Guidelines for LFT Monitoring with Oral Terbinafine for Onychomycosis

Monitoring Recommendations

• The British Journal of Dermatology recommends obtaining a complete blood count (CBC) at baseline in patients with a history of heavy alcohol consumption, pre-existing hepatitis, history of hematological abnormalities, or in children, as terbinafine is not licensed for pediatric onychomycosis 1, 2
• The British Journal of Dermatology advises more vigilant monitoring of liver function tests (LFTs) in patients with pre-existing liver disease, those receiving concomitant hepatotoxic medications, or those on continuous therapy for more than one month 1, 3

Clinical Considerations

• The British Journal of Dermatology recommends a treatment duration of 250 mg daily for 6 weeks for fingernail infections and 12-16 weeks for toenail infections, with re-evaluation of patients 3-6 months after treatment initiation 1

Important Considerations

• The British Journal of Dermatology notes that terbinafine has minimal drug-drug interactions compared to azole antifungals, but a potentially significant interaction is with drugs metabolized by cytochrome P450 2D6 isoenzyme 1

Common Pitfalls to Avoid

• The British Journal of Dermatology recommends not to fail to monitor patients with risk factors more closely, such as those with a history of heavy alcohol consumption, pre-existing hepatitis, or concomitant use of hepatotoxic drugs 1