Does terbinafine cause liver damage?
Terbinafine, an antifungal used for nail and skin infections like onychomycosis, can cause liver damage in rare cases. Hepatotoxicity occurs in about 1 in 50,000 to 120,000 patients, typically as elevated liver enzymes or, rarely, acute liver injury.[1][2] Most cases are reversible if caught early, but severe outcomes like liver failure have been reported, sometimes fatal.[3]
How common is liver damage from terbinafine?
Liver issues are uncommon. Clinical trials showed enzyme elevations in 3-4% of patients, but serious damage affects far fewer—post-marketing data from the FDA reports 1-2 cases per 100,000 prescriptions.[1][4] Risk is higher with longer treatment (over 6 weeks) or higher doses.[2]
What are the signs of liver problems on terbinafine?
Watch for jaundice (yellow skin/eyes), dark urine, pale stools, nausea, fatigue, or abdominal pain. These usually appear within 4-6 weeks of starting.[3] Routine liver tests are recommended before and during the first month of therapy.[1]
Who is at higher risk for liver damage?
People with pre-existing liver disease, heavy alcohol use, or concurrent drugs like statins or other hepatotoxins face elevated risk. Age over 65 or obesity may also contribute. Avoid in active liver conditions.[2][5]
What happens if liver enzymes rise?
Mild elevations often resolve without stopping the drug, but levels over 2-3 times normal require immediate discontinuation. Biopsy-confirmed cases show patterns like cholestatic hepatitis.[3] Recovery occurs in 90%+ of cases after stopping.[4]
How do doctors monitor for this?
Guidelines from the American Academy of Dermatology recommend baseline liver function tests (ALT, AST) and monitoring at 4-6 weeks. No need for ongoing tests if normal.[1][5] Patient education on symptoms is standard.
Can you take terbinafine with liver concerns?
Not if you have acute or chronic liver disease. Alternatives like itraconazole or fluconazole may be considered, though they carry similar risks. Topical antifungals avoid systemic exposure.[2]
Why does terbinafine affect the liver?
It inhibits fungal squalene epoxidase but can disrupt human cholesterol synthesis in hepatocytes, leading to oxidative stress and cell damage. Idiosyncratic reactions (immune-mediated) explain most severe cases, not dose-related toxicity.[3][6]
[1]: FDA Label for Lamisil (terbinafine)
[2]: LiverTox: Terbinafine
[3]: NEJM: Hepatotoxicity of Antifungals
[4]: FDA Adverse Event Reporting System (FAERS) Summary
[5]: AAD Guidelines on Onychomycosis
[6]: Drug Safety: Terbinafine Hepatotoxicity