Interactions on mixing diazepam with methadone or buprenorphine in maintenance patients

Polysubstance Use in Adults With Opioid Use Disorder Receiving Buprenorphine Maintenance

INTRODUCTION

Studying polysubstance use is a public health recommendation. In the United Arab Emirates, more than 80% of adults with opioid use disorder (OUD) use 2 or more nonopioid substances. This secondary analysis contrasts the characteristics of polysubstance users (OUD + ≥1 nonopioid) with OUD, explores the correlates and predictors of nonfatal overdose, and examines the impact of polysubstance use on OUD treatment outcomes using buprenorphine (BUP).

METHODS

This analysis uses data from a 16-week outpatient randomized controlled trial of 141 adults with OUD allocated to BUP + incentivized adherence and abstinence monitoring (n = 70) and BUP in usual care (control, n = 71). Outcomes were nonfatal overdose events over the preceding 12 months, positive drug screens, and treatment retention. Participant characteristics were contrasted, and bivariate statistical tests were conducted for simple associations followed by logistic regression.

RESULTS

Polysubstance use was reported by 117 participants (82.9%), the majority of whom used pregabalin 72.1% (n = 75). Compared with OUD, polysubstance users observed higher arrests (median, 1.0 [interquartile range, 0.0-3.0] vs 0.5 [interquartile range, 0.0-2.0]; P = 0.04]) and nonfatal overdose events (n = 33 [31.8%] vs 2 [10.8%], P = 0.003). Carisoprodol and injecting drug use independently predicted nonfatal overdose (adjusted odds ratio, 4.519 [95% confidence interval, 1.81-11.22] and 2.74 [95% confidence interval, 1.15-6.51], respectively). No significant difference was observed in opioid use and retention in treatment outcomes between groups.

CONCLUSION

Carisoprodol and injecting drug use increase the likelihood of nonfatal overdose in adults with OUD. Polysubstance use does not impact response to BUP treatment compared with OUD.

The effect of person, treatment and prescriber characteristics on retention in opioid agonist treatment: a 15-year retrospective cohort study

BACKGROUND AND AIMS

There is limited evidence on the relationship between retention in opioid agonist treatment for opioid dependence and characteristics of treatment prescribers. This study estimated retention in buprenorphine and methadone treatment and its relationship with person, treatment and prescriber characteristics.

DESIGN

Retrospective longitudinal study.

SETTING

New South Wales, Australia.

PARTICIPANTS

People entering the opioid agonist treatment programme for the first time between August 2001 and December 2015.

MEASUREMENTS

Time in opioid agonist treatment (primary outcome) was modelled using a generalized estimating equation model to estimate associations with person, treatment and prescriber characteristics.

FINDINGS

The impact of medication type on opioid agonist treatment retention reduced over time; the risk of leaving treatment when on buprenorphine compared with methadone was higher among those who entered treatment earlier [e.g. 2001-03: odds ratio (OR) = 1.59, 95% confidence interval (CI) = 1.45-1.75] and lowest among those who entered most recently (2013-15: OR = 1.23, 95% CI = 1.11-1.36). In adjusted analyses, risk of leaving was reduced among people whose prescriber had longer tenure of prescribing (e.g. 3 versus 8 years: OR = 0.94, 95% CI = 0.93-0.95) compared with prescribers with shorter tenure. Aboriginal and Torres Strait Islander people, being of younger age, past-year psychosis disorder and having been convicted of more criminal charges in the year prior to treatment entry were associated with increased risk of leaving treatment.

CONCLUSION

In New South Wales, Australia, retention in buprenorphine treatment for opioid dependence, compared with methadone, has improved over time since its introduction in 2001. Opioid agonist treatment retention is affected not only by characteristics of the person and his or her treatment, but also of the prescriber, with those of longer prescribing tenure associated with increased retention of people in opioid agonist treatment.

Buprenorphine Prevalence in DUID Cases in Southwestern Virginia: Case Studies and Observations

Buprenorphine, a semisynthetic mixed agonist/antagonist opioid used primarily for the treatment of opioid use disorder, was reported in 194 driving under the influence of drugs (DUID) cases in Southwestern Virginia during the period of 2017 through 2019. Identifying and confirming buprenorphine in DUID cases is common in this region. Interpretation is complex due to the large range of concentrations of buprenorphine found in blood and frequent combinations with other therapeutic and abused drugs. Buprenorphine was identified by immunoassay and quantified by liquid chromatography-tandem mass spectrometry (LC-MS-MS). A sensitive method was necessary as one-third of concentrations of buprenorphine and/or norbuprenorphine were less than 1.0 µg/L. Concentrations of buprenorphine ranged from < 0.5 µg/L to 11 µg/L (mean 2.5 µg/L, median 1.8 µg/L) and concentrations of norbuprenorphine ranged from < 0.5 µg/L to > 20 µg/L (mean 3.3 µg/L, median 2.2 µg/L). Buprenorphine polysubstance use was common. Only 10% of cases examined did not contain other drugs confirmed in routine DUID screening tests. The most common drug groups confirmed were benzodiazepines, amphetamines and cannabinoids. The DUID case histories presented represent examples of buprenorphine abuse, buprenorphine with no other drug groups, buprenorphine combined with other drug groups, cases consistent with impairment and cases with minimal impairment. Central nervous system depressant and narcotic analgesic symptoms were commonly observed; however, some cases contained stimulant symptoms. Buprenorphine to norbuprenorphine ratios (B/NB) had a mean and median ratio of 1.1 and 0.8, respectively. B/NB ratios greater than 3.0 were found in 4.7% of cases. The finding of a higher B/NB ratio may indicate a more recent buprenorphine administration and a greater potential for impairment. No relationship between the concentration of buprenorphine and/or norbuprenorphine in blood and performance on Drug Recognition Expert (DRE) evaluation or Standardized Field Sobriety Tests (SFST) could be determined.

Associations between prescribed benzodiazepines, overdose death and buprenorphine discontinuation among people receiving buprenorphine

BACKGROUND AND AIMS

Benzodiazepines are commonly prescribed to patients with opioid use disorder receiving buprenorphine treatment, yet may increase overdose risk. However, prescribed benzodiazepines may improve retention in care by reducing buprenorphine discontinuation and thus may prevent relapse to illicit opioid use. We aimed to test the association between benzodiazepine prescription and fatal opioid overdose, non-fatal opioid overdose, all-cause mortality and buprenorphine discontinuation.

DESIGN AND SETTING

This was a retrospective cohort study using five individually linked data sets from Massachusetts, United States government agencies.

PARTICIPANTS

We studied 63 389 Massachusetts residents aged 18 years or older who received buprenorphine treatment between January 2012 and December 2015.

MEASUREMENTS

Filled benzodiazepine prescription during buprenorphine treatment was the main independent variable. The primary outcome was time to fatal opioid overdose. Secondary outcomes were time to non-fatal opioid overdose, all-cause mortality and buprenorphine discontinuation. We defined buprenorphine discontinuation as having a 30-day gap without another prescription following the end date of the previous prescription. We used Cox proportional hazards models to calculate hazards ratios that tested the association between receipt of benzodiazepines and all outcomes, restricted to periods during buprenorphine treatment.

