Fluconazole Use in Patients with Abnormal Liver Function Tests
Fluconazole can be used cautiously in patients with deranged LFTs, but requires close monitoring for worsening hepatic injury and should be discontinued if clinical signs of liver disease develop that may be attributable to the drug. 1
Key Considerations from FDA Labeling
The FDA label explicitly states that fluconazole should be administered with caution to patients with liver dysfunction, as it has been associated with rare cases of serious hepatic toxicity, including fatalities. 1 Importantly:
- No obvious relationship exists between hepatotoxicity and total daily dose, duration of therapy, sex, or age 1
- Fluconazole hepatotoxicity has usually (but not always) been reversible upon discontinuation 1
- Patients who develop abnormal LFTs during fluconazole therapy should be monitored for development of more severe hepatic injury 1
- The drug should be discontinued if clinical signs and symptoms consistent with liver disease develop that may be attributable to fluconazole 1
Clinical Evidence on Hepatotoxicity Risk
Baseline Liver Disease as a Risk Factor
Pre-existing chronic liver disease significantly increases the risk of azole-induced liver injury. Patients with chronic liver disease had a 4.68-fold increased risk of aminotransferases >200 U/L and a 5.62-fold increased risk of severe acute liver injury compared to those without liver disease. 2
In patients with liver cirrhosis specifically, fluconazole pharmacokinetics are significantly altered, with terminal elimination reduced by half (0.0101/h vs 0.0214/h in normal subjects), mean residence time nearly tripled (134h vs 46.7h), and plasma clearance reduced by more than half (0.96 L/h.kg vs 2.16 L/h.kg). 3 However, despite these pharmacokinetic changes, dosage reduction in cirrhosis is not currently justified given the wide range of individual variation and low toxicity profile of fluconazole. 3
Overall Hepatotoxicity Rates
The incidence of serious hepatic adverse events with fluconazole is extremely low:
- Serious adverse liver events occur at a rate of 1.4 per 100,000 prescriptions 4
- In a large cohort of 195,334 azole initiators, fluconazole had an incidence rate of aminotransferases >200 U/L of 13.0 events per 1000 person-years 2
- Severe acute liver injury with fluconazole occurred at a rate of 2.0 events per 1000 person-years 2
Practical Management Algorithm
Before Initiating Fluconazole:
- Obtain baseline liver function tests in all patients, especially those with known liver disease or risk factors 5, 6
- Evaluate the severity of underlying liver dysfunction 1
- Assess for concomitant hepatotoxic medications 7
During Treatment:
Monitor LFTs periodically, particularly in patients with:
Monitoring frequency: Every 3-6 weeks after treatment commencement is suggested 6
If LFTs Worsen:
- Closely monitor for development of more severe hepatic injury 1
- Discontinue fluconazole if clinical signs and symptoms consistent with liver disease develop 1
- The prognosis is often good with swift discontinuation and proper treatment 6
- Hepatotoxicity is usually (but not always) reversible upon discontinuation 1
Important Caveats
The spectrum of hepatic reactions ranges from mild transient transaminase elevations to clinical hepatitis, cholestasis, and fulminant hepatic failure. 1 While asymptomatic increases in transaminases occur in 1-13% of patients, clinically significant hepatitis is much less common. 7
Critically ill patients may have elevated LFTs from multiple causes. In one ICU study, 55% of patients receiving fluconazole met Drug-Induced Liver Injury Network (DILIN) criteria, but only 14.5% of these actually met criteria for hepatocellular damage, suggesting DILIN criteria may overestimate fluconazole-associated liver injury in critically ill populations. 9
Fatal hepatic reactions have been reported primarily in patients with serious underlying medical conditions (predominantly AIDS or malignancy) who were often taking multiple concomitant medications. 1 However, transient hepatic reactions have also occurred in patients with no other identifiable risk factors. 1