Memantine improves buprenorphine/naloxone treatment for opioid dependent young adults

Interventions to Reduce Opioid Use in Youth At-Risk and in Treatment for Substance Use Disorders: A Scoping Review

BACKGROUND

Youth and young adults have been significantly impacted by the opioid overdose and health crisis in North America. There is evidence of increasing morbidity and mortality due to opioids among those aged 15-29. Our review of key international reports indicates there are few youth-focused interventions and treatments for opioid use. Our scoping review sought to identify, characterize, and qualitatively evaluate the youth-specific clinical and pre-clinical interventions for opioid use among youth.

METHOD

We searched MedLine and PsycInfo for articles that were published between 2013 and 2021. Previous reports published in 2015 and 2016 did not identify opioid-specific interventions for youth and we thus focused on the time period following the periods covered by these prior reports. We input three groups of relevant keywords in the aforementioned search engines. Specifically, articles were included if they targeted a youth population (ages 15-25), studied an intervention, and measured impacts on opioid use.

RESULTS

We identified 21 studies that examined the impacts of heterogeneous interventions on youth opioid consumption. The studies were classified inductively as psycho-social-educational, pharmacological, or combined pharmacological-psycho-social-educational. Most studies focused on treatment of opioid use disorder among youth, with few studies focused on early or experimental stages of opioid use. A larger proportion of studies focused heavily on male participants (i.e., male gender and/or sex). Very few studies involved and/or included youth in treatment/program development, with one study premised on previous research about sexual minority youth.

CONCLUSIONS

Research on treatments and interventions for youth using or at-risk of opioids appears to be sparse. More youth involvement in research and program development is vital. The intersectional and multi-factorial nature of youth opioid use and the youth opioid crisis necessitates the development and evaluation of novel treatments that address youth-specific contexts and needs (i.e., those that address socio-economic, neurobiological, psychological, and environmental factors that promote opioid use among youth).

Treatment approaches and outcome trajectories for youth with high-risk opioid use: A narrative review

AIM

First use of opioids often happens in adolescence and an increasing number of opioid overdoses are being reported among youth. The purpose of this narrative review was to present the treatment approaches for youth with high-risk opioid use, determine whether the literature supports the use of opioid agonist treatment among youth and identify evidence for better treatment outcomes in the younger population.

METHODS

A search of the literature on PubMed using MeSH terms specific to youth, opioid use and treatment approaches generated 1436 references. Following a screening process, 137 papers were found to be relevant to the treatment of high-risk opioid use among youth. After full-text review, 19 eligible studies were included: four randomized controlled trials, nine observational studies and six reviews.

RESULTS

Research for the different treatment options among youth is limited. The available evidence shows better outcomes in terms of retention in care and cost-effectiveness for opioid agonist treatment than abstinence-based comparisons. Integrating psychosocial interventions into the continuum of care for youth can be an effective way of addressing comorbid psychiatric conditions and emotional drivers of substance use, leading to improved treatment trajectories.

CONCLUSIONS

From the limited findings, there is no evidence to deny youth with high-risk opioid use the same treatment options available to adults. A combination of pharmacological and youth-specific psychosocial interventions is required to maximize retention and survival. There is an urgent need for more research to inform clinical strategies toward appropriate treatment goals for such vulnerable individuals.

Effectiveness of medication for opioid use disorders in transition-age youth: A systematic review

BACKGROUND

Sequalae of opioid misuse constitute a public health emergency in the United States. A robust evidence base informs the use of medication for opioid use disorders (MOUD) in adults, with far less research in transition-age youth. This systematic review evaluates the effectiveness of MOUD for transition-age youth (age 16 to 25).

METHODS

This synthesis was part of a larger systematic review focused on adolescent substance use interventions. The study team conducted literature searches in MEDLINE, the Cochrane CENTRAL Registry of Controlled Trials, EMBASE, PsycINFO, and CINAHL through October 31, 2019. We screened studies, extracted data, and assessed risk of bias using standard methods. The primary and secondary outcomes were the effect of MOUD on opioid abstinence and treatment retention, respectively.

