COMPLETE AND PROLONGED SUPPRESSION OF SYMPTOMS AND CONSEQUENCES OF ALCOHOL-DEPENDENCE USING HIGH-DOSE BACLOFEN: A SELF-CASE REPORT OF A PHYSICIAN

The use of baclofen to reduce alcohol-attributable hospitalizations and emergency department admissions

AIMS

The potential benefit of baclofen in reducing hospitalizations and emergency department (ED) admissions attributed to alcohol-related diagnoses has not been conclusively established. This study aimed to examine the relationship between baclofen use and the incidence of alcohol-attributable hospitalizations and ED admissions in the general population.

METHODS

We conducted a self-controlled case series study (SCCS) using data from the Taiwan National Health Insurance Research Database. 2904 patients who had at least one alcohol-attributable hospitalization or emergency department admission and were prescribed 28 or more days of baclofen unrelated to alcohol were included. Conditional Poisson regression was used to estimate the incidence rate ratio (IRR) and 95% confidence interval (CI) for the risk of alcohol-attributable hospitalizations and ED admissions during exposure to baclofen, as well as the pre- and post-exposure periods, relative to the baseline period. The contribution of concomitant psychotropic medication use was also assessed.

RESULTS

Baclofen was associated with a reduced incidence of alcohol-attributable hospitalizations (IRR = 0.64; 95% CI: 0.53∼0.77) and ED admissions (IRR = 0.56; 95% CI: 0.49∼0.65) in multivariate models. No statistically significant reduction was observed in any admission method in either the pre- or post-exposure period. A dose-dependent response in ED admissions was observed with baclofen, i.e. >60 mg/day associated with a greater decrease in the IRR (0.25, 95% CI: 0.10∼0.62) relative to doses of <30 (0.63, 95% CI: 0.53∼0.75) and 30-60 mg/day (IRR = 0.50, 95% CI: 0.40∼0.63).

CONCLUSIONS

These findings suggest a possible beneficial effect of baclofen in reducing the incidence of alcohol-attributable hospitalizations and ED admissions.

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.

GABAergic mechanisms in alcohol dependence

The target of alcohol's effect on the central nervous system has been sought for more than 50 years in the brain's GABA system. The behavioral and emotional effects of alcohol in humans and rodents are very similar to those of barbiturates and benzodiazepines, and GABAA receptors have been shown to be one of the sites of alcohol action. The mechanisms of GABAergic inhibition have been a hotspot of research but have turned out to be complex and controversial. Genetics support the involvement of some GABAA receptor subunits in the development of alcohol dependence and in alcohol use disorders (AUD). Since the effect of alcohol on the GABAA system resembles that of a GABAergic positive modulator, it may be possible to develop GABAergic drug treatments that could substitute for alcohol. The adaptation mechanisms of the GABA system and the plasticity of the brain are a big challenge for drug development: the drugs that act on GABAA receptors developed so far also may cause adaptation and development of additional addiction. Human polymorphisms should be studied further to get insight about how they affect receptor function, expression or other factors to make reasonable predictions/hypotheses about what non-addictive interventions would help in alcohol dependence and AUD.

Positive allosteric modulators of the GABAB receptor: a new class of ligands with therapeutic potential for alcohol use disorder

BACKGROUND

Positive allosteric modulators (PAMs) of the GABAB receptor constitute a new class of GABAB-receptor ligands. GABAB PAMs reproduce several pharmacological effects of the orthosteric GABAB receptor agonist, baclofen, although displaying a better safety profile.

AIMS

This paper reviews the reducing or, frequently, even suppressing effects of all GABAB PAMs tested to date on multiple alcohol-related behaviours in laboratory rodents exposed to validated experimental models of human alcohol use disorder.

RESULTS

Acute or repeated treatment with CGP7930, GS39783, BHF177, rac-BHFF, ADX71441, CMPPE, COR659, ASP8062, KK-92A, and ORM-27669 reduced excessive alcohol drinking, relapse- and binge-like drinking, operant alcohol self-administration, reinstatement of alcohol seeking, and alcohol-induced conditioned place preference in rats and mice.

CONCLUSIONS

These effects closely mirrored those of baclofen; notably, they were associated to remarkably lower levels of tolerance and toxicity. The recent transition of ASP8062 to clinical testing will soon prove whether these highly consistent preclinical data translate to AUD patients.

Repurposing drugs for treatment of alcohol use disorder

Repurposing drugs for the treatment of alcohol dependence involves the use of drugs that were initially developed for other conditions, but have shown promise in reducing alcohol use or preventing relapse. This approach can offer a more cost-effective and time-efficient alternative to developing new drugs from scratch. Currently approved medications for alcohol use disorder (AUD) include acamprosate, disulfiram, naltrexone, nalmefene, baclofen, and sodium oxybate. Acamprosate was developed specifically for AUD, while disulfiram's alcohol-deterrent effects were discovered incidentally. Naltrexone and nalmefene were originally approved for opioids but found secondary applications in AUD. Baclofen and sodium oxybate were repurposed from neurological conditions. Other drugs show promise. Topiramate and zonisamide, anticonvulsants, demonstrate efficacy in reducing alcohol consumption. Another anticonvulsant, gabapentin has been disappointing overall, except in cases involving alcohol withdrawal symptoms. Varenicline, a nicotinic receptor agonist, benefits individuals with less severe AUD or concurrent nicotine use. Ondansetron, a 5-HT3 antagonist, has potential for early-onset AUD, especially when combined with naltrexone. Antipsychotic drugs like aripiprazole and quetiapine have limited efficacy. Further investigation is needed for potential repurposing of α1 adrenergic receptor antagonists prazosin and doxazosin, glucocorticoid receptor antagonist mifepristone, the phosphodiesterase inhibitor Ibudilast, the cysteine prodrug N-acetylcysteine, and the OX1R and OX2R blocker Suvorexant. This review supports repurposing drugs as an effective strategy for expanding treatment options for AUD.

Baclofen in the treatment of alcohol use disorder: tailored doses matter

AIMS

To address the question of tailored baclofen prescribing in alcohol use disorder (AUD) in relation to dose-dependent efficacy and the potential danger of high doses and to provide suggestions for the use of high doses of baclofen in the treatment of AUD. The context is the approvement in France of baclofen in the treatment of AUD without dose limitation, making French physicians, who usually prescribe baclofen in a tailored manner, often use high or very high doses.

METHODS

A narrative review of the results of randomized controlled trials (RCTs) and observational studies that used tailored baclofen prescribing and of the severe adverse effects of baclofen that have been reported in the literature.

RESULTS

The results show that RCTs using tailored doses of baclofen in AUD are not completely demonstrative, though they are encouraging according to certain meta-analyses, while observational studies that used tailored doses constantly show a good effectiveness of baclofen treatment. The results suggest that many severe adverse effects of baclofen could be related to a nonrespect by physicians of prescription rules and appropriate treatment monitoring.

