What is Terbinafine used for?

Terbinafine is evaluated for the following indications with varying evidence strength: Onychomycosis (evidence tier A), Superficial fungal infections (evidence tier A), Severe nail fungus: topical-only treatment attempt (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Terbinafine?

Common side effects of Terbinafine (≥ 1 in 100): Dyspepsia, nausea, diarrhoea, Headache, Skin rash and pruritus, Taste disturbance or loss (may persist for weeks after discontinuation), Asymptomatic ALT and AST elevation. See the Safety section for uncommon and serious reactions.

Who should not take Terbinafine?

Terbinafine is contraindicated in: Hypersensitivity to terbinafine; Active liver disease or ALT/AST more than 3× upper limit of normal; Severe renal impairment (CrCl below 50 mL/min) for systemic forms; Children under 2 years of age. Full list in the Safety section.

FDA category B. FDA Category B. Systemic terbinafine in pregnancy is reserved for clinically significant indications; onychomycosis itself is not such an indication and treatment is usually deferred. Topical forms (cream, spray) have negligible systemic absorption and AEMPS considers them compatible with pregnancy. SEGO permits short topical courses for tinea pedis during gestation.

Onychomycosis

First line

Oral terbinafine 250 mg/day is first-line therapy for onychomycosis with matrix involvement or more than 50% nail plate disease. CKS Fungal nail infection 2023 and BAD 2018 recommend continuous courses: 6 weeks for fingernails and 12 weeks for toenails. Complete cure rates: toenails about 70%, fingernails about 80%. Pulse regimens (1 week on each month for 3-4 cycles) showed comparable efficacy in the Warshaw 2005 trial, but real-world adherence is lower and relapse rates higher; AEDV considers continuous therapy the standard. Topical forms (cream, spray, gel) do not penetrate the nail plate and are ineffective for onychomycosis. Monitor ALT and AST at 4-6 weeks because of drug-induced liver injury risk. If terbinafine was prescribed as a cream for nail fungus or as a short pulse course without discussion of continuous therapy, consider seeking a second opinion.

Superficial fungal infections

First line

Superficial dermatophyte infections (tinea pedis, corporis, cruris, capitis) are treated with terbinafine according to site. Tinea pedis and corporis: 1% cream once or twice daily for 1-2 weeks. Tinea capitis in children: oral tablets for 4-6 weeks, 2023 lists terbinafine as first line (replacing griseofulvin). Tinea unguium and persistent widespread forms: systemic tablets, as for onychomycosis. AEDV notes that tinea cruris and corporis usually respond to topical therapy; oral tablets are used when more than 5% of body surface is involved or topical therapy fails.

Sources

Severe nail fungus: topical-only treatment attempt

Not recommended

Terbinafine is an allylamine antifungal. As tablets it is first-line for onychomycosis. Terbinafine cream, spray or gel does not work for nail fungus: the molecule does not penetrate the nail plate at sufficient concentrations. CKS Fungal nail infection 2023 and BAD 2018: topical monotherapy in onychomycosis achieves complete cure rates of 0-12% and is not part of standard care. AEDV recommends oral tablets or a combination of tablets and antifungal lacquer (amorolfine 5%, ciclopirox 8%). The consumer marketing of «Lamisil cream for nail fungus» misleads patients. If terbinafine was prescribed as a cream for nail fungus, consider seeking a second opinion.

Sources

Contraindications

Hypersensitivity to terbinafine
Active liver disease or ALT/AST more than 3× upper limit of normal
Severe renal impairment (CrCl below 50 mL/min) for systemic forms
Children under 2 years of age

Serious adverse effects

Drug-induced liver injury, in rare cases fulminant hepatic failure
Agranulocytosis and thrombocytopenia
Depression and suicidal ideation
Stevens-Johnson syndrome and toxic epidermal necrolysis
DRESS syndrome

Common adverse effects

Dyspepsia, nausea, diarrhoea
Headache
Skin rash and pruritus
Taste disturbance or loss (may persist for weeks after discontinuation)
Asymptomatic ALT and AST elevation

PregnancyFDA B

FDA Category B. Systemic terbinafine in pregnancy is reserved for clinically significant indications; onychomycosis itself is not such an indication and treatment is usually deferred. Topical forms (cream, spray) have negligible systemic absorption and AEMPS considers them compatible with pregnancy. SEGO permits short topical courses for tinea pedis during gestation.

Breastfeeding

Systemic terbinafine is Hale L3 (probably compatible); it transfers into milk with RID about 4%. Short courses are acceptable under paediatric monitoring. Topical forms are Hale L2; do not apply to the nipple before a feed and wipe residue with warm water if used near the areola.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Terbinafine

Mechanism of action

Indications

Onychomycosis

Superficial fungal infections

Marketing claims without evidence base

Severe nail fungus: topical-only treatment attempt

Check interaction with another drug

Official sources

Safety