title: Injectable extended-release naltrexone (XR-NTX) for opioid dependence: long-term safety and effectiveness.
abstract: OBJECTIVE
  To describe drug use and safety with intramuscular injectable extended-release naltrexone (XR-NTX) in opioid dependence during a 1-year open-label extension phase.
  
  
  METHODS
  Following 6 months of randomized, double-blind, placebo (PBO)-controlled injections given every 28 days, patients receiving XR-NTX 380 mg continued and PBO patients were switched to open-label XR-NTX, with monthly individual drug counseling, for a further year.
  
  
  METHODS
  Thirteen clinical sites in Russia.
  
  
  METHODS
  Adult opioid-dependent outpatients.
  
  
  METHODS
  Monthly urine samples; reports of craving and functioning; adverse events.
  
  
  RESULTS
  For the open-label extension (n = 114), 67 continued on XR-NTX and 47 switched from PBO during the double-blind phase to XR-NTX during the open-label phase. Overall, 62.3% (95% CI: 52.7%, 71.2%) completed the extension. Discontinuation occurred most commonly because of withdrawal of consent (18.4%) and loss to follow-up (11.4%); two patients discontinued as a result of lack of efficacy and one because of adverse events. Urine testing revealed that 50.9% (41.5%, 60.4%) were abstinent from opioids at all assessments during the 1-year open-label phase. Adverse events reported by 21.1% of patients were judged to be study drug-related. Injection site reactions were infrequent (6.1%) and the majority were mild. Elevations in liver function tests occurred for 16.7% of patients, but none of these elevations was judged to be clinically significant. No patients died, overdosed or discontinued as a result of severe adverse events.
  
  
  CONCLUSIONS
  During a 1-year open-label extension phase of injectable XR-NTX for the prevention of relapse in opioid dependence, 62.3% of patients completed the phase and 50.9% were abstinent from opioids. No new safety concerns were evident.
authors.affiliation: Bekhterev Research Psychoneurological Institute and St. Petersburg State Pavlov Medical University, Bekhtereva Street 3, St. Petersburg, Russian Federation. kruenator@gmail.com
authors.forename: Evgeny
authors.initials: E
authors.lastname: Krupitsky
authors.forename: Edward V
authors.initials: EV
authors.lastname: Nunes
authors.forename: Walter
authors.initials: W
authors.lastname: Ling
authors.forename: David R
authors.initials: DR
authors.lastname: Gastfriend
authors.forename: Asli
authors.initials: A
authors.lastname: Memisoglu
authors.forename: Bernard L
authors.initials: BL
authors.lastname: Silverman
mesh_terms: D000328:Adult; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D055118:Medication Adherence; D009271:Naltrexone / Q000008:administration & dosage* / Q000009:adverse effects; D009292:Narcotic Antagonists / Q000008:administration & dosage* / Q000009:adverse effects; D009293:Opioid-Related Disorders / Q000534:rehabilitation*; D055502:Secondary Prevention; D057566:Self Report
chemical_list: D003692:Delayed-Action Preparations; D009292:Narcotic Antagonists; D009271:Naltrexone
keywords: Craving; depot naltrexone; extended-release naltrexone; heroin dependence; injectable naltrexone; long-term safety; naltrexone; opioid dependence; sustained release formulations