CONCLUSIONS

The use of tailored doses shows that the dose required to suppress cravings is highly variable, low or high, depending on each case. Analysis of the circumstances in which severe adverse effects occur suggest that a careful monitoring of baclofen prescribing might prevent a large majority of severe adverse effects. We propose that the education of the patients and the prescription skills, seriousness, and availability of the prescribing physicians are of major importance in the managing of tailored baclofen treatment of AUD.

Non-medical use of baclofen: A case series and review of the literature

BACKGROUND

Baclofen is widely used for spastic disorders and, most recently, for addictive disorders. The first signals of baclofen abuse occurred in the last decade. This study aims to assess the motives, diversion sources, and routes of administration associated with the non-medical use of baclofen and examine health problems related to the non-medical use of baclofen.

METHODS

Spontaneous reports of baclofen abuse reported to the addictovigilance centre of East France were analysed. A literature search was conducted using PubMed®, Web of Sciences®, and Google Scholar® databases. Both investigations were performed in February 2021 without a time limit.

RESULTS

Forty-six cases were analysed (33 from the literature review and 13 from the addictovigilance base). Baclofen's non-medical use mainly affected male subjects with addictive history, but issues of primary abuse in subjects without any substance abuse history were also observed. Euphoria search was the most common reason for misuse. The route of administration included oral, snorting, and sublingual use. Some cases involving illegal sources were also observed. Most patients misusing baclofen presented severe complications, mainly represented by neurological and respiratory disturbances. Physical and psychological dependence on baclofen was observed in three persons.

CONCLUSIONS

Although baclofen abuse remains relatively infrequent or (most likely) underestimated, this study helped confirm baclofen's intrinsic abuse potential and make visible the baclofen-abuse-related health visible harms. Careful consideration and benefit-risk analysis should be employed when prescribing baclofen, and emergency departments should be aware of baclofen dangers in abuse situations.

Baclofen during alcohol detoxification reduces the need for additional diazepam: a randomized placebo-controlled trial

Baclofen may reduce the symptoms of alcohol withdrawal, as an alternative or as an adjuvant for benzodiazepines, but the available data are insufficient to support baclofen-assisted alcohol withdrawal. This study investigated the need for diazepam during acute alcohol withdrawal in patients receiving baclofen. In a single-blind, dose-dependent randomized controlled trial with three study arms, 63 patients with alcohol use disorder, starting in-patient benzodiazepine-assisted alcohol detoxification, were randomly assigned to receive placebo (n = 18), baclofen 30 mg/day (N = 20), or baclofen 60 mg/day (N = 25) for 7 days. Diazepam was provided as needed based on the withdrawal symptoms stated by Clinical Institute Withdrawal Assessment for Alcohol-revised. The primary outcome measure was the number of patients in need of diazepam during alcohol detoxification. Secondary outcome measure included the between-group difference in the amount of diazepam needed during alcohol detoxification. Using baclofen 60 mg/day, 32% of patients needed additional diazepam compared to 35% on baclofen 30 mg/day and compared to 72% on placebo (P = .013). The median total amount of diazepam needed was significantly lower in patients receiving baclofen 60 mg/day (0 ± 10 mg diazepam) and baclofen 30 mg/day (0 ± 10 mg diazepam) compared to placebo (10 ± 43 mg diazepam; P = .017). Adverse events were comparable between patients on baclofen and placebo. Baclofen can reduce the withdrawal symptoms during alcohol detoxification. Baclofen was well tolerated and may be considered for the management of alcohol withdrawal syndrome, especially useful in situations where benzodiazepines should be withheld, such as patients with liver impairment.

Baclofen Combined With Psychosocial Care is Useful and Safe in Alcohol-Related Cirrhosis Patients: A Real-Life Multicenter Study

BACKGROUND

Alcohol-related cirrhosis is a frequent and difficult-to-treat disease. Despite the low hepatic metabolism of baclofen, data on its use in this subgroup are scarce. The French multicenter Observatory of patients treated with Baclofen for Alcohol DEpendence real-life cohort assessed: (a) prescription modalities of baclofen in liver units; (b) safety profile of baclofen; and (c) declared alcohol intake, biological markers of excessive alcohol intake and hepatic function at 12 months.

METHODS

All consecutive patients with cirrhosis who received baclofen to reduce alcohol consumption or maintain abstinence were prospectively included. Psychosocial management was always associated. Clinical and biological data were collected every 3 months for 1 year.

RESULTS

Between November 2013 and December 2016, 71 in- or outpatients were included from 10 liver units. Of the patients, 25% had ascites. After 12 months, 52 patients (73%) were still being followed, and 41 (57.7%) were still receiving baclofen at a mean dosage of 75 mg/day (r30-210). The overall declared consumption decreased from 100.2 to 14.7 g/day (P < 0.0001), and 29 patients (40.8%) reached abstinence. Significant improvement in the usual biomarkers of excessive alcohol intake (AST, GGT and MCV) and liver function (Prothrombin ratio (PTr), albumin levels) were observed. The usual side effects such as drowsiness were frequent (22%) but no serious adverse events (AEs) or overt encephalopathy related to baclofen was reported.

CONCLUSION

In this 1-year follow-up series, baclofen was combined with psychosocial treatment in patients with cirrhosis and was well tolerated. This treatment was associated with a significant decrease in declared alcohol consumption as well as improvement in hepatic function.

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.

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.

Baclofen in alcohol use disorder: An analysis of the data provided by the French "Temporary Recommendation for Use" 2014-2017 cohort

Alcohol use disorder (AUD) is a devastating illness for which effective treatments are lacking. Studies over the last two decades have shown that baclofen, a GABA-B agonist, could be a promising treatment for AUD. However, the efficacy of baclofen is still controversial, and studies have shown that it may be associated with an excess of hospitalizations and deaths. In March 2014, the French Health Safety Agency granted a "Temporary Recommendation for Use" (TRU) regulating the prescription of baclofen in subjects with AUD. The TRU allowed physicians to prescribe high-dose baclofen (up to 300 mg/d). The doses were adjusted, and tailored to the needs of each patient. Between March 2014 and March 2017, TRU clinical data were collected for a total of 6,939 subjects. The recorded data included information on alcohol consumption, the intensity of alcohol cravings, and adverse events. The present article proposes an analysis of the data provided by the TRU. Subjects for which data were missing regarding baclofen daily dosage, alcohol consumption or craving scores were discarded from the analyses. A cohort of two groups of subjects was analyzed. The first group included all TRU subjects suitable for analyses (5,550 subjects), and the second group included subjects followed for at least 365 days (169 subjects). Comparisons were made between baseline and endpoint of the follow-up period. The results show that a majority of subjects in the whole cohort had received doses of over 80 mg/d. The mean dose of baclofen at the endpoint was >110 mg/d in the second group of subjects. Doses of >80 mg/d were not associated with an increase in adverse events after adjustment for the follow-up duration. In terms of efficacy, comparisons between baseline and endpoint show that baclofen treatment significantly decreased alcohol consumption and alcohol cravings, and significantly increased the number of subjects with null or low-risk alcohol consumption according to WHO criteria.

