From the Guidelines
Allopurinol does not typically cause fatty liver disease. In fact, some research suggests it may actually have beneficial effects in patients with non-alcoholic fatty liver disease (NAFLD) due to its ability to reduce oxidative stress and uric acid levels. Allopurinol is primarily used to treat gout and high uric acid levels by inhibiting xanthine oxidase, an enzyme involved in puric acid production. While allopurinol can rarely cause liver injury, this typically presents as hepatitis (liver inflammation) rather than fat accumulation in the liver. The liver problems associated with allopurinol are usually allergic or hypersensitivity reactions that occur within the first few months of treatment and resolve when the medication is stopped 1.
Some studies have reported adverse events associated with allopurinol, including rash, abdominal pain, and diarrhea, but these are not typically related to fatty liver disease 1. In contrast, other medications and conditions like diabetes, obesity, high cholesterol, and excessive alcohol consumption are much more commonly associated with fatty liver disease than allopurinol use.
If you're taking allopurinol and concerned about liver health, regular liver function tests can be monitored by your healthcare provider, especially during the initial treatment period. However, the available evidence does not suggest a significant link between allopurinol use and fatty liver disease 1.
Key points to consider:
- Allopurinol is not typically associated with fatty liver disease
- Liver problems associated with allopurinol are usually allergic or hypersensitivity reactions
- Regular liver function tests can be monitored by your healthcare provider, especially during the initial treatment period
- Other medications and conditions are more commonly associated with fatty liver disease than allopurinol use
From the FDA Drug Label
A few cases of reversible clinical hepatotoxicity have been noted in patients taking allopurinol tablets, and in some patients, asymptomatic rises in serum alkaline phosphatase or serum transaminase have been observed. The FDA drug label does not explicitly mention fatty liver as an adverse reaction. However, it does mention hepatotoxicity and elevated liver enzymes, which may indicate liver damage.
- The label recommends monitoring liver function in patients with pre-existing liver disease.
- It also suggests evaluating liver function in patients who develop anorexia, weight loss, or pruritus while taking allopurinol. Based on the available information, it is unclear if allopurinol causes fatty liver specifically 2.
From the Research
Allopurinol and Fatty Liver
- The relationship between allopurinol and fatty liver is complex, with some studies suggesting that allopurinol may not cause fatty liver, while others indicate that it may be associated with hepatotoxicity in certain patients 3, 4.
- A study published in 2019 found that the incidence of hepatotoxicity was significantly lower in patients treated with febuxostat compared to allopurinol, suggesting that allopurinol may be associated with a higher risk of liver damage in patients with gout and fatty liver disease 3.
- However, another study published in 2023 found that adult gout patients exhibited similar hepatic safety profiles for both febuxostat and allopurinol treatment, with liver function abnormalities identified in all randomized controlled trials included in the systematic review 4.
- Some studies suggest that allopurinol may have protective effects against acute liver damage and cirrhosis, and may be effective in the treatment of liver diseases 5, 6.
- A 2023 study found that allopurinol decreased the controlled attenuation parameter (CAP) score, an indicator of steatosis, in patients with metabolic dysfunction-associated steatotic liver disease, suggesting that allopurinol may be beneficial in improving steatosis in these patients 7.
- A 2024 quadruple-blind placebo-controlled trial found that allopurinol reduced the relative risk of cirrhosis-related complications, including overt ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome, in patients with hepatic decompensation 6.