PHARMACOLOGY

Pharmacotherapeutic Group: Antifungal agent

 Pharmacodynamic properties: NAFIN (Terbinafine) is an allylamine which has a broad spectrum of antifungal activity. It is highly lipophilic in nature and tends to accumulate in skin, nails, and fatty tissues. Terbinafine acts by inhibiting squalene epoxidase, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. This inhibition also results in an accumulation of squalene.The resultant high concentration of squalene and decreased amount of ergosterol are both thought to contribute to terbinafine's antifungal activity.

 Pharmacokinetic properties:

Absorption: Absorbed well from the GI tract; Bioavailability (oral): 40%, Minimal absorption (topical); Peak plasma concentrations: 2 hr (oral).

Distribution: Distributed into stratum corneum of the skin, nail plate, hair (concentrations higher than plasma) and breastmilk; Protein-binding: Extensive.

Metabolism: Hepatic; converted to inactive metabolites.

Excretion: Via urine; 17-36 hr (plasma elimination half-life); up to 400 hr (terminal elimination half-life) in prolonged therapy.

 INDICATIONS

Onychomycosis; Relieving itching, burning, cracking, and scaling associated with jock itch, athlete's foot, ringworm, and other fungal infections of the skin.

 DOSE

Topical:Apply the cream in the affected area once or twice daily. Duration of therapy: 1-2 wk to treat Tinea corporis and Tinea cruris; 1-wk course is for Tinea pedis; 2-wk course in cutaneous candidiasis and pityriasis versicolor

Oral: 250mg once daily; Duration of treatment:Infection of groin area, skin and feet: 2-4weeks; Onychomycosis: Fingernail: 6weeks; Toenail: 12weeks

 CONTRAINDICATIONS

Hypersensitivity; Severe renal or hepatic impairment; Lactation

 SPECIAL PRECAUTIONS

Pre-existing liver or renal impairment; Pregnancy

 ADVERSE DRUG REACTIONS

Topical: Burning, irritation; itching; blistering/ swelling/ oozing at the application site. Oral: Anorexia, nausea, abdominal pain, taste disturbances, diarrhoea, rash, urticaria. Potentially Fatal: Liver failure, Stevens-Johnson syndrome, neutropaenia.

 DRUG INTERACTIONS

Possible increase in levels in drugs metabolised by CYP450 2D6; Decreased terbinafine concentration with rifampicin; Increased terbinafine concentration with cimetidine

 PRESENTATION

NAFIN 250: Each box contains 10 blister packs of 10 tablets per strip (inner catch cover per 2 strips).

NAFIN CREAM: Each tube contains 10g of cream.