A six-year evaluation of methadone prescribing practices at a substance misuse treatment centre in the UK

There is no age limit for methadone: a retrospective cohort study

Background

Data from the US indicates that methadone-maintained populations are aging, with an increase of patients aged 50 or older. Data from European methadone populations is sparse. This retrospective cohort study sought to evaluate the age trends and related developments in the methadone population of Basel-City, Switzerland.

Methods

The study included methadone patients between April 1, 1995 and March 31, 2003. Anonymized data was taken from the methadone register of Basel-City. For analysis of age distributions, patient samples were split into four age categories from '20-29 years' to '50 years and over'. Cross-sectional comparisons were performed using patient samples of 1996 and 2003.

Results

Analysis showed a significant increase in older patients between 1996 and 2003 (p < 0.001). During that period, the percentage of patients aged 50 and over rose almost tenfold, while the proportion of patients aged under 30 dropped significantly from 52.8% to 12.3%. The average methadone dose (p < 0.001) and the 1-year retention rate (p < 0.001) also increased significantly.

Conclusions

Findings point to clear trends in aging of methadone patients in Basel-City which are comparable, although less pronounced, to developments among US methadone populations. Many unanswered questions on medical, psychosocial and health economic consequences remain as the needs of older patients have not yet been evaluated extensively. However, older methadone patients, just as any other patients, should be accorded treatment appropriate to their medical condition and needs. Particular attention should be paid to adequate solutions for persons in need of care.

Patterns of attendance in methadone maintenance treatment program in Yunnan Province, China

OBJECTIVE

To describe the patterns of patients' attendance over the first three quarters of a year under methadone maintenance treatment (MMT) clinics in Yunnan Province, China.

METHODS

Data were obtained from drug abuse treatment databases from five MMT clinics in Yunnan Province. Patients registered between April 2007 and December 2007 were included in the analysis. The study period was divided into three phases consisting of 3 months each. Logistic regression was used to predict factors determining whether the patients attended the clinic on each day with repetition of the patients taken into account.

RESULTS

The median number of days attending the clinics was 61 in the total treatment period, and the likelihood of a patient attending the clinic in the second and third phases was significantly less [odds ratio (OR) = .44 and .30, 95% confidence interval (CI) = .40-.49 and .26-.34] compared with the first phase. The predictors for attendance at clinic were being unmarried (OR = .63, 95% CI = .49-.82), self-employed (OR = .18, 95% CI = .11-.28), having a history of syringe sharing (OR = .67, 95% CI = .48-.92), and having been in a detoxification program (OR = 1.59, 95% CI = 1.09-2.33).

CONCLUSION

Heroin users attended MMT programs irregularly and their periods of attendance significantly declined by duration of the time they stayed in the treatment program. Additional interventions should be employed to help patients adhere to this long-term treatment program.

Effects of a single 50% extra dose of methadone on heroin craving and mood in lower- versus higher-dose methadone patients

Some patients on steady-state methadone occasionally crave for extra opioids for different reasons (eg, cue-elicited craving, stress). This study examined the acute-on-chronic effects on heroin craving, mood, and opioid-like symptoms of a single, extra half-dose on top of the patient's prescribed daily methadone dosage. A randomized, double-blind, placebo-controlled, counterbalanced crossover design was used to test the safety of this practice and the hypotheses that extra methadone would reduce heroin craving and improve mood, with greater responses in lower-dose (20-60 mg/d) as compared with higher-dose patients (80-120 mg/d). Fourteen stabilized methadone-maintained volunteers of each dose group were examined predrug and postdrug on 2 separate days using a range of self-report measures (Heroin Craving Questionnaire, visual analogs, Befindlichkeits-Skala, Short Opiate Withdrawal Scale, and Opioid Agonist Scale). Additionally, patients' expectations and guesses regarding treatment were assessed predrug and postdrug, respectively. No adverse effects occurred after extra methadone. Participants could not reliably distinguish between extra methadone and placebo. Repeated-measures analyses of variance showed no effects of extra methadone on heroin craving and opioid agonist effects. However, extra methadone improved mood on the Befindlichkeits-Skala (F1/24 = 4.71, P = 0.04), with marginally greater effects in lower-dose patients ((F1/24 = 2.94, P = 0.099). A single 50% extra methadone dose is most likely safe in patients on stable methadone doses of 20 to 120 mg/d and may improve patients' mood. Extra methadone may constitute an important factor in the attractiveness of maintenance treatment and may enhance treatment outcome.

Trends in methadone maintenance treatment participation, retention, and compliance to dosing guidelines in British Columbia, Canada: 1996-2006

Aspects of methadone maintenance treatment (MMT) delivery, particularly daily dosing practices, are associated with longer retention in treatment. Our objective was to identify trends in compliance to MMT dosing guidelines at the population level in British Columbia, Canada, from 1996 to 2006. Analysis of a provincial drug dispensation database identified 31,724 MMT episodes initiated during the study period. The number of patients in treatment increased from 2,827 in 1996 to 9,601 in 2006. Long-term retention (>36 months) was achieved in 20%-25% of all episodes. Compliance to minimally effective dose guidelines, which is independently associated with retention, fell from 2001 to 2006. Accordingly, this decline was mirrored by 12-month retention figures, which fell from 45.9% in 2001 to 40.5% in 2005. Our evaluation has both highlighted the successes of the British Columbia Methadone program and identified aspects that may be improved to ensure safety and maximize the benefits of MMT.

Contribution of the activities of CYP3A, CYP2D6, CYP1A2 and other potential covariates to the disposition of methadone in patients undergoing methadone maintenance treatment

AIMS

To investigate the influence of different cytochrome P450 (CYP) activities and other potential covariates on the disposition of methadone in patients on methadone maintenance therapy (MMT).

METHODS

Eighty-eight patients (58 male; 21-55 years; 84 White) on MMT were studied. CYP2D6 activity [3 h plasma metabolic ratio of dextromethorphan (DEX) to dextrorphan (DOR)] was determined in 44 patients (29 male; 24-55 years), CYP1A2 activity (salivary caffeine elimination half-life) in 44 patients (21 male; 24-55 years) and CYP3A activity (oral clearance of midazolam) in 49 patients (33 male; 23-55 years). Data on all three CYPs were obtained from 32 subjects. Total plasma concentrations of (RS)-methadone and total and unbound plasma concentrations of both enantiomers were measured by LC/MS. Population pharmacokinetics and subsequent multiple regression analysis were used to calculate methadone oral clearance and to identify its covariates.

RESULTS

Between 61 and 68% of the overall variation in total plasma trough concentrations of (RS)-, (R)- and (S)-methadone was explained by methadone dose, duration of addiction before starting MMT, CYP3A activity and illicit morphine use. CYP3A activity explained 22, 16, 15 and 23% of the variation in unbound (R)-, unbound (S)-, total (RS)- and total (S)-methadone clearances, respectively. Neither CYP2D6 nor CYP1A2 activity was related to methadone disposition.

CONCLUSIONS

CYP3A activity has a modest influence on methadone disposition. Inhibitors and inducers of this enzyme should be monitored in patients taking methadone.

Hopping on the methadone bus

This paper investigates the impact of a 'free drug program' on the market equilibrium of drugs. We introduce a screening model of the hard drug market in which dealers use payment and punishment options to screen between high and low risk users. We show that, if a free drug program selects sufficiently many high-risk drug users, the pure-strategy separating market equilibrium ceases to exist and a symmetric mixed-strategy equilibrium results, in which drug users derive a higher expected utility. This encourages new drug users to enter the market. The novelty of the paper is the transmission mechanism for this effect, which is via the influence on market price.