API

Terbinafine (1% w/w)

Drug classification

Antifungal agent; allylamine subclass.

Dosage form

Topical cream containing terbinafine 1% w/w for external use.

API strength per dosage

Dose

Tyza Cream (terbinafine 1%) is typically applied once or twice daily to affected skin for 1–2 weeks, depending on the indication. For adults and children over 12 years; safety in younger children is not established. No dose adjustment is required for renal or hepatic impairment with topical use. Avoid contact with eyes.

Mechanism of action

Terbinafine inhibits the fungal enzyme squalene epoxidase, blocking ergosterol synthesis in the fungal cell membrane. This leads to accumulation of toxic squalene and disruption of membrane integrity, resulting in fungal cell death. It is fungicidal against dermatophytes and some other fungi.

Indications

Fungal skin infections

Side effects

Application site reactions burning irritation itching and redness Skin peeling Headache Diarrhea Rash Indigestion Abnormal liver enzyme Itching Taste change Nausea Abdominal pain Flatulence

Pregnancy category

Terbinafine topical use in pregnancy should be considered only if clearly needed; limited human data, animal studies show no teratogenicity. Consult healthcare provider.

Precautions

Avoid contact with eyes, mucous membranes, or broken skin, discontinue if irritation or allergic reaction occurs, use with caution in pregnancy and lactation, not for oral, ophthalmic, or intravaginal use, monitor for local adverse reactions, ensure full course completion, keep out of reach of children.

Contraindications

Hypersensitivity to terbinafine or any component of the formulation, history of allergic reactions to allylamine antifungals.