Varenicline treatment for methamphetamine dependence: A randomized, double-blind phase II clinical trial

Exploring the efficacy of cholinergic agents for the treatment of psychostimulant use disorder: a systematic review

RATIONALE

No drugs are currently validated to treat psychostimulant use disorder (PUD). Pathophysiological studies consistently highlight the contribution of cholinergic mechanisms in psychostimulant use, including the vulnerability to PUD, paving the way for potential therapeutic strategies.

OBJECTIVES

The aim of this systematic review is to describe and discuss the efficacy of cholinergic agents in drug trials for patients with PUD.

METHODS

A systematic review was conducted on April 4, 2024 in MedLine, Embase and Cochrane Library databases on controlled clinical drug trial of cholinergic agents in humans with PUD, psychostimulant abuse or dependence and psychostimulant use in recent year.

RESULTS

Twenty-eight articles were included, twenty-one on cocaine and seven on amphetamines. Cholinergic agents used in these studies were biperiden (a muscarinic antagonist), mecamylamine (a nicotinic antagonist), nicotinic agonists, acetylcholinesterase inhibitors (AChEI), or citicoline. Two types of trials were identified. There were seventeen randomized controlled clinical trials evaluating cholinergic agents on psychostimulant use reduction in outpatients seeking treatment. Additionally, we retrieved eleven short-term «proof-of-concept» laboratory trials mainly with supervised psychostimulant administration and/or triggered craving challenges. Outpatient trials were heterogeneous and for most, inconclusive. Only two studies on galantamine (AChEI) and citicoline, reported a significant reduction of cocaine consumption. «Proof-of-concept» laboratory trials showed no evidence of efficacy on the selected outcomes, notably on craving.

CONCLUSIONS

This review does not support the current prescription of cholinergic agents to treat PUD. Replication clinical trials notably on galantamine or other AChEI, and proof-of-concept trials on comedown symptoms will be necessary to identify a potential therapeutic indication for cholinergic agents in PUD.

Pharmacological Treatments for Methamphetamine Use Disorder: Current Status and Future Targets

The illicit use of the psychostimulant methamphetamine (METH) is a major concern, with overdose deaths increasing substantially since the mid-2010s. One challenge to treating METH use disorder (MUD), as with other psychostimulant use disorders, is that there are no available pharmacotherapies that can reduce cravings and help individuals achieve abstinence. The purpose of the current review is to discuss the molecular targets that have been tested in assays measuring the physiological, the cognitive, and the reinforcing effects of METH in both animals and humans. Several drugs show promise as potential pharmacotherapies for MUD when tested in animals, but fail to produce long-term changes in METH use in dependent individuals (eg, modafinil, antipsychotic medications, baclofen). However, these drugs, plus medications like atomoxetine and varenicline, may be better served as treatments to ameliorate the psychotomimetic effects of METH or to reverse METH-induced cognitive deficits. Preclinical studies show that vesicular monoamine transporter 2 inhibitors, metabotropic glutamate receptor ligands, and trace amine-associated receptor agonists are efficacious in attenuating the reinforcing effects of METH; however, clinical studies are needed to determine if these drugs effectively treat MUD. In addition to screening these compounds in individuals with MUD, potential future directions include increased emphasis on sex differences in preclinical studies and utilization of pharmacogenetic approaches to determine if genetic variances are predictive of treatment outcomes. These future directions can help lead to better interventions for treating MUD.

Psychosocial and pharmacologic interventions for problematic methamphetamine use: Findings from a scoping review of the literature

RATIONALE

Methamphetamine use and related harms have risen at alarming rates. While several psychosocial and pharmacologic interventions have been described in the literature, there is uncertainty regarding the best approach for the management of methamphetamine use disorder (MUD) and problematic methamphetamine use (PMU). We conducted a scoping review of recent systematic reviews (SR), clinical practice guidelines (CPG), and primary controlled studies of psychosocial and pharmacologic treatments for MUD/PMU.

METHODS

Guided by an a priori protocol, electronic database search updates (e.g., MEDLINE, Embase) were performed in February 2022. Screening was performed following a two-stage process, leveraging artificial intelligence to increase efficiency of title and abstract screening. Studies involving individuals who use methamphetamine, including key subgroups (e.g. those with mental health comorbidities; adolescents/youths; gay, bisexual, and other men who have sex with men) were sought. We examined evidence related to methamphetamine use, relapse, use of other substances, risk behaviors, mental health, harms, and retention. Figures, tables and descriptive synthesis were used to present findings from the identified literature.