FINDINGS

Of the 63 345 individuals who received buprenorphine, 24% filled at least one benzodiazepine prescription during buprenorphine treatment. Thirty-one per cent of the 183 deaths from opioid overdose occurred when individuals received benzodiazepines during buprenorphine treatment. Benzodiazepine receipt during buprenorphine treatment was associated with an increased risk of fatal opioid overdose adjusted hazard ratio (HR) = 2.92, 95% confidence interval (CI) = 2.10-4.06, non-fatal opioid overdose, adjusted HR = 2.05, 95% CI, 1.68-2.50, all-cause mortality, adjusted HR = 1.90, 95% CI, 1.48-2.44 and a decreased risk of buprenorphine discontinuation, adjusted HR = 0.87, 95% CI, 0.85-0.89.

CONCLUSIONS

Benzodiazepine receipt appears to be associated with both increased risk of opioid overdose and all-cause mortality and decreased risk of buprenorphine discontinuation among people receiving buprenorphine.

Prediction of Drug-Drug Interactions Between Opioids and Overdosed Benzodiazepines Using Physiologically Based Pharmacokinetic (PBPK) Modeling and Simulation

Background

Researchers have long been interested in the potential drug–drug interactions (DDIs) between opioids and benzodiazepines. However, much remains unknown concerning the interactions between these two drug classes. The objective of this work is to study the mechanism underlying the DDIs between opioids and benzodiazepines from the perspective of their pharmacokinetic (PK) interactions. A PK interaction occurs when two drugs are metabolized by the same cytochrome P450 enzymes and is one of the most common reasons for DDIs.

Methods

We quantitatively predicted the DDIs between three opioids (fentanyl, oxycodone and buprenorphine) and four benzodiazepines (alprazolam, diazepam, midazolam and triazolam) using a physiologically based pharmacokinetic (PBPK) modeling approach. A set of PBPK models was first constructed for these common opioids and benzodiazepines using SimCYP software, and the DDIs between them were then explored at various dosages.

Results

Our simulation results suggested there were no PK interactions between normal doses of opioids and benzodiazepines; but weak interactions can be expected with the combination of opioids and overdosed benzodiazepines. Particular attention should be given to the combination of fentanyl and overdosed alprazolam since a PK interaction can be observed between them.

Conclusion

Our results appear to indicate that pharmacodynamics may play a more important role than PKs in causing DDIs between opioids and benzodiazepines. This study also demonstrated that molecular modeling can be a very useful tool to mitigate the problem of “missing metabolic reaction parameters” in PK modeling and simulation.

Electronic supplementary material

The online version of this article (10.1007/s40268-019-00282-3) contains supplementary material, which is available to authorized users.

Profiles of visuospatial memory dysfunction in opioid-exposed and dependent populations

BACKGROUND

Chronic opioid exposure is common world-wide, but behavioural performance remains under-investigated. This study aimed to investigate visuospatial memory performance in opioid-exposed and dependent clinical populations and its associations with measures of intelligence and cognitive impulsivity.

METHODS

We recruited 109 participants: (i) patients with a history of opioid dependence due to chronic heroin use (n = 24), (ii) heroin users stabilised on methadone maintenance treatment (n = 29), (iii) participants with a history of chronic pain and prescribed tramadol and codeine (n = 28) and (iv) healthy controls (n = 28). The neuropsychological tasks from the Cambridge Neuropsychological Test Automated Battery included the Delayed Matching to Sample (DMS), Pattern Recognition Memory, Spatial Recognition Memory, Paired Associate Learning, Spatial Span Task, Spatial Working Memory and Cambridge Gambling Task. Pre-morbid general intelligence was assessed using the National Adult Reading Test.

RESULTS

As hypothesised, this study identified the differential effects of chronic heroin and methadone exposures on neuropsychological measures of visuospatial memory (p &lt; 0.01) that were independent of injecting behaviour and dependence status. The study also identified an improvement in DMS performance (specifically at longer delays) when the methadone group was compared with the heroin group and also when the heroin group was stabilised onto methadone. Results identified differential effects of chronic heroin and methadone exposures on various neuropsychological measures of visuospatial memory independently from addiction severity measures, such as injecting behaviour and dependence status.

Reinforcing effectiveness of midazolam, ethanol, and sucrose: behavioral economic comparison of a mixture relative to its component solutions

Benzodiazepines (BZs) are relatively safe when administered alone. However, these drugs can produce severe side effects when coadministered with ethanol. Despite these adverse consequences, rates of concurrent BZ and ethanol misuse are increasing, and it is unclear whether this behavior is maintained by an enhanced reinforcing effect of the mixture. To address this issue, the current study compared the reinforcing effectiveness of sucrose solutions mixed with midazolam, ethanol, or both. Eight male rats were trained to orally self-administer solutions of either sucrose (S), sucrose+midazolam (SM), sucrose+ethanol (SE), or sucrose+midazolam+ethanol (SME). The response requirement was increased between sessions until the number of reinforcers earned was zero and the relationship between response requirement and reinforcers earned was analyzed using the exponential model of demand. Although baseline intake was similar across drug conditions, consumption of SM was least affected by increases in cost, indicating that it possessed the highest reinforcing effectiveness (i.e. least elastic). The reinforcing effectiveness of S, SE, and SME did not differ significantly. The finding that the reinforcing effectiveness of the SME was less than that of SM does not support the supposition that BZ and ethanol coadministration is maintained by a higher reinforcing effectiveness of the mixture.

Preference for an Opioid/Benzodiazepine Mixture over an Opioid Alone Using a Concurrent Choice Procedure in Rhesus Monkeys

Increased abuse of opioids is contributing to an escalation in overdose deaths. Benzodiazepines are frequently abused with opioids, possibly because they increase the potency and/or effectiveness of opioids to produce reinforcing effects. This study used a concurrent-choice procedure to determine whether monkeys would choose to self-administer a mixture of the opioid remifentanil and the benzodiazepine midazolam over remifentanil alone. Initially, three monkeys could respond on one lever for saline and on a second lever for either remifentanil alone or midazolam alone. Thereafter, monkeys chose between a dose of remifentanil (0.32 µg/kg/infusion) that did not change and a dose of remifentanil that varied across sessions; for some sessions, midazolam was combined with varying doses of remifentanil. All monkeys received more infusions of remifentanil (0.0032-0.32 µg/kg/infusion) than saline, whereas only two monkeys responded more for midazolam than for saline. When 0.32 µg/kg/infusion remifentanil was available on one lever and a dose of remifentanil that varied across sessions (0.1-1 µg/kg/infusion) was available on the other lever, monkeys chose the larger dose. Combining 3.2 µg/kg/infusion midazolam with 0.32 µg/kg/infusion remifentanil increased responding for the mixture over 0.32 µg/kg/infusion remifentanil alone, although monkeys chose remifentanil alone over mixtures containing smaller doses of remifentanil. When 10 µg/kg/infusion midazolam was combined with 0.1 µg/kg/infusion remifentanil, monkeys chose the mixture over 0.32 µg/kg/infusion remifentanil alone. Thus, monkeys prefer some opioid/benzodiazepine mixtures to larger doses of the opioid alone, suggesting that opioid/benzodiazepine coabuse might be due to increased potency (and possibly effectiveness) of opioids to produce reinforcing effects.

