Effects of dilevalol, a beta-adrenoceptor antagonist with intrinsic sympathetic activity in asthmatic patients

The effects on baseline ventilation as well as beta 2-receptor stimulant-induced bronchodilation and tremor of atenolol and dilevalol, a beta-blocking agent with non-selective beta-antagonistic properties and intrinsic activity on the beta 2-receptor were evaluated in 8 patients with stable asthma. Both atenolol and dilevalol were found to significantly decrease both forced expiratory volume during 1 s (FEV1) and forced vital capacity (FVC). This decrease was significantly more pronounced after atenolol. Both agents decreased systolic and diastolic blood pressure as well as heart rate to a similar degree. Increased activation of beta 2-adrenoceptors by terbutaline infusion resulted in increased FEV1 and FVC as well as beta 2-adrenoceptor mediated reflex tachycardia and skeletal muscle tremor. The dose response curves for all these parameters were significantly shifted to the right and a decrease of the maximum relative response was seen after atenolol pretreatment. This effect was more pronounced after treatment with dilevalol with a further shift to the right of the response curve and a decrease of the maximum relative response. The haemodynamic and ventilatory effects of dilevalol are consistent with a non-selective beta-adrenoceptor blockade combined with intrinsic activity on the beta 2-receptors.