Naltrexone

Reverse the effects of opioid-agonist overdose (although IV therapy is preferred).

Prevent relapse in pts (including physicians) addicted to alcohol and/or opioids.

• Oral route is most common and popular.

• Newer formulations (e.g., Vivitrol [naltrexone for extended-release injectable suspension]) are once-monthly forms that release the drug over a long period so that pts (1) do not feel the effects of opioids if they try to abuse and (2) cannot stop taking naltrexone during the treatment window.

Treatment of intrathecal opioid-induced pruritus and nausea.

Included in the formulation of “tamper-resistant” extended-release opioids (e.g., morphine extended release + sequestered naltrexone) so as to discourage alteration (e.g., crushing) of these long-acting formulations.

Rapid detoxification of opioid dependence (performed under general anesthesia).

May precipitate acute opioid withdrawal in pts with chronic opioid use.

Pts on chronic naltrexone therapy may be more sensitive to dangerous side effects due to receptor upregulation and hypersensitivity.

Pts may be refractory to the effects of opioid agonists.