Same-day use of opioids and other central nervous system depressants amongst people who tamper with pharmaceutical opioids: A retrospective 7-day diary study

OBJECTIVE

The aims were to determine: (i) quantity and frequency of same-day use of opioids with benzodiazepines and/or alcohol amongst people who regularly tamper with pharmaceutical opioids; and (ii) socio-demographic, mental health, harms and treatment profile associated with same-day use of high doses.

METHOD

The cohort (n=437) completed a retrospective 7-day diary detailing opioid, benzodiazepine, and alcohol intake. Oral morphine equivalent (OME) units and diazepam equivalent units (DEU) were calculated, with >200mg OME, >40mg DEU and >4 standard alcoholic drinks (each 10g alcohol) considered a "high dose".

RESULTS

One-half (47%) exclusively consumed opioids without benzodiazepines/alcohol; 26% had days of opioid use with and without benzodiazepines/alcohol; and 26% always used opioids and benzodiazepines/alcohol. Same-day use of opioids with benzodiazepines/alcohol typically occurred on 1-3days in the past week. Six in ten (61%) participants reported high dose opioid use on at least one day; one in five (20%) reported high dose opioid and high dose benzodiazepine/alcohol use on at least one day. The latter group were more likely to use prescribed opioid substitution therapy, often alongside diverted pharmaceutical opioids. Socio-demographic and clinical profiles did not vary according to high dose opioid, alcohol and benzodiazepine use, and there was no association with harms.

CONCLUSIONS

Same-day use of opioids with benzodiazepines/alcohol, and high dose combinations, are common amongst people who tamper with pharmaceutical opioids. Assessment of concomitant benzodiazepine/alcohol use during opioid therapy, implementation of real-time prescription monitoring systems, and research to clarify upper safe limits for polydrug depressant use, are potential implications.

The Impact of Opioids on Cardiac Electrophysiology

Synthetic opioid agents have been used in modern medicine for over a century and for opioid addiction treatment for over a half-century. Liberal use of opioids in the United States has been attended by an extraordinary increase in opioid-related mortality, with over 16,000 deaths in 2012. As there have been advances in opioid agents for pain and addiction, so have there been advances in our understanding of the cardiac effects of these agents. In the last 10 years, significant data regarding electrophysiologic effects of these agents have been collected. We aim in this review to discuss the effects on cardiac electrophysiology of the various opioid agents currently in use and the evidence that these effects are contributing to the rise in opioid-related mortality.

Which medications are suitable for agonist drug maintenance?

BACKGROUND AND AIMS

We examine the feasibility of agonist maintenance treatment for the major psychoactive drug classes: opioids, nicotine, benzodiazepines, cannabis, psychostimulants and alcohol.

METHODS

Eight clinical criteria for an agonist maintenance drug were assessed for each major drug class. These related to pharmacological aspects of the drug (agonist, pharmacological stability, dose-response, non-toxic) and neurocognitive sequelae (psychiatric, cognitive, craving, salience).

RESULTS

Opioids and nicotine met all eight criteria for a maintenance drug. While nicotine has not been promoted widely or used for maintenance, it has the potential to fulfil that role. Cannabis met five criteria and has potential, but long-term data on cognitive impairment are required. Benzodiazepine maintenance would appear an option for the high-dose chaotic abuser, also meeting five criteria, although clinic dosing appears the safest option. Psychostimulants (three of eight criteria) and alcohol (one of eight) appear poor propositions for maintenance, in terms of both their pharmacological and their neurocognitive characteristics.

CONCLUSIONS

Drug classes have properties that distinguish them in their suitability for maintenance treatment. Some classes not yet used for maintenance (notably nicotine and cannabis) have potential to fulfil such a role. Others, however, by their inherent nature, appear unsuitable for such a treatment regimen.

The association between benzodiazepine prescription and aberrant drug-related behaviors in primary care patients receiving opioids for chronic pain

BACKGROUND

Benzodiazepine use has been associated with addiction-related risks, but little is known about its association with aberrant drug-related behaviors in patients receiving opioids for chronic pain. The authors examined the association between receipt of a benzodiazepine prescription and 2 aberrant drug-related behaviors, early opioid refills and illicit drug (cocaine) use in patients receiving opioids for noncancer chronic pain.

METHODS

This was a retrospective cohort study of 847 patients with ≥1 visit to either a hospital-based primary care clinic or one of two community health centers between September 1, 2011, and August 31, 2012. All patients received ≥3 opioid prescriptions written at least 21 days apart within 6 months, and ≥1 urine drug screen during the study period. A Cox proportional hazards model estimated the hazard of a second early opioid refill, defined as an opioid prescription written 7-25 days after the previous prescription for the same drug, as a function of time-varying benzodiazepine prescription. A logistic regression model examined the relationship between benzodiazepine prescription and a positive urine test for cocaine. Models were adjusted for demographics and mental/substance use disorder diagnoses.

RESULTS

Twenty-three percent (n = 196) of patients received ≥1 benzodiazepine prescription during the study period. Twenty-two percent (n = 183) of patients had ≥2 early opioid refills, and 11% (n = 93) had ≥1 positive urine drug tests for cocaine. Receipt of benzodiazepine prescription was associated with an increased hazard of having a second early opioid refill, adjusted hazard ratio = 1.54 (95% confidence interval [CI]: 1.09-2.18), but not associated with a positive cocaine test, adjusted odds ratio = 1.07 (95% CI: 0.55-2.23).

CONCLUSIONS

Among primary care patients receiving chronic opioid therapy, benzodiazepine prescription was associated with early opioid refills but not with cocaine use. Further research should better elucidate the risks and benefits of prescribing benzodiazepines to patients receiving opioids for chronic pain.

Medication-assisted treatment of opioid use disorder: review of the evidence and future directions

Medication-assisted treatment of opioid use disorder with physiological dependence at least doubles rates of opioid-abstinence outcomes in randomized, controlled trials comparing psychosocial treatment of opioid use disorder with medication versus with placebo or no medication. This article reviews the current evidence for medication-assisted treatment of opioid use disorder and also presents clinical practice imperatives for preventing opioid overdose and the transmission of infectious disease. The evidence strongly supports the use of agonist therapies to reduce opioid use and to retain patients in treatment, with methadone maintenance remaining the gold standard of care. Combined buprenorphine/naloxone, however, also demonstrates significant efficacy and favorable safety and tolerability in multiple populations, including youth and prescription opioid-dependent individuals, as does buprenorphine monotherapy in pregnant women. The evidence for antagonist therapies is weak. Oral naltrexone demonstrates poor adherence and increased mortality rates, although the early evidence looks more favorable for extended-release naltrexone, which has the advantages that it is not subject to misuse or diversion and that it does not present a risk of overdose on its own. Two perspectives-individualized treatment and population management-are presented for selecting among the three available Food and Drug Administration-approved maintenance therapies for opioid use disorder. The currently unmet challenges in treating opioid use disorder are discussed, as are the directions for future research.

Effects of methadone plus alcohol on cognitive performance in methadone-maintained volunteers

BACKGROUND

Methadone maintenance patients (MMP) often abuse other drugs, including alcohol. The combined use of methadone and alcohol could impair performance and daily functioning.

OBJECTIVE

To examine the effects of methadone in combination with alcohol, as well as acute increases in methadone, on performance outcomes.

