- What is terbinafine, and how does it work (mechanism of action)?
- What are the side effects of terbinafine?
- What is the dosage for terbinafine?
- Which drugs or supplements interact with terbinafine?
- Is terbinafine safe to take if I'm pregnant or breastfeeding?
- What else should I know about terbinafine?
What is terbinafine, and how does it work (mechanism of action)?
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.
What brand names are available for terbinafine?
Lamisil, Lamisil AT
Is terbinafine available as a generic drug?
Yes
Do I need a prescription for terbinafine?
Yes (Tablets), OTC (Topical preparations)
What are the side effects of terbinafine?
The most common side effects of terbinafine are:
Oral terbinafine can cause liver failure sometimes leading to liver transplantation or death.

IMAGES
Eczema Browse our medical image collection of allergic skin disorders such as psoriasis and dermatitis and more caused by allergies See ImagesWhat is the dosage for terbinafine?
- 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.
Which drugs or supplements interact with terbinafine?
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.
Is terbinafine safe to take if I'm pregnant or breastfeeding?
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.
Breastfeeding mothers should not use oral terbinafine because terbinafine passes into breast milk.
Summary
Terbinafine (Lamisil, Lamisil AT) is an antifungal medication prescribed for the treatment of fungal nails, jock itch, and athlete's foot. Side effects, drug interactions, warnings and precautions, and pregnancy safety information should be reviewed prior to using this medication.
Multimedia: Slideshows, Images & Quizzes
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Picture of Folliculitis
Folliculitis. Folliculitis affects skin around a hair follicle, usually causing tender, pus-filled inflammations. It can happen...
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Picture of Athlete's Foot 2
Athlete's foot is a fungus that causes itching, redness, and cracking. See a picture of Athlete's Foot and learn more about the...
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Picture of Fungal Nail Infection
Nails that are infected with a fungus may become discolored (yellowish-brown or opaque), thick and brittle, and may separate from...
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Picture of Types of Ringworm
Ringworm is a common skin disorder otherwise known as tinea. See a picture of Types of Ringworm and learn more about the health...
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Picture of Athlete's Foot 1
Athlete's foot is caused by a fungus that grows on or in the top layer of skin. See a picture of Athlete's Foot and learn more...
Related Disease Conditions
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Jock Itch
Jock itch is an itchy red rash that appears in the groin area. The rash may be caused by a bacterial or fungal infection. People with diabetes and those who are obese are more susceptible to developing jock itch. Antifungal shampoos, creams, and pills may be needed to treat fungal jock itch. Bacterial jock itch may be treated with antibacterial soaps and topical and oral antibiotics.
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Folliculitis
Folliculitis is a skin condition that causes small red bumps to form around the hair follicles. Skin bacteria such as Staphylococcus and Pseudomonas may infect the follicles. Treatment involves over-the-counter bacterial washes, topical antibiotics, and/or topical steroids.
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Ringworm
The term "ringworm" refers to a fungal infection on the surface of the skin. A physical examination of the affected skin, evaluation of skin scrapings under the microscope, and culture tests can help doctors make the appropriate distinctions. A proper diagnosis is essential to successful treatment. The different types of ringworm include the following: tinea barbae, tinea capitis, tinea corporis, tinea cruris, tinea faciei, tinea manus, tinea pedis, and tinea unguium.
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Fungal Nails
Fungal nails (onychomycosis) may be caused by many species of fungi, but the most common is Trichophyton rubrum. Distal subungal onychomycosis starts as a discolored area at the nail's corner and slowly spread toward the cuticle. In proximal subungal onychomycosis, the infection starts at the cuticle and spreads toward the nail tip. Yeast onychomycosis is caused by Candida and may be the most common cause of fungal fingernail.
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Athlete's Foot
Athlete's foot (tinea pedis) is a skin infection caused by the ringworm fungus. Symptoms include itching, burning, cracking, peeling, and bleeding feet. Treatment involves keeping the feet dry and clean, wearing shoes that can breathe, and using medicated powders to keep your feet dry.
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Ringworm vs. Eczema
While ringworm is a fungal infection, and eczema is a skin condition, both are characterized by itchiness. Eczema patches are leathery while ringworm involves ring formation on the skin. Over-the-counter antifungals treat ringworm. Topical creams and ointments treat eczema.
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Antibiotic Resistance (Drug Resistance, Antimicrobial Resistance)
Antibiotics are medications used to kill or slow the growth of bacteria and some fungi. The definition of antibiotic resistance is the ability of bacteria to change (mutate) and grow in the presence of a drug (an antibiotic) that would normally slow its growth or kill it. These antibiotic-resistant bacteria and fungi become harder to treat. Antibiotic-resistant infections can lead to longer hospital stays, higher treatment costs, and more deaths.
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
REFERENCE:
FDA Prescribing Information