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DERMATOLOGICALS › ANTIFUNGALS FOR DERMATOLOGICAL USE › ANTIFUNGALS FOR TOPICAL USE › Other antifungals for topical use
terbinafine
D01AE15
Forms & Strengths
- Oral tablets: 250 mg
- Topical cream: 1%
- Topical gel: 1%
- Topical spray: 1%
Adult Dosing
- Onychomycosis (fingernail): 250 mg orally once daily for 6 weeks
- Onychomycosis (toenail): 250 mg orally once daily for 12 weeks
- Tinea pedis / corporis / cruris (oral): 250 mg orally once daily for 2 to 4 weeks
- Tinea pedis (topical): Apply to affected area twice daily for 1 week or once daily for 1 week (depending on formulation)
Pediatric Dosing
- Tinea capitis (children >= 4 years): 10-20 kg: 62.5 mg once daily; 20-40 kg: 125 mg once daily; > 40 kg: 250 mg once daily for 6 weeks
- Topical formulations: Safety and efficacy not well established in children < 12 years
Indications
- Fungal infections of the skin caused by dermatophytes (tinea corporis, tinea cruris, tinea pedis)
- Onychomycosis of the toenail or fingernail due to dermatophytes (onychomycosis)
- Tinea capitis (oral formulation)
Mechanism of Action
- Synthetic allylamine antifungal agent that inhibits fungal squalene epoxidase
- Inhibition of squalene epoxidase leads to a deficiency in ergosterol and an intracellular accumulation of squalene
- Results in fungal cell death through both ergosterol depletion and squalene-induced toxicity
Contraindications
- Hypersensitivity to terbinafine or any component of the formulation
- Chronic or active hepatic disease (due to risk of severe hepatotoxicity)
Adverse Reactions
- Headache
- Gastrointestinal upset (diarrhea, dyspepsia, nausea, abdominal pain)
- Taste disturbance (ageusia/dysgeusia, can be prolonged)
- Elevated serum transaminases and severe hepatotoxicity
- Skin reactions (rash, urticaria, rare cases of Stevens-Johnson syndrome and toxic epidermal necrolysis)
- Neutropenia and thrombocytopenia (rare)
Drug Interactions
- CYP2D6 substrates: Terbinafine is a strong inhibitor of CYP2D6, potentially increasing plasma concentrations of tricyclic antidepressants, SSRIs, beta-blockers, and antiarrhythmics
- CYP inducer/inhibitors: Drugs that induce CYP enzymes (e.g., rifampin) may decrease terbinafine blood levels
- Cimetidine: May increase terbinafine plasma concentrations
- Caffeine: Terbinafine decreases clearance of caffeine
Curated Content: Needs Vetting Before Put to Clinical Use