• Type: Opioid antagonist
  • Dosage Forms:
  • Routes of Administration: PO, IM
  • Common Trade Names: ReVia, Vivitrol, Depade

Adult Dosing

  • Opioid dependence (prevention of relapse after opioid-free x 7-10d), ETOH dependence: 25-50mg PO daily OR 380mg IM q4w

Pediatric Dosing

Safety/efficacy not established

Special Populations

Pregnancy Rating

  • Category C

Lactation risk

  • Minimally excreted in breastmilk

Renal Dosing

  • Use caution

Hepatic Dosing

  • Use caution


  • Allergy to class/drug
  • Patients who are on opioid analgesics/partial agonists, are opioid-dependant, or in acute opioid withdrawal

Adverse Reactions


  • Depression, suicide, and suicidality
  • Vulnerability to opioid overdose: Patients should be alerted that they may be more sensitive to opioids, even at lower doses, after discontinuance of naltrexone
  • Hepatotoxicity
  • Severe injection-site reactions (e.g. necrosis, cellulitis, hematoma)


  • Injection site reaction
  • Nausea/vomiting, diarrhea, decreased appetite, dry mouth
  • LFT abnormalities,
  • Elevated CPK
  • Headache, dizziness, anxiety, insomnia, somnolence
  • URI, pharyngitis
  • Arthralgia, muscle cramps, back pain
  • Rash


  • Half-life: PO- 4-13h;IM- 5-10 days
  • Metabolism: Hepatic
  • Excretion: Urinary

Mechanism of Action

  • Potent nonselective opioid competitive receptor antagonist
  • Reduces the rewarding effects of alcohol consumption by inhibiting the activity of endogenous opioids in the mesolimbic system. [1]


See Also


  1. Anderson, E., Chamberlin, M., Zuluaga, M., Ullal, M., & Hawk, K. (2021). Annals of emergency medicine. Annals of Emergency Medicine, 78(6), 752–758.