RESULTS

The study team screened a total of 33,272 records and examined 1831 full-text articles. Four randomized trials met criteria for inclusion in the current analysis. All four trials assessed a combination of buprenorphine plus cognitive behavioral therapy versus a comparison condition. Some trials included additional behavioral interventions, and the specific duration/dosage of buprenorphine varied. Risk of bias was moderate for all studies. Studies found that buprenorphine was more effective than clonidine, effectively augmented by memantine, and that longer medication taper durations were more effective than shorter tapers in promoting both abstinence and retention. Notably, we did not identify any studies of methadone or naltrexone, adjunctive behavioral interventions were sparingly described, and treatment durations were far shorter than recommended guidelines in adults.

DISCUSSION

The literature guiding youth MOUD is limited, and more research should evaluate the effectiveness of options other than buprenorphine, optimal treatment duration, and the benefit of adjunctive behavioral interventions. Subgroup analyses of extant randomized clinical trials could help to extend knowledge of MOUD effectiveness in this age cohort.

Mechanistic insights into the efficacy of memantine in treating certain drug addictions

The deleterious effects of the drug addiction epidemic are compounded by treatment strategies that are only marginally efficacious. Memantine is a unique glutamatergic medication with proven ability to attenuate drug addiction in preclinical models. However, clinical translational studies are inconsistent. In this review, we summarize preclinical evidences and clinical trials that investigated the efficacy of memantine in treating patients with alcohol, opiate, cocaine, and nicotine use disorders and discuss the results from a mechanistic point of view. Memantine has shown efficacy in reducing alcohol and opiate craving, consumption, and withdrawal severity. However, in cocaine and nicotine use disorders, memantine did not have significant effect on cravings or consumption. Additionally, memantine was associated with increased subjective effects of alcohol, cocaine, and nicotine. We discuss possible mechanisms behind this variability. Since memantine transiently blocks NMDA receptors and protects neurons from overstimulation by excessive synaptic glutamate, its efficacy should be observed in drug phases that cause hyperglutamatergic states, while hypoglutamatergic drug use states would not resolve with blocking NMDA receptors. Second, memantine pharmacokinetic studies have been done in rodents and healthy volunteers, but not in patients with substance use disorder. Memantine, opiates, cocaine, and nicotine share the same transporter family at the blood brain barrier. This shared transport mechanism could impact brain concentrations of memantine and its effects. In conclusion, memantine remains an intriguing compound in our pharmacopeia with controversial results in treating certain aspects of drug addiction. Further studies are needed to understand the clinical and biological correlates of its efficacy.

The Effect of Adding Memantine to Clonidine in Reducing Withdrawal Symptoms in Opioid-Dependent Patients: A Double-Blind Randomized Controlled Trial

OBJECTIVE

Addiction is a complex condition and a brain disease manifested by compulsive substance use despite its harmful consequence. Addicted individuals have an intense focus on using substances. This study aimed to investigate the effect of adding memantine to clonidine and buprenorphine in reducing withdrawal symptoms, compared with placebo, in drug-dependent patients (opium and heroin).

MATERIALS AND METHODS

In this double-blind, randomized clinical trial study, 60 patients using opium or heroin were assigned to the intervention (n = 30) and control (n = 30) groups. Both groups were treated with buprenorphine and clonidine at the same dose in the detoxification process. The intervention group received memantine 10 mg daily for 10 days and then 20 mg daily for 21 days, and the control group received a placebo prepared in the same shape and size as memantine tablets. The severity of withdrawal symptoms was measured using the Short Opioid Withdrawal Scale over 3 weeks. Data analysis was performed using SPSS and descriptive and inferential tests.

RESULTS

The results showed that despite memantine's superiority in controlling some withdrawal symptoms such as feeling sick, stomach pain, muscle spasm, and feeling cold, no significant difference was found between the 2 groups. There was also no statistically significant difference between the 2 groups in the total score of symptoms.

CONCLUSIONS

No specific advantage of memantine was found for reducing the symptoms of withdrawal syndrome in the present study. However, this drug was well tolerated without any evidence of serious or significant adverse effects.

Investigating interventions that lead to the highest treatment retention for emerging adults with substance use disorder: A systematic review

BACKGROUND AND AIMS

Emerging adults (age 18-25) have the highest rate of substance use disorders (SUD) and often drop out of treatment earlier than those age twenty six or older. In order to increase treatment retention in emerging adults, there needs to be a better understanding of which SUD treatment interventions work best for this population. The purpose of this systematic review was to evaluate treatment interventions for emerging adults with SUD and identify which interventions show promise for retention in treatment.

