From the Research
Oral terbinafine is typically prescribed at a dose of 250 mg once daily for 2-4 weeks in adults for the treatment of tinea corporis. This recommendation is based on the most recent and highest quality study available, which compared the efficacy and safety of 250 mg versus 500 mg oral terbinafine in the treatment of tinea corporis and cruris 1. The study found that there was no significant difference in clinical parameters between the two groups, and that oral terbinafine 250 mg daily yielded a poor cure rate in tinea cruris and corporis after 4 weeks of treatment. However, other studies have shown that oral terbinafine is effective in the treatment of tinea corporis, with mycological cure rates ranging from 80-90% 2, 3, 4. It is generally recommended that children weighing 20-40 kg receive 125 mg daily, while those weighing less than 20 kg should take 62.5 mg daily for the same duration. Treatment should continue until clinical resolution is achieved, and patients should be advised to take the medication with food to minimize gastrointestinal side effects and to complete the full course of treatment even if symptoms improve before completion. Liver function tests should be considered before initiating therapy, especially for treatment courses longer than 2 weeks or in patients with pre-existing liver disease. Common side effects of oral terbinafine include headache, gastrointestinal disturbances, and rash. Some key points to consider when prescribing oral terbinafine for tinea corporis include:
- The medication is generally reserved for extensive disease, immunocompromised patients, or cases that have failed topical therapy
- Topical antifungals are the first-line treatment for most uncomplicated tinea corporis infections
- Terbinafine works by inhibiting the enzyme squalene epoxidase, disrupting fungal cell membrane synthesis
- Patients should be monitored for signs of terbinafine resistance, particularly in cases of recurrent or refractory disease 5.