From the Guidelines
Terbinafine can be used with caution in patients with slightly elevated ALT levels, but it is essential to obtain baseline liver function tests and monitor closely for any signs of liver dysfunction. According to the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1, terbinafine is not recommended in patients with active or chronic liver disease, but it can be considered in patients with mildly elevated ALT levels. The guidelines suggest that baseline liver function tests and a complete full blood count are recommended in patients with a history of heavy alcohol consumption, hepatitis, or haematological abnormalities.
Some key points to consider when using terbinafine in patients with slightly elevated ALT levels include:
- Monitoring liver function tests regularly, typically at 4-6 week intervals during treatment 1
- Discontinuing the medication if ALT rises to 3 times the upper limit of normal or if symptoms of liver dysfunction develop
- Considering alternative antifungal treatments like topical options or itraconazole (with appropriate monitoring) for patients with pre-existing liver disease or persistent ALT elevation
- Being aware of the potential for terbinafine to cause hepatotoxicity in approximately 0.1% of patients, as reported in the guidelines 1
The standard oral dose of terbinafine is 250 mg daily, typically for 6 weeks for fingernail infections and 12 weeks for toenail infections 1. Patients should be warned about the potential for taste disturbance, which can be permanent, and should be advised to stop the medication immediately and seek medical attention if they develop symptoms like fatigue, nausea, abdominal pain, dark urine, or jaundice.
From the FDA Drug Label
5.1 Hepatotoxicity ... Terbinafine tablets are not recommended for patients with chronic or active liver disease ... Measurement of serum transaminases (ALT and AST) is advised for all patients before taking terbinafine tablets. 5.8 Laboratory Monitoring Measurement of serum transaminases (ALT and AST) is advised for all patients before taking terbinafine tablets.
Terbinafine is not recommended for patients with chronic or active liver disease. Although it is advised to measure serum transaminases (ALT and AST) before taking terbinafine tablets, the label does not explicitly state that a slightly high ALT is a contraindication. However, as a conservative clinical decision, it is recommended to exercise caution and consider alternative treatments or closely monitor liver function if terbinafine is prescribed to a patient with slightly high ALT levels 2.
From the Research
Terbinafine and Elevated ALT Levels
- Terbinafine is an oral antifungal medication used to treat onychomycosis, a fungal infection of the nails 3, 4.
- Elevated alanine aminotransferase (ALT) levels are a concern when taking terbinafine, as they can indicate liver damage 5, 6.
- A study published in 2023 found that 8.4% of patients taking terbinafine had elevated ALT levels, while another study published in 2018 found that elevations in ALT measurements were detected infrequently and were comparable to baseline detection rates 3, 7.
- The same study in 2018 concluded that routine interval laboratory test result monitoring appears to be unnecessary in adults and children without underlying hepatic or hematologic conditions taking terbinafine for dermatophyte infections 7.
- However, another study published in 2023 recommends laboratory testing of liver function tests prior to the administration of any oral antifungals, especially when clinically indicated 4.
Contraindications and Precautions
- There is no clear contraindication for terbinafine in patients with slightly elevated ALT levels, but caution and monitoring are advised 3, 4.
- Patients with elevated ALT levels should be closely monitored for signs of liver damage, and terbinafine should be used with caution in patients with pre-existing liver conditions 5, 6.
- It is essential to consider the benefits and risks of terbinafine treatment in patients with elevated ALT levels and to monitor liver function tests regularly 4, 7.