Improving GHB withdrawal with baclofen: study protocol for a feasibility study for a randomised controlled trial

Abstract

Background: GHB (gamma-hydroxybutyrate) and its pro-drugs GBL (gamma-butyrolactone) and 1,4-butanediol (1,4-BD) are central nervous system depressants whose street names include 'G' and 'liquid ecstasy'. They are used recreationally predominately for their stimulant and pro-sexual effects or for sedation to help with sleep and/or to 'come down' after using stimulant recreational drugs. Although overall population prevalence is low (0.1 %), in some groups such as men who have sex with men, GHB/GBL use may reach 20 %. GHB/GBL dependence may be associated with severe withdrawal with individuals presenting either acutely to emergency departments or to addiction services for support. Benzodiazepines are currently prescribed for GHB/GBL detoxification but do not prevent all complications, such as behavioural disinhibition, that may require hospitalisation or admission to a high dependency/intensive care unit. The GABA_B receptor mediates most effects of GHB/GBL and the GABA_B agonist, baclofen, has shown promise as an adjunct to benzodiazepines in reducing withdrawal severity when prescribed both during withdrawal and as a 2-day 'preload' prior to detoxification. The key aim of this feasibility study is provide information about recruitment and characteristics of the proposed outcome measure (symptom severity, complications including delirium and treatment escalation) to inform an application for a definitive randomised placebo controlled trial to determine the role of baclofen in the management of GHB/GBL withdrawal and whether starting baclofen 2 days earlier improves outcomes further.

Methods/design: This is a prospective, randomised, double-blind, placebo-controlled feasibility study that will recruit participants (aged over 18 years) who are GHB/GBL-dependent and wish to undergo planned GHB/GBL detoxification or are at risk of acute withdrawal and are inpatients requiring unplanned withdrawal. We aim to recruit 88 participants: 28 unplanned inpatients and 60 planned outpatients. During detoxification we will compare baclofen 10 mg three times a day with placebo as an adjunct to the usual benzodiazepine regimen. In the planned outpatient arm, we will also compare a 2-day preload of baclofen 10 mg three times a day with placebo. Ratings of GHB/GBL withdrawal, sleep, depression, anxiety as well as GHB/GBL use will be collected. The main data analyses will be descriptive about recruitment and characterising the impact of adding baclofen to the usual benzodiazepine regimen on measures and outcomes of GHB/GBL withdrawal to provide estimates of variability and effect size. A qualitative approach will evaluate research participant and clinician acceptability and data collected to inform cost-effectiveness.

Discussion: This feasibility study will inform a randomised controlled trial to establish whether adding baclofen to a benzodiazepine regimen reduces the severity and complications of GHB/GBL withdrawal.

Trial registration: ISRCTN59911189 . Registered 14 October 2015.

Protocol: v3.1, 1 February 2016.

Keywords: Baclofen; Benzodiazepine; GABAB; GBL; GHB; GHB/GBL dependence; GHB/GBL withdrawal; Gamma-butyrolactone; Gamma-hydroxybutyrate.

Fig. 1

a CNWL Club Drug Clinic – Planned (outpatient) withdrawal, N = 60 (three groups). b GSTT clinical toxicology service – Unplanned (inpatient) withdrawal, N = 28 (two groups). CNWL Central North West London NHS Foundation Trust, GSTT Guy’s and St. Thomas’s NHS Foundation Trust