Off-label baclofen prescribing practices among French alcohol specialists: results of a national online survey

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.

Sex-related differences in the efficacy of Baclofen enantiomers on self-administered alcohol in a binge drinking pattern and dopamine release in the core of the nucleus accumbens

Introduction: Clinical studies on the effectiveness of Baclofen in alcohol use disorder (AUD) yielded mixed results possibly because of differential effects of the enantiomers and sex-related differences. Here we examined the effect of the different Baclofen enantiomers on alcohol intake and on evoked dopamine release in the core of the nucleus accumbens (NAcc) in male and female Long Evans rats.

Methods: Rats were trained to chronically self-administer 20% alcohol solution in daily binge drinking sessions and were treated with the different forms of Baclofen [RS(±), R(+) and S(−)]. The effects on the evoked dopamine release within the core of the nucleus accumbens were measured in brain slices from the same animals and the alcohol naïve animals using the fast scan cyclic voltammetry technique.

Results: RS(±)-Baclofen reduced alcohol intake regardless of sex but more females were non-responders to the treatment. R(+)-Baclofen also reduced alcohol intake regardless of sex but females were less sensitive than males. S(−)-Baclofen did not have any effect on average but in some individuals, especially in the females, it did increase alcohol intake by at least 100%. There were no sex differences in Baclofen pharmacokinetic but a strong negative correlation was found in females with a paradoxical effect of increased alcohol intake with higher blood Baclofen concentration. Chronic alcohol intake reduced the sensitivity to the effect of Baclofen on evoked dopamine release and S(−)-Baclofen increased dopamine release specifically in females.

Discussion: Our results demonstrate a sex-dependent effect of the different forms of Baclofen with no or negative effects (meaning an increase in alcohol self-administration) in subgroup of females that could be linked to a differential effect on dopamine release and should warrant future clinical studies on alcohol use disorder pharmacotherapy that will deeply analyze sex difference.

Recommendations from the EXTRIP workgroup on extracorporeal treatment for baclofen poisoning

Baclofen toxicity results from intentional self-poisoning ("acute baclofen poisoning") or accumulation of therapeutic dose in the setting of impaired kidney function. Standard care includes baclofen discontinuation, respiratory support and seizure treatment. Use of extracorporeal treatments (ECTRs) is controversial. To clarify this, a comprehensive review of the literature on the effect of ECTRs in baclofen toxicity was performed and recommendations following EXTRIP methods were formulated based on 43 studies. (1 comparative cohort, 1 aggregate results cohort, 1 pharmacokinetic modeling, and 40 patient reports or series). Toxicokinetic data were available for 20 patients. Baclofen's dialyzability is limited by a high endogenous clearance and a short half-life in patients with normal kidney function. The workgroup assessed baclofen as "Moderately dialyzable" by intermittent hemodialysis for patients with normal kidney function (quality of evidence C) and "Dialyzable" for patients with impaired kidney function (quality of evidence C). Clinical data were available for 25 patients with acute baclofen poisoning and 46 patients with toxicity from therapeutic baclofen in kidney impairment. No deaths or sequelae were reported. Mortality in historical controls was rare. No benefit of ECTR was identified in patients with acute baclofen poisoning. Indirect evidence suggests a benefit of ECTR in reducing the duration of toxic encephalopathy from therapeutic baclofen in kidney impairment. These potential benefits were balanced against added costs and harms related to the insertion of a catheter, the procedure itself, and the potential of baclofen withdrawal. Thus, the EXTRIP workgroup suggests against performing ECTR in addition to standard care for acute baclofen poisoning and suggests performing ECTR in toxicity from therapeutic baclofen in kidney impairment, especially in the presence of coma requiring mechanical ventilation.