METHODS

Following the PRISMA guidelines, Medline, PsycInfo, CINAHL (all via EBSCO), and Embase were systematically searched for articles that evaluated treatment interventions for emerging adults with SUD. From here, the authors identified treatment interventions that showed promise for retention in treatment.

RESULTS

Nine studies were included. The main findings indicate (1) behavioral therapy such as cognitive behavioral therapy and contingency management for cannabis and alcohol use disorders, or (2) cognitive behavioral therapy paired with opioid-agonist-therapy for opioid use disorder demonstrate the most promise for retention in treatment.

CONCLUSION

The interventions identified that show promise for emerging adults was similar to studies evaluating interventions for all ages. Given that retention rates are often lower in emerging adults despite the application of the full range of effective adult treatments, this review suggests they may require something different. While further studies are warranted to determine with more certainty what works best to keep emerging adults in treatment, some tentative suggestions are included.

Improving Translational Research Outcomes for Opioid Use Disorder Treatments

Purpose of Review

Pharmacotherapies are the most effective means of reducing the harms associated with opioid use disorder (OUD). Translational research seeking to develop novel medications to treat OUD has been challenging due to the complex etiology of addiction. Preclinical outcome measures are often behavioral, and it is difficult, if not impossible, to fully mirror the various emotional and cognitive processes that motivate opioid use in humans. The goal of the current narrative review was to summarize the translational progression of three potential medications for OUD, which had varying levels of success.

Recent Findings

Memantine, lorcaserin, and lofexidine all showed promise in preclinical studies; however, only lofexidine was able to consistently replicate these findings in human subjects, and receive FDA approval. It was the authors' objective to use this review to identify areas of needed improvement in translational research for OUD.

Summary

Preclinical studies vary significantly in their ability to forecast effectiveness in clinical trials. Among the various preclinical models, suppression of opioid self-administration appears to have the best predictive validity. As they model a mostly physiological phenomenon, preclinical assessments of opioid withdrawal also appear to have high predictive validity. In our review of the literature, the authors noted numerous examples of clinical trials that were underpowered, lack precision, and proper outcomes. Better-validated preclinical targets and improved design of proof-of-concept human studies should allow investigators to more efficiently develop and test medications for OUD.

Adherence to and Retention in Medications for Opioid Use Disorder Among Adolescents and Young Adults

The volatile opioid epidemic is associated with higher levels of opioid use disorder (OUD) and negative health outcomes in adolescents and young adults. Medications for opioid use disorder (MOUD) demonstrate the best evidence for treating OUD. Adherence to and retention in MOUD, defined as continuous engagement in treatment, among adolescents and young adults, however, is incompletely understood. We examined the state of the literature regarding the association of age with adherence to and retention in MOUD using methadone, buprenorphine, or naltrexone among persons aged 10-24 years, along with related facilitators and barriers. All studies of MOUD were searched for that examined adherence, retention, or related concepts as an outcome variable and included adolescents or young adults. Search criteria generated 10,229 records; after removing duplicates and screening titles and abstracts, 587 studies were identified for full-text review. Ultimately, 52 articles met inclusion criteria for abstraction and 17 were selected for qualitative coding and analysis. Younger age was consistently associated with shorter retention, although the overall quality of included studies was low. Several factors at the individual, interpersonal, and institutional levels, such as concurrent substance use, MOUD adherence, family conflict, and MOUD dosage and flexibility, appeared to have roles in MOUD retention among adolescents and young adults. Ways MOUD providers can tailor treatment to increase retention of adolescents and young adults are highlighted, as is the need for more research explaining MOUD adherence and retention disparities in this age group.

Clinical benefits and risks of N-methyl-d-aspartate receptor antagonists to treat severe opioid use disorder: A systematic review

BACKGROUND

Demand for treatments for severe opioid use disorder is increasing worldwide. The current pharmacotherapy is mainly focused on opioid and adrenergic receptors. The N-methyl-d-aspartate receptor (NMDAR) is among other receptors that can also be targeted to treat the disease. Findings from randomized controlled trials (RTCs) on NMDAR antagonists to treat severe opioid use disorder amply varied. This study aimed to evaluate the clinical benefits and assess the potential risks for adverse events or side effects of NMDAR antagonists that were investigated for the treatment of severe opioid use disorder.