METHODS

This double-blind, double-dummy, crossover study included eight opioid-dependent participants stabilized on methadone. Participants completed six inpatient sessions corresponding to methadone (100% or 150% of daily dose) and beverage (placebo, 0.25 or 0.50 g/kg alcohol). Performance tasks were completed before and after drug administration. Area under the time-course values were analyzed by a 2 (methadone dose) by 3 (alcohol dose) repeated measures analysis of variance.

RESULTS

Main effects of methadone were observed for two attention outcomes, suggesting reduced accuracy and slowed responding at an elevated methadone dose. In addition, main effects of alcohol were observed for episodic memory (false alarms and response bias) suggesting more impulsive responding as alcohol dose increased. No robust interactions of methadone and alcohol were observed for any outcome.

CONCLUSIONS

Study findings indicate that an acute increase in methadone (150%) and a moderate dose of alcohol (2-3 drinks) can impair distinct aspects of performance, although no significant interactive effect between methadone and alcohol was found. Future studies with larger sample sizes, larger doses, and more clinically informative tasks could expand on the present findings and further explore the cognitive consequences of concurrent opioid and alcohol use.

Use of Medicines from the Group of Benzodiazepines in the Period of 2003-2013 Year in the Republic of Macedonia

AIM

The aim of this study was to analyze the use of benzodiazepines in the period of 2003-2013 year in the Republic of Macedonia (MKD).

METHOD

The study was cross sectional and analyzes the available data on the use of benzodiazepines in the country. This study used several sources of data: Statistical Reports of the United Nations regarding the consumption of psychotropic substances; data from the Ministry of Health associated with the use of benzodiazepines (BZD), derived from reports of Ministry of Health stakeholders; Data extracted from the database of the Ministry of Health in the electronic database "My term" and Analysis of reports of Health Insurance Fund.

RESULTS

The analysis for the period 2003-2013 showed that the most consumed drug in MKD from the group of BZD is Diazepam, with 54.8 and predominantly is use of diazepam of 5 mg with 59 %. According to the Health Insurance Fund, Diazepam is second most prescribed medicaments of all medicaments with marketing authorization in MKD.

CONCLUSIONS

The analysis shows that the use of BZD in MKD is particularly high. Limited number of studies was performed for this kind of drugs relating to their effects; differences in use between genders; adult population. There is need for additional focused research that will contribute to developing a full picture of the situation.

Benzodiazepine use during buprenorphine treatment for opioid dependence: clinical and safety outcomes

BACKGROUND

Prescribing benzodiazepines during buprenorphine treatment is a topic of active discussion. Clinical benefit is unclear. Overdose, accidental injury, and benzodiazepine misuse remain concerns. We examine the relationship between benzodiazepine misuse history, benzodiazepine prescription, and both clinical and safety outcomes during buprenorphine treatment.

METHODS

We retrospectively examined outpatient buprenorphine treatment records, classifying patients by past-year benzodiazepine misuse history and approved benzodiazepine prescription at intake. Primary clinical outcomes included 12-month treatment retention and urine toxicology for illicit opioids. Primary safety outcomes included total emergency department (ED) visits and odds of an ED visit related to overdose or accidental injury during treatment.

RESULTS

The 12-month treatment retention rate for the sample (N=328) was 40%. Neither benzodiazepine misuse history nor benzodiazepine prescription was associated with treatment retention or illicit opioid use. Poisson regressions of ED visits during buprenorphine treatment revealed more ED visits among those with a benzodiazepine prescription versus those without (p<0.001); benzodiazepine misuse history had no effect. The odds of an accidental injury-related ED visit during treatment were greater among those with a benzodiazepine prescription (OR: 3.7, p<0.01), with an enhanced effect among females (OR: 4.7, p<0.01). Overdose was not associated with benzodiazepine misuse history or prescription.

CONCLUSIONS

We found no effect of benzodiazepine prescriptions on opioid treatment outcomes; however, benzodiazepine prescription was associated with more frequent ED visits and accidental injuries, especially among females. When prescribing benzodiazepines during buprenorphine treatment, patients need more education about accidental injury risk. Alternative treatments for anxiety should be considered when possible, especially among females.

Urine specimen detection of concurrent nonprescribed medicinal and illicit drug use in patients prescribed buprenorphine

Patients being treated with buprenorphine usually have a history of opioid dependence and may be predisposed to misuse of drugs. Concurrent drug misuse increases the risk of life-threatening drug interactions. This retrospective data analysis observed which nonprescribed and illicit drugs were most commonly detected in the urine of patients from pain management clinics taking buprenorphine with or without a prescription. GC, LC/MS and LC-MS-MS were used to quantify 20,929 urine specimens. The most prevalent illicit drug used in both the groups (prescribed and nonprescribed buprenorphine) was marijuana, followed by cocaine. The most prevalent nonprescribed medications abused by both the groups were benzodiazepines, followed by oxycodone and hydrocodone. The overall prevalence of illicit and nonprescribed drug use was significantly higher in subjects who used buprenorphine without a prescription versus prescribed use. Of the concurrent use of marijuana and cocaine with buprenorphine, cocaine is most concerning since it decreases exposure to buprenorphine (lower area under the concentration-time curve and maximum concentration). The concurrent use of nonprescribed benzodiazepines with buprenorphine can cause excess sedation leading to respiratory depression and even death. These findings highlight the importance of educating patients about these potential toxicities. Furthermore, pain providers should consider expanding the spectrum of drugs that they monitor in patients under treatment.

Do drug treatment variables predict cognitive performance in multidrug-treated opioid-dependent patients? A regression analysis study

Background

Cognitive deficits and multiple psychoactive drug regimens are both common in patients treated for opioid-dependence. Therefore, we examined whether the cognitive performance of patients in opioid-substitution treatment (OST) is associated with their drug treatment variables.

Methods

Opioid-dependent patients (N = 104) who were treated either with buprenorphine or methadone (n = 52 in both groups) were given attention, working memory, verbal, and visual memory tests after they had been a minimum of six months in treatment. Group-wise results were analysed by analysis of variance. Predictors of cognitive performance were examined by hierarchical regression analysis.

Results

Buprenorphine-treated patients performed statistically significantly better in a simple reaction time test than methadone-treated ones. No other significant differences between groups in cognitive performance were found. In each OST drug group, approximately 10% of the attention performance could be predicted by drug treatment variables. Use of benzodiazepine medication predicted about 10% of performance variance in working memory. Treatment with more than one other psychoactive drug (than opioid or BZD) and frequent substance abuse during the past month predicted about 20% of verbal memory performance.

Conclusions

Although this study does not prove a causal relationship between multiple prescription drug use and poor cognitive functioning, the results are relevant for psychosocial recovery, vocational rehabilitation, and psychological treatment of OST patients. Especially for patients with BZD treatment, other treatment options should be actively sought.

Polydrug abuse: a review of opioid and benzodiazepine combination use

This paper reviews studies examining the pharmacological interactions and epidemiology of the combined use of opioids and benzodiazepines (BZDs). A search of English language publications from 1970 to 2012 was conducted using PubMed and PsycINFO(®). Our search found approximately 200 articles appropriate for inclusion in this paper. While numerous reports indicate that the co-abuse of opioids and BZDs is ubiquitous around the world, the reasons for the co-abuse of these medications are not entirely clear. Though the possibility remains that opioid abusers are using BZDs therapeutically to self-medicate anxiety, mania or insomnia, the data reviewed in this paper suggest that BZD use is primarily recreational. For example, co-users report seeking BZD prescriptions for the purpose of enhancing opioid intoxication or "high," and use doses that exceed the therapeutic range. Since there are few clinical studies investigating the pharmacological interaction and abuse liability of their combined use, this hypothesis has not been extensively evaluated in clinical settings. As such, our analysis encourages further systematic investigation of BZD abuse among opioid abusers. The co-abuse of BZDs and opioids is substantial and has negative consequences for general health, overdose lethality, and treatment outcome. Physicians should address this important and underappreciated problem with more cautious prescribing practices, and increased vigilance for abusive patterns of use.