Is R(+)-Baclofen the best option for the future of Baclofen in alcohol dependence pharmacotherapy? Insights from the preclinical side

For several decades, studies conducted to evaluate the efficacy of RS(±)-Baclofen in the treatment of alcohol dependence yielded contrasting results. Human and animal studies recently questioned the use of the racemic drug in patients since a potential important role of the different enantiomers has been revealed with an efficacy thought to reside with the active R(+)-enantiomer. Here we conducted experiments in the postdependent rat model of alcohol dependence to compare the efficacy of R(+)-Baclofen or S(-)-Baclofen to that of RS(±)-Baclofen on ethanol intake, seeking, and relapse. R(+)-Baclofen was more effective than RS(±)-Baclofen in reducing ethanol intake and seeking during acute withdrawal and during relapse after abstinence. We also used an original population approach in order to identify drug responders. We found a significant proportion of responders to S(-)-Baclofen and RS(±)-Baclofen, displaying an increase in ethanol intake, and this increasing effect on alcohol intake was not seen in the R(+)-Baclofen group. At an intermediate dose of R(+)-Baclofen, devoid of any motor side effects, we identified a very large proportion of responders (75%) with a large decrease in ethanol intake (90% decrease). Finally, the response to RS(±)-Baclofen on ethanol intake was correlated to plasma level of Baclofen. R(+)-Baclofen and RS(±)-Baclofen were effective in reducing sucrose intake. Our study has important clinical implication since it suggests that the wide variability in the therapeutic responses of patients to RS(±)-Baclofen may come from the sensitivity to the R(+)-Baclofen but also to the one of the S(-)-Baclofen that can promote an increase in ethanol intake.

The use of off-label medications in substance abuse treatment programs

Background: Substance use disorder (SUD) treatment centers serve a population of clients who have diverse needs, and may desire or require access to varied treatments while seeking care for their SUDs. While pharmacotherapies have increased in popularity for the treatment of SUDs, adoption rates do remain quite low. But a wider array of pharmacotherapies has become available in recent years which may shift the trend. This article helps shed light on how variations in SUD treatment centers develop and persist with regard to the adoption and delivery of off-label medications. Methods: We use a nationally representative and longitudinal sample of SUD treatment centers in the US (N = 196). We use a logistic regression to analyze the relationship between organizational characteristics and offering any medications, off-label. We also use a negative binomial regression to analyze the relationship between organizational characteristics and the number of medications that were used off-label. Results: Our findings reveal that older centers, accredited centers, and centers that offer mental health screenings are all positively associated with the provision of off-label medication in SUD treatment. We also find a positive relationship between private funding and offering a greater number of off-label medications. Conclusions: Our results suggest that SUD clients who seek treatment from centers that offer medications off-label, may have access to a greater number of medication-assisted treatment options.

A capture-recapture method for estimating the incidence of off-label prescriptions: the example of baclofen for alcohol use disorder in France

The local/regional incidence of off-label prescriptions can be difficult to estimate. Capture-recapture models can be used to indirectly estimate population sizes. Here, we used a capture-recapture model to estimate the number of patients treated off-label with baclofen for alcohol use disorder in northern France in 2013. Three capture sources were used: (i) the active case file at the region's largest Addiction Unit, (ii) the regional pharmacovigilance centre, and (iii) a sample of community pharmacies. After between-source overlaps had been identified, we used a log-linear model to produced eight estimates. Two models displayed the best goodness-of-fit, with estimates [95% confidence interval] of 1123 [714-2162] and 2180 [1598-2870] subjects, respectively. These two values are in line with a previous estimate of 1624 patients, based on an analysis of the French national health insurance database in 2013. Capture-recapture methods can be usefully applied to estimate the prevalence of OLPs in a specific geographical area, when direct counting is not feasible or the estimate through claim database is not possible.

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.

Pharmacologically controlled drinking in the treatment of alcohol dependence or alcohol use disorders: a systematic review with direct and network meta-analyses on nalmefene, naltrexone, acamprosate, baclofen and topiramate

BACKGROUND AND AIMS

Pharmacologically controlled drinking in the treatment of alcohol dependence or alcohol use disorders (AUDs) is an emerging concept. Our objective was to explore the comparative effectiveness of drugs used in this indication.

