Abstract
1 The effect of α-adrenoceptor blocking drug, thymoxamine alone and in combination with isoprenaline, was studied on the specific airways conductance (SGaw) in ten patients with extrinsic asthma. 2 Thymoxamine when given together with isoprenaline produced significantly greater increase in SGaw as compared to improvement achieved with isoprenaline alone. 3 It is suggested that the potentiation of isoprenaline induced bronchodilatation by thymoxamine is mediated by increased cyclic AMP formation in the bronchial smooth muscle.