Separate and combined psychopharmacological effects of alprazolam and oxycodone in healthy volunteers

BACKGROUND

There are epidemiological data indicating that medical and/or nonmedical use of prescription opioids oftentimes involves concurrent use of other substances. One of those substances is benzodiazepines. It would be of relevance to characterize the effects of an opioid and a benzodiazepine when taken together to determine if measures related to abuse liability-related effects and psychomotor performance impairment are increased compared to when the drugs are taken alone.

METHODS

Twenty volunteers participated in a crossover, randomized, double-blind study in which they received placebo, 0.5mg alprazolam, 10mg oxycodone, and 0.5mg alprazolam combined with 10 mg oxycodone, all p.o. Subjective, psychomotor, and physiological measures were assessed during each of the four sessions.

RESULTS

Oxycodone by itself increased drug liking and "take again" ratings relative to placebo, but these ratings were not increased when oxycodone was taken with alprazolam, which by itself did not increase either of these ratings. The two drugs in combination produced stronger effects (larger in magnitude or longer lasting) than when either was taken alone on a number of measures, including psychomotor performance impairment.

CONCLUSIONS

In healthy volunteers, abuse liability-related subjective effects of oxycodone were not enhanced by alprazolam. There was enhanced behavioral toxicity when the drugs were taken together, and thus, this is of significant concern from a public safety standpoint.

BAP updated guidelines: evidence-based guidelines for the pharmacological management of substance abuse, harmful use, addiction and comorbidity: recommendations from BAP

The British Association for Psychopharmacology guidelines for the treatment of substance abuse, harmful use, addiction and comorbidity with psychiatric disorders primarily focus on their pharmacological management. They are based explicitly on the available evidence and presented as recommendations to aid clinical decision making for practitioners alongside a detailed review of the evidence. A consensus meeting, involving experts in the treatment of these disorders, reviewed key areas and considered the strength of the evidence and clinical implications. The guidelines were drawn up after feedback from participants. The guidelines primarily cover the pharmacological management of withdrawal, short- and long-term substitution, maintenance of abstinence and prevention of complications, where appropriate, for substance abuse or harmful use or addiction as well management in pregnancy, comorbidity with psychiatric disorders and in younger and older people.

A rapid UPLC-MS/MS method for simultaneous determination of flunitrazepam, 7-aminoflunitrazepam, methadone and EDDP in human, rat and rabbit plasma

A simple, high-throughput, sensitive LC-ESI-MS/MS method is presented for the simultaneous determination of methadone (MET), flunitrazepam (FNZ) and their major metabolites, EDDP (2-ethilidene-1,5-dimethyl-3,3-diphenylpyrrolidone) and 7-aminoflunitrazepam (7-AFNZ), respectively, in human, rat and rabbit plasma. The isolation of the selected compounds involved a liquid-liquid extraction with ethyl acetate at a basic pH. Good chromatographic separation was achieved on a HSS T3 column (1.8 μm particle size), with a 3 min gradient elution using a mixture of acetonitrile with 0.1% formic acid (solvent A) and 5mM ammonium acetate (solvent B) as the mobile phase. The tandem mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode with ionization of the analytes in positive mode. The assay was fully validated according to current acceptance criteria for bioanalytical methods validation. It was proved to be linear in the range of 0.5-250 ng/mL, with adequate accuracy and precision over this range. Based on accuracy and CV% values the LOQ and ULOQ values were set at 0.509 ng/mL and 2036 ng/mL for MET, 0.520 ng/mL and 2080 ng/mL for EDDP, 0.524 ng/mL and 2096 ng/mL for FNZ and 0.528 ng/mL and 2114 ng/mL for 7-AFNZ, respectively. The method was tested for potential matrix effects, without observing significant ion suppression. The investigated compounds stability was examined in plasma at room temperature and after three freeze-thaw cycles and in the final extract when maintained at 4 °C in the autosampler. Potential stability issues were observed only for FNZ at room temperature. The method was successfully applied to quantify the selected compounds in human, rat and rabbit plasma samples, after exposure to FNZ or simultaneous exposure to FNZ and MET.

Methadone: a review of drug-drug and pathophysiological interactions

Numerous established and potential drug interactions with methadone are clinically important in people treated with methadone either for addiction or for chronic pain. Methadone users often have comorbidities and are prescribed drugs that may interact with methadone. Methadone is extensively metabolized by cytochrome P450 (CYP) 3A4 and to a lesser extent by CYP 1A2, 2D6, 2D8, 2C9/2C8, 2C19, and 2B6. Eighty-six percent of methadone is protein bound, predominately to α1-acid glycoprotein (AGP). Polymorphisms in or interactions with CYPs that metabolize methadone, changes in protein binding, and other pathophysiological conditions affect the pharmacokinetic properties of methadone. It is critical for health care providers who treat patients on methadone to have adequate information on the interactions of methadone with other drugs of abuse and other medications. We set out to describe drug-drug interactions as well as physiological and pathophysiological factors that may impact the pharmacokinetics of methadone. Using MEDLINE, we conducted a systematic search for papers and related abstracts published between 1966 and June 2010. Keywords that included methadone, drug-drug interactions, CYP P450 and AGP identified a total of 7709 papers. Other databases, including the Cochrane Database of Systematic Reviews and Scopus, were also searched; an additional 929 papers were found. Final selection of 286 publications was based on the relevance of each paper to the topic. Over 50 such interactions were found. Interactions of methadone with other drugs can lead to increased or decreased methadone drug levels in patients and result in potential overdose or withdrawal, respectively. The former can contribute to methadone's fatality. Prescribers of methadone and pharmacists should enquire about any new medications (including natural products and over-the-counter medications) periodically, and especially when an otherwise stable patient suddenly experiences drug craving, withdrawal or intoxication.

Benzodiazepines revisited--will we ever learn?

AIMS

To re-examine various aspects of the benzodiazepines (BZDs), widely prescribed for 50 years, mainly to treat anxiety and insomnia. It is a descriptive review based on the Okey Lecture delivered at the Institute of Psychiatry, King's College London, in November 2010.

METHODS

A search of the literature was carried out in the Medline, Embase and Cochrane Collaboration databases, using the codeword 'benzodiazepine(s)', alone and in conjunction with various terms such as 'dependence', 'abuse', etc. Further hand-searches were made based on the reference lists of key papers. As 60,000 references were found, this review is not exhaustive. It concentrates on the adverse effects, dependence and abuse.