DESIGN

Systematic review with direct and network meta-analysis of double-blind randomized controlled trials (RCTs) assessing the efficacy of nalmefene, naltrexone, acamprosate, baclofen or topiramate in non-abstinent adults diagnosed with alcohol dependence or AUDs. Two independent reviewers selected published and unpublished studies on Medline, the Cochrane Library, Embase, ClinicalTrials.gov, contacted pharmaceutical companies, the European Medicines Agency and the Food and Drug Administration, and extracted data.

SETTING

Thirty-two RCTs.

PARTICIPANTS

A total of 6036 patients.

MEASUREMENTS

The primary outcome was total alcohol consumption (TAC). Other consumption outcomes and health outcomes were considered as secondary outcomes.

FINDINGS

No study provided direct comparisons between drugs. A risk of incomplete outcome data was identified in 26 studies (81%) and risk of selective outcome reporting in 17 (53%). Nalmefene [standardized mean difference (SMD) = -0.19, 95% confidence interval (CI) = -0.29, -0.10; I²  = 0%], baclofen (SMD = -1.00, 95% CI = -1.80, -0.19; one study) and topiramate (SMD = -0.77, 95% CI = -1.12, -0.42; I²  = 0%) showed superiority over placebo on TAC. No efficacy was observed for naltrexone or acamprosate. Similar results were observed for other consumption outcomes, except for baclofen (the favourable outcome on TAC was not reproduced). The number of withdrawals for safety reasons increased under nalmefene and naltrexone. No treatment demonstrated any harm reduction (no study was powered to explore health outcomes). Indirect comparisons suggested that topiramate was superior to nalmefene, naltrexone and acamprosate on consumption outcomes, but its safety profile is known to be poor.

CONCLUSIONS

There is currently no high-grade evidence for pharmacological treatment to control drinking using nalmefene, naltrexone, acamprosate, baclofen or topiramate in patients with alcohol dependence or alcohol use disorder. Some treatments show low to medium efficacy in reducing drinking across a range of studies with a high risk of bias. None demonstrates any benefit on health outcomes.

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.

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.

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.

The dose-effect relationship of baclofen in alcohol dependence: A 1-year cohort study

OBJECTIVE

Our aim is to study the relationship between dose of baclofen and effectiveness in alcohol dependence.

METHODS

Two hundred two patients with alcohol dependence, who received baclofen treatment for drinking reduction, were followed up for 1 year. For each patient-month of treatment, the maximum daily dose of baclofen (DDB) and average weekly alcohol consumption (AWAC) were calculated. We defined a favorable drinking outcome as an AWAC under 200 g/w for at least 2 consecutive months. We divided the DDB of each patient-month into 3 categories (low dose: <90 mg/d, medium dose: 90-150 mg/d, and high dose: >150 mg/d) and investigated the relationship between reaching a favorable outcome and the concurrent DDB category in a time-varying Cox regression analysis. Hazard ratios (HRs) were adjusted based on age, sex, and initial AWAC.

RESULTS

One hundred forty subjects were followed during at least 1 month. Of these patients, 58 (41%) had a favorable drinking outcome. In comparison to low dose, medium dose was associated with a decreased rate of favorable drinking outcome (HR = 0.42; 95% CI [0.20, 0.88]), whereas no difference was found with high dose (HR = 1.31; 95% CI [0.65, 2.64]).

CONCLUSION

The relationship between dose of baclofen and favorable drinking outcome was U-shaped, that is, was increased at low and high doses compared to medium doses.

Synergistic antipruritic effects of gamma aminobutyric acid A and B agonists in a mouse model of atopic dermatitis

BACKGROUND

Despite recent insights into the pathophysiology of acute and chronic itch, chronic itch remains an often intractable condition. Among major contributors to chronic itch is dysfunction of spinal cord gamma aminobutyric acidergic (GABAergic) inhibitory controls.

OBJECTIVES

We sought to test the hypothesis that selective GABA agonists as well as cell transplant-derived GABA are antipruritic against acute itch and in a transgenic mouse model of atopic dermatitis produced by overexpression of the T_H2 cell-associated cytokine, IL-31 (IL-31Tg mice).