Preventive Effects of Baclofen but Not Diazepam on Hippocampal Memory and Glucocorticoid Alterations After Prolonged Alcohol Withdrawal in Mice

Our study aims at comparing in C57/Bl male mice, the impact of repeated injections of baclofen (an agonist of GABAB receptor) or diazepam (a benzodiazepine acting through a positive allosteric modulation of GABAA receptor) administered during the alcohol-withdrawal period on hippocampus-dependent memory impairments and brain regional glucocorticoid dysfunction after a short (1-week) or a long (4-week) abstinence. Hence, mice were submitted to a 6-month alcohol consumption (12%v/v) and were progressively withdrawn to water. Then, after a 1- or 4-weeks abstinence, they were submitted to a contextual memory task followed by measurements of corticosterone concentrations in the dorsal hippocampus (dHPC), the ventral hippocampus (vHPC) and the prefrontal cortex (PFC). Results showed that 1- and 4-week withdrawn mice exhibited a severe memory deficit and a significant abnormal rise of the test-induced increase of corticosterone (TICC) in the dHPC, as compared to water-controls or to mice still under alcohol consumption. Repeated daily systemic administrations of decreasing doses of diazepam (ranged from 0.5 to 0.12 mg/kg) or baclofen (ranged from 1.5 to 0.37 mg/kg) during the last 15 days of the withdrawal period, normalized both memory and TICC scores in the dHPC in 1-week withdrawn animals; in contrast, only baclofen-withdrawn mice showed both normal memory performance and TICC scores in the dHPC after a 4-week withdrawal period. In conclusion, the memory improvement observed in 4-week withdrawn mice administered with baclofen stem from the protracted normalization of glucocorticoid activity in the dHPC, a phenomenon encountered only transitorily in diazepam-treated withdrawn mice.

Recent Advances in the Potential of Positive Allosteric Modulators of the GABAB Receptor to Treat Alcohol Use Disorder

Aims

The effects of alcohol on gamma-aminobutyric acid (GABA) transmission are key for the development and maintenance of alcohol use disorder (AUD). Previous research consistently indicates that GABA_B receptor agonists such as baclofen can attenuate addiction-related behaviors in preclinical models of AUD. More importantly, baclofen has also shown promise in clinical studies, particularly in severely alcohol-dependent patients. However, despite this promise, other clinical studies have not confirmed its efficacy and chiefly, larger clinical trials have not been conducted. Therefore, with the exception of France, baclofen is not approved for the treatment of AUD in any other country. Furthermore, it is also important to keep in mind that some patients treated with baclofen may experience important side-effects, including sedation, drowsiness and sleepiness.

Methods

This short review will first discuss the history of baclofen for AUD treatment. We will then summarize preclinical behavioral results that have investigated the efficacy of GABA_B PAMs for addiction treatment, with a special focus on our recent work that investigated the effects of ADX71441, a novel GABA_B PAM, on several alcohol-related behaviors in rats that model important aspects of human AUD. Finally, in light of the recent criticism about the translational value of animal models of addiction, the specific translational potential of our work and of other preclinical studies that have unanimously reported the efficacy of GABA_B PAMs to attenuate multiple alcohol-related behaviors will be discussed.

Results

Positive allosteric modulators (PAMs) of the GABA_B receptor offer an attractive alternative approach to baclofen and have the potential to achieve mechanistic and therapeutic effects similar to GABA_B agonists, while avoiding the tolerance and toxicity issues associated with baclofen. To date, all preclinical behavioral results have invariably shown the efficacy of GABA_B PAMs for addiction treatment.

Conclusions

Preclinical studies indicate that GABA_B PAMs have a higher therapeutic index than orthosteric agonists, at least in terms of mitigating the sedative effects of GABA_B agonism. This predicts that GABA_B PAMs have a high translational potential in humans and merit being tested clinically, in particular in patients with severe AUD.

[Pharmacotherapy of alcohol withdrawal: update and new developments]

Bislang sind nur wenige Medikamente zur pharmakologischen Rückfallprophylaxe der Alkoholabhängigkeit zugelassen. Neben dem in Deutschland nicht mehr vertriebenen Disulfiram sind es die Opioidantagonisten Naltrexon und Nalmefen sowie das vermutlich über glutamaterge Neurone wirkende Acamprosat. Baclofen und γ‑Hydroxybutyrat (GHB) sind in einzelnen Ländern zugelassen. Wirkstoffe wie z. B. Vareniclin, Gabapentin und Topiramat können für die Rückfallprophylaxe der Alkoholabhängigkeit von Interesse sein, jedoch ist bislang keine Zulassung erfolgt. Vor dem Hintergrund der zur Revision anstehenden S3-Leitlinie zur Diagnose und Behandlung alkoholbezogener Störungen wird der heutige Kenntnisstand zur Pharmakotherapie der Alkoholabhängigkeit dargestellt.

Synthesis and biological analysis of anti-addiction effect and hepatotoxicity of tow baclofen analogues complexed with β-Cyclodextrin

AIM AND OBJECTIVE

The excessive consumption of alcohol and the installation of a dependence is, in most cases, facilitated by favorable psychological factors which trigger and maintain the behavior of consumption. Examples more frequently encountered in individuals having difficulty with alcohol are in particular: one or more anxiety disorders, deficits in the capacities to manage stress and anxiety. The main objective of this work was study in vivo the anti-addiction effect and hepatotoxicity of tow baclofen analogues complexed with β-Cyclodextrin (βCD) on an alcohol-dependent rat model.

MATERIALS AND METHODS

The synthesis of two analogues ABF1 and ABF2 close to baclofen was reported. The structural determination of the two compounds was confirmed by NMR and IR analysis. The complexation of analogues with βCyclodextrin (βCD) was performed in water at room temperature (25 °C). The interactions of ABF with β-Cyclodextrin, and the stability constant (Ka) of the inclusion complex formed between them were investigated by using UV-visible spectroscopy. The biological effects of baclofen and the two analogues on alcohol dependence were studied in wistar rats. The anti-addiction effect of the analogues was tested by measuring the alcohol intake and the variation of the animal behaviour. The toxicity of the compounds was also analysed on liver injury markers.

RESULTS

The amino-3-phenylbutanoic acid (ABF1) and 3,4,5-trihydroxy-N-(methyl-2-acetate) benzamide (ABF2) were synthesized. The complexation of both analogues of baclofen (BF) with β-cyclodextrin (βCD) (ABF- βCD) was realized and confirmed by the stability constant of the inclusion complex (Ka) and Job's method. The evaluation of anti-addiction activity in vivo showed that ABF1-βCD inhibits the consumption of alcohol at the doses equivalent to those of baclofen. Both baclofen analogues have shown an anxiolytic effect. Regarding the toxicity of the two compounds, our results showed that ABF1-βCD has less toxic effect than baclofen, it reduces the activity of ALT and AST enzymes. Histologically ABF1-βCD has no effect on structure of the liver in addition and has a protective effect against lesions alcohol-induced liver disease.

CONCLUSION

Therefore, it can be suggested that ABF1 analogue combined with β-Cyclodextrin can be used as a treatment for alcohol dependence. Further clinical works are needed to confirm its effectiveness.

