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.

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.

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.

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.

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.

Moderation of baclofen response by a GABAB receptor polymorphism: results from the BacALD randomized controlled trial

BACKGROUND AND AIMS

Baclofen has been shown to reduce alcohol consumption in alcohol-dependent individuals, but there is marked heterogeneity in response. An association between GABBR1 rs29220 and alcohol dependence has been demonstrated previously. The present study evaluated whether the response to baclofen is moderated by a single nucleotide polymorphism (rs29220) in the GABAB receptor subunit 1 gene (GABBR1).

DESIGN

Double-blind, placebo-controlled study.

SETTING

Australia.

PARTICIPANTS

Seventy-two alcohol-dependent men and women receiving 12 weeks of 30 mg/day of baclofen, 75 mg baclofen or placebo.

MEASUREMENTS

Primary outcomes included time to lapse (any drinking) and relapse (> 5 drinks per day in men and > 4 in women). We also examined alcohol consumption at follow-up (drinks per drinking day, number of heavy drinking days and percentage days abstinent).

FINDINGS

We observed significant medication × genotype interaction effect for time to relapse (P = 0.049) and a near-significant interaction effect for time to lapse (P = 0.055). For the CC genotype group, the relapse hazard ratio for baclofen versus placebo was 0.32 [95% confidence interval (CI) = 0.14-0.75] and for the G- group it was 1.07 (95% CI = 0.43-2.63). There was also a significant medication × genotype interaction for follow-up alcohol consumption (drinks per drinking day, heavy drinking days and days abstinent) (P = 0.02). Covarying for baseline levels of craving, aspartate aminotransferase and abstinence before enrolment reduced the medication × genotype effect for time to lapse and relapse but not for alcohol consumption at follow-up.

CONCLUSIONS

The GABBR1 rs29220 polymorphism may influence treatment response and possibly predict adverse effects to baclofen in the treatment of alcohol dependence.

Baclofen Response in Alcohol Dependent Patients Concurrently Receiving Antidepressants: Secondary Analysis From the BacALD Study

Background and Aims: There is little information with regards to the efficacy of baclofen among alcohol patients concurrently receiving antidepressants (AD). The present study aimed to conduct a secondary analysis of the moderating role of antidepressants in the BacALD trial which evaluated the efficacy of baclofen to reduce alcohol consumption in alcohol dependent patients. Methods: Alcohol dependent patients (N = 104) were treated for 12 weeks with 30 mg/day of baclofen (21 = AD and 15 = no AD), 75 mg baclofen (19 = AD and 16 = no AD) or placebo (17 = AD and 16 = no AD). Patients were included in the trial if they were concurrently receiving anti-depressants upon enrolment but were excluded if they commenced antidepressants 2 months prior to enrolment. Patients were also excluded in the case of concurrent psychotropic medications, active major mental disorder such as bipolar disorder, psychosis, or history of suicide attempt. Predefined primary outcomes included time to lapse (any drinking), relapse (>5 drinks per day in men and >4 in women). Other outcomes included drinks per drinking day, number of heavy drinking days, and percentage days abstinent and frequency of adverse events. Results: For the number of days to first lapse, there was a trend of significance for the interaction baclofen × AD (Log Rank: χ2 = 2.98, P = 0.08, OR: 0.41, 95%CI: 0.15-1.12). For the number of days to relapse, there was a trend of significance for the interaction of baclofen × AD (Log Rank: χ2 = 3.72, P = 0.05, OR: 3.40, 95%CI: 1.01-11.46). Placing significant baseline variables into the models as covariates (tobacco, ALD) weakened these interactions (P's > 0.15). There were no significant effects of ADs on the frequency of adverse events reported (P's > 0.19). Conclusion: Concurrent receipt of ADs commenced more than 2 months prior to baclofen treatment did not negatively impact on drinking outcomes. Future research examining the interaction between commencing ADs during baclofen treatment on alcohol dependent patients is required. Trial Registration: ClinicalTrials.gov, NCT01711125, https://clinicaltrials.gov/ct2/show/NCT01711125.

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.

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.

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.

Baclofen in the treatment of alcohol dependence with or without liver disease: multisite, randomised, double-blind, placebo-controlled trial

BACKGROUND

There are no available medications for the management of alcohol dependence for patients with alcoholic liver disease (ALD).AimsTo conduct a multisite, double blind, placebo-controlled, randomised clinical trial of baclofen in the treatment of alcohol dependence, with or without liver disease (trial registration: ClinicalTrials.gov, NCT01711125).

