It antagonizes histamine and acetylcholine, relieves bronchospasm and has an anti-asthmatic effect; it has a strong inhibitory effect on the cough center; it causes increased secretions, thins thick sputum, reduces sputum viscosity, and makes it easier to cough up; it has a similar effect to aminophylline in relaxing bronchial smooth muscles; it increases the electrical stimulation threshold of the cerebral cortex, inhibits synaptic conduction of electrical stimulation and the spread of epileptic electricity.

It can directly stimulate adrenaline receptors, and can also indirectly stimulate adrenaline receptors by prompting adrenaline nerve endings to release norepinephrine. It has a stimulating effect on both alpha and beta receptors. It can dilate bronchi and constrict local blood vessels, and its action time is longer; it strengthens myocardial contractility, increases cardiac output, and makes venous return to the heart sufficient; it has a stronger central nervous system stimulating effect than adrenaline.

It has ① antihistamine effect, which can compete with histamine released from tissues for H1 receptors on effector cells, thereby stopping allergic reactions; ② at the same time, it inhibits central nervous system activity and causes sedative and hypnotic effects; ③ it enhances the effect of antitussive drugs.

Extract from the above information

1. It has a positive inotropic effect on the myocardium, mainly acting on beta 1 receptors, and has relatively little effect on beta 2 and alpha receptors; 2. It can directly excite cardiac beta 1 receptors to enhance myocardial contraction and increase stroke volume, thereby increasing cardiac output; 3. It can reduce peripheral vascular resistance (reduced afterload), but systolic blood pressure and pulse pressure generally remain unchanged, or only increase due to increased cardiac output; 4. It can reduce ventricular filling pressure and promote atrioventricular node conduction; 5. Myocardial contractility is enhanced, and coronary blood flow and myocardial oxygen consumption often increase; 6. Due to increased cardiac output, renal blood flow and urine volume often increase; 7. Unlike dopamine, dobutamine does not act indirectly through the release of endogenous norepinephrine, but directly on the heart.

No specific pharmacological effects mentioned