METHODS

Articles were searched in PubMed, Scopus, Google Scholar, Proquest. Cochrane Review Database, Medline Ovid, and EMBASE from their inception to March 2019. RTCs on NMDAR antagonists for the treatment of severe opioid use disorder were independently screened and assessed by two authors. The results were synthesized qualitatively.

RESULTS

Nineteen RTCs of 1459 participants met the inclusion criteria. There is moderate evidence suggesting that ketamine, memantine, amantadine, and dextromethorphan may be able to manage opioid withdrawal symptoms. There is little evidence suggesting that memantine may be able to reduce methadone maintenance dose in participants on methadone, reduce opioid use, and reduce craving. Dropout is noticeable among dextromethorphan's participants. Safety concerns are more likely associated with dextromethorphan and ketamine.

CONCLUSIONS

NMDAR antagonists have the potentiality to treat severe opioid use disorder. There is insufficient evidence to recommend them for the treatment of severe opioid use disorder due to several limitations inherent to the RCTs reviewed. Further exploration is needed.

Influence of combined treatment with naltrexone and memantine on alcohol drinking behaviors: a phase II randomized crossover trial

Glutamate and opioid systems play important roles in alcohol drinking behaviors. We examined if combined treatment with the NMDA antagonist memantine and the opioid antagonist naltrexone, when compared with naltrexone alone, would have a greater influence on alcohol drinking behaviors. Fifty-six, non-treatment-seeking heavy drinkers, with alcohol dependence and a positive family history (FHP) of alcoholism, participated in a randomized, double-blind, crossover trial, including two 6-8 days treatment periods, separated by a 6-day washout, and 3 alcohol drinking paradigm (ADP) sessions. After the first baseline (BAS) ADP1 session, participants were randomized to receive either naltrexone (NTX; 50 mg/day) + placebo memantine, or NTX (50 mg/day) + memantine (MEM; 20 mg/day), during the first treatment period, following which they completed ADP2. After a 6-day washout, participants were crossed over to the treatment they did not receive during the first treatment period, following which they completed ADP3. During each ADP, participants received a priming drink of alcohol followed by 3 1-hour, self-administration periods during which they had ad-lib access to 12 drinks. Individually, both NTX and NTX + MEM, when compared to BAS ADP1, significantly reduced the number of drinks consumed (p's < 0.001) and craving (p's < 0.001). When comparing NTX + MEM vs. NTX on number of drinks consumed, there was a significant treatment* sequence interaction (p = 0.004). Specifically, when NTX + MEM followed NTX alone, NTX + MEM resulted in a further reduction in drinking (mean: -1.94; 95% CI: -2.6, -0.8, p = 0.0005). However, when NTX alone followed NTX + MEM, NTX alone did not lead to further reduction in drinking (mean: 0.59; 95% CI: -0.67, 1.43, p = 0.47). Similar patterns were observed for alcohol craving; specifically, a significant reduction in craving was observed when NTX + MEM followed NTX alone (p = 0.009), but craving reduction was maintained when NTX + MEM was followed by NTX alone. Neither treatment condition significantly influenced alcohol-induced stimulation or sedation. Memantine (at a dose of 20 mg/day) enhances the efficacy of naltrexone (50 mg/day) in reducing alcohol drinking and craving among FHP drinkers with beneficial effects that appear to carryover after discontinuation of memantine treatment.

A systematic review and meta-analysis of memantine for the prevention or treatment of chronic pain

BACKGROUND AND OBJECTIVE

N-methyl-D-aspartate (NMDA) receptors are involved in pain signalling and neuroplasticity. Memantine has been shown to have analgesic properties in pre-clinical and small clinical studies. We conducted a systematic review and meta-analysis to assess the efficacy of memantine to prevent or reduce chronic pain.

DATABASES AND DATA TREATMENT

MEDLINE, EMBASE and CENTRAL databases were searched for comparative trials using memantine, either against placebo or active medications, for chronic pain in adults. Pain relief was considered our primary outcome. Meta-analyses were conducted if outcomes were reported in two or more studies. Outcomes were reported as mean differences (MD) or risk ratios (RR) with 95% confidence intervals (CI). Quality was assessed using the GRADE approach.