METHODS

We injected wild-type and IL-31Tg mice with combinations of GABA-A (muscimol) or GABA-B (baclofen) receptor agonists 15 to 20 minutes prior to injection of various pruritogens (histamine, chloroquine, or endothelin-1) and recorded spontaneous scratching before and after drug administration. We also tested the antipruritic properties of intraspinal transplantation of precursors of GABAergic interneurons in the IL-31Tg mice.

RESULTS

Systemic muscimol or baclofen are antipruritic against both histamine-dependent and -independent pruritogens, but the therapeutic window using either ligand alone was very small. In contrast, combined subthreshold doses of baclofen and muscimol produced a significant synergistic antipruritic effect, with no sedation. Finally, transplant-mediated long-term enhancement of GABAergic signaling not only reduced spontaneous scratching in the IL-31Tg mice but also dramatically resolved the associated skin lesions.

CONCLUSIONS

Although additional research is clearly needed, existing approved GABA agonists should be considered in the management of chronic itch, notably atopic dermatitis.

Phone-based safety monitoring of the first year of baclofen treatment for alcohol use disorder: the BACLOPHONE cohort study protocol

BACKGROUND

In France, baclofen is frequently used off-label for alcohol use disorder (AUD). Baclofen has been associated with diverse adverse events (AEs), but the causality of these AEs has never been properly assessed.

METHODS/DESIGN

BACLOPHONE is a prospective multicenter cohort study conducted in the Hauts-de-France and Normandie French regions. BACLOPHONE consists of the phone-based monitoring of 792 patients during their first year of baclofen treatment for AUD. Two initial phone interviews assess the medical history, current medications, and substance use as well as complete the alcohol use identification test (AUDIT) and severity of alcohol dependence questionnaire (SADQ). Daily alcohol use and baclofen doses are noted throughout the follow-up. For every reported AE, additional phone interviews determine the seriousness of the AE, the causality of baclofen using validated causality algorithms, and the final outcome. The main objective of the study is to determine the rate of patients who stop baclofen due to an AE during the first year of treatment.

DISCUSSION

BACLOPHONE will provide important safety data on baclofen as a complement to the forthcoming efficacy data of randomized clinical trials.

Treatment of alcohol use disorders in patients with alcoholic liver disease

Alcohol use disorders (AUDs) is one of the leading causes of disease and disability in almost all European countries. Among the alcohol-related diseases, alcoholic liver disease (ALD) is the most common. At present, alcohol is the most frequent cause of liver cirrhosis in the Western world. The cornerstone of treatment for ALD is achieving total alcohol abstinence and preventing relapse; medical and surgical treatments for ALD are limited when drinking continues. This narrative review summarizes current treatments for AUDs with a particular emphasis to the treatment of AUDs in patients with ALD. Medical management, psychosocial and pharmacological interventions are analyzed, underlying limits and options in AUD patients. Finally, this review discusses the most appropriate setting for the management of AUD patients with advanced liver disease as well as the indications for liver transplantation in AUD patients.

Characteristics of Patients with Alcohol Dependence Seeking Baclofen Treatment in France: A Two-Centre Comparative Cohort Study

AIM

To characterize the profile of patients seeking baclofen treatment for alcohol dependence in France.

METHOD

We compared retrospectively baclofen seekers and baclofen non-seekers within a cohort of consecutive outpatients with alcohol dependence who attended a first appointment for alcohol treatment at two French addiction centres between September 2012 and March 2014. We documented socio-demographic characteristics; comorbid psychiatric, addiction, alcohol dependence features; patients' initial drinking goal, and referral status; and treatment retention at 6 and 12 months.

RESULTS

Of the 289 patients identified, 107 were baclofen seekers and 182 were baclofen non-seekers. The only parameters significantly associated with baclofen seekers in multivariate analyses were a greater baseline alcohol consumption (β = 15.4, 95% CI: 0.18-30.65, P = 0.05), a controlled-drinking initial goal (OR = 14.9, 95% CI: 7.7-29, P < 0.0001) and self-referral (OR = 6.6, 95% CI: 3.7-12, P < 0.0001), baclofen seekers being eight times more likely to be self-referred and treatment-naïve (OR = 8.8, 95% CI: 4.1-18.9, P < 0.0001). Baclofen seekers were more likely to be retained in treatment at 6 months (OR = 3.5, 95% CI: 1.8-6.7, P < 0.0001) and 12 months (OR = 1.9, 95% CI: 1.1-3.2, P = 0.019).

