Pulmonary pharmacology & therapeutics

Levodropropizine does not affect P0.1 and breathing pattern in healthy volunteers and patients with chronic respiratory impairment.

PMID 12850126


To evaluate whether the peripherally acting antitussive levodropropizine could affect the respiratory drive and the breathing pattern, we performed a double-blind, randomised, cross-over trial in 12 healthy volunteers and 12 patients with chronic respiratory impairment associated with chronic obstructive pulmonary disease. Levodropropizine 6% drops (at the recommended dose for adults) or placebo were administered orally t.i.d. for 10 consecutive administrations. Mouth occlusion pressure (P0.1), minute ventilation (V(e)), tidal volume (V(t)), respiratory rate (RR), mean inspiratory flow (V(t)/T(i)), end-tidal CO(2) (EtCO(2)), oxygen saturation (SaO(2)), forced expiratory volume in 1 s (FEV(1)), and the response to a hypercapnic stimulus were measured before and 1 h after the first and the last drug administration. Levodropropizine did not modify P0.1 in basal conditions and after a hypercapnic stimulus, either in healthy volunteers or in patients. In parallel, levodropropizine did not significantly affect V(t), RR, V(e), V(t)/T(i) and EtCO(2) in both the populations. Minor changes were induced by levodropropizine on SaO(2) in healthy volunteers, which despite a statistical difference, were too low to gain a clinical significance. These results confirmed the respiratory safety of levodropropizine 6% drops administered at the recommended dosage either in healthy volunteers or patients with chronic respiratory impairment.