tested in pediatric patients with lower tract respiratory disorders, in association with ampicillin, demonstrating a high symptoms reduction. In pediatric population with acute bronchitis, tracheobronchitis and pneumonia, erdosteine showed a significantly high reduction in cough intensity and improvement of clinical symptoms, with very good tolerability. Pharmacokinetics Erdosteine, administered in single doses from 150 mg to 1200 mg to adult volunteers, shows a linear kinetic, with Met I serum concentration approximately 4-fold higher than those of erdosteine. The pharmacokinetic parameters of erdosteine and Met I are fully comparable after single and multiple doses, therefore there is no accumulation or metabolic activation after repeated administrations. Food does not significantly affect the absorption of erdosteine. After oral administration, erdosteine is rapidly absorbed in the gastro-intestinal tract and the plasmatic peak concentration (Cmax) is reached after 30–60 minutes (Tmax) from consumption. The molecule is rapidly transformed through a first-pass metabolism to the biologically active metabolite Met I. The drug bioavailability by oral route is very good. The half-life is 3 hours and the plasma binding protein is 65%. With respect to pharmacokinetics in special populations, a study in 12 health volunteers (mean age 70 years) confirmed that pharmacokinetic parameters for both erdosteine and Met I were similar to those observed in younger adults (mean age 31 years). Moderate renal dysfunction in elder volunteers did not affect erdosteine and Met I pharmacokinetics. Toxicity The LD50 in rats is very high, between 3.500 and 5.000 mg/kg. Clinical uses Clinical studies in more than 4.000 patients demonstrated that erdosteine is effective is the treatment of acute and chronic affections of upper and lower respiratory tract with mucus hypersecretion. It modules the sputum viscosity in the respiratory tract, making it more fluid and less thick, bringing to an increase of mucociliary rate which allows the mucus removal from respiratory tract. Erdosteine is used as mucolytic and fluidifying agent in upper and lower respiratory disorders. It modules the sputum viscosity. Erdosteine efficacy is significant in reducing symptoms associated with Chronic Obstructive Pulmonary Disease. A multicentric, multinational study on more than 450 patients with COPD demonstrated that erdosteine is able to reduce both the frequency and the duration of symptomatic exacerbations, typical of this disease. The GOLD (Global Initiative for Chronic Obstructive Lung Disease) International Guidelines indicate that a regular treatment with a mucolytic like erdosteine can reduce exacerbations and improve the health status of patients with COPD. In some