Summary

This double-blind, placebo-controlled trial found that naltrexone implant was more effective than oral naltrexone or placebo at maintaining treatment without relapse, and reducing opiate use, as confirmed with urine tests. Implants with naltrexone lead to more wound infections than placebo implants, all of which resolved with antibiotics.

Design

• N=306 patients with opioid addiction, undergoing detoxification, received biweekly counseling and were randomized to receive 24 weeks of one of the following:
  • 1,000 mg naltrexone implant + oral placebo (NI+OP, n=102)
  • Placebo implant + 50 mg oral naltrexone hydrochloride (PI+ON, n=102)
  • Placebo implant + oral placebo (PI+OP, n=102)
• Implant was placed bimonthly. Oral naltrexone (or placebo) was taken daily.
• Urine drug screens performed biweekly.
• Setting: Addiction treatment programs in St. Petersburg, Russia, 2006-2009.
• Primary outcome: Percent of patients who remained in treatment without relapse.

Results

• Naltrexone implant was associated with significantly higher rates of remaining in treatment without relapse at 6 months compared with oral or placebo (P<0.001):
  • 52.9% of NI+OP (Implant)
  • 15.7% of PI+ON (Oral)
  • 10.8% of PI+OP (Double placebo)
• Percent of negative urine opiate screening tests were significantly higher with implant than with oral or placebo (P<0.001):
  • 63.6% of NI+OP (Implant)
  • 42.7% of PI+ON (Oral)
  • 34.1% of PI+OP (Double placebo)
• Wound infections occurred more frequently in the naltrexone implant group, all within first 2 weeks after implantation, and all resolved with antibiotics. Percentage of implantations leading to infection:
  • 4.9% of NI+OP (Implant)
  • 1.1% of PI+ON (Oral)
  • 0.7% of PI+OP (Double placebo)

Reference

Krupitsky E, Zvartau E, Blokhina E, et al. Randomized trial of long-acting sustained-release naltrexone implant vs oral naltrexone or placebo for preventing relapse to opioid dependence. Arch Gen Psychiatry. 2012;69(9):973-981. doi:10.1001/archgenpsychiatry.2012.1a.