Effectiveness and safety of oral terbinafine for dermatophyte distal subungual onychomycosis

ABSTRACT

Introduction

Terbinafine has been a cornerstone in dermatophyte infection treatment. Despite its global efficacy, the emergence of terbinafine resistance raises concerns, requiring ongoing vigilance.

Areas Covered

This paper focuses on evaluating the efficacy and safety of terbinafine in treating dermatophyte toenail infections. Continuous and pulse therapies, with a 24-week continuous regimen and a higher dosage of 500 mg/day have demonstrated superior efficacy to the FDA approved regimen of 250 mg/day x 12 weeks. Pulse therapies, though showing comparable effectiveness, present debates with regards to their efficacy as conflicting findings have been reported. Safety concerns encompass hepatotoxicity, gastrointestinal, cutaneous, neurologic, hematologic and immune adverse-effects, and possible drug interactions, suggesting the need for ongoing monitoring.

Expert Opinion

Terbinafine efficacy depends on dosage, duration, and resistance patterns. Continuous therapy for 24 weeks and a dosage of 500 mg/day may enhance outcomes, but safety considerations and resistance necessitate individualized approaches. Alternatives, including topical agents and alternative antifungals, are to be considered for resistant cases. Understanding the interplay between treatment parameters, adverse effects, and resistance mechanisms is critical for optimizing therapeutic efficacy while mitigating resistance risks. Patient education and adherence are vital for early detection and management of adverse effects and resistance, contributing to tailored and effective treatments.

KEYWORDS:

• Terbinafine
• continuous therapy
• pulse therapy
• terbinafine efficacy
• terbinafine safety
• onychomycosis

Article highlights

• Terbinafine, introduced in the 1990s, is a widely used oral antifungal for dermatophyte infections, particularly onychomycosis.

• Increasing reports of terbinafine resistance globally highlight the need for continual monitoring and adaptation of treatment strategies.

• Continuous and pulse therapies for onychomycosis with terbinafine are explored, with conflicting findings on their comparative efficacy and cost-effectiveness.

• Special populations, such as HIV patients and transplant recipients, can benefit from terbinafine treatment with careful monitoring for systemic abnormalities.

• Safety concerns include hepatotoxicity, drug interactions, nephrotoxicity, hematologic and immune side effects, neurological side effects, and cutaneous reactions.

• Terbinafine efficacy against dermatophyte infections is dose-dependent, with considerations for treatment duration, potential variations in effectiveness based on therapy regimens, and adverse effects based on patient parameters.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14656566.2024.2305304

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.