Efficacy and Safety of the Use of Baclofen in the Treatment of Alcohol Dependent (a Double-Blind, Randomized, Placebo-Controlled Pilot Study)

Optimal Dose of Baclofen for the Treatment of Alcohol Use Disorder: A Systematic Review and Dose-Response Meta-analysis

BACKGROUND AND OBJECTIVES

Baclofen, a traditional treatment for spasticity, is gaining interest for its use in alcohol use disorder (AUD). To assist clinicians in using baclofen for effective and safe treatment of AUD, we investigated the optimal target dosage of baclofen through a systematic review and dose-response meta-analysis.

METHODS

We searched Cochrane, EMBASE, MEDLINE via PubMed, PsycINFO, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for randomized controlled trials on 1 and 2 April 2024. Inclusion criteria were patients aged ≥ 18 years diagnosed with AUD according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV, DSM-IV-TR, or International Classification of Diseases (ICD)-10, and treated with baclofen monotherapy. Continuous outcomes-percent days abstinent, drinks per drinking day, heavy drinking days (HDDs), craving, and anxiety-were analyzed as mean or standardized mean differences. Binary outcomes-relapse and dropout, including due to adverse events-were analyzed as odds ratios. Each outcome was assessed using the Cochrane Risk of Bias 2.0 tool. A one-stage random-effects dose-response meta-analysis was performed using restricted cubic splines with fixed knots at 10%, 50%, and 90% percentiles.

RESULTS

A total of 14 trials (1344 patients) were included. Increasing the dose of baclofen up to 50-60 mg/day was associated with a higher percent days abstinent and reduced craving. However, a higher baclofen dose increases the risk of dropout due to adverse events. Commonly observed adverse events were drowsiness, sedation, somnolence and fatigue. Baclofen up to 50-60 mg/day did not significantly affect drinks per drinking day, HDDs, anxiety, relapse or dropout. Doses > 60 mg/day lacked reliable evaluation due to limited data and study heterogeneity.

CONCLUSIONS

Baclofen up to 50-60 mg/day may increase percent days abstinent and reduce craving, but may increase dropout due to adverse events. Clinicians should carefully consider individual patient factors when prescribing baclofen to patients with AUD.

Efficacy and safety of alcohol reduction pharmacotherapy according to treatment duration in patients with alcohol dependence or alcohol use disorder: A systematic review and network meta-analysis

BACKGROUND AND AIMS

Relapse is common in alcohol dependence (AD) and alcohol use disorder (AUD), so alcohol reduction therapy should be measured over as long a period as possible; however, existing reviews do not consider the duration of treatment and therefore alcohol reduction therapy may not have been appropriately evaluated. This review evaluated the efficacy and safety of alcohol reduction pharmacotherapy in patients with AD or AUD according to the duration of treatment.

METHODS

We conducted a systematic review and network meta-analysis of randomized controlled trials (RCTs) that assessed 15 pharmacological agents. MEDLINE, Embase, PsycINFO, the Cochrane Central Register of Controlled Trials, the ClinicalTrials.gov and the International Clinical Trials Registry Platform were searched for eligible trials through to May 2021. Outcomes were heavy drinking days (HDD), total alcohol consumption (TAC), any adverse event and days without drinking.

RESULTS

Fifty-five RCTs (n = 8891) were included. Nalmefene was superior to placebo for reducing HDD (standard mean difference [SMD] -0.28, 95% confidence interval [CI] -0.37, -0.18) and TAC (SMD -0.25, 95% CI -0.35, -0.16) in the long-term, but not in the short-term. Topiramate was superior to placebo for reducing HDD (SMD -0.35, 95% CI -0.59, -0.12) and days without drinking (SMD 0.46, 95% CI 0.11, 0.82), and baclofen was superior for reducing TAC (SMD -0.70, 95% CI -1.29, -0.11), in the short-term. The frequency of adverse events was higher with nalmefene and topiramate than with placebo.

CONCLUSION

Nalmefene, topiramate and baclofen may be effective as alcohol reduction pharmacotherapy; however, only nalmefene has demonstrated long-term efficacy, and nalmefene and topiramate have a significantly higher frequency of adverse events compared with placebo.