CONCLUSION

In France, the perspective of controlled drinking offered by baclofen treatment may have attracted more self-referred patients, including those without previous alcohol treatment, to attend treatment, than the usual treatment options. These findings raise the question as to whether future public health strategies on alcohol should more prominently promote some aspects of alcohol treatment, such as patient's preference and treatment options, in order to reduce the treatment gap in alcohol dependence.

R(+)-Baclofen, but Not S(-)-Baclofen, Alters Alcohol Self-Administration in Alcohol-Preferring Rats

Racemic baclofen [(±)-baclofen] has repeatedly been reported to suppress several -alcohol-motivated behaviors, including alcohol drinking and alcohol -self-administration, in rats and mice. Recent data suggested that baclofen may have bidirectional, stereospecific effects, with the more active enantiomer, R(+)-baclofen, suppressing alcohol intake and the less active enantiomer, S(-)-baclofen, stimulating alcohol intake in mice. The present study was designed to investigate whether this enantioselectivity of baclofen effects may also extend to the reinforcing properties of alcohol in rats. To this end, selectively bred Sardinian alcohol-preferring (sP) rats were initially trained to lever respond on a fixed ratio 4 (FR4) schedule of reinforcement for alcohol (15%, v/v) in daily 30-min sessions. Once responding had stabilized, rats were tested with vehicle, (±)-baclofen (3 mg/kg), R(+)-baclofen (0.75, 1.5, and 3 mg/kg), and S(-)-baclofen (6, 12, and 24 mg/kg) under the FR4 schedule of reinforcement. Treatment with 3 mg/kg (±)-baclofen reduced the number of lever responses for alcohol and estimated amount of self-administered alcohol by approximately 60% in comparison to vehicle treatment. R(+)-baclofen was approximately twice as active as (±)-baclofen: treatment with 1.5 mg/kg R(+)-baclofen decreased both variables to an extent similar to that of the decreasing effect of 3 mg/kg (±)-baclofen. Conversely, treatment with all doses of S(-)-baclofen failed to affect alcohol self administration. These results (a) confirm that non-sedative doses of (±)-baclofen effectively suppressed the reinforcing properties of alcohol in sP rats and (b) apparently do not extend to operant alcohol self-administration in sP rats the capability of S(-)-baclofen to stimulate alcohol drinking in mice.

Pharmacotherapy for Alcohol Dependence: The 2015 Recommendations of the French Alcohol Society, Issued in Partnership with the European Federation of Addiction Societies

BACKGROUND

The latest French good practice recommendations (GPRs) for the screening, prevention, and treatment of alcohol misuse were recently published in partnership with the European Federation of Addiction Societies (EUFAS). This article aims to synthesize the GPRs focused on the pharmacotherapy of alcohol dependence.

METHODS

A four-member European steering committee defined the questions that were addressed to an 18-member multiprofessional working group (WG). The WG developed the GPRs based on a systematic, hierarchical, and structured literature search and submitted the document to two review processes involving 37 French members from multiple disciplines and 5 non-French EUFAS members. The final GPRs were graded A, B, or C, or expert consensus (EC) using a reference recommendation grading system.

