Can Lamisil (terbinafine) and Diflucan (fluconazole) cause brain fog and tunnel vision in a patient with mycosis after 4 months of use?

From the Guidelines

Both Lamisil (terbinafine) and Diflucan (fluconazole) can potentially cause brain fog and tunnel vision after prolonged use of 4 months, though these side effects are not common. The patient's symptoms could be related to the use of these medications, as terbinafine may cause neurological side effects including altered thinking, confusion, and visual disturbances in approximately 1-2% of patients 1. Fluconazole can similarly affect the central nervous system, with reported cases of visual changes and cognitive effects, particularly at higher doses or with extended treatment 1. These symptoms may result from the medications' ability to cross the blood-brain barrier or from interactions with liver enzymes that affect drug metabolism. Some key points to consider include:

• Terbinafine has a long half-life and persists in the body for 6 months after completion of treatment 1
• Fluconazole is generally well tolerated, but high doses or extended treatment can increase the risk of adverse effects 1
• The patient should contact their healthcare provider immediately if experiencing these symptoms, but should not discontinue the medications abruptly without medical guidance
• The provider may consider reducing the dose, switching to a different antifungal medication, or implementing a drug holiday depending on the severity of the fungal infection and the patient's response to treatment 1. It is essential to weigh the benefits of continued treatment against the potential risks and consider alternative treatment options if necessary. Some possible alternatives include:
• Monitoring the patient's liver function and adjusting the treatment plan accordingly 1
• Considering a different antifungal medication with a lower risk of neurological side effects 1
• Implementing a drug holiday to assess the patient's response to treatment and minimize the risk of adverse effects 1.

From the Research

Potential Side Effects of Lamisil and Diflucan

• The patient's symptoms of brain fog and tunnel vision may be related to the use of Lamisil (terbinafine) and Diflucan (fluconazole) for mycosis treatment, as these medications can cause various side effects 2, 3.
• According to the studies, terbinafine is generally well-tolerated, with common side effects including gastrointestinal symptoms, allergy, and miscellaneous mild non-specific symptoms 2.
• However, fluconazole and other oral antifungals have been associated with several interactions with cytochrome-p450, which can facilitate adverse events, including neurological effects 3.
• There is also a rare incidence of reversible hepatic damage associated with oral antifungal agents, including terbinafine and fluconazole 4, 5.
• Additionally, antifungal agents, including triazoles like fluconazole, may cause hepatic toxicity ranging from mild abnormalities in liver function tests to substantial liver injury and fulminant hepatic failure 5.

Hepatotoxicity and Liver Function Monitoring

• The risk of hepatotoxicity associated with antifungal agents, including terbinafine and fluconazole, highlights the importance of liver function monitoring before and during treatment 4, 5, 6.
• Studies suggest that liver function evaluation before treatment and periodic monitoring every three to six weeks after commencement of treatment is recommended to minimize the risk of antifungal-induced acute liver failure 6.
• Although the incidence of abnormal liver function tests from oral antifungal therapy is extremely low, patients should be advised to inform their physician if any warning symptoms are noticed 4.