Broad-spectrum antiviral drug. It has the effect of inhibiting the growth of multiple viruses such as respiratory syncytial virus, influenza virus, hepatitis A virus, adenovirus, etc. in vitro, and its mechanism is not fully understood. After entering the virus-infected cells, the drug is rapidly phosphorylated, and its product acts as a competitive inhibitor of viral synthase, inhibiting inosine monophosphate dehydrogenase, influenza virus RNA polymerase and mRNA guanosine transferase, thereby causing a decrease in intracellular guanosine triphosphate, impairing viral RNA and protein synthesis, and inhibiting viral replication and transmission. It may also have an immune effect and neutralizing antibody effect on respiratory syncytial virus.

Broad-spectrum antiviral drug. It has the effect of inhibiting the growth of multiple viruses such as respiratory syncytial virus, influenza virus, hepatitis A virus, adenovirus, etc. in vitro. After entering the virus-infected cells, the drug is rapidly phosphorylated, and its product acts as a competitive inhibitor of viral synthase, inhibiting inosine monophosphate dehydrogenase, influenza virus RNA polymerase and mRNA guanosine transferase, thereby causing a decrease in intracellular guanosine triphosphate, impairing viral RNA and protein synthesis, and inhibiting viral replication and transmission. It may also have an immune effect and neutralizing antibody effect on respiratory syncytial virus.

Extract from the above information

It acts on dihydrofolate synthase, interfering with the first step of folic acid synthesis. When used in combination with trimethoprim, it can double-block the bacterial folic acid metabolism and enhance the synergistic antibacterial effect.

It acts on the second step of folic acid anabolism and selectively inhibits the action of dihydrofolate reductase. When used in combination with sulfamethoxazole, it can double-block the bacterial folic acid metabolism and enhance the synergistic antibacterial effect.