Baclofen overdose following recreational use in adolescents and young adults: A case report and review of the literature

Over the past twenty years, psychotropic drug abuse by young people, especially by teenagers, has received special attention. Here, we present the case of baclofen overdose in a 16-year-old male who recreationally, and probably recurrently, self-administered baclofen. In addition, a review of other cases was conducted. The 16-year-old boy presented to emergency department with digestive signs followed by agitated confusion. Detection and determination of baclofen concentration were achieved using liquid chromatography tandem mass spectrometry. Baclofen was detected in plasma and urine, at 420 ng/mL and 64 900 ng/mL respectively. Further, an English exhaustive literature search was performed using several different scientific databases without any limiting period in order to identify scientific articles dealing with baclofen overdose following a recreational use among adolescent and young adults. Five publications describing baclofen overdoses following a recreational use among adolescents and young adults have been published reporting19 cases, all involving a non-fatal overdose, with baclofen concentrations ranging from less than 20-1322 ng/mL. Baclofen is a psychotropic drug and its recreational use among adolescents and young adults represent a serious problem and should be considered by healthcare professionals. Among young people, baclofen poisoning remains relatively infrequent or most likely underestimated and these observations highlight the importance of constructive communication and joining efforts of clinicians and analytical toxicologists.

Pharmacotherapies and personalized medicine for alcohol use disorder: a review

Alcohol use disorder (AUD) is highly prevalent and among the leading causes of morbidity and mortality in the United States. Pharmacotherapies for AUD are limited, thus making identification of patient subgroups that are most likely to respond favorably crucial. In this article, pharmacogenetic research on US FDA-approved and commonly prescribed off-label medications for the treatment of AUD is comprehensively reviewed. While the field has advanced in understanding pharmacotherapies for AUD and potential genetic moderators of treatment responses, the pharmacogenetic data to guide the prescribing clinician are limited and should be interpreted with caution. Precision medicine for AUD with more beneficial treatment responses and minimal side effects remains a high priority for further research.

Toxicological considerations in the prescription of baclofen for the treatment of substance use disorders

Introduction: For many years, applications for baclofen have widened in the treatment of substance abuse disorder (SUD), mainly alcohol use disorder, with a growing rate of off-label prescriptions in Europe. Clinical effects seem to be both a decrease of craving and anxiety, leading to a decrease of drug or alcohol consumption. We described baclofen poisoning circumstances, therapeutic options and outcomes when used in substance use disorders.Areas covered: This review summarizes the toxicological considerations where baclofen was prescribed in humans for substance use or abuse disorder in randomized clinical trials, case series, case reports and observational studies between 1990 and 2020 according to the Preferred Reporting Items for Systemic reviews and Meta-Analysis.Expert opinion: The most frequent cause of severe intoxication is self-poisoning. A dose above 180 mg are expected to cause severe toxicity and death. The treatment is only symptomatic as no antidote is available. Off-label prescription remains unsafe because the optimal dose is not known and varies greatly between patients. As SUD are frequently associated with psychiatric disorders and such patients may have suicidal thoughts, the risk of self-poisoning is high. Potential co-ingestants should also be considered, especially CNS depressants, and they need to be closely monitored.

GABAB Receptors and Alcohol Use Disorders: Clinical Studies

Harmful alcohol use and alcohol use disorders (AUD) result in major health and community burden worldwide, yet treatment options are limited. Novel pharmacotherapies are urgently required, and treatments involving GABA_B receptors have been used in treating alcohol-related disorders. This chapter will review the clinical evidence of GABA_B pharmacotherapies, such as baclofen and γ-hydroxybutyric acid. This includes the use of these treatments in individuals experiencing alcohol withdrawal symptoms and outlining the outcomes of studies of alcohol relapse prevention relapse including case studies, comparative studies and randomised controlled trials. Laboratory research investigating biobehavioural effects of baclofen will also be summarised and polymorphisms associated with baclofen treatment, and safety concerns of GABA_B treatments will be addressed. In summary, pharmacological treatments targeting GABA_B receptors such as baclofen may be modestly effective in the management of alcohol use disorder, but safety concerns limit the widespread applicability of the currently available agents.

GABAB receptor positive allosteric modulators with different efficacies affect neuroadaptation to and self-administration of alcohol and cocaine

Drugs of abuse induce widespread synaptic adaptations in the mesolimbic dopamine (DA) neurons. Such drug-induced neuroadaptations may constitute an initial cellular mechanism eventually leading to compulsive drug-seeking behavior. To evaluate the impact of GABA_B receptors on addiction-related persistent neuroplasticity, we tested the ability of orthosteric agonist baclofen and two positive allosteric modulators (PAMs) of GABA_B receptors to suppress neuroadaptations in the ventral tegmental area (VTA) and reward-related behaviors induced by ethanol and cocaine. A novel compound (S)-1-(5-fluoro-2,3-dihydro-1H-inden-2-yl)-4-methyl-6,7,8,9-tetrahydro-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-one (ORM-27669) was found to be a GABA_B PAM of low efficacy as agonist, whereas the reference compound (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) had a different allosteric profile being a more potent PAM in the calcium-based assay and an agonist, coupled with potent PAM activity, in the [³⁵ S] GTPγS binding assay in rat and human recombinant receptors. Using autoradiography, the high-efficacy rac-BHFF and the low-efficacy ORM-27669 potentiated the effects of baclofen on [³⁵ S] GTPγS binding with identical brain regional distribution. Treatment of mice with baclofen, rac-BHFF, or ORM-27669 failed to induce glutamate receptor neuroplasticity in the VTA DA neurons. Pretreatment with rac-BHFF at non-sedative doses effectively reversed both ethanol- and cocaine-induced plasticity and attenuated cocaine i.v. self-administration and ethanol drinking. Pretreatment with ORM-27669 only reversed ethanol-induced neuroplasticity and attenuated ethanol drinking but had no effects on cocaine-induced neuroplasticity or self-administration. These findings encourage further investigation of GABA_B receptor PAMs with different efficacies in addiction models to develop novel treatment strategies for drug addiction.