RESULTS

The treatment of alcohol dependence consists of either alcohol detoxification or abstinence maintenance programs or drinking reduction programs. The therapeutic objective is the result of a decision made jointly by the physician and the patient. For alcohol detoxification, benzodiazepines (BZDs) are recommended in first-line (grade A). BZD dosing should be guided by regular clinical monitoring (grade B). Residential detoxification is more appropriate for patients with a history of seizures, delirium tremens, unstable psychiatric comorbidity, or another associated substance use disorder (grade B). BZDs are only justified beyond a 1-week period in the case of persistent withdrawal symptoms, withdrawal events or associated BZD dependence (grade B). BZDs should not be continued for more than 4 weeks (grade C). The dosing and duration of thiamine (vitamin B1) during detoxification should be adapted to nutritional status (EC). For relapse prevention, acamprosate and naltrexone are recommended as first-line medications (grade A). Disulfiram can be proposed as second-line option in patients with sufficient information and supervision (EC). For reducing alcohol consumption, nalmefene is indicated in first line (grade A). The second-line prescription of baclofen, up to 300 mg/day, to prevent relapse or reduce drinking should be carried out according to the "temporary recommendation for use" measure issued by the French Health Agency (EC). During pregnancy, abstinence is recommended (EC). If alcohol detoxification is conducted during pregnancy, BZD use is recommended (grade B). No medication other than those for alcohol detoxification should be initiated in pregnant or breastfeeding women (EC). In a stabilized pregnant patient taking medication to support abstinence, the continuation of the drug should be considered on a case-by-case basis, weighing the benefit/risk ratio. Only disulfiram should be always stopped, given the unknown risks of the antabuse effect on the fetus (EC). First-line treatments to help maintain abstinence or reduce drinking are off-label for people under 18 years of age and should thus be considered on a case-by-case basis after the repeated failure of psychosocial measures alone (EC). Short half-life BZDs should be preferred for the detoxification of elderly patients (grade B). The initial doses of BZDs should be reduced by 30 to 50% in elderly patients (EC). In patients with chronic alcohol-related physical disorders, abstinence is recommended (EC). Any antidepressant or anxiolytic medication should be introduced after a psychiatric reassessment after 2-4 weeks of alcohol abstinence or low-risk use (grade B). A smoking cessation program should be offered to any smokers involved in an alcohol treatment program (grade B).

Baclofen for alcohol dependence: Relationships between baclofen and alcohol dosing and the occurrence of major sedation

High-dose baclofen, i.e., 300 mg/d or more, has recently emerged as a strategy for treating alcohol dependence. The impact that the co-exposure of large amounts of alcohol and baclofen has on sedation is unclear. In a prospective cohort of 253 subjects with alcohol dependence, we collected daily alcohol and baclofen doses across the first year of baclofen treatment and the monthly maximum subjective sedation experienced by each patient (0-10 visual analog scale). For each patient-month, we determined the average weekly alcohol consumption (AWAC; standard-drinks/week) and the maximum daily dose of baclofen (DDB; mg/d). The occurrence of an episode of major sedation (EMS) during a patient-month was defined as a sedation score ≥7. The relationship between the EMS occurrence and the concurrent AWAC and DDB was investigated using a generalized estimating equation model. In total, 1528 patient-months were compiled (70 with an EMS). Univariate analyses demonstrated that the rate of patient-month to EMS increased gradually with AWAC (p<0.001), from 0.9% for AWAC=0 to 9.4% for AWAC >35. There was also a significant gradual risk for EMS associated with DDB (<0.001). Multivariate analysis demonstrated a significant interaction between DDB and AWAC on EMS risk (p=0.047). Each 20mg/d increase in DDB was associated with an OR of EMS in AWAC >35 of 1.22 (95%CI, 1.08-1.38) versus 1.11 (95%CI, 0.96-1.29) in AWAC=1-35, and 0.95 (95%CI, 0.76-1.19) in AWAC=0. The level of sedation observed in patients using baclofen for alcohol dependence appears to directly depend on the immediate doses of both the baclofen and the alcohol.

Unintentional baclofen intoxication in the management of alcohol use disorder

In recent years, there has been a growing interest in using baclofen for the management of alcohol use disorder. This off-label indication usually involves high doses of the medication. We report a case of severe baclofen overdose in a 66-year-old man. The patient was found severely agitated, and he presented with delirium and auditory hallucinations. At hospital admission, his daily dose was 180 mg baclofen. He was admitted to the intensive care unit for sedation and supportive care. When sedation was withdrawn, the patient presented with a normal neurological status. In this clinical context, baclofen intoxication was suspected. This was confirmed by measuring blood baclofen levels. This intoxication was probably mediated by a combination of risk factors including a high daily dose of baclofen and acute renal failure, conducive to drug accumulation.

