Achieving long-term continuous blood naltrexone and 6-β-naltrexol coverage following sequential naltrexone implants
Hulse, G. K., Arnold-Reed, D. E., O’Neil, G., Chan, C-T., Hansson, R., & O’Neil, P. (2004). Achieving long-term continuous blood naltrexone and 6-β-naltrexol coverage following sequential naltrexone implants. Addiction Biology, 9(1), 67-72. doi: 10.1080/13556210410001674103
The aim of this study was to assess blood free naltrexone and 6-β-naltrexol levels with time following treatment with sequential sustained-release naltrexone preparations. Data were collected from blood samples analysed independently for naltrexone and 6-β-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-β-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-β-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.