API

Terbinafine (1% w/w)

Drug classification

Antifungal agent; allylamine subclass.

Dosage form

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

API strength per dosage

Dose

Apply a thin layer of Terbinafine 1% cream once or twice daily to affected skin, usually for 1–2 weeks depending on infection type. For adults and children over 12 years. Safety and efficacy in children under 12 not established. Use with caution in hepatic impairment; no dose adjustment for renal impairment. Avoid contact with eyes.

Mechanism of action

Terbinafine in Terbinaforce Cream 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.

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

Safety of topical terbinafine in pregnancy is not well established; use only if potential benefits justify potential risks to the fetus. Avoid extensive use.

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 area is clean and dry before application, avoid occlusive dressings.

Contraindications

Hypersensitivity to terbinafine or any excipients, active or chronic liver disease, caution in pregnancy and lactation, avoid ocular, oral, or intravaginal use, not for use in children unless prescribed.