Terbinafine is an antifungal medication used to treat infections caused by fungi, especially those that affect the skin and nails. It works by stopping the growth of fungi, helping the body clear the infection over time.
This medication is commonly prescribed for conditions like athlete’s foot, ringworm, and fungal nail infections. It is available in different forms, including tablets taken by mouth and creams or sprays applied directly to the skin.
Terbinafine is widely used in the United States and is generally effective when taken as prescribed. However, the length of treatment and safety depend on the type of infection and the form of terbinafine used.
Indications for use
Terbinafine is used to treat fungal infections such as:
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Toenail and fingernail fungal infections (onychomycosis)
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Athlete’s foot (tinea pedis)
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Ringworm of the body (tinea corporis)
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Jock itch (tinea cruris)
Oral terbinafine is typically prescribed for nail infections or more severe cases, while topical terbinafine is used for mild skin infections.
How to take it
Dosing for this medication depends on the form it is prescribe in:
1. Oral tablets
The typical adult dose of terbinafine is 250 mg once daily. Treatment usually lasts 6 weeks for fingernail infections and 12 weeks for toenail infections. Terbinafine tablets can be taken with or without food, but they should be taken at the same time each day for best results.
2. Oral granules
These may be prescribed for children and are usually sprinkled onto soft food and taken once daily. The dose depends on body weight.
3. Topical forms (cream, gel, spray)
Topical terbinafine is applied directly to the affected skin once or twice daily. Treatment usually lasts 1 to 2 weeks, depending on the infection. Topical terbinafine should be applied to clean, dry skin and used for the full recommended duration, even if symptoms improve early.
Possible side effects
Terbinafine is generally well tolerated, but some side effects may occur. Common side effects include headache, upset stomach, diarrhea, and skin rash. Less common but more serious side effects include changes in taste or smell, liver problems that may cause fatigue, nausea, or yellowing of the skin or eyes, blood-related disorders, and severe skin reactions. Liver-related side effects are rare but important, especially with oral terbinafine, and monitoring may be recommended in some cases.
Contraindications
Terbinafine should not be used in certain situations, including chronic or active liver disease and known allergy to terbinafine or any of its components. Caution is also advised for people who take medications that may interact with terbinafine, have a history of liver problems, or are pregnant or breastfeeding. A healthcare provider may assess potential risks before starting terbinafine treatment.
Terbinafine can interact with other medications by affecting how they are processed in the body. Examples include some antidepressants, beta-blockers, certain heart medications, and drugs metabolized by liver enzymes. These interactions may increase or decrease the effects of other medications, so a full medication review is important before starting terbinafine.
When to expect results
Improvement in skin infections may appear within a few days to weeks. Nail infections take longer to improve because the nail needs time to grow out, which can take several months. Even if symptoms improve early, completing the full course of terbinafine is important to help prevent the infection from returning.