RESULTS

Almost from their introduction the BZDs have been controversial, with polarized opinions, advocates pointing out their efficacy, tolerability and patient acceptability, opponents deprecating their adverse effects, dependence and abuse liability. More recently, the advent of alternative and usually safer medications has opened up the debate. The review noted a series of adverse effects that continued to cause concern, such as cognitive and psychomotor impairment. In addition, dependence and abuse remain as serious problems. Despite warnings and guidelines, usage of these drugs remains at a high level. The limitations in their use both as choice of therapy and with respect to conservative dosage and duration of use are highlighted. The distinction between low-dose 'iatrogenic' dependence and high-dose abuse/misuse is emphasized.

CONCLUSIONS

The practical problems with the benzodiazepines have persisted for 50 years, but have been ignored by many practitioners and almost all official bodies. The risk-benefit ratio of the benzodiazepines remains positive in most patients in the short term (2-4 weeks) but is unestablished beyond that time, due mainly to the difficulty in preventing short-term use from extending indefinitely with the risk of dependence. Other research issues include the possibility of long-term brain changes and evaluating the role of the benzodiazepine antagonist, flumazenil, in aiding withdrawal.

Cognitive functioning in opioid-dependent patients treated with buprenorphine, methadone, and other psychoactive medications: stability and correlates

BACKGROUND

In many but not in all neuropsychological studies buprenorphine-treated opioid-dependent patients have shown fewer cognitive deficits than patients treated with methadone. In order to examine if hypothesized cognitive advantage of buprenorphine in relation to methadone is seen in clinical patients we did a neuropsychological follow-up study in unselected sample of buprenorphine- vs. methadone-treated patients.

METHODS

In part I of the study fourteen buprenorphine-treated and 12 methadone-treated patients were tested by cognitive tests within two months (T1), 6-9 months (T2), and 12-17 months (T3) from the start of opioid substitution treatment. Fourteen healthy controls were examined at similar intervals. Benzodiazepine and other psychoactive comedications were common among the patients. Test results were analyzed with repeated measures analysis of variance and planned contrasts. In part II of the study the patient sample was extended to include 36 patients at T2 and T3. Correlations between cognitive functioning and medication, substance abuse, or demographic variables were then analyzed.

RESULTS

In part I methadone patients were inferior to healthy controls tests in all tests measuring attention, working memory, or verbal memory. Buprenorphine patients were inferior to healthy controls in the first working memory task, the Paced Auditory Serial Addition Task and verbal memory. In the second working memory task, the Letter-Number Sequencing, their performance improved between T2 and T3. In part II only group membership (buprenorphine vs. methadone) correlated significantly with attention performance and improvement in the Letter-Number Sequencing. High frequency of substance abuse in the past month was associated with poor performance in the Letter-Number Sequencing.

CONCLUSIONS

The results underline the differences between non-randomized and randomized studies comparing cognitive performance in opioid substitution treated patients (fewer deficits in buprenorphine patients vs. no difference between buprenorphine and methadone patients, respectively). Possible reasons for this are discussed.

Increased cardiac risk in concomitant methadone and diazepam treatment: pharmacodynamic interactions in cardiac ion channels

Methadone, a synthetic opioid for treatment of chronic pain and withdrawal from opioid dependence, has been linked to QT prolongation, potentially fatal torsades de pointes, and sudden cardiac death. Concomitant use of diazepam or other benzodiazepines in methadone maintenance treatment can increase the risk of sudden death. Therefore, we determined the effects of methadone and diazepam singly and in combination on cardiac action potentials (APs) and on the major ion channels responsible for cardiac repolarization. Using patch clamp recording in human stem cell-derived cardiomyocytes and stably transfected mammalian cells, we found that methadone produced concentration-dependent AP prolongation and ion channel block at low micromolar concentrations: hERG (IC50 = 1.7 μM), hNav1.5 (11.2 μM tonic block; 5.5 μM phasic block), and hCav1.2 (26.7 μM tonic block; 7.7 μM phasic block). Methadone was less potent in hKv4.3/hKChIP2.2 (IC50 = 39.0 μM) and hKvLQT1/hminK (53.3 μM). In contrast, diazepam blocked channels only at much higher concentrations and had no effect on AP duration at 1 μM. However, coadministration of 1-μM diazepam with methadone caused a statistically significant increase in AP duration and a 4-fold attenuation of hNav1.5 block (IC50 values were 44.2 μM and 26.6 μM, respectively, for tonic and phasic block), with no significant effect on methadone-induced block of hERG, hCav1.2, hKv4.3/hKChIP2.2, and hKvLQT1/hminK channels. Thus, although diazepam alone does not prolong the QT interval, the relief of methadone-induced Na channel block may leave hERG K channel block uncompensated, thereby increasing cardiac risk.

Pharmacokinetic drug interactions and adverse consequences between psychotropic medications and pharmacotherapy for the treatment of opioid dependence

BACKGROUND

Psychiatric comorbidities among opioid-dependent patients are common. Many medications used to treat both conditions are metabolized through complimentary cytochrome P450 isoenzymes. When medication-assisted treatment for opioid dependence is concurrently used with psychotropic medications, problematic pharmacokinetic drug interactions may occur.

METHODS

We reviewed relevant English language articles identified through the MedLine, Scopus, and Embase databases from 1950 to December 2009 using the specific generic names of medications and keywords such as pharmacokinetics and drug interactions with buprenorphine, methadone, and naltrexone. Selected references from these articles were reviewed. Additionally, a review was conducted of abstracts and conference proceedings from national and international meetings from 1990 to 2009. A total of 60 studies were identified and reviewed.

RESULTS

Clinical case series and carefully controlled pharmacokinetic interaction studies have been conducted between methadone, buprenorphine, or naltrexone and some psychoactive medications. Important pharmacokinetic drug interactions have been demonstrated within each class of medications affecting either methadone and buprenorphine or psychoactive drugs. Few studies, however, have been conducted with naltrexone.

CONCLUSIONS

Several interactions between methadone, buprenorphine, or naltrexone and psychoactive medications are described and may have important clinical consequences. To optimize care, clinicians must be alerted to these interactions.

Impact of pharmacist and clinician dual intervention on prescribed benzodiazepines in prisoner patients: a retrospective study

High-dose benzodiazepine (BDZs) represents an important risk factor for dependence, particularly in a prison environment. In Lyon's prison, BDZs and/or opioid maintenance treatment are often prescribed to patients with mental disorders. The aim of this retrospective study was to assess the impact of psychiatrist and pharmacist collaboration on reducing the BDZs dose prescribed to prisoner patients. Since 2001, clinicians and pharmacists have been holding monthly meetings to develop prescribing guidelines and discuss those patients receiving high-dose BDZs. All prescribed psychotropic drugs were noted for each included patient in the control (before guidelines) and intervention groups. Criteria used to define each patient profile included age, diagnosis (mental disorder), and concomitant treatment (opioids, antidepressants). To compare each group, the daily dose of prescribed BDZs was used as a quantitative variable and expressed in diazepam equivalent. Four hundred and seventy-three patients were included, 222 in the control group and 251 in the intervention group. The two groups showed no difference in terms of diagnosis. The daily dose of BDZ was higher in the control group when all patients were considered (mean(CONTROL GROUP) = 46 mg in diazepam equivalent vs. mean(INTERVENTIION GROUP) = 34 mg) and for each of the following patient categories: 'mental disorder' (48 mg vs. 30 mg), 'no opioid treatment' (44 mg vs. 31 mg), 'buprenorphin treatment' (58 mg vs. 63 mg), 'no antidepressant treatment' (41 mg vs. 29 mg), and 'antidepressant treatment' (53 mg vs. 38 mg). The results of this retrospective study show the positive impact of multidisciplinary intervention on reducing the prescribed daily dose of BDZs. This experience confirms the positive impact that pharmacist feedback on prescriptions and the development of treatment guidelines by clinician and pharmacist collaboration have on improving the prescribing practice in a prison environment.

