Enantioselective effects of levodropropizine and dropropizine on psychomotor functions in normal volunteers: A placebo-controlled, double-blind comparative study

Abstract

Levodropropizine is the I-isomer of dropropizine, a racemic drug widely used as a cough suppressant. Compared with the racemate, levodropropizine retains equal antitussive activity but exhibits considerably lower central nervous system (CNS) depressant effects in animal models. In order to assess whether the same differential pharmacodynamic profile also applies to man, a double-blind placebo-controlled study was carried out to investigate the effects of single oral doses (60 and 120 mg) of levodropropizine and dropropizine on subjective alertness (scored on visual analogue scales), general tolerability and psychomotor function tests (cancellation, tapping, choice reaction times and critical..