Risks

Liver Health: Naltrexone can cause liver damage, particularly at higher doses. Individuals with pre-existing liver conditions or those who consume large amounts of alcohol should use naltrexone with caution and under medical supervision.

Allergic Reactions: Some individuals may experience severe allergic reactions to naltrexone, including symptoms like hives, difficulty breathing, and swelling of the face, lips, tongue, or throat.

Depression and Suicidal Thoughts: Naltrexone may increase the risk of depression and suicidal thoughts, especially in individuals with a history of mental health disorders. It is important to monitor mood changes closely.‍

Acute Opioid Withdrawal: Individuals who are physically dependent on opioids should not take naltrexone until they have been opioid-free for at least 7-10 days, as it can precipitate severe withdrawal symptoms.

Overdose Risk: Because naltrexone blocks the effects of opioids, individuals who attempt to overcome this blockade by taking large amounts of opioids may be at risk of overdose.

Renal Function: Naltrexone should be used with caution in individuals with renal impairment as it is primarily excreted by the kidneys.

Side Effects

Sleep: Approximately 4% of patients reported sleep disturbances when starting naltrexone, though most patients experienced improvement within the first few weeks.

Gastrointestinal Issues: About 10% of patients reported mild to moderate gastrointestinal symptoms such as nausea, vomiting, or diarrhea. Severe cases were rare, affecting less than 1% of users.

Headache: Around 7% of patients experienced headaches, which were generally mild and transient.

Dizziness: Approximately 5% of patients reported dizziness, which was usually mild and decreased over time.

Fatigue: Fatigue was reported by about 6% of patients, with most cases being mild and improving within the first month of treatment.

Nervousness: Some patients (around 3%) reported feelings of nervousness or anxiety, particularly when beginning treatment.

Disclaimer

Naltrexone is a prescription medication used to treat alcohol dependence. It is available only if prescribed by a healthcare provider. You should not take naltrexone if you use opioids, including prescription drugs or street drugs that contain opioids, as naltrexone can cause sudden opioid withdrawal. Common side effects of naltrexone include nausea, sleepiness, headache, dizziness, vomiting, decreased appetite, painful joints, muscle cramps, and trouble sleeping. These are not all of the side effects of naltrexone. Tell your healthcare provider if you have any side effects that bother you or do not go away.