Effects of sedating and nonsedating antihistamines on flying performance.

The purpose of this double-blind study was to compare the effects on flying performance of a nonsedating antihistamine, (terfenadine), two sedating antihistamines, (chlorpheniramine and diphenhydramine), and a placebo. Twelve USAF pilots were tested at 1-month intervals with the above medications, administered during separate testing periods. Medication was given twice daily for 3 days. On the third day, each pilot performed three landing approaches in a C5-B flight simulator, followed by assessment with psychological and neuropsychological tests. Evaluation of the flight data showed no significant differences in flight performance among any of the pilots while on four different medications. Psychological and neuropsychological testing demonstrated no significant differences in performance with the exception of the SCL-90-R, where pilots reported psychological and physiological subjective symptoms with diphenhydramine and chlorpheniramine, but not with terfenadine. While pilots were on each medication, open-ended questionnaires corroborated the results of the SCL-90-R. Both the flight and neuropsychological testing data suggest that terfenadine has no detectable effects on overall flying performance.