Suppressing effect of CMPPE, a new positive allosteric modulator of the GABAB receptor, on alcohol self-administration and reinstatement of alcohol seeking in rats

Positive allosteric modulators (PAMs) of the GABA_B receptor constitute a class of pharmacological agents gaining increasing attention in the alcohol research field because of their ability to suppress several alcohol-related behaviors in rodents. CMPPE is a novel GABA_B PAM, still limitedly characterized in vivo. It was therefore of interest to test its ability to affect operant, oral self-administration of alcohol and cue-induced reinstatement of alcohol seeking in alcohol-preferring rats. To this end, female Sardinian alcohol-preferring (sP) rats were trained to lever-respond for alcohol (15% v/v) under the fixed ratio (FR) 5 (FR5) schedule of reinforcement. Once lever-responding had stabilized, rats were exposed to test sessions (under the FR5 [Experiment 1] and progressive ratio [PR; Experiment 2] schedules of reinforcement) preceded by treatment with CMPPE (0, 2.5, 5, and 10 mg/kg; intraperitoneally [i.p.]). In Experiment 3, once lever-responding had stabilized, rats underwent an extinction responding phase and then a single reinstatement session during which lever-responding was resumed by the non-contingent presentation of a complex of alcohol-associated cues; CMPPE (0, 2.5, 5, and 10 mg/kg; i.p.) was administered before the reinstatement session. Selectivity of CMPPE action was assessed by evaluating the effect of CMPPE (0, 2.5, 5, and 10 mg/kg; i.p.) on self-administration of a chocolate solution in male Wistar rats (Experiment 4). In Experiments 1 and 2, treatment with 5 and 10 mg/kg CMPPE reduced lever-responding and breakpoint for alcohol. In Experiment 3, treatment with 5 and 10 mg/kg CMPPE suppressed reinstatement of alcohol seeking. In Experiment 4, no dose of CMPPE affected lever-responding for the chocolate solution. These results extend to CMPPE the ability of all previously tested GABA_B PAMs to affect alcohol-motivated behaviors in rodents and confirm that these effects are a shared feature of the entire class of GABA_B PAMs. This conclusion is of relevance in view of the forthcoming transition of GABA_B PAMs to clinical testing.

Medication Development for Alcohol Use Disorder: A Focus on Clinical Studies

Compared to other medical disorders, including other brain diseases, the number of medications approved for alcohol use disorder (AUD) is very small. Disulfiram, naltrexone (oral and long-acting), and acamprosate are approved by the US Food and Drug Administration (FDA) to treat patients with AUD. These medications are also approved in other countries, including in Europe, where the European Medicines Agency (EMA) also approved nalmefene for AUD. Furthermore, baclofen was recently approved for AUD in France. These approved medications have small effect sizes, which are probably the consequence of the fact that they only work for some patients, yet a personalized approach to match the right medication with the right patient is still in its infancy. Therefore, research is needed to expand the armamentarium of medications that clinicians can use to treat their patients, as well as to better develop personalized approaches. This book chapter reviews other medications, beyond those approved by the FDA, that have shown efficacy in clinical trials, as well as medications which are still in the early stages of evaluation in human studies.

Targeting the Glucocorticoid Receptors During Alcohol Withdrawal to Reduce Protracted Neurocognitive Disorders

Persistent regional glucocorticoid (GC) dysregulation in alcohol-withdrawn subjects emerges as a key factor responsible for protracted molecular and neural alterations associated with long-term cognitive dysfunction. Regional brain concentrations of corticosterone vary independently from plasma concentrations in alcohol-withdrawn subjects, which may account for the treatment of alcohol withdrawal-induced persistent pathology. Thus, from a pharmacological point of view, a main issue remains to determine the relative efficacy of compounds targeting the GC receptors to attenuate or suppress the long-lasting persistence of brain regional GC dysfunctions in abstinent alcoholics, as well as persistent changes of neural plasticity. Data from animal research show that acting directly on GC receptors during the withdrawal period, via selective antagonists, can significantly counteract the development and persistence of cognitive and neural plasticity disorders during protracted abstinence. A critical remaining issue is to better assess the relative long-term efficacy of GC antagonists and other compounds targeting the corticotropic axis activity such as gamma-aminobutyric acid A (GABA_A) and GABA_B agonists. Indeed, benzodiazepines (acting indirectly on GABA_A receptors) and baclofen (agonist of the GABA_B receptor) are the compounds most widely used to reduce alcohol dependence. Clinical and preclinical data suggest that baclofen exerts an effective and more powerful counteracting action on such persistent cognitive and endocrine dysfunctions as compared to diazepam, even though its potential negative effects on memory processes, particularly at high doses, should be better taken into account.

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.

Risk of hospitalisation and death related to baclofen for alcohol use disorders: Comparison with nalmefene, acamprosate, and naltrexone in a cohort study of 165 334 patients between 2009 and 2015 in France

PURPOSE

Baclofen is widely used off-label for alcohol use disorders (AUD) in France, despite its uncertain efficacy and safety, particularly at high doses. This study was designed to evaluate the safety of this off-label use compared to the main approved drugs for AUD (acamprosate, naltrexone, nalmefene).

METHODS

This cohort study from the French Health Insurance claims database included patients, aged 18 to 70 years, with no serious comorbidity (assessed by the Charlson score) initiating baclofen or approved drugs for AUD between 2009 and 2015. The risk of hospitalisation or death associated with baclofen, at variable doses over time (from low doses <30 mg/day to high doses ≥180 mg/day), compared to approved drugs, was evaluated by a Cox model adjusted to sociodemographic and medical characteristics.

RESULTS

The cohort included 165 334 patients, 47 614 of whom were exposed to baclofen. Patients exposed to baclofen differed from those treated with approved drugs in terms of sociodemographic and medical characteristics (more females, higher socioeconomic status, fewer hospitalisations for alcohol-related problems), but these differences tended to fade at higher doses of baclofen. Baclofen exposure was significantly associated with hospitalisation (hazard ratio [HR] = 1.13 [95%CI: 1.09-1.17]) and death (HR = 1.31 [95%CI: 1.08-1.60]). The risk increased with dose, reaching 1.46 [1.28-1.65] for hospitalisation and 2.27 [1.27-4.07] for death at high doses. Similar results were in patients with a history of hospitalisation for alcohol-related problems.

CONCLUSIONS

This study raises concerns about the safety of baclofen for AUD, particularly at high doses, with higher risks of hospitalisation and mortality than approved drugs.

Effects of high-dose baclofen on cue reactivity in alcohol dependence: A randomized, placebo-controlled pharmaco-fMRI study

Increased functional brain response towards alcohol-associated stimuli is a neural hallmark of alcohol dependence and a promising target for pharmacotherapy. For the first time, we assessed the effects of individually titrated high-dose baclofen on cue reactivity and functional connectivity in alcohol-dependent (AD) patients in a randomized controlled trial (RCT). We investigated 23 recently detoxified AD patients and 23 matched healthy controls (HC) with a cue reactivity functional magnetic resonance imaging task. Patients were further scanned at baseline without medication and during treatment with high-dose baclofen/placebo (30-270 mg/d). Analyses were conducted for alcohol cue-elicited brain response, alcohol cue-modulated and stimulus-independent functional connectivity with left ventral tegmental area (VTA) as seed region. At baseline, AD patients (N = 23) showed increased cue-elicited brain activation in the ventral striatum (VS) compared to HC (N = 23), which was decreased at the second scanning session compared to baseline. Patients receiving baclofen (N = 10) showed a significant stronger decrease in cue-elicited brain activation in left orbitofrontal cortex (OFC), bilateral amygdala and left VTA than patients receiving placebo (N = 13). Treatment with baclofen further led to a decrease in alcohol cue-modulated functional connectivity between left VTA and left anterior cingulate cortex (ACC) as well as left medial prefrontal cortex (MPFC). Regarding clinical outcome, significantly more patients of the baclofen group remained abstinent during the high-dose period. Baclofen specifically decreased cue-elicited brain responses in areas known to be involved in the processing of salient (appetitive and aversive) stimuli. Treatment with high-dose baclofen seems to provide a pharmacological relief of this neural "warning signal" evoked by alcohol-related cues, thereby possibly supporting patients in remaining abstinent. Trial Registration Identifier of the main trial [BACLAD study] at clinicaltrials.gov: NCT01266655.

