From the FDA Drug Label
Before prescribing terbinafine tablets, liver function tests should be performed since hepatotoxicity may occur in patients with and without pre-existing liver disease. Periodic monitoring of liver function tests is recommended. Terbinafine tablets should be immediately discontinued in case of elevation of liver function tests Measurement of serum transaminases (ALT and AST) is advised for all patients before taking terbinafine tablets.
The patient is currently taking Terbinafine 250 QD for 90 days. Given the information from the drug label, it is recommended to:
- Monitor liver function tests periodically while the patient is on terbinafine tablets.
- Discontinue terbinafine tablets immediately if there is an elevation of liver function tests. It is also advised to measure serum transaminases (ALT and AST) before taking terbinafine tablets. Since the liver and kidney profile was not performed last time, it should be done now to establish a baseline before continuing treatment with terbinafine tablets 1 1.
From the Research
I strongly recommend repeating the liver and kidney function tests for this 42-year-old male patient who is currently taking Terbinafine (Lamisil) 250 mg once daily for a broad fungal infection affecting his feet, hands, and scalp. These tests are essential because Terbinafine can cause hepatotoxicity and, less commonly, renal adverse effects, as highlighted in a recent study published in 2023 2. The patient should have these tests performed as soon as possible, ideally within the next few days, to ensure safe continuation of his 90-day treatment course. Specifically, liver function tests should include ALT, AST, alkaline phosphatase, bilirubin, and albumin, while kidney function should be assessed through BUN, creatinine, and eGFR. If any abnormalities are detected, particularly elevated liver enzymes exceeding three times the upper limit of normal, the medication may need to be discontinued. The monitoring is particularly important since the patient is on a prolonged course of therapy (90 days), which increases the risk of adverse effects, as noted in another study published in 2023 3. Patients on Terbinafine should typically have baseline liver and kidney function tests before starting therapy and periodic monitoring throughout treatment, especially for extended courses. It is also crucial to advise the patient to discontinue treatment and seek medical care if symptoms of liver injury occur, such as jaundice, abdominal pain, and general malaise, as reported in a study published in 2017 4. In terms of the risk-benefit ratio, the benefits of Terbinafine in treating fungal infections often outweigh the risks, but careful monitoring is necessary to minimize the risk of hepatotoxicity and other adverse effects, as discussed in a study published in 2017 5 and another in 1993 6. Key points to consider include:
- Terbinafine can cause hepatotoxicity and renal adverse effects
- Liver function tests should be performed before starting therapy and periodically throughout treatment
- Kidney function should be assessed through BUN, creatinine, and eGFR
- Patients should be advised to discontinue treatment and seek medical care if symptoms of liver injury occur
- The risk-benefit ratio of Terbinafine should be carefully considered, with monitoring necessary to minimize the risk of adverse effects.