Harmen Beurmanjer

84 Chapter 6 Discussion This is the first case-control study evaluating the effectiveness of baclofen to prevent relapse in GHB-dependent patients. Patients receiving baclofen per protocol after detoxification showed reduced relapse rates, compared to patients receiving TAU, supported by a similar trend towards beneficial effects of baclofen in the ITT analysis. Mild tiredness, sleepiness and depressed feelings were reported in the baclofen group as most relevant side effects of baclofen. These results are comparable with an earlier case series (n=11) on baclofen treatment inGHB-dependent patients, showing 81%abstinence rates during threemonths follow-up, without significant side effects (Kamal, Loonen, et al., 2015). Similarly, Fattore et al. (2001) showed prevention of self-administration of GHB in mice when treated with baclofen (0.625 and 1.25 mg/kg). Importantly, a lower dosage of baclofen (0.312 mg/kg) did not prevent GHB self-administration. There is currently no consensus on the most appropriate dose of baclofen in addiction treatment. In linewith the previous case series, we prescribed a relatively low dosage of baclofen (45-60mg daily) in comparison with studies on alcohol dependence (up to 300mg daily(Rolland et al., 2015). As higher doses of baclofen might be more effective, future studies on baclofen effectiveness in GHB dependence should also study higher doses of baclofen. However, caution is warranted as data about safety of high dose baclofen are limited. Table 2b Comparison of (re)lapse in GHB use in the three months after detoxification between patients prescribed baclofen according to the study protocol (PP) and patients who receive treatment as usual. Treatment as usual Baclofen + Treatment as usual Test statistic p-value Patient completed follow-up Lapse (any use) n=55 47% (n=26) n=12 25% (n=3) χ²=1.99 .158 Relapse Patients including drop-out 38% (n=21) n=70 8% (n=1) n=13 χ²=3.97 .046 Relapse† 50% (n=35) 15% (n=2) χ²=5.31 .021 † Drop-out is considered relapse in GHB dependent patients, therefore only relapse is mentioned.