Pharmacological options for management of opioid dependence

Buprenorphine diversion and injection in Melbourne, Australia: an emerging issue?

AIMS

To examine indicators of buprenorphine diversion and injection among injecting drug users in Melbourne, Australia and to determine the factors associated with buprenorphine injection.

DESIGN

Melbourne arm of the 2002 Illicit Drug Reporting System (IDRS) cross-sectional study.

SETTING

Five Needle and Syringe Programme sites in Melbourne, Australia.

PARTICIPANTS

A total of 156 current injecting drug users (IDU). Study eligibility criteria were at least monthly injection during the previous 6 months, and Melbourne residence for at least the preceding 12 months.

MEASUREMENTS

Structured questionnaire covering demographic characteristics, drug use history, the price, purity and availability of drugs, criminal activity, risk-taking behaviours, health-related issues and general drug use trends.

FINDINGS

Over one-third (37%) of the study sample reported injecting buprenorphine in their life-time and 33% reported injecting the drug in the last 6 months. Recent buprenorphine injection was associated with the injection of other drug types (i.e. polydrug injectors), opioid substitution treatment, injection-related health problems and involvement in crime. Almost half (47%) of those who reported recent buprenorphine injection reported obtaining the drug illicitly at least once during that time.

CONCLUSIONS

Given the significant health harms associated with intravenous buprenorphine use (e.g. vein damage, abscesses and infections, precipitated withdrawal, blood-borne virus transmission, hospitalization and death), routine monitoring of the misuse of buprenorphine in Melbourne is warranted. These results suggest the need for development of effective countermeasures to address diversion and injection of buprenorphine in this setting.

A randomized control trial of group counseling in a naltrexone treatment program

This study evaluated the additional effectiveness of a 12-week manualized group counseling program over a structured naltrexone treatment program. The randomized controlled trial, the first of its kind in Australia, was conducted at Turning Point Alcohol and Drug Centre, Melbourne, Australia. Ninety-seven participants received a 50 mg dose of naltrexone daily and were randomized to either the experimental (n = 52) or control (n = 45) conditions. The experimental group received a structured group counseling program, which used a cognitive-behavioral relapse prevention approach. Using intention-to-treat analyses, there was only one statistically significant difference between the groups, with the control group reporting a significantly higher level of physical functioning at Week 6. All participants improved significantly in their level of heroin use and in psychosocial functioning between Baseline and Weeks 6, 12, and 24. It is not possible to conclude from these results whether or not group counseling provides additional benefit to naltrexone treatment.

Formulation and stability of naltrexone oral liquid for rapid withdrawal from methadone

OBJECTIVE

To assess the stability of naltrexone oral liquid prepared from tablets and powder, and to evaluate its use in precipitating rapid withdrawal from methadone.

DESIGN

Naltrexone 1 mg/mL oral liquids were prepared from tablets and powder and stored in the dark at 4, 25, and 70 degrees C. Similar formulations containing 5 mg/mL were stored at 70 degrees C. The 1-mg/mL formulation prepared from tablets was clinically evaluated in inducing rapid withdrawal in two drug-dependent individuals receiving methadone maintenance treatment using a naltrexone dose titration protocol.

SETTING

A university pharmacy school and affiliated urban teaching hospital.

MAIN OUTCOME MEASURES

Samples removed at six time points were analyzed for naltrexone concentration to assess decomposition over 90 days. An opioid withdrawal symptom checklist was used to assess the severity of the withdrawal symptoms prior to, and 30 minutes after, each dose of naltrexone.

RESULTS

Decomposition of naltrexone in all formulations stored at 4 and 25 degrees C was not significant over 90 days. Both patients tolerated naltrexone 1 mg/mL oral liquid, but found it bitter and gritty. Withdrawal symptoms were experienced immediately after the first dose, but were resolving by the end of day 3 of naltrexone treatment, at which stage both patients were able to tolerate a 50-mg tablet of naltrexone as maintenance.

CONCLUSIONS

Naltrexone 1 mg/mL oral liquids prepared from tablets or powder are stable when stored in the dark for 60 days at 4 degrees C and for 30 days at 25 degrees C. The formulation prepared from tablets provides flexible dosing in patients undergoing rapid withdrawal from methadone.