Effects of treatment with etizolam 0.5 mg BID on cognitive performance: a 3-week, multicenter, randomized, double-blind, placebo-controlled, two-treatment, three-period, noninferiority crossover study in patients with anxiety disorder

Background: Etizolam is an anxiolytic drug with a pharmacologic profile similar to that of the classic benzodiazepines. Neurochemical research suggests that etizolam may have selectivity for the subpopulation of Y-aminobutyric acid type A receptors associated with anxiety (ie, alpha1, beta2, gamma2). This property, plus its characterization as a ligand with fewer of the adverse events typical of full agonists (impaired cognitive function, tolerance, and dependence), led to its selection for this study.

Objectives: The primary aim of this study was to test for the noninferiority of etizolam 0.5 mg BID versus placebo in affecting cognitive function in patients with mild to moderate anxiety disorder of recent onset (<1 month). Anxiety measures and tolerability were also assessed.

Methods: Patients between the ages of 18 and 65 years were eligible for enrollment. This double-blind, placebo-controlled study was performed in 5 centers in Italy using a 2-treatment, 3-period crossover design. Patients were randomized to 3-week sequences of either etizolam-placebo-placebo or placebo-etizolam-etizolam. They were evaluated at 4 scheduled visits (screening and days 7, 14, and 21). Cognitive function was assessed using scores from the Wechsler Adult Intelligence Scale (WAIS) Digit Span test (total forward and backward scores and the time required to perform the test). Anxiety was measured using the Hamilton Anxiety Rating Scale (HAM-A) and the State-Trait Anxiety Inventory (STAI) for screening and to monitor adequacy of therapy. Blood pressure, heart rate, weight, and adverse events were also recorded.

Results: A total of 77 white patients were enrolled (mean age, 33.3 years [range, 22-60 years]; 62.3% female; mean weight, 65.2 kg). With a power of 0.80, the difference between the effects of etizolam and placebo on WAIS Digit Span performance was not significant for total score (0.102 [90% CI, -0.130 to 0.335]) or time required for completion (0.029 second [90% CI, -0.574 to 0.632]). Anxiety, as measured using the HAM-A and STAI instruments, did not differ significantly between groups. No significant differences were found between etizolam 0.5 mg BID and placebo for cardiovascular events, weight changes, or adverse events. Mild or moderate somnolence was reported by 7 of 77 patients (9.1% [3 patients while receiving etizolam and 4 patients while receiving etizolam and placebo]).

Conclusions: No significant differences between etizolam 0.5 mg BID and placebo were found for cognitive function or anxiety measures in these patients with anxiety. Etizolam was well tolerated.