METHOD

Patients (n = 104) were randomised to placebo, baclofen 30 mg/day or 75 mg/day for 12 weeks. Primary outcomes included survival time to lapse (any drinking), relapse (≥5 drinks per day in men and ≥4 in women), and the composite outcome of drinks per drinking day, number of heavy drinking days, and percentage days abstinent.

RESULTS

There was a significant effect of baclofen (composite groups) on time to lapse (χ2 = 6.44, P<0.05, Cohen's d = 0.56) and relapse (χ2 = 4.62, P<0.05, d = 0.52). A significant treatment effect of baclofen was observed for percentage days abstinent (placebo 43%, baclofen 30 mg 69%, baclofen 75 mg 65%; P<0.05). There was one serious adverse event (overdose) directly related to medication (75 mg).

CONCLUSIONS

Baclofen may be an effective treatment option for patients with ALD. However, given the profile of adverse events, the role for this medication might be best limited to specialist services.Declaration of interestNone.

Neurometabolite Levels in Alcohol Use Disorder Patients During Baclofen Treatment and Prediction of Relapse to Heavy Drinking

Background and Aims: Baclofen, a GABA_B agonist, is used as a treatment for alcohol dependence. We aimed to examine brain metabolites following administration of baclofen or placebo in alcohol dependent individuals enrolled in a randomized placebo-controlled trial. Methods: Participants included 31 alcohol dependent individuals (recent drinking: N = 16; and abstinent: N = 15) who had received daily baclofen (BAC 30-75 mg = 20) or placebo (PL = 11) for at least 2 weeks (average 17 days). Using in vivo proton magnetic resonance spectroscopy (¹H-MRS), spectra from the right parietal lobe were analyzed to obtain measures of GABA, Glutamate (Glu), Glutathione (GSH) and N-Acetyl Apartate (NAA) 120 min following administration of PL or BAC. Results: When weighting alcohol dependent participants according to recent alcohol consumption (within 24 h), there were significant differences between BAC and PL on parietal concentrations of GSH (p < 0.01) and NAA (p < 0.05). Multiple linear regression revealed a significant predictive effect of GSH on heavy drinking days at 12 weeks follow-up (Model: F = 14.28, R² = 0.85; GSH: B = -1.22, p = 0.01) and also percentage days abstinent at 12 weeks follow-up (Model: F = 6.50, R² = 0.72; GSH: B = 0.99, p = 0.06). Conclusion: Our data provide preliminary evidence that the effect of baclofen may be mediated by increased parietal concentrations of the antioxidant GSH and NAA in recently drinking alcohol dependent patients. GSH/Cr levels were also predictive of improved drinking outcomes in the trial and suggests a role for neural oxidative stress in alcohol use disorder.

Safety Challenges of Using High Dose Baclofen for Alcohol Use Disorder: A Focused Review

Since the early 2000s, the gamma-aminobutyric acid type B (GABA-B) receptor agonist baclofen has been extensively used for treating alcohol use disorder (AUD). In some countries, like France, Australia, or Germany, baclofen has been used at patient-tailored dose regimens, which can reach 300 mgpd or even more in some patients. The GABA-B-related pharmacology of baclofen expose patients to a specific profile of neuropsychiatric adverse drug reactions (ADRs), primarily some frequent sedative symptoms whose risk of occurrence and severity are both related to the absolute baclofen dosing and the kinetics of dose variations. Other frequent neuropsychiatric ADRs can occur, i.e., tinnitus, insomnia, or dizziness. More rarely, other serious ADRs have been reported, like seizures, manic symptoms, or sleep apnea. However, real-life AUD patients are also exposed to other sedative drugs, like alcohol of course, but also benzodiazepines, other drugs of abuse, or other sedative medications. Consequently, the occurrence of neuropsychiatric safety issues in these patients is essentially the result of a complex multifactorial exposure, in which baclofen causality is rarely obvious by itself. As a result, the decision of initiating baclofen, as well as the daily dose management should be patient-tailored, according the medical history but also the immediate clinical situation of the patient. The overall safety profile of baclofen, as well as the clinical context in which baclofen is used, have many similarities with the use of opiate substitution medications for opiate use disorder. This empirical statement has many implications on how baclofen should be managed and dosing should be adjusted. Moreover, this constant patient-tailored adjustment can be difficult to adapt in the design of clinical trials, which may explain inconsistent findings in baclofen-related literature on AUD.