Baclofen in the Treatment of Patients With Alcohol Use Disorder and Other Mental Health Disorders

A limited number of medications are approved to treat Alcohol Use Disorder (AUD). Furthermore, the magnitude of their therapeutic effect is relatively modest, suggesting the potential for subtypes of patients who respond to a specific medication. The use of these medications is also limited in clinical practice by a series of contraindications such as medical comorbidities and/or concurrent use of other medications. In recent years, animal and human studies have been conducted to evaluate the efficacy of baclofen, a GABAB receptor agonist approved for clinical use as a muscle relaxant, in the treatment of AUD. However, these studies have yielded contrasting results. Despite this discrepancy, baclofen is often used off-label to treat AUD, especially in some European countries and Australia. Recently, several factors have been considered to try to shed light on the potential reasons and mechanisms underlying the inconsistent results obtained until now. The presence of a psychiatric comorbidity may be amongst the abovementioned factors playing a role in explaining different responses to baclofen treatment in terms of alcohol drinking outcomes. Therefore, the aim here was to conduct a narrative review of the scientific literature related to the use of baclofen in AUD, both in patients with and without concomitant psychiatric disorders. All clinical studies (randomized and controlled, open-label, retrospective, human laboratory studies, and case reports) were analyzed and discussed, bearing in mind other potential factors that may have influenced baclofen response, including dose administered, severity of AUD, use of other psychosocial therapies, and the presence of physical disorders. This review indicates that the most frequent psychiatric comorbidities in patients affected by AUD undergoing baclofen treatment are anxiety and mood disorders. Unfortunately, no definitive conclusions can be drawn due to the lack of specific analyses on whether baclofen efficacy is different in AUD patients with comorbid psychiatric disorders vs. those without. Therefore, it will be critical that psychiatric comorbidities are considered in the planning of future studies and in the analysis of the data, with the ultimate goal of understanding whether subtypes of AUD patients may respond best to baclofen.

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.

Brain Functional Magnetic Resonance Imaging Cue-reactivity Can Predict Baclofen Response in Alcohol Use Disorders

Objective

Baclofen is a promising treatment for alcohol use disorders (AUD), although its clinical response in humans is mixed. The present study aimed at investigating the impact of baclofen treatment on cue-induced brain activation pattern and its relationship with relapse outcomes.

Methods

Twenty-three inpatients with AUD underwent a functional magnetic resonance imaging cue-reactivity task before beginning medication with baclofen and 2 weeks later. Twelve additional inpatients with AUD, who did not receive any anticraving medications, formed the control group. All subjects were prospectively followed up for 90 days post-discharge or until lapse to first alcohol use.

Results

Whole-brain linear mixed effects analysis revealed a significant group-by-time interaction with greater activation of the bilateral dorsolateral pre-frontal cortex and right anterior cingulate cortex (ACC) following baclofen treatment in comparison with the control group. Further, cox regression analysis revealed that increased activation of ACC and deactivation of insular cortex (IC) was associated with longer time to first alcohol use only in the baclofen treatment group but not in the control group.

Conclusion

This study provides preliminary evidence for the neural predictors of baclofen treatment response in AUD. Baclofen treatment in AUD was associated with changes in cue-reactivity at critical brain regions within the incentive-salience network. Importantly, baclofen treatment-related specific activation of regions involved in cognitive control (ACC) and deactivation of regions involved in reward anticipation (IC) prolonged the time to first alcohol drink.

Can baclofen change alcohol-related cognitive biases and what is the role of anxiety herein?

BACKGROUND

Baclofen has shown promise in the treatment of alcohol dependence. However, its precise (neuro-) psychological working mechanism is still under debate.

AIMS

This study aimed to get a better understanding of baclofen's working mechanism by examining the effect of baclofen on cognitive biases. It was hypothesized that baclofen, compared to placebo, would lead to weaker cognitive biases. Furthermore, given a suggested anxiolytic effect of baclofen, we expected that anxiety would moderate this effect.

METHODS

From a larger randomized clinical trial (RCT) with 151 participants, a subset of 143 detoxified alcohol-dependent patients, either taking baclofen or placebo, was examined. Attentional bias for alcohol (500 and 1500 ms), alcohol approach tendencies, implicit alcohol-relaxation associations and trait anxiety were assessed before the administration of baclofen or placebo. Four weeks later, 94 patients were still abstinent (53 in the baclofen and 41 in the placebo condition) and cognitive biases were assessed again.

RESULTS

At baseline, patients showed a vigilance-avoidance pattern for the attentional bias (at 500 and 1500 ms, respectively) and alcohol-negative associations. After 4 weeks, an indication for an attentional bias away from alcohol at 500 ms was found only in the baclofen group; however, cognitive biases did not differ significantly between treatment groups. No moderating role of anxiety on cognitive biases was found.

CONCLUSIONS

Baclofen did not lead to a differential change in cognitive biases compared with placebo, and trait anxiety levels did not moderate this. A better understanding of the working mechanism of baclofen and predictors of treatment success would allow prescribing of baclofen in a more targeted manner.

Baclofen: its effectiveness in reducing harmful drinking, craving, and negative mood. A meta-analysis

BACKGROUND AND AIMS

There are a limited number of pharmacotherapies licensed for alcohol use disorders (AUDs). Baclofen is a γ-aminobutyric acid B (GABA-B) agonist which is used increasingly as an off-label treatment. A meta-analysis of randomized controlled trials (RCTs) was conducted to determine the efficacy of baclofen in reducing drinking behaviour, craving, depression and anxiety compared with placebo.

METHODS

Random-effects meta-analyses were computed on outcome data from 12 RCTs comparing baclofen with placebo. Included RCTs provided data on at least one of the primary outcome measures (drinking-related: heavy drinking days, abstinent days, abstinence rates) or secondary outcome measures (craving, anxiety, depression).

RESULTS

Baclofen had a significant effect on abstinence rates when using intention-to-treat analysis [total n baclofen = 307, total n control = 283: odds ratio (OR) = 2.67, 95% confidence interval (CI) = 1.03, 6.93; Z = 2.01, P = 0.04, I²  = 76%, number needed to treat = 8]. No other significant effects of treatment efficacy [e.g. heavy drinking days: standardized mean differences (SMD) = -0.26, 95% CI = -0.68, 0.15; Z = 1.24, P = 0.21, I²  = 95%] or mechanism of action (e.g. craving: SMD = -0.13, 95% CI = -0.36, 0.09; Z = 1.18, P = 0.24, I²  = 87%) were observed. There was substantial heterogeneity in effect sizes across each analysis.

