Methods
Patients (n = 61) receving treatment with sustained release naltrexone implants were offered a second naltrexone implant after 6 months. Patients who remained in treatment were compared to those who did not, on drug use, mental health, and social problems before and during naltrexone implant treatment. Information was obtained on other treatments sought by patients who discontinued naltrexone. Blood samples were used to verify naltrexone release, and hair samples to confirm opioid intake.
Results
Of the patients who received the first naltrexone implant, 51% (n = 31) remained in naltrexone implant treatment. Among those who discontinued treatment, 21% expressed a wish to reimplant but failed to attend for reimplantation and 28% declined reimplantation: 6 non-retained patients initiated maintenance or residential treatment. Remaining in naltrexone treatment was related to pre-study length of employment, illicit drug use, and concern for family problems. Higher levels of substance misuse and criminal activity during naltrexone treatment were negatively related to subsequent retention.
Conclusion
Rates of retention among opioid-dependent patients receiving naltrexone implant treatment are encouraging and support this as a feasible long-term treatment option.