The effect of inhaled clonidine in patients with asthma.

To study the effect of inhaled clonidine on broncho-obstruction in asthmatics, 10 patients with extrinsic asthma were broncho-provoked twice with an allergen that had been shown to give positive skin prick test results. Before the provocations, saline or clonidine (75 micrograms) was inhaled via a DeVilbiss no. 40 nebulizer. Clonidine slightly improved the basal respiratory function without significantly influencing the blood pressure. There was a reduction in the allergen-evoked broncho-obstruction by 42 to 65% after pretreatment with clonidine. The eosinophilic leukocytes in peripheral blood had a slight tendency to leave the circulatory system during the provocation preceded by the clonidine treatment. These data add further evidence to the finding that clonidine may be of interest in the treatment of broncho-obstructive diseases.