It has a direct relaxant effect on the smooth muscles of the respiratory tract; it increases the intracellular cAMP content by inhibiting phosphodiesterase; its bronchodilator effect is partly due to the release of endogenous adrenaline and norepinephrine; it is a purine receptor blocker and can counteract the contractile effect of adenine and other substances on the respiratory tract; it enhances the contractility of the diaphragm to improve respiratory function; it slightly relaxes the smooth muscles of the coronary arteries, peripheral blood vessels and bile ducts; it slightly increases myocardial contractility and has a diuretic effect.

This product is a pyrimidine antiviral drug that can competitively inhibit phosphorylase, especially DNA polymerase, with thymidine nucleoside, thereby inhibiting the synthesis of thymidine nucleoside in viral DNA, or replacing thymidine nucleoside to penetrate into viral DNA, producing defective DNA, making it lose its infectivity or unable to recombine, so that the virus stops reproducing or loses its activity and is inhibited.

Potassium is the main cation in cells, with a concentration of 150-160 mmol/L, while the main cation outside cells is sodium ions, and the serum potassium concentration is only 3.5-5.0 mmol/L. The body mainly relies on Na+-K+ ATPase on the cell membrane to maintain the difference in K+Na+ concentration inside and outside cells. The acid-base balance in the body has an impact on potassium metabolism. For example, when acidosis occurs, H+ enters the cell. In order to maintain the potential difference inside and outside the cell, K+ is released outside the cell, causing or aggravating hyperkalemia, and metabolic disorders can also affect acid-base balance. The normal intracellular potassium ion concentration and concentration difference are closely related to certain functions of cells, such as carbohydrate metabolism, glycogen storage and protein metabolism, and the excitability and conductivity of nerves and muscles including the myocardium.

Potassium is the main cation in cells, with a concentration of 150-160 mmol/L, while the main cation outside cells is sodium ions, and the serum potassium concentration is only 3.5-5.0 mmol/L. The body mainly relies on Na+-K+ ATPase on the cell membrane to maintain the difference in K+ and Na+ concentrations inside and outside cells. The acid-base balance in the body has an impact on potassium metabolism. For example, when acidosis occurs, H+ enters the cell. In order to maintain the potential difference inside and outside the cell, K+ is released outside the cell to cause or aggravate hyperkalemia, and metabolic disorders can also affect acid-base balance. The normal intracellular potassium ion concentration and concentration difference are closely related to certain functions of cells, such as carbohydrate metabolism, glycogen storage and protein metabolism, excitability and conductivity of nerves and muscles (including myocardium), etc.

This product belongs to Class Ic antiarrhythmic drugs, which can reduce the depolarization effect during contraction, prolong conduction, slightly prolong the duration of action potential and the effective refractory period, increase the threshold potential of myocardial cells, and reduce the spontaneous excitability of the myocardium; reduce the irritability of the myocardium, prolong the effective refractory period of the atria and atrioventricular nodes, and combat various types of experimental arrhythmias; have membrane stabilizing effects and competitive β-blocking effects, weak calcium antagonism, mild myocardial inhibition, and blood pressure and heart rate reduction effects; can relax coronary artery and bronchial smooth muscles, and has a local anesthetic effect similar to procaine.