Drug interactions of clinical importance among the opioids, methadone and buprenorphine, and other frequently prescribed medications: a review

Drug interactions are a leading cause of morbidity and mortality. Methadone and buprenorphine are frequently prescribed for the treatment of opioid addiction. Patients needing treatment with these medications often have co-occurring medical and mental illnesses that require medication treatment. The abuse of illicit substances is also common in opioid-addicted individuals. These clinical realities place patients being treated with methadone and buprenorphine at risk for potentially toxic drug interactions. A substantial literature has accumulated on drug interactions between either methadone or buprenorphine with other medications when ingested concomitantly by humans. This review summarizes current literature in this area.

The comparative toxicology and major organ pathology of fatal methadone and heroin toxicity cases

In order to determine the comparative toxicology and systemic disease of cases of death due to methadone and heroin toxicity, 1193 coronial cases of opioid overdose that occurred in New South Wales, Australia between 1 January 1998 and 31 December 2007 were inspected. These comprised 193 cases in which cause of death involved methadone toxicity (METH) and 1000 cases in which cause of death involved heroin toxicity in the absence of methadone (HER). METH cases were significantly more likely to have benzodiazepines (63.7% vs. 32.2%), and less likely to have alcohol (23.6% vs. 42.7%) detected. METH cases were significantly more likely to be diagnosed with pre-existing systemic pathology (94.3% vs. 79.9%), and multiple organ system pathology (68.8% vs. 41.4%). Specifically, METH cases were more likely to have cardiac (58.9% vs. 34.5%), pulmonary (53.6% vs. 30.9%), hepatic (80.7% vs. 62.8%) and renal (25.0% vs. 9.5%) disease. Given the notable differences in toxicology and disease patterns, great caution appears warranted in prescribing benzodiazepines to methadone users, and regular physical examinations of methadone treatment patients would appear clinically warranted.

Memory function in opioid-dependent patients treated with methadone or buprenorphine along with benzodiazepine: longitudinal change in comparison to healthy individuals

BACKGROUND

Opioid-substitution treatment (OST) for opioid dependence (OD) has proven effective in retaining patients in treatment and reducing illegal opiate abuse and crime. Consequently, the World Health Organization (WHO) has listed the opioid agonists methadone and buprenorphine as essential drugs for OD that should be available worldwide. In many areas of the world, OD is often associated with concomitant benzodiazepine (BZD) dependence and abuse, which complicates treatment. However, possible changes in the cognitive functioning of these patients are not well-known. The present study is the first to examine longitudinal stability of memory function in OST patients with BZD use, thus providing a new tool for health policy authorities in evaluating the usefulness of OST.

METHODS

Within the first two months (T1) and between 6-9 months (T2) after OST admission, we followed the working memory, immediate verbal memory, and memory consolidation of 13 methadone- and 15 buprenorphine- or buprenorphine/naloxone-treated patients with BZD dependence or abuse disorder. The results were compared to those of fifteen normal comparison participants. All participants also completed a self-reported memory complaint questionnaire on both occasions.

RESULTS

Both patient groups performed statistically significantly worse than normal comparison participants in working memory at time points T1 and T2. In immediate verbal memory, as measured by list learning at T1, patients scored lower than normal comparison participants. Both patient groups reported significantly more subjective memory problems than normal comparison participants. Patients with more memory complaints recalled fewer items at T2 from the verbal list they had learned at T1 than those patients with fewer memory complaints. The significance of the main analyses remained nearly the same when the statistical tests were performed without buprenorphine-only patients leaving 12 patients to buprenorphine/naloxone group.

CONCLUSION

Working memory may be persistently affected in OST patients with BZD use. A high number of memory complaints among OST patients with BZD use may indicate memory consolidation impairment. These findings show that recovery of memory function in OD patients treated along with BZDs takes time, and their memory complaints may have practical relevance.

Self-report of illicit benzodiazepine use on the Addiction Severity Index predicts treatment outcome

The relationship between pre-treatment illicit benzodiazepine use (days of use in the last 30) assessed on the Addiction Severity Index (ASI) and treatment outcome was investigated by retrospective analysis of data from two controlled clinical trials in 361 methadone maintained cocaine/opiate users randomly assigned to 12-week voucher- or prize-based contingency management (CM) or control interventions. Based on screening ASI, participants were identified as non-users (BZD-N; 0 days of use) or users (BZD-U; >0 days of use). Outcome measures were: urine drug screens (thrice weekly); quality of life and self-reported HIV-risk behaviors (every 2 weeks); and current DSM-IV diagnosis of cocaine and heroin dependence (study exit). In the CM group, BZD-U had significantly worse outcomes on in-treatment cocaine use, quality-of-life scores, needle-sharing behaviors, and current heroin dependence diagnoses at study exit compared to BZD-N. In the control group, BZD-U had significantly higher in-treatment cocaine use but did not differ from BZD-N on psychosocial measures. Thus, in a sample of non-dependent BZD users, self-reported illicit BZD use on the ASI, even at low levels, predicted worse outcome on cocaine use and blunted response to CM.

Case series of buprenorphine injectors in Kuala Lumpur, Malaysia

Diversion of buprenorphine has been described in settings where it is legally prescribed and has become an increasing concern in Malaysia; it resulted in banning of buprenorphine in Singapore where unsubstantiated case reports suggested that buprenorphine injection was associated with particularly poor outcomes. We therefore conducted a case series of qualitative interviews with buprenorphine injectors in Kuala Lumpur, Malaysia to examine further the issues surrounding buprenorphine injection as well as the abuse of midazolam in combination with buprenorphine. Interviews with 19 men do not suggest significant adverse health consequences from buprenorphine injection alone and injectors have adapted diverted buprenorphine as a treatment modality. A subset of these injectors, however, combined buprenorphine and midazolam for euphoric effects with resultant symptoms of a possible pharmacological interaction. Prospective cohort studies, rather than hospital-derived samples, are needed to better understand the safety of buprenorphine injection.

Office-based treatment in opioid dependence: a critical survey of prescription practices for opioid maintenance medications and concomitant benzodiazepines in Vienna, Austria

BACKGROUND

The success of maintenance treatment for opioid dependence in office-based settings is influenced by the extent of treatment coverage, the availability of effective medications and the capacity of general practitioners to prescribe opioids in adequate doses with a minimum of concomitant benzodiazepine prescriptions.

METHODS

This study compares prescriptions for opioid maintenance and concomitant benzodiazepine from Viennese physicians in 2002 and 2005 using health insurance prescription records (n = 30,309).

RESULTS

Between 2002 and 2005, the number of patients prescribed opioids more than doubled (ratio 1:2.3), slow-release oral morphine replaced methadone as the most frequently prescribed medication (57.1 vs. 23.4%; buprenorphine 19.5%), and the ratio of benzodiazepine to opioid prescriptions significantly declined (0.76:1 vs. 0.42:1). Many patients were prescribed concomitant benzodiazepines (27%), in some cases from a secondary physician.

