Products
Terbinafine is commercially available in tablet form (Lamisil, generic). It has been approved in many countries since 1991.
Structure and properties
Terbinafine (C21H25N, Mr = 291.4 g/mol) is present in drugs as terbinafine hydrochloride, a white powder that is very sparingly soluble in water. It is an allylamine and naphthalene derivative.
Effects
Terbinafine (ATC D01BA02) has fungicidal properties against dermatophytes, molds, and certain dimorphic fungi. It inhibits ergosterol synthesis by inhibiting the enzyme squalene epoxidase. This leads to intracellular accumulation of squalene. Terbinafine distributes well into the skin and nails.
Indications
For the treatment of nail fungus of the fingernails and/or toenails caused by dermatophytes. Terbinafine is also approved for other fungal infections. This article refers to onychomycosis.
Dosage
According to the drug label. Tablets are taken once a day at the same time of day, regardless of meals. The duration of treatment for fingernails is 6 weeks, for toenails 3 months. After that, the nail must still grow out completely. A pulse therapy was also investigated. In this case, the medication is taken, for example, during one week of each month. The healing success was somewhat lower than with continuous use. Therapy breaks or alternative therapy regimens are possible in principle, however.
Contraindications
- Hypersensitivity
For complete precautions, see the drug label.
Interactions
Terbinafine is a substrate of several CYP isozymes and an inhibitor of CYP2D6. Corresponding drug-drug interactions are possible.
Adverse effects
The most common possible adverse effects include a loss of appetite, headache, gastrointestinal discomfort, rash, joint pain, and muscle pain.