Uses

Indicated for the treatment of alcohol dependence and for the blockade of the effects of exogenously administered opioids in patients who have been detoxified. Used as part of a comprehensive addiction management program.

Do not use if

Contraindicated in patients currently receiving opioid analgesics, dependent on opioids, or in acute opioid withdrawal. Also contraindicated in patients who fail the naloxone challenge test or have a positive urine screen for opioids. Contraindicated in acute hepatitis or liver failure.

Side effects

Nausea is the most common side effect, occasionally causing treatment discontinuation. Other reported effects include headache, fatigue, anxiety, and abdominal pain. Hepatotoxicity may occur at high doses; liver enzyme monitoring is recommended.

Warnings

Patients completing naltrexone therapy have reduced opioid tolerance; resumption of opioid use may cause fatal overdose at previously tolerated doses. Hepatotoxicity risk exists at supratherapeutic doses. Use with caution in patients with hepatic impairment. Not recommended during pregnancy unless clearly necessary.

How it works

Naltrexone is a pure opioid antagonist that competitively and reversibly blocks mu-opioid receptors, thereby attenuating or completely blocking the subjective effects of opioids. Its mechanism in alcohol dependence is less fully understood but may involve modulation of the endogenous opioid system.

Storage

Store at room temperature. Keep in original container. Keep out of reach of children.