RESULTS

Among 454 citations, 15 studies were included with populations predominantly consisting of neuropathic conditions and fibromyalgia. Overall, we observed unclear reporting of randomization and allocation methods, apart from potential for publication bias. Among the 11 studies looking at chronic pain treatment, the difference in end pain score with memantine was not significant: MD = -0.58 units (95% CI -1.31, 0.14); I²  = 82% (low quality). In two surgical studies using memantine for pain prevention, memantine decreased pain intensity: MD = -1.02 units (95% CI -1.38, -0.66); I²  = 0%. Dizziness was significantly more common with memantine: RR = 4.90 (95% CI 1.26, 18.99); I²  = 52% (moderate quality).

CONCLUSION

The current evidence regarding the use of memantine for chronic pain is limited and uncertain. Despite its potential, pain relief achieved in clinical studies is small and is associated with an increase in dizziness.

SIGNIFICANCE

Despite a sound rationale, the benefit of using memantine for chronic pain is unclear. Our systematic review and meta-analysis show that memantine may have the potential to decrease pain. However, it can also increase common adverse effects. Considering the small number of studies with potential for bias and inconclusive evidence, there was low to very low certainty. Hence, no clear recommendations can be made about its routine clinical use until larger and more definitive studies are conducted.

Pharmacological therapies for management of opium withdrawal

BACKGROUND

Pharmacologic therapies for management of heroin withdrawal have been studied and reviewed widely. Opium dependence is generally associated with less severe dependence and milder withdrawal symptoms than heroin. The evidence on withdrawal management of heroin might therefore not be exactly applicable for opium.

OBJECTIVES

To assess the effectiveness and safety of various pharmacologic therapies for the management of the acute phase of opium withdrawal.

SEARCH METHODS

We searched the following sources up to September 2017: CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO, regional and national databases (IMEMR, Iranmedex, and IranPsych), main electronic sources of ongoing trials, and reference lists of all relevant papers. In addition, we contacted known investigators to obtain missing data or incomplete trials.

SELECTION CRITERIA

Controlled clinical trials and randomised controlled trials on pharmacological therapies, compared with no intervention, placebo, other pharmacologic treatments, different doses of the same drug, and psychosocial intervention, to manage acute withdrawal from opium in a maximum duration of 30 days.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 13 trials involving 1096 participants. No pooled analysis was possible. Studies were carried out in three countries, Iran, India, and Thailand, in outpatient and inpatient settings. The quality of the evidence was generally very low.When the mean of withdrawal symptoms was provided for several days, we mainly focused on day 3. The reason for this was that the highest severity of opium withdrawal is in the second to fourth day.Comparing different pharmacological treatments with each other, clonidine was twice as good as methadone for completion of treatment (risk ratio (RR) 2.01, 95% confidence interval (CI) 1.69 to 2.38; 361 participants, 1 study, low-quality evidence). All the other results showed no differences between the considered drugs: baclofen versus clonidine (RR 1.06, 95% CI 0.63 to 1.80; 66 participants, 1 study, very low-quality evidence); clonidine versus clonidine plus amantadine (RR 1.03, 95% CI 0.86 to 1.24; 69 participants, 1 study); clonidine versus buprenorphine in an inpatient setting (RR 1.04, 95% CI 0.90 to 1.20; 1 study, 35 participants, very low-quality evidence); methadone versus tramadol (RR 0.95, 95% CI 0.65 to 1.37; 1 study, 72 participants, very low-quality evidence); methadone versus methadone plus gabapentin (RR 1.17, 95% CI 0.96 to 1.43; 1 study, 40 participants, low-quality evidence), and tincture of opium versus methadone (1 study, 74 participants, low-quality evidence).Comparing different pharmacological treatments with each other, adding amantadine to clonidine decreased withdrawal scores rated at day 3 (mean difference (MD) -3.56, 95% CI -5.97 to -1.15; 1 study, 60 participants, very low-quality evidence). Comparing clonidine with buprenorphine in an inpatient setting, we found no difference in withdrawal symptoms rated by a physician (MD -1.40, 95% CI -2.93 to 0.13; 1 study, 34 participants, very low-quality evidence), and results in favour of buprenorpine when rated by participants (MD -11.80, 95% CI -15.56 to -8.04). Buprenorphine was superior to clonidine in controlling severe withdrawal symptoms in an outpatient setting (RR 0.35, 95% CI 0.19 to 0.64; 1 study, 76 participants). We found no difference in the comparison of methadone versus tramadol (MD 0.04, 95% CI -2.68 to 2.76; 1 study, 72 participants) and in the comparison of methadone versus methadone plus gabapentin (MD -2.20, 95% CI -6.72 to 2.32; 1 study, 40 participants).Comparing clonidine versus buprenorphine in an outpatient setting, more adverse effects were reported in the clonidine group (1 study, 76 participants). Higher numbers of participants in the clonidine group experienced hypotension at days 5 to 8, headache at days 1 to 8, sedation at days 5 to 8, dizziness and dry mouth at days 1 to 10, and nausea at days 1 to 9. Sweating was reported in a significantly higher number of participants in the buprenorphine group at days 1 to 10. We found no difference between groups for all the other comparisons considering this outcome.Comparing different dosages of the same pharmacological detoxification treatment, a high dose of clonidine (1 to 1.2 mg/day) did not differ from a low dose of clonidine (0.5 to 0.6 mg/day) in completion of treatment in an inpatient setting (RR 1.00, 95% CI 0.84 to 1.19; 1 study, 68 participants), however a higher number of participants with hypotension was reported in the high-dose group (RR 3.25, 95% CI 1.77 to 5.98). Gradual reduction of methadone was associated with more adverse effects than abrupt withdrawal of methadone (RR 2.25, 95% CI 1.02 to 4.94; 1 study, 20 participants, very low-quality evidence).

