A preliminary study of the effects of flosequinan on psychomotor function in healthy volunteers

The central nervous system effects of flosequinan (100 mg), a chemically novel quinolone vasodilator, were assessed by a double-blind crossover comparison with placebo and diazepam (10 mg) in 12 healthy volunteers. After five practice sessions on a battery of automated psychomotor tests, assessments of psychomotor function and mood ratings were made on each volunteer at baseline and 1, 3, 6 and 24 h after dosing. Compared with placebo, diazepam (10 mg), the verum control, significantly (p less than 0.05) reduced subjective alertness, impaired critical flicker fusion threshold at 1 and 3 h, digit symbol substitution at 6 h, overall total choice reaction time and overall rate on two of five finger tapping tests. Flosequinan (100 mg), however, was indistinguishable from placebo in all tests with two contrasting exceptions: improved alternate right and left finger tapping (mean 5.1/s) compared to either diazepam (4.7/s) or placebo (4.8/s) (p less than 0.05), and impaired digit symbol substitution at 6 h (45.7/min) in comparison with placebo (50.7/min) (p less than 0.01). Ten volunteers reported 12 adverse effects after flosequinan treatment (10 of which were headaches), two reported drowsiness after diazepam and one reported headache after placebo. It was concluded that flosequinan has no central nervous system depressant effects despite the occurrence of headache in 10 volunteers.