CONCLUSIONS

As a treatment for alcohol use disorders, baclofen is associated with higher rates of abstinence than placebo. However, there is no superior effect of baclofen on increasing number of abstinent days, or decreasing heavy drinking, craving, anxiety or depression. These results suggest that the current increasing use of baclofen as a treatment for alcohol use disorders is premature.

Efficacy, tolerability, and safety of low-dose and high-dose baclofen in the treatment of alcohol dependence: A systematic review and meta-analysis

A systematic review of the current literature on the efficacy of baclofen, particularly the effect of dosing, for the treatment of alcohol dependence (AD) is missing. We therefore conducted a systematic review and meta-analysis of currently available randomized placebo-controlled trials (RCTs). A systematic literature search for RCTs in AD patients comparing baclofen to placebo was performed in September 2017. The effect of baclofen treatment, and the moderating effects of baclofen dosing (low-dose (LDB) 30-60 mg versus high-dose (HDB) targeted as >60 mg/day), and the amount of alcohol consumption before inclusion were studied. Three treatment outcomes were assessed: time to lapse (TTL), percentage days abstinent (PDA), and percentage of patients abstinent at end point (PAE). 13 RCTs from 39 records were included. Baclofen was superior to placebo with significant increases in TTL (8 RCTs, 852 patients; SMD=0.42; 95% CI 0.19-0.64) and PAE (8 RCTs, 1244 patients; OR=1.93; 95% CI 1.17-3.17), and a non-significant increase in PDA (7 RCTs, 457 patients; SMD=0.21; 95% CI -0.24 to 0.66). Overall, studies with LDB showed better efficacy than studies with HDB. Furthermore, tolerability of HDB was low, but serious adverse events were rare. Meta-regression analysis showed that the effects of baclofen were stronger when daily alcohol consumption before inclusion was higher. Baclofen seems to be effective in the treatment of AD, especially among heavy drinkers. HDB is not necessarily more effective than LDB with low tolerability of HDB being an import limitation.

New steps for treating alcohol use disorder

Alcohol use disorder is a complex syndrome with multiple treatment points including drug-induced pathology, withdrawal management, behavioral/cognitive strategies, and relapse prevention. These different components may be complicated by genotype and phenotype. A huge milestone for the treatment of alcohol use disorder across several countries in the last 10 years was the introduction of practice guidelines integrating clinical expertise and research evidence. These provide a summary of interventions that have been shown to be effective following rigorous and replicated clinical trials. Inspection of these guidelines reveals good consistency, but little evidence of progress in treatment approaches for alcohol use disorder over the past decade. In this mini-review, we discuss emerging treatments for alcohol use disorder that may supplement or improve the evidence-based treatments that are currently recommended. New medications, the emergence of digital technology, and other novel approaches such as transcranial magnetic stimulation are all discussed with reference to treatments already in practice. We also consider how individual differences in genotype and phenotype may affect outcomes. Together with improvements in technology, this knowledge offers a powerful tool for designing personalized approaches to treatment, and hence improving prognosis for rehabilitation programs.

Advances in Pharmacotherapy Development: Human Clinical Studies

For more than 25 years, researchers have made advances in developing medications to treat alcohol use disorder (AUD), highlighted by the US Food and Drug Administration's (FDA's) approval of disulfiram, naltrexone (oral and long-acting), and acamprosate. These medications are also approved in Europe, where the European Medicines Agency (EMA) recently added a fourth medication, nalmefene, for AUD. Despite these advances, today's medications have a small effect size, showing efficacy for only a limited number of individuals with AUD. However, a host of new medications, which act on variety of pharmacologic targets, are in the pipeline and have been evaluated in numerous human studies. This article reviews the efficacy and safety of medications currently being tested in human trials and looks at ongoing efforts to identify candidate compounds in human studies. As mentioned in the National Institute on Alcohol Abuse and Alcoholism's Strategic Plan 2017-2021 ( https://www.niaaa.nih.gov/sites/default/files/StrategicPlan_NIAAA_optimized_2017-2020.pdf ), medications development remains a high priority. By developing more effective and safe medications, and identifying those patients who will benefit the most from these treatments, we can provide clinicians with the tools they need to treat this devastating disorder, providing relief for patients and their families and markedly improving public health and safety.

Using Baclofen to Explore GABA-B Receptor Function in Alcohol Dependence: Insights From Pharmacokinetic and Pharmacodynamic Measures

Background: The role of GABA-B neurotransmission in addiction has recently received increased attention, with clinical trials indicating that baclofen, a GABA-B receptor agonist, may reduce alcohol consumption, craving and promote abstinence. However, the optimal dose to treat alcohol dependence is unclear with patients requesting and tolerating much higher doses of baclofen, compared with other clinical uses. We assessed the pharmacokinetics and pharmacodynamics (PK/PD) of baclofen to provide insight into GABA-B sensitivity in this patient group, relative to controls. Methods: Male healthy volunteers (controls, n = 12) and abstinent alcohol dependent individuals (AD, n = 8) received single oral doses of baclofen or placebo in a 3-way crossover design. Controls received placebo/10 mg/60 mg baclofen in a randomized, double-blind design, AD received placebo/60 mg/90 mg baclofen in a single-blind design. PK/PD measures were recorded at baseline and multiple time-points up to 6 h post-dosing, including plasma baclofen, plasma growth hormone (GH), Subjective High Assessment Scale (SHAS) and biphasic alcohol effects scale (BAES). Repeated measures ANOVA analysis explored "change from baseline" dose, time, group, and interaction effects, t-tests compared peak effects. Results: Dose-dependent effects of baclofen on PK and PD measures were observed in both control and AD groups. Whilst there were no significant group differences in any baclofen PK parameters (t _1/2, t _max , C _max , AUC), marked differences in PD effects were clearly evident. In controls, 60 mg baclofen significantly increased total SHAS and BAES scores, and significantly increased plasma GH levels compared with placebo, with peak effects at 60-120 min, in line with its PK profile. In AD, 60 mg baclofen had limited effects on these parameters; SHAS scores, BAES scores and plasma GH levels were significantly blunted compared with controls (significant group^*time interactions P = 0.0014, 0.0015 and P < 0.0001, respectively). Conclusions: Our study shows blunted sensitivity to baclofen in AD relative to controls, with no difference in PK suggesting a lower GABA-B receptor sensitivity. This may explain why higher baclofen doses are requested and tolerated in the treatment of alcohol dependence. Our data has implications for choice of dose in future clinical trials in AD and possibly other substances of dependence.

