Psychomotor Effects of Mexazolam vs Placebo in Healthy Volunteers

Mexazolam is an oxazolo-benzodiazepine demonstrating chemical similarities to oxazolam and cloxazolam. This trial aimed to assess the effect of mexazolam on psychomotor performance.

The study was a double-blind, single-dose, randomised, two-way crossover, placebo-controlled trial.

33 healthy male and female adult volunteers.

Psychomotor performance was evaluated through the Leeds Psychomotor Test Battery [critical flicker fusion (CFF) threshold and choice reaction time with its three components (recognition reaction time — RRT, motor reaction time — MRT, and total reaction time — TRT)] and, in an exploratory way, a car-driving simulation (CDS). After performing a baseline test set, each volunteer received, in a randomised fashion, either a single oral dose of mexazolam 1mg or placebo and, 3 hours later, the test set was repeated. After a washout of at least 10 days, the procedures were repeated in a crossover way. Tolerability was assessed through the reporting of adverse events.

A total of 33 healthy subjects were enrolled. In the Leeds Psychomotor Test Battery, no statistically significant differences were found between post-versus pre-placebo results, post-versus pre-mexazolam results, and placebo versus mexazolam results (post-administration: CFF: p = 0.480, RRT: p = 0.195, MRT: p = 0.470, TRT: p = 0.169). In the CDS, there were no statistical differences between placebo and mexazolam scores [pre-administration: total time score (TTS): p = 0.519, best lap time (BLT): p = 0.499; post-administration: TTS: p = 0.940, RRT: p = 0.995]. There was a statistically significant improvement between post- and pre-placebo scores (TTS: p = 0.032, BLT: p = 0.023) and between post- and pre-mexazolam scores (TTS: p = 0.016, BLT: p = 0.030), indicating a learning effect induced by the repetition of the tests. A total of three volunteers reported a total of three adverse events: somnolence, which occurred following mexazolam administration, and headache and flu-like syndrome, which occurred after placebo administration.

Mexazolam does not have psychomotor performance-impairing effects at therapeutic doses. Reduced effects on psychomotor performance in anxious patients may lead to better compliance and to specific indications for this benzodiazepine.