terbinafine, Lamisil, Lamisil AT

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GENERIC NAME: terbinafine

BRAND NAME: Lamisil, Lamisil AT

DRUG CLASS AND MECHANISM: Terbinafine is an antifungal agent that is taken by mouth or applied to the skin. Terbinafine acts by interfering with the ability of fungi to make chemicals called sterols that are an important part of the membrane that surrounds fungal cells and holds them together. This weakens the cell membrane. Oral terbinafine is more effective for treating fungal nail infections than griseofulvin (Fulvicin; Gris-Peg) and itraconazole (Sporanox), two other antifungal agents used for treating fungal nail infections. Topical terbinafine was approved by the FDA in 1993. Terbinafine oral tablets were approved in 1996.

PRESCRIPTION: Yes (Tablets), OTC (Topical preparations)


PREPARATIONS: Tablets: 250 mg. Oral Granule: 125 and 187.5 mg. Cream, Gel, solution, or spray: 1%.

STORAGE: All formulations should be stored at room temperature, 15-30 C (59-86 F).


  • Tablets: Fungal infections of the toe, or fingernail, caused by the fungus, tinea unguium.
  • Topical formulations (cream, gel, spray, solution): Fungal infections of the skin including tinea pedis (athlete's foot), tinea corporis (ringworm), and tinea cruris (jock itch).


  • Tablets: The usual dose is 250 mg once daily for 6 weeks for treatment of the fingernails, and 12 weeks for treatment of toenails. Optimal results will not be seen for several months after treatment because it takes time for new healthy nails to grow. Terbinafine may be taken with or without food.
  • Cream, gel, spray, solution: Apply to affected area (s) once (jock itch, ringworm) or twice daily (athletes foot) for about for 1 week.

DRUG INTERACTIONS: Rifampin reduces oral terbinafine blood concentrations, potentially reducing the efficacy of terbinafine. Cimetidine (Tagamet) may increase oral terbinafine blood levels, potentially increasing side effects of terbinafine. Fluconazole (Diflucan) increases the blood levels of oral terbinafine by 52%-69%. Potentially leading to increased side effects.

PREGNANCY: There are no adequate studies in pregnant women. Since nail fungus treatment can be delayed until after pregnancy there is no reason to use oral terbinafine during pregnancy.

NURSING MOTHERS: Breastfeeding mothers should not use oral terbinafine because terbinafine passes into breast milk.

SIDE EFFECTS: The most common side effects of terbinafine are headache, cough, diarrhea, abdominal pain, hives, itching and altered taste and smell sensation. Oral terbinafine can cause liver failure sometimes leading to liver transplantation or death.

Reference: FDA Prescribing Information

Last Editorial Review: 2/15/2012

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