Baclofen-Associated Onset of Central Sleep Apnea in Alcohol Use Disorder: A Case Report

A 61-year-old patient with alcohol use disorder (AUD) was referred for suspicion of sleep apnea syndrome (SAS). He had incurred three road accidents attributed to sleepiness over the previous year, shortly after initiation of high-dose (100 mg b.i.d.) treatment with baclofen, a molecule increasingly used in the management of AUD. Polysomnography revealed a severe central SAS (CSAS) with an apnea-hypopnea index (AHI) of 81.6/h. Baclofen was suggested as a possible cause of the CSAS, and after its withdrawal, a second polysomnography was done, showing the disappearance of the central apneas and a shift to severe obstructive SAS (AHI 43.9/h), for which a positive airway pressure (CPAP) treatment was initiated. A third polysomnography was performed under CPAP after reintroduction of baclofen (50 mg b.i.d.) by the patient, showing reappearance of the CSAS (AHI 42.1/h). This case report illustrates the deleterious effect of baclofen on breathing physiology during sleep. Since it is typically prescribed off label at high doses to a population of patients potentially using other substances that inhibit the ventilatory drive, this possible adverse effect is a major concern. When considering the use of baclofen in patients with AUD, the potential for sleep-disordered breathing should be weighed and carefully monitored.

Correlates of Baclofen Effectiveness in Alcohol Dependence

Alcohol dependence is a global concern. Baclofen has shown promise as an anti-craving agent but its efficiency remains to be settled. We reviewed 549 male cases diagnosed with alcohol dependence who received Acamprosate (201) or Baclofen (348). 'Time to first drink' was compared between two groups and multiple regression analysis was done in baclofen group to identify correlates of effectiveness. There was a significant difference in outcome measure between Baclofen (M = 4.44, SD = 3.75) and Acamprosate group (M = 3.73, SD = 2.19); t (547) = 2.45, P = 0.01. Initial regression analysis with six predictor variables (average daily alcohol units, current age, age at onset of dependence, family history, duration of dependence and dose of baclofen in mg/day) showed significant correlation of outcome variable with only two predictor variables - dose of baclofen and average daily intake. Using the hierarchical method it was found that 'dose of baclofen' and 'average alcohol intake' explain a significant amount of variance in 'time to first drink'. [F (1, 345) = 182.8, P < 0.001, R2 = 0.52, R2adjusted = 0.51]. This information can be used to select patients in long term longitudinal studies and may explain variable results seen in clinical trials of baclofen done earlier.

Targeting GABAB receptors for anti-abuse drug discovery

INTRODUCTION

There is increasing evidence encouraging the development of drugs that positively modulate the γ-aminobutyric acid type B (GABA(B)) receptor for combating addiction. Compounds that target GABA(B) receptors are unique as anti-abuse therapies because of their impact against multiple addictive drugs.

AREAS COVERED

The authors present the basic information concerning the drug actions of GABA and GABA(B) receptor orthosteric agonists and positive allosteric modulators (PAM). Furthermore, they discuss several recent excellent reviews and newer results pertaining to GABA(B) receptor drug effects on responses to and self-administration of: alcohol (ethanol), nicotine, cocaine, (meth)amphetamine, and opioids. Preclinical and clinical data are considered.

EXPERT OPINION

Clinical data exist only for baclofen and mostly for alcohol use disorders. Additional trials are needed, but effects are promising. Whether PAMs, given alone or in combination with a direct GABA(B) receptor agonist, will be clinically effective and have fewer side effects requires investigation. The sedative effects of baclofen, a Food and Drug Administration (FDA)-approved drug, become less severe over time. Based on existing data, baclofen is well-tolerated. However, genetic and physiological differences are likely to contribute to individual responses to different therapeutic agents. The more immediate development of baclofen as a therapeutic for alcohol use disorders may be of significant benefit to some individuals.