RESULTS

We identified 2 SRs, one CPG, and 54 primary studies reported in 69 publications that met our eligibility criteria. Amongst SRs, one concluded that psychostimulants had no effect on methamphetamine abstinence or treatment retention while the other reported no effect of topiramate on cravings. The CPG strongly recommended psychosocial interventions as well as self-help and family support groups for post-acute management of methamphetamine-related disorders. Amongst primary studies, many interventions were assessed by only single studies; contingency management was the therapy most commonly associated with evidence of potential effectiveness, while bupropion and modafinil were analogously the most common pharmacologic interventions. Nearly all interventions showed signs of potential benefit on at least one methamphetamine-related outcome measure.

DISCUSSION

This scoping review provides an overview of available interventions for the treatment of MUD/PMU. As most interventions were reported by a single study, the effectiveness of available interventions remains uncertain. Primary studies with longer durations of treatment and follow-up, larger sample sizes, and of special populations are required for conclusive recommendations of best approaches for the treatment of MUD/PMU.

The World Federation of Societies of Biological Psychiatry guidelines on the assessment and pharmacological treatment of compulsive sexual behaviour disorder

OBJECTIVES

The current guidelines aim to evaluate the role of pharmacological agents in the treatment of patients with compulsive sexual behaviour disorder (CSBD). They are intended for use in clinical practice by clinicians who treat patients with CSBD.

METHODS

An extensive literature search was conducted using the English-language-literature indexed on PubMed and Google Scholar without time limit, supplemented by other sources, including published reviews.

RESULTS

Each treatment recommendation was evaluated with respect to the strength of evidence for its efficacy, safety, tolerability, and feasibility. Psychoeducation and psychotherapy are first-choice treatments and should always be conducted. The type of medication recommended depended mainly on the intensity of CSBD and comorbid sexual and psychiatric disorders. There are few randomised controlled trials. Although no medications carry formal indications for CSBD, selective-serotonin-reuptake-inhibitors and naltrexone currently constitute the most relevant pharmacological treatments for the treatment of CSBD. In cases of CSBD with comorbid paraphilic disorders, hormonal agents may be indicated, and one should refer to previously published guidelines on the treatment of adults with paraphilic disorders. Specific recommendations are also proposed in case of chemsex behaviour associated with CSBD.

CONCLUSIONS

An algorithm is proposed with different levels of treatment for different categories of patients with CSBD.

Goofballing of Opioid and Methamphetamine: The Science Behind the Deadly Cocktail

Globally, millions of people suffer from various substance use disorders (SUD), including mono-and polydrug use of opioids and methamphetamine. Brain regions such as the cingulate cortex, infralimbic cortex, dorsal striatum, nucleus accumbens, basolateral and central amygdala have been shown to play important roles in addiction-related behavioral changes. Clinical and pre-clinical studies have characterized these brain regions and their corresponding neurochemical changes in numerous phases of drug dependence such as acute drug use, intoxication, craving, withdrawal, and relapse. At present, many studies have reported the individual effects of opioids and methamphetamine. However, little is known about their combined effects. Co-use of these drugs produces effects greater than either drug alone, where one decreases the side effects of the other, and the combination produces a prolonged intoxication period or a more desirable intoxication effect. An increasing number of studies have associated polydrug abuse with poorer treatment outcomes, drug-related deaths, and more severe psychopathologies. To date, the pharmacological treatment efficacy for polydrug abuse is vague, and still at the experimental stage. This present review discusses the human and animal behavioral, neuroanatomical, and neurochemical changes underlying both morphine and methamphetamine dependence separately, as well as its combination. This narrative review also delineates the recent advances in the pharmacotherapy of mono- and poly drug-use of opioids and methamphetamine at clinical and preclinical stages.

Varenicline for the Treatment of Cocaine Dependence

OBJECTIVES

Varenicline is a partial agonist at the α2β4 and α6β2 nAChR receptors and a full agonist at α7 receptors. Both α7 and α6β2 receptors are implicated in the neural reward circuitry activated by cocaine use. A preliminary clinical trial suggested that varenicline treatment reduced cocaine use. This trial was intended to replicate and extend the findings of the previous trial.

