting seen in ~1-6% of patients