A Review of the Potential Mechanisms of Action of Baclofen in Alcohol Use Disorder

Baclofen, a GABA-B receptor agonist, is a promising treatment for alcohol use disorder (AUD). Its mechanism of action in this condition is unknown. GABA-B receptors interact with many biological systems potentially involved in AUD, including transduction pathways and neurotransmitter systems. Preclinical studies have shown that GABA-B receptors are involved in memory storage and retrieval, reward, motivation, mood and anxiety; neuroimaging studies in humans show that baclofen produces region-specific alterations in cerebral activity; GABA-B receptor activation may have neuroprotective effects; baclofen also has anti-inflammatory properties that may be of interest in the context of addiction. However, none of these biological effects fully explain the mechanism of action of baclofen in AUD. Data from clinical studies have provided a certain number of elements which may be useful for the comprehension of its mechanism of action: baclofen typically induces a state of indifference toward alcohol; the effective dose of baclofen in AUD is extremely variable from one patient to another; higher treatment doses correlate with the severity of the addiction; many of the side effects of baclofen resemble those of alcohol, raising the possibility that baclofen acts as a substitution drug; usually, however, there is no tolerance to the effects of baclofen during long-term AUD treatment. In the present article, the biological effects of baclofen are reviewed in the light of its clinical effects in AUD, assuming that, in many instances, clinical effects can be reliable indicators of underlying biological processes. In conclusion, it is proposed that baclofen may suppress the Pavlovian association between cues and rewards through an action in a critical part of the dopaminergic network (the amygdala), thereby normalizing the functional connectivity in the reward network. It is also proposed that this action of baclofen is made possible by the fact that baclofen and alcohol act on similar brain systems in certain regions of the brain.

The Use of Baclofen as a Treatment for Alcohol Use Disorder: A Clinical Practice Perspective

Alcohol use disorder (AUD) is a brain disorder associated with high rates of mortality and morbidity worldwide. Baclofen, a selective gamma-aminobutyric acid-B (GABA-B) receptor agonist, has emerged as a promising drug for AUD. The use of this drug remains controversial, in part due to uncertainty regarding dosing and efficacy, alongside concerns about safety. To date there have been 15 randomized controlled trials (RCTs) investigating the use of baclofen in AUD; three using doses over 100 mg/day. Two additional RCTs have been completed but have not yet been published. Most trials used fixed dosing of 30-80 mg/day. The other approach involved titration until the desired clinical effect was achieved, or unwanted effects emerged. The maintenance dose varies widely from 30 to more than 300 mg/day. Baclofen may be particularly advantageous in those with liver disease, due to its limited hepatic metabolism and safe profile in this population. Patients should be informed that the use of baclofen for AUD is as an "off-label" prescription, that no optimal fixed dose has been established, and that existing clinical evidence on efficacy is inconsistent. Baclofen therapy requires careful medical monitoring due to safety considerations, particularly at higher doses and in those with comorbid physical and/or psychiatric conditions. Baclofen is mostly used in some European countries and Australia, and in particular, for patients who have not benefitted from the currently used and approved medications for AUD.

Tailored-Dose Baclofen in the Management of Alcoholism: A Retrospective Study of 144 Outpatients Followed for 3 Years in a French General Practice

Background: More information is needed about the efficacy and safety of long-term baclofen in the treatment of alcohol use disorders. The objective of this study was to assess the effect of treatment with tailored-dose baclofen on alcohol consumption in patients with alcohol use disorders followed for 3 years after first initiating baclofen treatment. Methods: This retrospective descriptive cohort included outpatients followed in a French general practice clinic for 3 years and treated with tailored-dose baclofen to reduce or eliminate alcohol consumption. At 3 years, treatment was considered successful if alcohol consumption was at or below levels defined as low-risk by the WHO (≤ 40 g/d in men and ≤ 20 g/d in women). Results: The study population included 144 patients (88 men and 56 women). The participants' mean age was 46 ± 11 years and mean daily alcohol intake before treatment was 167 ± 77 grams. At the end of the study, treatment was successful for 91 (63.2%) patients. Participants' mean dose of baclofen at the end of study period was 100 ± 101 mg/d. We identified 75 (52.1%) patients for whom treatment was successful at each annual follow-up appointment: at 1, 2, and 3 years. The mean maximum dose of baclofen over follow-up of the 144 patients was 211 ± 99 mg/d (dose range: 40 mg/d to 520 mg/d). Conclusion: In this study, tailored-dose baclofen appears to be an effective treatment in patients with alcohol use disorders, with sustainable effect over time (3 years). There are many adverse effects but they are consistent with those already described in the literature.

Systematic review: Baclofen dosing protocols for alcohol use disorders used in observational studies

The popularity of baclofen as an anti-craving agent in the treatment of alcohol use disorders (AUDs) has increased, especially in patients with established liver disease. However, evidence-based guidelines to inform practice are lacking. The aim of this systematic review is explore the prescribing practices of baclofen in AUD treatment. Electronic databases were searched for relevant articles from 2002. Assessment of eligibility criteria for inclusion was performed independently by two investigators. The main outcomes of interest were maximum dose, starting dose, titration regimen, effectiveness, and tolerability. Twenty-five studies reporting outcomes in 613 patients treated with baclofen for an AUD were identified. Starting doses ranged between 5 and 50mg/d. Titration was study-dependent, and doses were increased until either therapeutic target (abstinence or study-defined low risk drinking) was achieved or adverse events resulted in a dose reduction or discontinuation. The maximum dose for individual patients ranged between 20 and 630mg/d. Seven studies reported at least one patient using >300mg/d. In studies with 10 or more patients, we found a negative correlation between dose and proportion of patients achieving the therapeutic goal. However, this was skewed by one study. A range of serious adverse events were reported. Most were reported at doses over 100mg/d, but others presented at lower doses. Baclofen is a promising therapeutic in this area. Evidence is required, however, to support practitioners in prescribing doses that optimise outcomes and reduce adverse events.

Microinjection of baclofen and CGP7930 into the ventral tegmental area suppresses alcohol self-administration in alcohol-preferring rats

Systemic administration of the orthosteric agonist, baclofen, and several positive allosteric modulators (PAMs) of the GABA_B receptor has repeatedly been reported to decrease operant oral alcohol self-administration in rats. The aim of the present study was to evaluate the contribution of the mesolimbic dopamine system to the reducing effect of baclofen and GABA_B PAMs on the reinforcing properties of alcohol. To this end, baclofen or the GABA_B PAM CGP7930 were microinjected into the ventral tegmental area (VTA) of selectively bred, Sardinian alcohol-preferring (sP) rats trained to self-administer alcohol. Baclofen (0, 0.03, 0.1, and 0.3 μg) or CGP7930 (0, 5, 10, and 20 μg) were microinjected via indwelling unilateral guide cannula aiming at the left hemisphere of the VTA. Treatment with baclofen resulted in a dose-related suppression of the number of lever-responses for alcohol and the amount of self-administered alcohol. No dose of baclofen altered rat motor-performance, evaluated by the inverted screen test immediately before the self-administration session. Treatment with CGP7930 halved the number of lever-responses for alcohol and amount of self-administered alcohol, with no effect on rat motor-performance. Site-specificity was investigated testing the effect of microinjection of baclofen and CGP7930 into the left hemisphere of deep mesencephalic nucleus: compared to vehicle, neither 0.3 μg baclofen nor 20 μg CGP7930 altered lever-responding for alcohol and amount of self-administered alcohol. Collectively, the results of the present study suggest the involvement of GABA_B receptors located in the VTA in the mediation of alcohol reinforcing properties in sP rats. This article is part of the "Special Issue Dedicated to Norman G. Bowery".