It works by acting on the 50S subunit of bacterial ribosomes, inhibiting the synthesis of bacterial proteins, and is a growth-stage antibacterial drug. Its antibacterial properties are similar to those of erythromycin, showing strong antibacterial effects on Gram-positive bacteria and mycoplasmas, and also on some Gram-negative bacteria such as Neisseria meningitidis and Neisseria gonorrhoeae.

After entering the body, this product can combine with poisons containing hydroxyl or carboxyl groups to form low-toxic or non-toxic combinations that are excreted in the urine, protecting the liver and detoxifying. In addition, glucuronic acid can increase the content of liver glycogen and reduce fat reserves.

This drug belongs to Class 2A, i.e., a β1-receptor blocker without partial agonist activity (cardioselective β-receptor blocker). It has a selective blocking effect on β1-receptors, no PAA (partial agonist activity), and no membrane stabilizing effect. Its effect on blocking β-receptors is approximately equal to that of propranolol (PP), and its selectivity for β1-receptors is slightly inferior to that of atenolol. Metoprolol's effects on the heart, such as slowing heart rate, inhibiting cardiac contractility, reducing automaticity, and delaying atrioventricular conduction time, are similar to those of propranolol and atenolol (AT). Its effect on reducing elevated blood pressure and heart rate during exercise testing is also similar to that of PP and AT. Its contraction effect on vascular and bronchial smooth muscle is weaker than that of PP, so its effect on the respiratory tract is also smaller, but still stronger than that of AT. Metoprolol can also reduce plasma renin activity.

Iron is a component of hemoglobin in red blood cells. When iron is deficient, the amount of hemoglobin synthesized by red blood cells decreases, causing the red blood cells to become smaller and their oxygen-carrying capacity to decrease, resulting in iron-deficiency anemia. Oral administration of this product can supplement iron and correct iron-deficiency anemia.