Lack of gastric adverse effects of erdosteine in rats and men.

Erdosteine is a thiol derivative endowed with mucolytic, mucomodulator and free radical scavenging properties. Studies were performed in rats and men with the aim to assess its safety on gastric mucous barrier. Two experiments were performed in rats by comparing the effects of erdosteine, homocysteine thiolactone (HTL), carbocysteine, tiopronin and placebo on a) macroscopic appearance of G. I. ulcer, total HCl, pH and volume of gastric juice 4 and 6 hours after, respectively, pylorus ligation in Shay rats and drug oral treatment, and on b) macroscopic appearance of G. I. ulcer in fasting rats for 50 hours, during which the animals received 4 oral doses of each compound. In both conditions erdosteine was completely inactive in the dose-range of 500-1000 mg/kg p.o. while HTL, carbocysteine and tiopronin were ulcerogenic already at the dose of 500 mg/kg p.o. Accordingly, 15 human beings, undergoing gastroscopy, well tolerated erdosteine at the oral dose of 300 mg TID for 9-13 days. In this open study the patients neither revealed worsening of their pre-existing gastric complains, nor indicated new subjective symptoms, nor manifested macroscopic and histological alterations concerning the parietal tonus, the status of epithelial mucosa and of gastric content (including: volume, total acidity and total, bound and free sialic acid).