METHODS

This was a 12-week, double-blind, placebo-controlled clinical trial involving 156 subjects with DSM IV cocaine dependence. Subjects received up to 2 mg of varenicline or identical placebo daily along with weekly relapse prevention psychotherapy. The primary outcome measure was cocaine use measured by thrice-weekly urine drug screens. Additional outcome measures included end of study cocaine abstinence, cocaine craving, cocaine withdrawal symptom severity, cigarette use, and global improvement measure by the Clinical Global Improvement Scale.

RESULTS

End of study cocaine abstinence, measured by urine drug screens during the last 3 weeks of the trial, was not different between groups (8% in the varenicline treated subjects and versus 9% in placebo-treated subjects). Generalized estimating equations analysis of urine drug screen results showed no significant difference between groups in cocaine abstinence over the 12 weeks of the trial. There were no significant differences between the 2 groups in cocaine craving or cocaine withdrawal symptom severity. Varenicline was well-tolerated. There were no medication-associated serious adverse events.

CONCLUSIONS

Varenicline plus cognitive-behavioral therapy does not seem to be an efficacious treatment for cocaine dependence.

Effects of cytidine-5'-diphosphate choline on gray matter volumes in methamphetamine-dependent patients: A randomized, double-blind, placebo-controlled study

BACKGROUND

Cytidine-5'-diphosphate choline (CDP-choline) has been suggested to exert neuroprotective and neuroreparative effects and may be beneficial for patients with stimulant dependence. This randomized, double-blind, placebo-controlled study in methamphetamine (MA) dependence investigated effects of CDP-choline on the brain structures and their associations with craving and MA use.

METHODS

MA users (n = 44) were randomized to receive 2 g/day of CDP-choline (n = 22) or placebo (n = 22) for 8 weeks. Patients underwent brain magnetic resonance imaging (MRI) at baseline and 8-week follow-up. Healthy individuals (n = 27) were also examined using brain MRI at the same interval. Voxel-based morphometry analysis was conducted to examine changes in gray matter (GM) volumes and their associations with craving and MA use.

RESULTS

Craving for MA was significantly reduced after the 8 week-treatment with CDP-choline (p = 0.01), but not with the placebo treatment (p = 0.10). There was no significant difference in the total number of MA-negative urine samples between the two groups (p = 0.19). With CDP-choline treatment, GM volumes in the left middle frontal gyrus (p = 0.001), right hippocampus (p = 0.009), and left precuneus (p = 0.001) were significantly increased compared to the placebo and control groups. Increased GM volumes in the left middle frontal gyrus with CDP-choline treatment were associated with reduced craving for MA (Spearman's ρ = -0.56, p = 0.03). In addition, the right hippocampal volume increases were positively associated with the total number of MA-negative urine results in the CDP-choline group (Spearman's ρ = 0.67, p = 0.006).

CONCLUSION

Our findings suggest that CDP-choline may increase GM volumes of MA-dependent patients, which may be related to decreases in MA use and craving.

Pharmacological Treatment of Methamphetamine/Amphetamine Dependence: A Systematic Review

BACKGROUND

Stimulant drugs are second only to cannabis as the most widely used class of illicit drug globally, accounting for 68 million past-year consumers. Dependence on amphetamines (AMPH) or methamphetamine (MA) is a growing global concern. Yet, there is no established pharmacotherapy for AMPH/MA dependence. A comprehensive assessment of the research literature on pharmacotherapy for AMPH/MA dependence may inform treatment guidelines and future research directions.

METHODS

We systematically reviewed the peer-reviewed literature via the electronic databases PubMed, EMBASE, CINAHL and SCOPUS for randomised controlled trials reported in the English language examining a pharmacological treatment for AMPH/MA dependence or use disorder. We included all studies published to 19 June 2019. The selected studies were evaluated for design; methodology; inclusion and exclusion criteria; sample size; pharmacological and (if included) psychosocial interventions; length of follow-up and follow-up schedules; outcome variables and measures; results; overall conclusions and risk of bias. Outcome measures were any reported impact of treatment related to AMPH/MA use.

RESULTS

Our search returned 43 studies that met our criteria, collectively enrolling 4065 participants and reporting on 23 individual pharmacotherapies, alone or in combination. Disparate outcomes and measures (n = 55 for the primary outcomes) across studies did not allow for meta-analyses. Some studies demonstrated mixed or weak positive signals (often in defined populations, e.g. men who have sex with men), with some variation in efficacy signals dependent on baseline frequency of AMPH/MA use. The most consistent positive findings have been demonstrated with stimulant agonist treatment (dexamphetamine and methylphenidate), naltrexone and topiramate. Less consistent benefits have been shown with the antidepressants bupropion and mirtazapine, the glutamatergic agent riluzole and the corticotropin releasing factor (CRF-1) antagonist pexacerfont; whilst in general, antidepressant medications (e.g. selective serotonin reuptake inhibitors [SSRIs], tricyclic antidepressants [TCAs]) have not been effective in reducing AMPH/MA use.

