Residual effects on actual car driving of evening doses of chlorpheniramine 8 and 12 mg when used with terfenadine 60mg in the morning.

The study was conducted according to a 4-way, observer- and subject-blind, cross-over design. Its purpose was to compare the repeated dose effects on actual driving performance of the following: the combination of chlorpheniramine 8 and 12 mg, in sustained release formulations, administered at bedtime and terfenadine 60 mg the following morning; flurazepam 30 mg at bedtime and placebo the following morning; and, placebo at both times. Subjects were 24 healthy female volunteers. Drug effects were assessed in two driving tests (highway driving and car-following) in the morning of the third treatment day. Results show no significant differences in driving performance between both chlorpheniramine/terfenadine treatments and placebo. Flurazepam significantly impaired driving in both tests