[Loop diuretics and the treatment of asthma]

Current data in the literature show a protective effect of loop diuretics in relation to certain types of experimental bronchospasm. This action has sometimes been observed after the administration of diuretics as aerosols in less severe cases of asthma. The initial observations on bronchospasm induced by physical stimuli (exercise, distilled water and hyperventilation), have been extended to bronchospasm provoked by allergens or certain chemical stimuli (metabisulphide, adenosine 5'-monophosphate, and salicylic acid). On the other hand provocation tests using histamine or acetylcholine are modified, either a little or not at all by diuretics. The proposed mechanisms of action are multiple, but are still very hypothetical: an action on ionic fluxes in the epithelial cells, in mastocytes, in nerve cells and in muscle cells inducing the secretion of prostaglandin. Diuretics certainly have opened some interesting patho-physiological approaches, but current data concerning their efficacy in asthmatics are still fragmentary and do not, at the current time, allow them to take a significant place in the therapeutic arsenal of asthma drugs.