Mucolytic and antitussive effects of erdosteine

To investigate the influence of erdosteine, a new homocysteine-derived expe ctorant, on airway clearance we studied the effects of the drug on the visc osity of mucin, on the mucociliary transport rate in quails, on airway secr etion in rats and on the cough reflex in guinea-pigs. The active metabolite of erdosteine, M1 (10 mu M to 1 mM), significantly re duced the viscosity of porcine stomach mucin. Erdosteine by itself did not reduce viscosity. Erdosteine significantly promoted mucociliary transport i n quails and increased airway secretion in rats. The effect was still appar ent 24 h after administration. Erdosteine significantly suppressed citric a cid-induced cough reflexes in guinea-pigs but did not suppress mechanical s timuli-induced cough reflexes. Erdosteine suppressed the reduction of the r ecovery volume of bronchoalveolar lavage fluid and albumin leakage into the fluid in citric acid-exposed guinea-pigs. These results indicate that erdosteine removes sputum by reducing its visco sity, and by promoting mucociliary transport and sustained enhancement of a irway secretion. It also suppressed the chemical stimulation-induced cough reflex and plasma leakage into the airway. These results suggest that erdos teine is an excellent expectorant with several modes of action.