Pharmacodynamic mechanism and therapeutic activity of ambroxol in animal experiments.

The mucokinetic activity of ambroxol was demonstrated as an increase in mucus or particle transport rate on the frog palate and in guinea pig tracheas. To clarify the mechanism we examined the influence of the drug on the ciliary beat frequency (CBF) of isolated cells from guinea pig tracheas. Ambroxol significantly stimulated the CBF up to 10.8%, salbutamol up to 19.5%. The effect of ambroxol on CBF certainly contributes to, but does not explain the more pronounced increase in transport rate. Thus a stimulation of the mucociliary transport rate by the other major pharmacodynamic mechanisms, secretagogue activity and stimulation of pulmonary surfactant, has to be considered. The therapeutic activity of ambroxol in models of the infant and adult respiratory distress syndrome and of the chronic bronchitic syndrome is reviewed.

The pharmacology of ambroxol--review and new results.

The major pharmacodynamic actions of ambroxol are surfactant stimulation, mucokinetic and secretagogue activity. The therapeutic activities of the drug in animal models of the infant and adult respiratory distress syndrome (IRDS and ARDS) are reviewed. SO2 exposed rats, which exhibited increased airway resistance and work of breathing, were used as an animal model of a bronchitic syndrome. The active group was treated with 25 mg kg-1 oral ambroxol for 10 days. The airway resistance of this group (53.6 +/- 7.0 Pa.ml-1.s) was significantly lower than that of the control (81.2 +/- 11.4). Specific work of breathing was also lower in the treated group (0.26 +/- 0.02 mJ.ml-1, control: 0.35 +/- 0.029). The alleviation of airflow limitation was a consequence of subacute treatment and not of acute bronchodilatation. Treatment with the beta 2-adrenergic drug clenbuterol further improved both active and placebo groups.