AUTHORS' CONCLUSIONS

Results did not support using any specific pharmacological approach for the management of opium withdrawal due to generally very low-quality evidence and small or no differences between treatments. However, it seems that opium withdrawal symptoms are significant, especially at days 2 to 4 after discontinuation of opium. All of the assessed medications might be useful in alleviating symptoms. Those who receive clonidine might experience hypotension.

Buprenorphine-naloxone treatment responses differ between young adults with heroin and prescription opioid use disorders

BACKGROUND AND OBJECTIVES

Opioid use disorder among young adults is rising sharply with an increase in morbidity and mortality. This study examined differences in treatment response to a fixed dose of buprenorphine-naloxone between heroin (HU) and prescriptions opioids (POU) users.

METHODS

Eighty opioid dependent young adults (M = 22 years) were treated with buprenorphine-naloxone 16-4 mg/day for 8 weeks. Differences between HU (N = 17) and POU (N = 63) on changes in weekly opioid use, opioid craving, withdrawal, and depression symptoms were analyzed with mixed-effects regression models.

RESULTS

The HU had an overall mean proportion of weekly opioid use of .32 (SD = .14) compared to POU's weekly mean of .24 (SD = .15) showing a significant main effect (Z = 2.21, p = .02). Depressive symptoms (CES-D scores) were elevated at baseline for both groups (HU: M = 23.1, SD = 11.9; PO: M = 22.2, SD = 9.4), but only POU improved significantly to a score of 9.88 (SD = 7.4) compared to HU's score of 18.58 (SD = 10.3) at week 8 (Z = 2.24, p = .02). There were no significant differences in treatment retention, craving, or withdrawal symptoms.

DISCUSSION AND CONCLUSIONS

Treatment response to 16-4 mg/day of buprenorphine-naloxone was significantly diminished for heroin users relative to opioid prescription users in weekly opioid use. Heroin users also had persistent depressive symptoms suggesting the need for close monitoring.

SCIENTIFIC SIGNIFICANCE

These data suggest that young heroin users might require higher doses of buprenorphine. (Am J Addict 2017;26:838-844).

Buprenorphine for managing opioid withdrawal

BACKGROUND

Managed withdrawal is a necessary step prior to drug-free treatment or as the endpoint of substitution treatment.

