Desloratadine shows no effect on performance during 6 h at 8,000 ft simulated cabin altitude

Sustained vigilance is required by pilots and crew during flight; therefore, the use of antihistamines with sedating properties is widely prohibited. The purpose of this study was to determine the effects of desloratadine, a long-acting, nonsedating antihistamine, on healthy volunteers placed under conditions of simulated cabin pressure.

In a double-blind crossover study, 21 subjects randomly received single doses of desloratadine 5 mg, diphenhydramine 50 mg (active control), and placebo on different days separated by washout periods of 7 d. On test days, predose levels of alertness and fatigue were determined, as were post-dose levels at 1, 2, 3, 5, and 6 h. Measurements included vigilance and tracking, a multi-attribute task battery, the Stanford Sleepiness Scale, and pulse oximetry.

Desloratadine had no detrimental effects on sleepiness or performance of tasks associated with flying ability. Conversely, diphenhydramine (active control) caused significantly more sleepiness than did the placebo [F (2,40) = 6.52, p < 0.01], as well as impaired performance (tracking performance p < 0.05 at 3 h post dose), and an increased percentage of omissions (p < 0.05 at 2 h post dose).

A single dose of desloratadine 5 mg did not cause sleepiness and did not impair the performance of tasks associated with flying ability.