CONCLUSIONS

No pharmacotherapy yielded convincing results for the treatment of AMPH/MA dependence; mostly studies were underpowered and had low treatment completion rates. However, there were positive signals from several agents that warrant further investigation in larger scale studies; agonist therapies show promise. Common outcome measures should include change in use days. Future research must address the heterogeneity of AMPH/MA dependence (e.g. coexisting conditions, severity of disorder, differences between MA and AMPH dependence) and the role of psychosocial intervention.

Pharmacotherapy for methamphetamine/amphetamine use disorder-a systematic review and meta-analysis

AIMS

Addiction to methamphetamine/amphetamine (MA/A) is a major public health problem. Currently there are no pharmacotherapies for MA/A use disorder that have been approved for use by the US Food and Drug Administration or the European Medicines Agency. We reviewed the effectiveness of pharmacotherapy for MA/A use disorder to assess the quality, publication bias and overall strength of the evidence.

METHODS

Systematic review and meta-analysis. We searched multiple data sources (MEDLINE, PsycINFO and Cochrane Library) to April 2019 for systematic reviews (SRs) and randomized controlled trials (RCTs). Included studies recruited adults who had MA/A use disorder; sample sizes ranged from 19 to 229 participants. Outcomes of interest were abstinence, defined as 3 or more consecutive weeks with negative urine drug screens (UDS); overall use, analyzed as the proportion of MA/A negative UDS specimens; and treatment retention. One SR of pharmacotherapies for MA/A use disorder and 17 additional RCTs met our inclusion criteria encompassing 17 different drugs (antidepressants, antipsychotics, psychostimulants, anticonvulsants and opioid antagonists). We combined the findings of trials with comparable interventions and outcome measures in random-effects meta-analyses. We assessed quality, publication bias and the strength of evidence for each outcome using standardized criteria.

RESULTS

There was low-strength evidence from two RCTs that methylphenidate may reduce MA/A use: 6.5 versus 2.8% MA/A-negative UDS in one study (n = 34, P = 0.008) and 23 versus 16% in another study (n = 54, P = 0.047). Antidepressants as a class had no statistically significant effect on abstinence or retention on the basis of moderate strength evidence. Studies of anticonvulsants, antipsychotics (aripiprazole), opioid antagonists (naltrexone), varenicline and atomoxetine provided either low-strength or insufficient evidence of no effect on the outcomes of interest. Many of the studies had high or unclear risk of bias.

CONCLUSIONS

On the basis of low- to moderate-strength evidence, most medications evaluated for methamphetamine/amphetamine use disorder have not shown a statistically significant benefit. However, there is low-strength evidence that methylphenidate may reduce use.

Pharmacotherapeutic strategies for methamphetamine use disorder: mind the subgroups

Introduction: Drug use related deaths are increasing and the lack of effective treatment for psychostimulants can be largely held responsible. Particularly, no pharmacotherapy is approved for methamphetamine (METH) use disorder despite decades of research. Only psychosocial interventions are clinically used, with limited long-term recovery and relapse.Areas covered: This review aims to select and describe the most relevant findings to date. Selected clinical trials were found in PubMed using the following keywords ('methamphetamine') and ('addiction' OR 'withdrawal' OR 'treatment' OR 'pharmacotherapy'). Randomized placebo-controlled trials enrolling treatment-seeking METH-dependent subjects and inherent secondary analysis were included.Expert opinion: Overall, end-of-treatment abstinence, reduced METH use or lower relapse rates were seen on METH dependent subgroups or attained significance only following post hoc analysis, irrespective of the medication tested. For example, light and heavy METH users seem to respond differently to pharmacotherapy. This together with the heterogeneous nature of the METH dependent population strongly suggests that some drugs herein described (e.g. mirtazapine, methylphenidate) should be further tested in clinical trials focused on subgroups. Lastly, objective measures, such as urinalysis, are mandatory to include in clinical trials and early treatment response and/or medication compliance should be carefully monitored and considered as predictors of success/failure.