From the Research
Naltrexone can be initiated when liver enzymes (transaminases) are less than 3-5 times the upper limit of normal (ULN), as supported by the most recent and highest quality study 1. For most patients, this means AST and ALT should ideally be below 150-250 U/L before starting treatment. If a patient has transaminases above this threshold, it's recommended to address the underlying liver condition first and recheck levels before initiating naltrexone. Once treatment begins, monitor liver function tests periodically, especially during the first few months of therapy. For patients with elevated but acceptable baseline transaminases, more frequent monitoring (every 2-4 weeks initially) is advisable. The caution regarding liver enzymes stems from naltrexone's potential hepatotoxicity, particularly at higher doses. The standard dosing for alcohol use disorder is 50 mg daily, while for opioid use disorder, doses typically range from 50-100 mg daily. Patients should be educated about symptoms of liver injury including abdominal pain, jaundice, dark urine, or unusual fatigue, and instructed to seek medical attention if these develop during treatment. Some key points to consider when initiating naltrexone therapy include:
- The safety of naltrexone in patients with cirrhosis has been demonstrated in a recent study 1, which found no association between naltrexone use and drug-induced liver injury.
- Another study 2 found that naltrexone is safe to use in patients with underlying liver disease, including those with compensated cirrhosis.
- However, more safety data are needed for those with decompensated cirrhosis. It's essential to weigh the benefits of naltrexone therapy against the potential risks, particularly in patients with pre-existing liver disease. By carefully monitoring liver function and adjusting treatment as needed, healthcare providers can minimize the risks associated with naltrexone use and maximize its benefits for patients with alcohol or opioid use disorders.