Factors associated with willingness to take extended release naltrexone among injection drug users.
BACKGROUND
Although opioid-agonist therapy with methadone or buprenorphine/naloxone is currently the mainstay of medical treatment for opioid use disorder, these medications often are not well accepted or tolerated by patients. Recently, extended release naltrexone (XR-NTX), an opioid antagonist, has been advanced as an alternative treatment. The willingness of opioid-addicted patients to take XR-NTX has not been well described.


METHODS
Opioid-using persons enrolled in a community-recruited cohort in Vancouver, Canada, were asked whether or not they would be willing to take XR-NTX. Logistic regression was used to independently identify factors associated with willingness to take the medication.


RESULTS
Among the 657 participants surveyed between June 1, 2013, and November 30, 2013, 342 (52.1%) were willing to take XR-NTX. One factor positively associated with willingness was daily heroin injection (adjusted odds ratio [AOR] = 1.53; 95% confidence interval [CI] = 1.02-2.31), whereas Caucasian ethnicity was negatively associated (AOR = 0.59; 95% CI = 0.43-0.82). Satisfaction with agonist therapy (13.4%) and unwillingness to stop opioids being used for pain (26.9%) were the most common reasons for being unwilling to take XR-NTX.


CONCLUSIONS
A high level of willingness to take XR-NTX was observed in this setting. Interestingly, daily injection heroin use was positively associated with willingness, whereas Caucasian participants were less willing to take XR-NTX. Although explanations for unwillingness were described in this study, further research is needed to investigate real-world acceptability of XR-NTX as an additional option for the treatment of opioid use disorder.
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. keithahamad@gmail.com.|Department of Family Practice, University of British Columbia, 5950 University Boulevard Street, Vancouver, BC, V6T 1Z3, Canada. keithahamad@gmail.com.
Keith
K
Ahamad
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. mjmilloy@cfenet.ubc.ca.
M J
MJ
Milloy
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. pnguyen@cfenet.ubc.ca.
Paul
P
Nguyen
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. sashauhlmann@yahoo.ca.
Sasha
S
Uhlmann
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. cheyenne.johnson@cfenet.ubc.ca.
Cheyenne
C
Johnson
Department of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA. korthuis@ohsu.edu.|Department of Public Health-Preventive Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA. korthuis@ohsu.edu.
Todd P
TP
Korthuis
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. uhri-tk@cfenet.ubc.ca.
Thomas
T
Kerr
British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. uhri-ew@cfenet.ubc.ca.|Department of Medicine, University of British Columbia, 10th Floor 2775 Laurel Street, Vancouver, BC, V5Z 1M9, Canada. uhri-ew@cfenet.ubc.ca.|Division of Epidemiology and Population Health, BC Centre for Excellence in HIV/AIDS, 608-1081 Burrard Street, Vancouver, BC, V6Z 1Y6, Canada. uhri-ew@cfenet.ubc.ca.
Evan
E
Wood
D000328:Adult; D002170:Canada; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009271:Naltrexone / Q000008:administration & dosage / Q000627:therapeutic use*; D009292:Narcotic Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D009293:Opioid-Related Disorders / Q000188:drug therapy* / Q000523:psychology; D010342:Patient Acceptance of Health Care / Q000523:psychology*; D012959:Socioeconomic Factors; D015819:Substance Abuse, Intravenous / Q000188:drug therapy* / Q000523:psychology
D003692:Delayed-Action Preparations; D009292:Narcotic Antagonists; D009271:Naltrexone