Hepatic Safety of Oral Terbinafine in Onychomycosis: Is Routine Monitoring of Liver Function Tests Necessary?

INTRODUCTION: Onychomycosis is the most common disease of the nail treated commonly with oral antifungals mainly with terbinafine, itraconazole, and fluconazole. Given concerns regarding the potential hepatotoxic effects of systemic antifungal therapy, our study aims to investigate the hepatic safety profile of terbinafine in patients with onychomycosis.
METHODS: A retrospective study was carried out at our dermatology clinic between October 2024 and February 2025. 150 patients (aged 18–65 years) with onychomycosis, who underwent liver function tests before and after two months of terbinafine (250 mg daily) treatment were included. Patients with known renal, liver, biliary, or pancreatic diseases, abnormal baseline liver function tests, or potential drug interactions were excluded. Aspartate transaminase (AST), alanine aminotransferase (ALT), and gamma-glutamyl transferase (GGT) were analyzed. P-values < 0.05 are considered as a level of significance.
RESULTS: 52 (34.7%) of the patients were female 98 (65.3%) were male, and the mean age was 48.53 ± 7.85 years. The mean age for females was 49.38 ± 7.73 years and 48.07 ± 7.91 years for males (p = 0.329). The mean ALT values were 30.74 ± 11.94 IU/L pre-treatment and 32.41 ± 12.15 IU/L post-treatment (p = 0.169). AST values were 26.45 ± 10.46 IU/L pre-treatment and 28.17 ± 8.60 IU/L post-treatment (p = 0.055), while GGT levels were 35.21 ± 13.65 IU/L pre-treatment and 35.87 ± 13.35 IU/L post-treatment (p = 0.084).
DISCUSSION AND CONCLUSION: After two months of treatment, oral terbinafine did not cause significant alterations in laboratory values among patients with onychomycosis. Based on our limited patient sample and short follow-up duration, baseline liver function testing may not be necessary in otherwise healthy patients; however, further prospective studies are needed to confirm this finding.