Substitution therapy for patients with alcohol dependence: Mechanisms of action and efficacy

New approaches for the treatment of alcohol dependence (AD) may improve patient outcomes. Substitution maintenance therapy is one of the most effective treatment options for opioid and nicotine use disorders. So far, there has been little attention to substitution therapy for the treatment of AD. Here, we explain the mechanistic foundations of alcohol substitution maintenance therapy. Alcohol has many primary targets in the brain (and other organs) and the physical interaction of ethanol molecules with these specific ethanol-sensitive sites on a variety of ionotropic receptors (e.g. GABA-A, NMDA, and nicotinic acetylcholine (nACh) receptors) and ion channels provides the rationale for substitution. As such, a variety of compounds can interact with those ethanol-sensitive sites and can thus substitute for some of the effects of alcohol. For some of these compounds, alcohol discrimination studies have shown their substitution potential. Accordingly, potential substitution treatments include agonists acting at GABA receptors such as sodium oxybate, baclofen and benzodiazepines, NMDA receptor antagonists such as ketamine and memantine, or nAChRs agonists such as varenicline. All these compounds are already approved for other indications and we present clinical evidence for these drugs in the treatment of alcohol withdrawal syndrome (AWS) and in the long-term treatment of AD, and outline future steps for their acceptance as substitution treatment in AD. Finally, we discuss the substitution approach of managed alcohol programs for the most severely affected homeless populations. Results showed that sodium oxybate is probably the closest to a substitution therapy for AD and is already approved for the treatment of AWS and in the long-term treatment of AD in some countries. In conclusion, we argue that better AD treatment can be provided if substitution maintenance treatments for alcohol are implemented at a similar scale as for opioid and nicotine use disorder.

Baclofen for alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) is one of the most widespread psychiatric disorders leading to detrimental consequences to people with this disorder and others. Worldwide, the prevalence of heavy episodic drinking (30-day prevalence of at least one occasion of 60 g of pure alcohol intake among current drinkers) is estimated at 20% and the prevalence of AUD at 5% of the adult general population, with highest prevalence in Europe and North America. Therapeutic approaches, including pharmacotherapy, play an important role in treating people with AUD. This is an update of a Cochrane Review first published in 2018.

OBJECTIVES

To evaluate the benefits and harms of baclofen on achieving and maintaining abstinence or reducing alcohol consumption in people with AUD compared to placebo, no treatment or any other pharmacological relapse prevention treatment.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was 22 November 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least four weeks' treatment duration and 12 weeks' overall study duration comparing baclofen for AUD treatment with placebo, no treatment or other treatments.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. relapse, 2. frequency of use, 3. amount of use, 4. adverse events, 5. dropouts from treatment and 6. dropouts from treatment due to adverse events. Our secondary outcomes were 7. craving, 8. anxiety, 9. depression and 10. frequency of most relevant adverse events.

