Abstract
BACKGROUND: Silexan is a lavender essential oil with established anxiolytic and calming efficacy. Here we asked whether there is a potential for abuse in human patients. METHODS: We carried out a phase I abuse liability single-center, double-blind, 5-way crossover study in healthy users of recreational central nervous system depressants. They received single oral doses of 80 mg (therapeutic dose) and 640 mg Silexan, 2 mg and 4 mg lorazepam (active control) and placebo in randomized order, with 4- to 14-day washout periods between treatments. Pharmacodynamic measures included validated visual analogue scales assessing positive, negative, and sedative drug effects and balance of effects; a short form of the Addiction Research Center Inventory; and a drug similarity assessment. The primary outcome measure was the individual maximum value on the drug liking visual analogue scale during 24 hours post-dose. RESULTS: Forty participants were randomized and 34 were evaluable for pharmacodynamic outcomes. In intraindividual head-to-head comparisons of the drug liking visual analogue scale maximum value, both doses of Silexan were rated similar to placebo whereas differences were observed between Silexan and lorazepam and between placebo and lorazepam (P < .001). These data were supported by all secondary measures of positive drug effects and of balance of effects. Differences between placebo and both doses of Silexan were always negligible in magnitude. Moreover, Silexan showed no sedative effects and was not perceived to be similar to commonly used drugs that participants had used in the past. CONCLUSIONS: Silexan did not exhibit any abuse potential in a standard abuse potential detection screen study and is unlikely to be recreationally abused.