The prescribing information for naltrexone hydrochloride tablets (50 mg) reports cases of hepatitis and clinically significant liver dysfunction. It also says depression and suicidal thoughts have been reported and that no causal relationship has been demonstrated. Its information for patients section says when patients should contact a physician or doctor. Every statement below about naltrexone comes from the 50 mg tablet label. The two mental health statements come from a general NIMH page. None of these sources says what applies at low doses, and this guide does not either.
What the 50 mg label says about the liver
The label for naltrexone hydrochloride 50 mg tablets states that cases of hepatitis and clinically significant liver dysfunction "were observed in association with naltrexone hydrochloride exposure during the clinical development program and in the postmarketing period."
The same label says patients should be warned of the risk of hepatic injury and advised to seek medical attention if they experience symptoms of acute hepatitis. It adds that use of naltrexone hydrochloride "should be discontinued in the event of symptoms and/or signs of acute hepatitis." Those are the label's words for the 50 mg tablet. This guide does not advise anyone to start, stop or change a dose.
The dose wording in the liver statements
Two passages in the same label name a dose in connection with the liver. In both, the dose is described as higher than the dose recommended for opiate receptor blockade.
| Question | What the source says |
|---|---|
| What does the adverse reactions section say about dose and liver injury? | Studies "employing up to five-fold higher doses of naltrexone hydrochloride (up to 300 mg per day) than that recommended for use in opiate receptor blockade have shown that naltrexone hydrochloride causes hepatocellular injury in a substantial proportion of patients exposed at higher doses." |
| What study with numbers does the label describe? | A study in obese subjects given a dose "approximately five-fold that recommended for the blockade of opiate receptors (300 mg per day)." In it, 19% (5/26) of naltrexone hydrochloride recipients and 0% (0/24) of placebo-treated patients developed elevations of serum transaminases. |
| Is 300 mg per day the recommended dose? | No. The label describes it as higher than the dose recommended for opiate receptor blockade. |
The "substantial proportion" wording refers to patients exposed at higher doses. The passages used here give no liver figures for low doses.
Depression, suicide and suicidal thoughts
The label says: "Depression, suicide, attempted suicide and suicidal ideation have been reported in the postmarketing experience with naltrexone hydrochloride used in the treatment of opioid dependence." The next sentence is "No causal relationship has been demonstrated."
The information for patients section of the same label says it is important that patients inform family members and the people closest to the patient that they are taking naltrexone hydrochloride and that they should call a doctor right away should they become depressed or experience symptoms of depression.
The National Institute of Mental Health (NIMH) says: "If you or someone you know is struggling or having thoughts of suicide, call or text the 988 Suicide & Crisis Lifeline at 988." It also says: "In life-threatening situations, call 911." These are the NIMH's own statements from its suicide prevention page, which is not about naltrexone.
Other symptoms and sensitivity
The information for patients section of the label says to advise patients that naltrexone hydrochloride may cause liver injury and that patients should immediately notify their physician if they develop symptoms and/or signs of liver disease. The passage used here does not list those symptoms or signs, so this guide does not either.
The contraindications section of the label lists any individual with a history of sensitivity to naltrexone hydrochloride or any other components of the product. It says it is not known if there is any cross-sensitivity with naloxone or the phenanthrene containing opioids.
What this does not tell you
None of these statements is about low-dose naltrexone. The label covers the 50 mg tablet. No source used here reports liver or mood findings for low-dose naltrexone, so this guide cannot say whether any warning does or does not apply at low doses.
"No causal relationship has been demonstrated" is not a finding that there is no link. The 19% (5/26) figure comes from one study at a dose the label describes as higher than the dose recommended for opiate receptor blockade. It should not be read as a figure for any other dose.
A licensed provider decides whether any naltrexone product is suitable for a person. For the symptoms above, the label says to notify a physician or call a doctor, and the NIMH says to call or text 988 or to call 911 in the situations it describes.