MAIN RESULTS

We included 17 RCTs (1818 participants) with a diagnosis of alcohol dependence according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition or International Classification of Diseases 10th edition criteria. Mean age was 46.5 years and 70% were men. Ten studies compared baclofen to placebo or another medication; seven compared two baclofen doses to placebo or another medication. Globally, 15 studies compared baclofen to placebo, two baclofen to acamprosate and two baclofen to naltrexone. In 16 studies, participants received psychosocial treatments. We judged most studies at low risk of selection, performance, detection (subjective outcome), attrition and reporting bias. Ten studies detoxified participants before treatment; in seven studies, participants were still drinking at the beginning of treatment. Treatment duration was 12 weeks for 15 RCTs and longer in two studies. Baclofen daily dose was 30 mg to 300 mg: 10 RCTs used low doses (30 mg or less); eight RCTs medium doses (above 30 and 100 mg or less) and four RCTs high doses (above 100 mg). Compared to placebo, moderate-certainty evidence found that baclofen probably decreases the risk to relapse (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.77 to 0.99; 12 studies, 1057 participants). This result was confirmed among detoxified participants but not among other subgroups of participants. High-certainty evidence found that baclofen increases the percentage of days abstinent (mean difference (MD) 9.07, 95% CI 3.30 to 14.85; 16 studies, 1273 participants). This result was confirmed among all subgroups of participants except non-detoxified or those who received medium doses. There was no difference between baclofen and placebo in the other primary outcomes: heavy drinking days (standardised mean difference (SMD) -0.18, 95% CI -0.48 to 0.11; 13 studies, 840 participants; moderate-certainty evidence); number of drinks per drinking days (MD -0.45, 95% CI -1.20 to 0.30; 9 studies, 392 participants; moderate-certainty evidence); number of participants with at least one adverse event (RR 1.05, 95% CI 0.99 to 1.11; 10 studies, 738 participants; high-certainty evidence); dropouts (RR 0.88, 95% CI 0.74 to 1.03; 17 studies, 1563 participants; high-certainty evidence); dropouts due to adverse events (RR 1.39, 95% CI 0.89 to 2.18; 16 studies, 1499 participants; high-certainty evidence). These results were confirmed by subgroup analyses except than for the dropouts that resulted lower among participants who received high doses of baclofen and studies longer than 12 weeks. Compared to placebo, there was no difference in craving (SMD -0.16, 95% CI -0.37 to 0.04; 17 studies, 1275 participants), anxiety (MD -0.01, 95% CI -0.14 to 0.11; 15 studies, 1123 participants) and depression (SMD 0.07, 95% CI -0.12 to 0.27; 11 studies, 1029 participants). Concerning the specific adverse events, baclofen increases fatigue, dizziness, somnolence/sedation, dry mouth, paraesthesia and muscle spasms/rigidity. There was no difference in the other adverse events. Compared to acamprosate, one study (60 participants) found no differences in any outcomes but the evidence was very uncertain: relapse (RR 1.25, 95% CI 0.71 to 2.20; very low-certainty evidence); number of participants with at least one adverse event (RR 0.63, 95% CI 0.23 to 1.69; very low-certainty evidence); dropouts (RR 0.56, 95% CI 0.21 to 1.46; very low-certainty evidence); dropouts due to adverse events (RR 0.33, 95% CI 0.01 to 7.87; very low-certainty evidence) and craving (MD 5.80, 95% CI -11.84 to 23.44); and all the adverse events evaluated. Compared to naltrexone, baclofen may increase the risk of relapse (RR 2.50, 95% CI 1.12 to 5.56; 1 study, 60 participants; very low-certainty evidence) and decrease the number of participants with at least one adverse event (RR 0.35, 95% CI 0.15 to 0.80; 2 studies, 80 participants; very low-certainty evidence) but the evidence is very uncertain. One study (60 participants) found no difference between baclofen and naltrexone in the dropouts at the end of treatment (RR 1.00, 95% CI 0.32 to 3.10; very low-certainty evidence), craving (MD 2.08, 95% CI -3.71 to 7.87), and all the adverse events evaluated.

AUTHORS' CONCLUSIONS

Baclofen likely reduces the risk of relapse to any drinking and increases the percentage of abstinent days, mainly among detoxified participants. It does not increase the number of participants with at least one adverse event, those who dropout for any reason or due to adverse events. It probably does not reduce number of heavy drinking days and the number of drinks per drinking days. Current evidence suggests that baclofen may help people with AUD in maintaining abstinence. The results of comparisons of baclofen with acamprosate and naltrexone were mainly based on only one study.

The influence of anxiety symptoms on clinical outcomes during baclofen treatment of alcohol use disorder: A systematic review and meta-analysis

Given the high coexistence of anxiety symptoms in people with alcohol use disorder (AUD), we aimed to determine the influence of anxiety symptoms on outcomes in patients with AUD treated with the GABA_B receptor agonist baclofen. A meta-analysis of 13 comparisons (published 2010-2020) including baseline and outcome data on alcohol consumption and anxiety after 12 weeks was undertaken. There were significantly higher rates of abstinent days in patients treated with baclofen compared to placebo (p = 0.004; high certainty evidence); specifically in those with higher baseline anxiety levels (p < 0.00001; high certainty evidence) compared to those with lower baseline anxiety levels (p = 0.20; moderate certainty evidence). The change in anxiety ratings over 12 weeks did not differ between those treated with baclofen or placebo (p = 0.84; moderate certainty evidence). This may be due to different anxiety constructs being measured by scales not validated in this patient group, or that anxiety is not a biobehavioral mechanism by which baclofen may reduce alcohol drinking. Given the prevalence of anxiety symptoms in AUD all these factors warrant further research.