CONCLUSION

Increased utilization of opioid medications in office-based settings will facilitate better treatment coverage. However, safeguards are necessary to ensure that general practitioners have sufficient training and support to safely and appropriately provide treatment, including the reduction in concomitant benzodiazepine use.

Pharmacodynamics of diazepam co-administered with methadone or buprenorphine under high dose conditions in opioid dependent patients

BACKGROUND

Benzodiazepine abuse is common among methadone- and buprenorphine-maintained patients; however interactions between these drugs under high dose conditions have not been adequately examined under controlled conditions.

OBJECTIVE

To investigate the effects of co-administering diazepam with methadone or buprenorphine under high dose conditions.

DESIGN

Double-blind, randomly ordered, 2 x 2 cross-over design in which the effects of diazepam dose (0mg versus 40 mg) and opioid dose (100% versus 150% normal dose) were examined over four sessions in methadone- and buprenorphine-maintained patients.

PARTICIPANTS

Four methadone- and seven buprenorphine-prescribed patients without concurrent dependence on other substances or significant medical co-morbidity.

MEASURES

Physiological (pulse rate, blood pressure, pupil size, respiratory rate and peripheral SpO2), subjective (ARCI, VAS ratings) and performance (reaction time, cancellation task and Digit Symbol Substitution Test, DSST) measures were taken prior to and for 6h post-dosing.

RESULTS

High dose diazepam was associated with time-dependent increases in the intensity of subjective drug effects (strength of drug effect, sedation) and decreases in psychological performance (reaction time, DSST) for both methadone and buprenorphine patients. These effects were generally independent of the opioid dose administered. High dose opioid administration (150% normal dose) was associated with reductions in overall SpO2 levels and performance (reaction time, DSST) in the methadone patients, but had virtually no impact on pharmacodynamic responses in the buprenorphine group.

CONCLUSION

High dose diazepam significantly alters subjective drug responses and psychological performance in patients maintained on methadone and buprenorphine.

Benzodiazepine prescription for patients in opioid maintenance treatment in Norway

BACKGROUND

Opioid maintained patients report high levels of anxiety, but the use of benzodiazepines among these patients has been associated with negative outcomes such as increased risk of overdose and death and poorer retention in programmes. Previous research has used interview or urine analysis to assess benzodiazepine use. In this study a prescription database was applied.

METHODS

The Norwegian Prescription Database covers all prescriptions for the entire population from 1 January 2004. Benzodiazepine prescriptions to patients receiving methadone (N=1364) or buprenorphine (N=805) in 2004 and 2005 were studied. Type and amount of drugs received were investigated.

RESULTS

Overall 40% of the patients received at least one prescription for a benzodiazepine drug. Oxazepam was the most frequently prescribed drug. Female patients, methadone-maintained patients and patients in the liberal programmes received a prescription more often. Prescribed doses were high and highest in the liberal programmes. Older patients received more hypnotics. Dose of maintenance drug was positively related to amount of anxiolytics prescribed.

CONCLUSIONS

This study showed that more benzodiazepines were prescribed to opioid maintenance treatment patients than previously shown by investigations using interview or urine analysis. The doses prescribed were generally high. In light of the negative outcomes following benzodiazepine use in these patients, Norwegian doctors need to review their prescription practices.

Self administration of cocaine in monkeys receiving LAAM acutely or chronically

Polydrug abuse remains a common problem among opioid abusers as well as patients in opioid maintenance programs. Although cocaine abuse has been reported in patients receiving methadone, the incidence of cocaine use in patients receiving l-alpha-acetylmethadol (LAAM) has not been well established. The goal of this study was to determine whether acute or chronic administration of LAAM modified the reinforcing effects of cocaine using a self-administration procedure in rhesus monkeys. Four monkeys responded under a fixed ratio (FR) 30 schedule to receive i.v. infusions of cocaine (0.0032-0.32 mg/kg/infusion) in the absence of other treatment, after acute LAAM administration (0.1-1.0 mg/kg, s.c.), and during daily administration of 1.0 mg/kg of LAAM. Cocaine maintained self-administration responding that exceeded responding maintained by saline; acutely administered LAAM had small and variable effects on self administration of cocaine. Daily LAAM administration increased the number of infusions received of at least one dose of cocaine. These studies indicated that LAAM administration did not attenuate the reinforcing effects of cocaine, suggesting that LAAM would not likely alter cocaine abuse in patients undergoing treatment for opioid abuse.

Methadone vs. buprenorphine/naloxone during early opioid substitution treatment: a naturalistic comparison of cognitive performance relative to healthy controls

BACKGROUND

Both methadone- and buprenorphine-treated opioid-dependent patients frequently show cognitive deficits in attention, working memory, and verbal memory. However, no study has compared these patient groups with each other during early opioid substitution treatment (OST). Therefore, we investigated attention, working memory, and verbal memory of opioid-dependent patients within six weeks after the introduction of OST in a naturalistic setting and compared to those of healthy controls.

METHODS

The sample included 16 methadone-, 17 buprenorphine/naloxone-treated patients, and 17 healthy controls matched for sex and age. In both groups buprenorphine was the main opioid of abuse during the recent month. Benzodiazepine codependence, recent use, and comedication were also common in both patient groups. Analysis of variance was used to study the overall group effect in each cognitive test. Pair-wise group comparisons were made, when appropriate

RESULTS

Methadone-treated patients, as a group, had significantly slower simple reaction time (RT) compared to buprenorphine/naloxone-treated patients. In Go/NoGo RT methadone patients were significantly slower than controls. Both patient groups were significantly debilitated compared to controls in working memory and verbal list learning. Only methadone patients were inferior to controls in story recall. In simple RT and delayed story recall buprenorphine/naloxone patients with current benzodiazepine medication (n = 13) were superior to methadone patients with current benzodiazepine medication (n = 13). When methadone patients were divided into two groups according to their mean dose, the patient group with a low dose (mean 40 mg, n = 8) showed significantly faster simple RT than the high dose group (mean 67 mg, n = 8).

CONCLUSION

Deficits in attention may only be present in methadone-treated early phase OST patients and may be dose-dependent. Working memory deficit is common in both patient groups. Verbal memory deficit may be more pronounced in methadone-treated patients than in buprenorphine/naloxone-treated patients. In sum, to preserve cognitive function in early OST, the use of buprenorphine/naloxone may be more preferable to methadone use of, at least if buprenorphine has been recently abused and when benzodiazepine comedication is used. Longitudinal studies are needed to investigate if the better performance of buprenorphine/naloxone-treated patients is a relatively permanent effect or reflects "only" transient opioid switching effect.

Opioid maintenance: a comparative review of pharmacological strategies

The use of opioids outside of medical practice is a significant health problem with important social and political implications. Although treatment of opioid dependence is traditionally focused on heroin users, there is increasing recognition that a large number of people become dependent through the use of prescription opioids. The necessity for long-term treatment has also been increasingly recognised. At present, there are several pharmacotherapies available for maintenance treatment, including drugs that are full agonists at the opioid receptor (e.g., methadone, slow-release oral morphine), a partial agonist (buprenorphine) and an opioid antagonist (naltrexone). This review examines the existing strategies, highlights problems associated with their use and discusses the opportunities for new treatment approaches, particularly the use of long-acting formulations.