title: Achieving long-term continuous blood naltrexone and 6-beta-naltrexol coverage following sequential naltrexone implants.
abstract: The aim of this study was to assess blood free naltrexone and 6-beta-naltrexol levels with time following treatment with sequential sustained-release naltrexone preparations. Data were collected from blood samples analysed independently for naltrexone and 6-beta-naltrexol and from clinical record review at a community heroin treatment clinic in Perth, Western Australia. Five patients received sequential 3.4 g (3.49+/-0.01 g and 3.36+/-0.05 g, respectively) naltrexone implants. The second implant was received on average within 131.2+/-15.67 days of the first implant. The mean length of follow-up was 307.2+/-18.28 days of the first implant. Blood naltrexone levels have the potential to remain above 2 and 1 ng/ml for a total of 390 and 524 days, respectively, and blood 6-beta-naltrexol was maintained above 10 ng/ml for a total of 222 days following insertion of these implants. No patient relapsed to dependent heroin use during the implant coverage period while blood naltrexone concentrations were above 2 ng/ml. Results indicate that blood naltrexone and 6-beta-naltrexol levels can be maintained above therapeutic levels for prolonged periods following use of sequential 3.4 g naltrexone implants. These extended periods of coverage will offer significant benefits for managing the heroin-dependent patient.
authors.affiliation: Unit for Research and Education in Drugs and Alcohol, School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, Australia.
authors.forename: G K
authors.initials: GK
authors.lastname: Hulse
authors.forename: D E
authors.initials: DE
authors.lastname: Arnold-Reed
authors.forename: G
authors.initials: G
authors.lastname: O'Neil
authors.forename: C-T
authors.initials: CT
authors.lastname: Chan
authors.forename: R C
authors.initials: RC
authors.lastname: Hansson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D004343:Drug Implants; D005260:Female; D005500:Follow-Up Studies; D006556:Heroin Dependence / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009271:Naltrexone / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood* / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000008:administration & dosage* / Q000097:blood* / Q000627:therapeutic use; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D004343:Drug Implants; D009292:Narcotic Antagonists; D009271:Naltrexone