Prospects for pharmacotherapies to treat alcohol use disorder: an update on recent human studies

PURPOSE OF REVIEW

The aim of this study was to provide an update on medication development efforts for alcohol use disorder (AUD) by reviewing recently published (past 2 years) human studies that evaluated medications' effects on alcohol-related outcomes.

RECENT FINDINGS

Forty-five publications were found suitable for this review. A variety of compounds have been tested in the past 2 years as potential pharmacological options for AUD, including medications that act on multiple targets (topiramate, aripiprazole, quetiapine), calcium channels (gabapentin), gamma-Aminobutyric acid receptors (baclofen, diazepam), glutamate receptors (ifenprodil, memantine, glycine), nicotinic acetylcholine receptors (varenicline, mecamylamine), α1 adrenergic receptors (prazosin, doxazosin), neuroendocrine pathways (oxytocin, a vasopressin receptor 1b antagonist, a ghrelin receptor inverse agonist) and others (samidorphan, ibudilast, N-acetylcysteine, citoline). Important findings and limitations regarding the effects of these medications on alcohol-related outcomes are discussed.

SUMMARY

There is a critical need to increase the armamentarium of medications for AUD. Human laboratory studies may help screen and prioritize promising targets and compounds before running large clinical trials. Given the complexity of AUD and the heterogeneity of afflicted patients, future studies should also investigate potential moderators and predictors of response to each pharmacological intervention.

Selecting an appropriate alcohol pharmacotherapy: review of recent findings

PURPOSE OF REVIEW

Only a few pharmacological treatments are available for treating alcohol use disorders (AUDs). Disulfiram, naltrexone and acamprosate are Food and Drug Administration (FDA)-approved and nalmefene is EMA-approved in European Union. Off-label medications, such as baclofen, gabapentin, ondansetron and topiramate are medications commonly prescribed for the treatment of AUD. The aim of this review is to give an update on recent randomized controlled trials (RCTs) and reviews evaluating pharmacological treatment for AUD.

RECENT FINDINGS

A literature search was conducted for pharmacological treatment for alcohol use disorder, published from January 2017 to January 2019. An additional search from two ongoing-study databases was performed. A total of 13 studies, 11 reviews and 7 on-going clinical trials were identified. Interest in studying baclofen as a treatment for AUD was greater compared with other medications, yet with inconclusive results. Three new RCTs of first-line medication naltrexone showed reduction in drinking.

SUMMARY

Three new published RCTs focus on baclofen and naltrexone. These results are consistent with old findings demonstrating that naltrexone reduces heavy drinking. Several RCT on baclofen do not support the use of baclofen for treatment of AUD. Encouraging results have been reported for topiramate, gabapentin and also varenicline, which might be useful in patients with comorbid nicotine dependence.

Baclofen for alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) and alcohol-related impairments belong to the most widespread psychiatric disorders leading to specific psychophysical, affective and cognitive symptoms and consequences for psychosocial well-being and health. Alcohol consumption is increasingly becoming a problem in many developing regions and AUD prevalence is estimated at 4.1% worldwide, with highest prevalence in European countries (7.5%), and the North America (6.0%). Therapeutic approaches, including pharmacotherapy, play an important role in treating patients with AUD.

OBJECTIVES

To assess the efficacy and safety of baclofen for treating people with AUD, who are currently drinking, with the aim of achieving and maintaining abstinence or reducing alcohol consumption.

