[Comparative clinical evaluation of two mucolytic agents: S-carboxy-methyl-cysteine and letosteine (author's transl)].

A controlled double-blind clinical trial comparing a noval medicament, letosteine, to a known bronchial fluidifier, S-carboxy-methyl-cysteine, was conducted on a total of 47 hospitalized patients suffering from various types of chronic obstructive lung disease. Daily observations were made on the patients themselves and on sputum samples obtained from them before, during and after the course of mucolytic therapy. When the code was broken at the end of the trial, there appeared no significant difference between the patient groups treated with the two drugs regarding either changes in respiratory symptoms or changes in sputum characteristics. Thus, in this study, letosteine (50 mg t.i.d.) appeared equivalent to S-carboxy-methyl-cysteine (750 mg t.i.d.) in the treatment of chronic obstructive lung disease in adults.