Harmen Beurmanjer

85 Baclofen for GHB-Dependent Patients 6 GHB, baclofen and alcohol share a similar pharmacological profile. Studies on alcohol dependence have shown that GHB is effective in reducing alcohol craving and intake (Giovanni Addolorato, Leggio, Ferrulli, Caputo, & Gasbarrini, 2009). So it’s conceivable that baclofen should be effective in reducing GHB dependence in view of its efficacy to reduce alcohol dependence (Mirijello et al., 2015). In light of the longer half-life of baclofen compared to GHB, it can also be speculated that baclofenmight be considered a substitute for GHB(Rolland et al., 2014). The currently poor prognosis in GHB dependence and severity of complications might justify a substitution therapy approach (Dijkstra et al., 2017). Recently, baclofen raised attention for its potential effectiveness for the detoxification of GHB (Lingford-Hughes et al., 2016). One could also suggest using baclofen to ameliorate GHB withdrawal during detoxification, without tapering off completely, in order to prevent relapse. This would likely increase treatment adherence in some patents, preventing them from dropping out of treatment and relapse in GHB use. Given the explorative, non-randomized, open-label design of our study, the results need to be interpreted with caution and further studies are needed in order to confirm our findings. Several limitations should be considered when interpreting the results. First, sample size was limited and lower than anticipated. Moreover, patients who chose baclofen treatment might have been more motivated for full abstinence, adding to the chance of good outcome at follow-up. Yet, we did observe similar findings to previous animal work and a case series of GHB-dependent patients (Fattore et al., 2001; Kamal, Loonen, et al., 2015). The observed effectiveness of baclofen, despite a limited sample size, does suggest treatment potential of baclofen in patients with GHB use disorders. Second, TAU was not specified in the current study. Any variation in TAU between groups might confound the results. While we have no such indication when it comes to psychosocial treatment, it is however possible that some patients in the TAU group were prescribed benzodiazepines on top of their psychosocial treatment. Therefor a potential confounding effect cannot be fully ruled out. Third, abstinence was not confirmed using systematic urine or blood tests, due to the narrow timeframe in which GHB can be detected as a result of its short half-life (Schep, Knudsen, Slaughter, Vale, & Mégarbane, 2012). We relied on self-report measures, with potential recall bias, particularly given the open-label design of the study. Compliance with the baclofen treatment also was assessed by self-report, during weekly meetings between the prescribing physician and the patient. Pill count was not used. This is a potential confound of the data, since compliance is considered highly relevant for the effectiveness of baclofen. Finally, follow-up duration was three months after detoxification, which makes drawing conclusions about long-term effects impossible. Fourth, side effects where not measured in the TAU group, therefor reported side effects cannot be solely attributed to baclofen. Many of the reported side effects are common in GHB-dependent patients in general after detoxification (Dijkstra et al., 2017). Future studies should address long-termefficacy of baclofen in GHB dependence, using placebo-controlled, randomized designs in substantially large samples.