SEARCH METHODS

We searched the Cochrane Drugs and Alcohol Specialised Register, CENTRAL, MEDLINE, Embase, two further databases and two clinical trials registries, conference proceedings, and the reference lists of retrieved articles. The date of the most recent search was 30 January 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least four weeks' treatment duration and 12 weeks' overall study duration comparing baclofen for relapse prevention of AUD with placebo, no treatment or other treatments.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 12 RCTs (1128 participants). All studies but three recruited fewer than 100 participants. Participants had a diagnosis of alcohol dependence according the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV or the International Classification of Diseases (ICD)-10 criteria who were currently drinking. The mean age of participants was 48 years, and there were more men (69%), than women. All studies compared baclofen to placebo, except for one study that evaluated baclofen versus acamprosate. The included studies considered baclofen at different doses (range 10 mg a day to 150 mg a day). In all but one of the studies, participants in both the baclofen and placebo groups received psychosocial treatment or counselling of various intensity.We judged most of the studies at low risk of selection, performance, detection (subjective outcome), attrition and reporting bias.We did not find any difference between baclofen and placebo for the primary outcomes: relapse-return to any drinking (RR 0.88, 95% CI 0.74 to 1.04; 5 studies, 781 participants, moderate certainty evidence); frequency of use by percentage of days abstinent (MD 0.39, 95% CI -11.51 to 12.29; 6 studies, 465 participants, low certainty evidence) and frequency of use by percentage of heavy drinking days at the end of treatment (MD 0.25, 95% CI -1.25 to 1.76; 3 studies, 186 participants, moderate certainty evidence); number of participants with at least one adverse event (RR 1.04, 95% CI 0.99 to 1.10; 4 studies, 430 participants, high certainty evidence); the dropout rate at the end of treatment (RR 0.98, 95% CI 0.77 to 1.26, 8 studies, 977 participants, high certainty evidence) and dropout due to adverse events (RR 1.11, 95% CI 0.59 to 2.07; 7 studies, 913 participants, high certainty evidence).We found evidence that baclofen increases amount of use (drink per drinking days), (MD 1.55, 95% CI 1.32 to 1.77; 2 studies, 72 participants, low certainty evidence).Among secondary outcomes, there was no difference on craving (MD 1.38, 95% CI -1.28 to 4.03, 5 studies, 469 participants), and anxiety (SMD 0.07, 95% CI -0.14 to 0.28; 5 trials, 509 participants). We found that baclofen increased depression (SMD 0.27, 95% CI 0.05 to 0.48; 3 studies, 387 participants).Concerning the specific adverse events we found that baclofen increased: vertigo (RR 2.16, 95% CI 1.24 to 3.74; 7 studies, 858 participants), somnolence/sedation (RR 1.48, 95%CI 1.11 to 1.96; 8 studies, 946 participants), paraesthesia (RR 4.28, 95% CI 2.11 to 8.67; 4 studies, 593 participants), and muscle spasms/rigidity (RR 1.94, 95%CI 1.08 to 3.48; 3 studies, 551 participants). For all the other adverse events we did not find significant differences between baclofen and placebo.For the comparison baclofen versus acamprosate, we were only able to extract data for one outcome, craving. For this outcome, we found that baclofen increased craving compared with acamprosate (MD 14.62, 95% CI 12.72 to 16.52; 1 study, 49 participants).

AUTHORS' CONCLUSIONS

None of the primary or secondary outcomes of the review showed evidence of a difference between baclofen and placebo. The high heterogeneity among primary studies results limits the interpretation of the summary estimate, the identification of moderators and mediators of baclofen's effects on alcohol use remains a challenge for further research. Even though some results from RCTs are promising, current evidence remains uncertain regarding the use of baclofen as a first-line treatment for people with AUDs.

Baclofen for alcohol use disorder-a systematic meta-analysis

OBJECTIVE

To evaluate the efficacy and tolerability of baclofen vs. placebo for long-term treatment of alcohol use disorder.

METHOD

Systematic review and meta-analysis following methods of the Cochrane Collaboration Handbook (PROSPERO registration: CRD42017073663). Primary outcome was the random-effects summary estimate of all standardized mean differences (SMDs), as calculated from the primary outcomes of each study.

RESULTS

Fourteen double-blind RCTs (1522 patients) were included. Heterogeneity was substantial for most analyses (I² about 75%). Baclofen showed a small, but not statistically significant superiority over placebo: SMD = 0.22 ([95% CI: -0.03; 0.47], P = 0.09). This result was supported by a leave-one-out-analysis, and Orwin's fail-safe N, by predefined secondary analyses (on abstinence rates and amount of drinking), and by a post hoc-analysis of high-dose studies (>80 mg/day). An analysis of low risk of bias studies (SMD = 0.10 [-0.20; 0.41], P = 0.51, I²  = 43.3%) found no effect. Exclusion of four studies focusing on patients with comorbidity yielded a small positive effect. Drop-out rates were similar.

CONCLUSION

Our results question baclofen's utility in the long-term treatment of alcohol use disorder at both normal and high doses. While the confidence intervals indicate that marginally harmful or moderately beneficial effects of baclofen remain a possibility, the most likely effect size is slightly above placebo effects.