It achieves antibacterial effect by inhibiting the activity of bacterial topoisomerase IV and DNA gyrase, hindering the replication of bacterial DNA. It has good antibacterial effect on most Enterobacteriaceae, some methicillin-sensitive Staphylococci, Streptococcus pneumoniae, Streptococcus pyogenes, hemolytic Streptococcus and other Gram-positive bacteria and Legionella, Mycoplasma, Chlamydia, but has poor effect on anaerobic bacteria and enterococci.

It has an antihistamine effect and can compete with histamine released from tissues for the H1 receptors on effector cells, thereby stopping allergic reactions; it inhibits central nervous system activity and causes sedative and hypnotic effects; it enhances the effects of antitussive drugs; it has anti-vertigo and anti-tremor paralysis effects; it has local anesthetic, antiemetic and anti-M cholinergic effects.

It stimulates adrenaline receptors in the sympathetic nervous system and dopamine receptors located in the kidneys, mesentery, coronary arteries, and cerebral arteries. Its effect is dose-dependent. (1) At low doses (0.5-2 mu;g/kg per minute based on body weight), it mainly acts on dopamine receptors, dilating renal and mesenteric blood vessels, increasing renal blood flow and glomerular filtration rate, and increasing urine volume and sodium excretion; (2) At small to medium doses (2-10 mu;g/kg per minute based on body weight), it can directly stimulate beta;1 receptors and indirectly promote the release of norepinephrine from storage sites, exerting a positive stress effect on the myocardium, increasing myocardial contractility and stroke volume, and ultimately increasing cardiac output, systolic blood pressure, and possibly pulse pressure, with no change or slight increase in diastolic blood pressure, and usually no change in total peripheral resistance, while coronary blood flow and oxygen consumption improve; (3) At high doses (greater than 10 mu;g/kg per minute based on body weight), it stimulates alpha;1 receptors, leading to increased peripheral vascular resistance, renal vasoconstriction, and reduced renal blood flow and urine volume. Due to the increase in cardiac output and peripheral vascular resistance, both systolic and diastolic blood pressure increase. ① It has a much stronger effect on stimulating cardiac beta-1 receptors and increasing myocardial contractility; ② It can prevent the malignant development of shock caused by ischemia of these organs by increasing the blood flow to the kidneys and mesentery. Under the same condition of increasing myocardial contractility, the effects of causing arrhythmias and increasing myocardial oxygen consumption are weaker. In short, dopamine is particularly suitable for shock patients with weakened myocardial contractility, reduced urine output, and sufficient blood volume.

This product is a phenothiazine antipsychotic, and its mechanism of action is mainly related to its blocking of dopamine receptors (DA2) in the mesolimbic system and mesocortical pathways. It has a blocking effect on dopamine (DA1) receptors, 5-hydroxytryptamine receptors, M-type acetylcholine receptors, and α-adrenaline receptors, and has a wide range of effects. In addition, this product can inhibit the dopamine receptors in the medulla oblongata emetic chemoreceptor area at low doses, and directly inhibit the vomiting center at high doses, producing a strong antiemetic effect. It inhibits the body temperature regulation center and lowers the body temperature. The body temperature can change with changes in the external environment. It blocks the action of peripheral α-adrenaline receptors, dilates blood vessels, causes a drop in blood pressure, and also has a certain effect on the endocrine system.

As a histamine H1 receptor antagonist, this product can counteract the capillary dilation caused by allergic reactions, reduce the permeability of capillaries, and relieve wheezing caused by bronchial smooth muscle contraction. This product has a long-lasting antihistamine effect and also has a significant central inhibitory effect, which can increase the effects of anesthetics, analgesics, hypnotics and local anesthetics. This product is mainly metabolized in the liver.