Topiramate decreases the salience of motivationally relevant visual cues among smokers with alcohol use disorder

Pharmacological treatment for substance use disorder: A systematic review

INTRODUCTION

There is strong evidence of the substance dependence has a negative impact on key dimensions of health. The scientific evidence suggests that pharmacological treatment could play a fundamental role in its clinical management.

OBJECTIVE

The aim of this systematic review is to explore the existing pharmacological options for the treatment of substance use disorders.

METHODS

Following PRISMA recommendations, a review of recent scientific literature was conducted using three sources of information: Pubmed /Medline, Web of Science, and Scopus. Only randomized controlled trials published in the last five years, in both English and Spanish, and subjected to peer review were selected. The quality of the methodology used was defined through the application of the PEDro scale for quantitative studies. It was registered in the PROSPERO database.

RESULTS

After filtering through the respective advanced search engines, a total of 49 articles suitable for qualitative analysis were retrieved. Literature related to pharmacotherapy for alcohol use, as well as for cocaine, tobacco, cannabis, and opioid dependence, was identified among them.

CONCLUSIONS

There is a wide variety of drugs that can be used for the clinical management of dependence on these substances. Reflections are offered on the evidence of their effectiveness and the methodological rigor of the literature.

Neural cue reactivity and intrinsic functional connectivity in individuals with alcohol use disorder following treatment with topiramate or naltrexone

RATIONALE

Both topiramate and naltrexone have been shown to affect neural alcohol cue reactivity in alcohol use disorder (AUD). However, their comparative effects on alcohol cue reactivity are unknown. Moreover, while naltrexone has been found to normalize hyperactive localized network connectivity implicated in AUD, no studies have examined the effect of topiramate on intrinsic functional connectivity or compared functional connectivity between these two widely used medications.

OBJECTIVE

This study compared topiramate versus naltrexone on alcohol cue-elicited brain activation and intrinsic functional connectivity in patients with alcohol use disorder.

METHODS

Forty-seven participants with alcohol use disorder received daily topiramate (titrating the dose up to 200 mg/day n = 21) or naltrexone (50 mg/day, n = 26) for at least 6 weeks. Using functional magnetic resonance imaging (fMRI), we examined intrinsic functional connectivity during rest and alcohol cue-elicited neural activation during a visual alcohol cue reactivity task 120 min following treatment administration. Functional connectivity and alcohol cue reactivity and percentage of heavy drinking days (% HDD) associations were assessed.

RESULTS

No differences in either intrinsic functional connectivity or alcohol cue-elicited neural activity were seen between topiramate and naltrexone-treated groups. Overall, participants showed increased alcohol cue-elicited activation in three clusters spanning occipital regions involved in visual recognition of stimuli, and hypoactivation to both alcohol and control cues in three clusters involved in salience attribution and processing of emotional valence of external stimuli. No differences between topiramate versus naltrexone were observed for either functional measure or associations with post-scan % HDD.

CONCLUSIONS

Topiramate and naltrexone enacted comparable alcohol cue reactivity and intrinsic functional connectivity patterns. Some overall responses of increased brain activation to alcohol cues in visual processing regions coupled with reduced activation to alcohol and control cues were evidenced for both treatments. These activation patterns were in regions expected to show attenuation of brain activity resulting from treatment. Topiramate and naltrexone may thus enact functional effects through similar modulation of functional neural activity in individuals with AUD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03479086 https://www.

CLINICALTRIALS

gov/study/NCT03479086 .

A scoping review of electroencephalographic (EEG) markers for tracking neurophysiological changes and predicting outcomes in substance use disorder treatment

Substance use disorders (SUDs) constitute a growing global health crisis, yet many limitations and challenges exist in SUD treatment research, including the lack of objective brain-based markers for tracking treatment outcomes. Electroencephalography (EEG) is a neurophysiological technique for measuring brain activity, and although much is known about EEG activity in acute and chronic substance use, knowledge regarding EEG in relation to abstinence and treatment outcomes is sparse. We performed a scoping review of longitudinal and pre-post treatment EEG studies that explored putative changes in brain function associated with abstinence and/or treatment in individuals with SUD. Following PRISMA guidelines, we identified studies published between January 2000 and March 2022 from online databases. Search keywords included EEG, addictive substances (e.g., alcohol, cocaine, methamphetamine), and treatment related terms (e.g., abstinence, relapse). Selected studies used EEG at least at one time point as a predictor of abstinence or other treatment-related outcomes; or examined pre- vs. post-SUD intervention (brain stimulation, pharmacological, behavioral) EEG effects. Studies were also rated on the risk of bias and quality using validated instruments. Forty-four studies met the inclusion criteria. More consistent findings included lower oddball P3 and higher resting beta at baseline predicting negative outcomes, and abstinence-mediated longitudinal decrease in cue-elicited P3 amplitude and resting beta power. Other findings included abstinence or treatment-related changes in late positive potential (LPP) and N2 amplitudes, as well as in delta and theta power. Existing studies were heterogeneous and limited in terms of specific substances of interest, brief times for follow-ups, and inconsistent or sparse results. Encouragingly, in this limited but maturing literature, many studies demonstrated partial associations of EEG markers with abstinence, treatment outcomes, or pre-post treatment-effects. Studies were generally of good quality in terms of risk of bias. More EEG studies are warranted to better understand abstinence- or treatment-mediated neural changes or to predict SUD treatment outcomes. Future research can benefit from prospective large-sample cohorts and the use of standardized methods such as task batteries. EEG markers elucidating the temporal dynamics of changes in brain function related to abstinence and/or treatment may enable evidence-based planning for more effective and targeted treatments, potentially pre-empting relapse or minimizing negative lifespan effects of SUD.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.