Prescription drug use during pregnancy in France: a study from the national health insurance permanent sample

PURPOSE

To provide an up-to-date account of drug prescription during pregnancy in France from 2011 to 2014 using the permanent sample of the French national computerized healthcare database and with a focus on recommended supplementations, fetotoxic drugs and teratogenic drugs.

METHODS

All pregnancies identified by the International Classification of Diseases, 10th Revision codes list in the hospitalization database, lasting more than 9 weeks of amenorrhea and whose delivery occurred between 01/01/2011 and 12/31/2014, were included. Drugs delivered between the trimester before and until the end of the pregnancy were included. Drug exposure prevalence was calculated for each year and according to pregnancy trimesters.

RESULTS

The study included 28,491 pregnancies with a median number of 9 [5-13] (median [IQ range]) drugs delivered. The most prescribed drug class was antianemia (in 72.5% of exposed). The prescription rate of recommended vitamins (B9 and D) increased over the study period (+10%). Influenza vaccination also increased but remained at a low rate (1%). Exposure to fetotoxic drugs decreased as pregnancy advanced. Exposure to the main teratogenic antiepileptics was stable over the study period. Low-income pregnant women had a higher average drug consumption except for recommended vitamins.

CONCLUSION

Pregnant French women are among the largest consumers of prescription medications worldwide. Overall, the dispensation trends observed in this study are in line with the recommendations of the French National College of Gynecologists and Obstetricians. Nevertheless, while being low, exposure to fetotoxic drugs, teratogenic drugs or those under safety alerts still occurred. Supplementations and vaccines in low-income pregnant women should also be increased.

Efficacy and safety of high-dose baclofen for the treatment of alcohol dependence: A multicentre, randomised, double-blind controlled trial

Previous randomised placebo-controlled trials with low-to-medium doses of baclofen (30-60mg) showed inconsistent results, but case studies suggested a dose-response effect and positive outcomes in patients on high doses of baclofen (up to 270mg). Its prescription was temporary permitted for the treatment of alcohol dependence (AD) in France, and baclofen is now widely prescribed. Recently, a small RCT found a strong effect of a mean dose of 180mg baclofen. In the present study the efficacy and safety of high doses of baclofen was examined in a multicentre, double-blind, placebo-controlled trial. 151 patients were randomly assigned to either six weeks titration and ten weeks high-dose baclofen (N=58; up to 150mg), low-dose baclofen (N=31; 30mg), or placebo (N=62). The primary outcome measure was time to first relapse. Nine of the 58 patients (15.5%) in the high-dose group reached 150mg and the mean baclofen dose in this group was 93.6mg (SD=40.3). No differences between the survival distributions for the three groups were found in the time to first relapse during the ten-weeks high-dose phase (χ²=0.41; p=0.813) or the 16-weeks complete medication period (χ²=0.04; p=0.982). There were frequent dose-related adverse events in terms of fatigue, sleepiness, and dry mouth. One medication related serious adverse event occurred in the high-dose baclofen group. Neither low nor high doses of baclofen were effective in the treatment of AD. Adverse events were frequent, although generally mild and transient. Therefore, large-scale prescription of baclofen for the treatment of AD seems premature and should be reconsidered.

Drug-drug interactions with imatinib: An observational study

Many patients treated with imatinib, used in cancer treatment, are using several other drugs that could interact with imatinib. Our aim was to study all the drug-drug interactions (DDIs) observed in patients treated with imatinib.We performed 2 observational studies, between the 1st January 2012 and the 31st August 2015 in the Midi-Pyrénées area (South Western France), using the French health insurance reimbursement database and then the French Pharmacovigilance Database (FPVD).A total of 544 patients received at least 1 reimbursement for imatinib. Among them, 486 (89.3%) had at least 1 drug that could potentially interact with imatinib. Paracetamol was the most frequent drug involved (77.4%). Proton pump inhibitors, dexamethasone and levothyroxine, were found in >10% of patients. In the FPVD, among a total of 25 reports of ADRs with imatinib recorded in the Midi-Pyrénées area, 10 (40%) had potential DDIs with imatinib. Imatinib was most frequently prescribed by hospital physicians and drugs interacting with imatinib, by general practitioners.Our study showed that at least 40% of the patients treated with imatinib were at risk of DDIs and that all prescribers must be cautious with DDIs in patients treated with imatinib. During imatinib treatment, we particularly recommend to limit the dose of paracetamol at 1300 mg per day, to avoid the use of dexamethasone, and to double the dose of levothyroxine.

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.