From the Guidelines
Terbinafine can cause gastrointestinal problems in 49% of patients when used chronically, and patients should be monitored for these side effects, which can be managed by taking the medication with food, using antacids, or temporarily reducing the dose from the standard 250mg daily. Common GI issues include nausea, diarrhea, or taste disturbance, as reported in a postmarketing surveillance study 1. If GI symptoms develop, they can often be managed by taking the medication with food, using antacids, or temporarily reducing the dose. For severe or persistent symptoms, the medication may need to be discontinued and an alternative antifungal considered, such as itraconazole 200mg daily or fluconazole, as suggested in the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1.
Key Considerations
- Patients with pre-existing liver disease or those taking multiple medications should be monitored more closely, as terbinafine is metabolized in the liver and can affect the gastrointestinal tract directly 1.
- 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 1.
- Most GI symptoms resolve after discontinuation of the medication, though taste disturbances may persist for weeks to months 1.
- Patients should be advised to report persistent or severe GI symptoms promptly rather than continuing the medication while experiencing significant discomfort.
Alternative Treatments
- Itraconazole 200mg daily or fluconazole may be considered as alternative antifungal treatments for patients who experience severe or persistent GI symptoms with terbinafine 1.
- Griseofulvin, amorolfine, and ciclopirox may also be considered as alternative treatments, although they may have lower efficacy or higher relapse rates compared to terbinafine and itraconazole 1.
From the FDA Drug Label
5.1 Hepatotoxicity Cases of liver failure, some leading to liver transplant or death, have occurred with the use of terbinafine tablets in individuals with and without pre-existing liver disease. Patients prescribed terbinafine tablets should be warned to report immediately to their physician any symptoms of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain or jaundice, dark urine, or pale stools.
The FDA drug label mentions GI problems such as nausea, vomiting, and abdominal pain as symptoms that may indicate liver injury, but it does not directly address the relationship between chronic terbinafine use and GI problems.
- The label does mention that terbinafine can cause vomiting and abdominal pain as part of its adverse reaction profile 2.
- Additionally, the label notes that malaise, fatigue, and vomiting have been reported as adverse reactions 2. However, the label does not provide information on the long-term effects of terbinafine on the gastrointestinal system. Therefore, a conservative clinical decision would be to monitor patients for any adverse GI symptoms while taking terbinafine.
From the Research
Chronic Terbinafine and GI Problems
- There is limited information available on the specific topic of chronic terbinafine and GI problems in the provided studies.
- However, some studies mention the potential side effects and interactions of terbinafine, which may be relevant to GI problems:
- A study published in 2017 3 found that terbinafine-induced severe liver injury can cause symptoms such as jaundice, flu-like symptoms, dark urine, and pruritus.
- Another study published in 1999 4 mentions that terbinafine has a lower potential for clinically significant drug interactions compared to other oral antifungal agents like fluconazole and itraconazole.
- It is essential to note that the provided studies do not directly address the topic of chronic terbinafine and GI problems, and more research may be needed to fully understand the relationship between the two.
- Some studies suggest that terbinafine can be used in combination with other antifungal agents, such as itraconazole, to achieve better therapeutic effects in fungal skin diseases 5.
- The management of drug interactions with terbinafine, fluconazole, and itraconazole is crucial to minimize the risk of adverse reactions, and prescribers should be aware of the potential interactions and take necessary precautions 6.