OBJECTIVES

To assess the effects of buprenorphine versus tapered doses of methadone, alpha2-adrenergic agonists, symptomatic medications or placebo, or different buprenorphine regimens for managing opioid withdrawal, in terms of the intensity of the withdrawal syndrome experienced, duration and completion of treatment, and adverse effects.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 11, 2016), MEDLINE (1946 to December week 1, 2016), Embase (to 22 December 2016), PsycINFO (1806 to December week 3, 2016), and the Web of Science (to 22 December 2016) and handsearched the reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials of interventions using buprenorphine to modify the signs and symptoms of withdrawal in participants who were primarily opioid dependent. Comparison interventions involved reducing doses of methadone, alpha2-adrenergic agonists (clonidine or lofexidine), symptomatic medications or placebo, and different buprenorphine-based regimens.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 27 studies involving 3048 participants. The main comparators were clonidine or lofexidine (14 studies). Six studies compared buprenorphine versus methadone, and seven compared different rates of buprenorphine dose reduction. We assessed 12 studies as being at high risk of bias in at least one of seven domains of methodological quality. Six of these studies compared buprenorphine with clonidine or lofexidine and two with methadone; the other four studies compared different rates of buprenorphine dose reduction.For the comparison of buprenorphine and methadone in tapered doses, meta-analysis was not possible for the outcomes of intensity of withdrawal or adverse effects. However, information reported by the individual studies was suggestive of buprenorphine and methadone having similar capacity to ameliorate opioid withdrawal, without clinically significant adverse effects. The meta-analyses that were possible support a conclusion of no difference between buprenorphine and methadone in terms of average treatment duration (mean difference (MD) 1.30 days, 95% confidence interval (CI) -8.11 to 10.72; N = 82; studies = 2; low quality) or treatment completion rates (risk ratio (RR) 1.04, 95% CI 0.91 to 1.20; N = 457; studies = 5; moderate quality).Relative to clonidine or lofexidine, buprenorphine was associated with a lower average withdrawal score (indicating less severe withdrawal) during the treatment episode, with an effect size that is considered to be small to moderate (standardised mean difference (SMD) -0.43, 95% CI -0.58 to -0.28; N = 902; studies = 7; moderate quality). Patients receiving buprenorphine stayed in treatment for longer, with an effect size that is considered to be large (SMD 0.92, 95% CI 0.57 to 1.27; N = 558; studies = 5; moderate quality) and were more likely to complete withdrawal treatment (RR 1.59, 95% CI 1.23 to 2.06; N = 1264; studies = 12; moderate quality). At the same time there was no significant difference in the incidence of adverse effects, but dropout due to adverse effects may be more likely with clonidine (RR 0.20, 95% CI 0.04 to 1.15; N = 134; studies = 3; low quality). The difference in treatment completion rates translates to a number needed to treat for an additional beneficial outcome of 4 (95% CI 3 to 6), indicating that for every four people treated with buprenorphine, we can expect that one additional person will complete treatment than with clonidine or lofexidine.For studies comparing different rates of reduction of the buprenorphine dose, meta-analysis was possible only for treatment completion, with separate analyses for inpatient and outpatient settings. The results were diverse, and we assessed the quality of evidence as being very low. It remains very uncertain what effect the rate of dose taper has on treatment outcome.

AUTHORS' CONCLUSIONS

Buprenorphine is more effective than clonidine or lofexidine for managing opioid withdrawal in terms of severity of withdrawal, duration of withdrawal treatment, and the likelihood of treatment completion.Buprenorphine and methadone appear to be equally effective, but data are limited. It remains possible that the pattern of withdrawal experienced may differ and that withdrawal symptoms may resolve more quickly with buprenorphine.It is not possible to draw any conclusions from the available evidence on the relative effectiveness of different rates of tapering the buprenorphine dose. The divergent findings of studies included in this review suggest that there may be multiple factors affecting the response to the rate of dose taper. One such factor could be whether or not the initial treatment plan includes a transition to subsequent relapse prevention treatment with naltrexone. Indeed, the use of buprenorphine to support transition to naltrexone treatment is an aspect worthy of further research.Most participants in the studies included in this review were male. None of the studies reported outcomes on the basis of sex, preventing any exploration of differences related to this variable. Consideration of sex as a factor influencing response to withdrawal treatment would be relevant research for selecting the most appropriate type of intervention for each individual.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.