GABAB receptor ligands for the treatment of alcohol use disorder: preclinical and clinical evidence

The present paper summarizes the preclinical and clinical studies conducted to define the "anti-alcohol" pharmacological profile of the prototypic GABAB receptor agonist, baclofen, and its therapeutic potential for treatment of alcohol use disorder (AUD). Numerous studies have reported baclofen-induced suppression of alcohol drinking (including relapse- and binge-like drinking) and alcohol reinforcing, motivational, stimulating, and rewarding properties in rodents and monkeys. The majority of clinical surveys conducted to date-including case reports, retrospective chart reviews, and randomized placebo-controlled studies-suggest the ability of baclofen to suppress alcohol consumption, craving for alcohol, and alcohol withdrawal symptomatology in alcohol-dependent patients. The recent identification of a positive allosteric modulatory binding site, together with the synthesis of in vivo effective ligands, represents a novel, and likely more favorable, option for pharmacological manipulations of the GABAB receptor. Accordingly, data collected to date suggest that positive allosteric modulators of the GABAB receptor reproduce several "anti-alcohol" effects of baclofen and display a higher therapeutic index (with larger separation-in terms of doses-between "anti-alcohol" effects and sedation).

Magnesium for alcohol withdrawal

BACKGROUND

Patients have been given magnesium to treat or prevent alcohol withdrawal syndrome (AWS). Evidence to support this practice is limited, and is often based on the controversial link between hypomagnesaemia and AWS.

OBJECTIVES

To assess the effects of magnesium for the prevention or treatment of AWS in hospitalised adults.

SEARCH METHODS

We searched the Cochrane Drugs and Alcohol Group Register of Controlled Trials (August 2012), PubMed (from 1966 to August 2012 ), EMBASE (from 1988 to August 2012), CINAHL (from 1982 to March 2010), Web of Science (1965 to August 2012). We also carried out Internet searches.

SELECTION CRITERIA

Randomised or quasi-randomised trials of magnesium for hospitalised adults with, or at risk for, acute alcohol withdrawal.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data with a standardised data extraction form, contacting the correspondence investigator if the necessary information was not available in the reports. Dichotomous outcomes were analysed by calculating the risk ratio (RR) for each trial, with the uncertainty in each result expressed with a 95% confidence interval (CI). Continuous outcomes were to be analysed by calculating the standardised mean difference (SMD) with 95% CI. For outcomes assessed by scales we compared and pooled the mean score differences from the end of treatment to baseline (post minus pre) in the experimental and control groups.

MAIN RESULTS

Four trials involving 317 people met the inclusion criteria. Three trials studied oral magnesium, with doses ranging from 12.5 mmol/day to 20 mmol/day. One trial studied parenteral magnesium (16.24 mEq q6h for 24 hours). Each trial demonstrated a high risk of bias in at least one domain. There was significant clinical and methodological variation between trials.We found no study that measured all of the identified primary outcomes and met the objectives of this review. Only one trial measured clinical symptoms of seizure, delirium tremens or components of the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) score. A single outcome (handgrip strength) in three trials (113 people), was amenable to meta-analysis. There was no significant increase in handgrip strength in the magnesium group (SMD 0.04; 95% CI -0.22 to 0.30). No clinically important changes in adverse events were reported.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine whether magnesium is beneficial or harmful for the treatment or prevention of alcohol withdrawal syndrome.