What is the dose and frequency of terbinafine (Lamisil) for the treatment of onychomycosis (fungal infection of the nail)?

From the Guidelines

For onychomycosis, the recommended dose of terbinafine is 250 mg per day for 6 weeks in fingernail and 12–16 weeks in toenail infection, as it has been shown to be more effective and have higher tolerability compared to other treatments. This dosage is based on the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1. The guidelines suggest that terbinafine should be considered as the first choice of treatment unless there are contraindications, due to its higher efficacy and tolerability.

Some key points to consider when prescribing terbinafine for onychomycosis include:

• The medication should be taken continuously for the recommended duration, as intermittent or 'pulse' treatment regimens may not be as effective for all patients.
• Patients should be re-evaluated 3–6 months after treatment initiation and further treatment should be given if the disease persists.
• Terbinafine has been shown to have higher efficacy rates compared to itraconazole, with complete cure rates of 55% compared to 26% for pulsed itraconazole at follow-up at 72 weeks 1.
• Long-term effectiveness of treatment has also been demonstrated, with mycological cure without a second therapeutic intervention found in 46% of terbinafine-treated patients compared to 13% of itraconazole-treated patients at the end of a 5-year blinded prospective follow-up study 1.

It is essential to monitor patients for potential side effects, including rare hepatotoxicity, and to advise them on the importance of completing the full treatment course to ensure optimal outcomes.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Fingernail onychomycosis: One 250 mg tablet, once daily for 6 weeks. Toenail onychomycosis: One 250 mg tablet, once daily for 12 weeks

The dose and frequency of terbinafine for onychomycosis is:

• Fingernail onychomycosis: 250 mg once daily for 6 weeks
• Toenail onychomycosis: 250 mg once daily for 12 weeks 2

From the Research

Dose and Frequency of Terbinafine for Onychomycosis

• The recommended dose of terbinafine for onychomycosis is 250 mg/day 3, 4, 5.
• The treatment duration can vary from 6 to 24 weeks, with 12 weeks being sufficient for toenail onychomycosis 4.
• A pulse regimen of 500 mg/day for 1 week, every 4 weeks, has also been shown to be effective 6, 7.
• A quarterly terbinafine pulse regimen, with 500 mg/day for 7 days every 3 months, can be a possible alternative for treating onychomycosis caused by dermatophytes 6.
• The pulsed regimen has been found to be at least as effective as continuous dosing, with fewer side effects and lower cost 7.

Treatment Duration and Efficacy

• A treatment period of 12 weeks has been shown to be sufficient for toenail onychomycosis, with a complete cure rate of 82% 4.
• A 24-week treatment period has been found to have a complete cure rate of 85% 4.
• The mycological and clinical cure rates have been found to be higher with terbinafine compared to other treatments, such as itraconazole and griseofulvin 3, 5.

Safety and Tolerability

• Terbinafine has been found to be generally well tolerated, with few side effects reported 3, 4, 5, 7.
• The most common adverse events are gastrointestinal complaints, such as nausea and diarrhea 3.
• Terbinafine has a low potential for drug interactions, making it a safe choice for patients with other medical conditions 3, 5.