A pilot evaluation of the safety and tolerability of repeat dose administration of long-acting injectable naltrexone (Vivitrex) in patients with alcohol dependence

Alcohol Clin Exp Res. 2004 Sep;28(9):1356-61. doi: 10.1097/01.alc.0000139823.30096.52.


Background: : Oral naltrexone is currently used as part of a treatment regimen for alcohol-dependent patients, but its clinical utility is hampered by poor patient adherence. A long-acting injectable naltrexone formulation (Vivitrex) was designed to facilitate patient adherence by providing an extended duration of therapeutic naltrexone over 1 month, thereby eliminating the need for daily dosing.

Methods: : A multicenter, randomized, double-blind, placebo-controlled pilot study was conducted to evaluate the safety and tolerability of intramuscular repeat dose administration of this extended-release naltrexone formulation in DSM-IV alcohol-dependent patients. Thirty patients were randomized to treatment with injectable naltrexone (400 mg; n = 25) or a matching placebo injection (n = 5) and were dosed once every 28 days over 4 months. Psychosocial treatment was offered to patients in both treatment groups. Outcome measures related to drinking activity and trough plasma concentrations of naltrexone and its primary metabolite, 6-beta-naltrexol, were evaluated.

Results: : Injectable naltrexone was generally safe and well tolerated. Reported adverse events were mild to moderate and resolved without intervention; only two patients discontinued due to adverse events. The most common adverse events (nausea and headache) occurred at a similar rate for patients in both treatment groups. Pharmacokinetic analysis confirmed that therapeutic levels of naltrexone were delivered throughout the four 1-month treatment cycles.

Conclusions: : The results of this pilot study provide the basis and methods for a larger, more definitive trial to determine the utility of this long-acting injectable naltrexone formulation in the treatment of alcohol-dependent patients.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Alcoholism / drug therapy*
  • Delayed-Action Preparations / administration & dosage
  • Delayed-Action Preparations / adverse effects
  • Double-Blind Method
  • Drug Evaluation / methods
  • Female
  • Gastrointestinal Diseases / chemically induced
  • Humans
  • Male
  • Naltrexone / administration & dosage*
  • Naltrexone / adverse effects*
  • Pilot Projects


  • Delayed-Action Preparations
  • Naltrexone