Azithromycin is a 15-membered macrolide antibiotic. In vitro tests have shown that azithromycin has antibacterial effects on a variety of common clinical pathogens, including: Gram-positive aerobic bacteria (such as Staphylococcus aureus, Streptococcus pyogenes, Pneumococcus, etc.), some Gram-negative aerobic bacteria (such as Haemophilus influenzae, Moraxella catarrhalis, etc.), anaerobic bacteria (such as Bacteroides fragilis), sexually transmitted disease microorganisms (such as Treponema pallidum, Neisseria gonorrhoeae, etc.) and other microorganisms (such as Borrelia tenuissima, Mycoplasma pneumoniae, Chlamydia trachomatis, etc.). The mechanism of action is the same as that of erythromycin, mainly binding to the 50S subunit of bacterial ribosomes and inhibiting RNA-dependent protein synthesis.

Antiviral drug. It has the effect of inhibiting the growth of many viruses such as respiratory syncytial virus, influenza virus, hepatitis A virus, adenovirus, etc. in vitro, and its mechanism is not fully understood. This product does not change the adsorption, invasion and uncoating of viruses, nor does it induce the production of interferon. 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.

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.

Antiviral drug. It has an inhibitory effect on herpes simplex virus, varicella zoster virus, cytomegalovirus, etc. in vitro. After entering the cells infected by herpes virus, this product competes with deoxynucleoside for viral thymidine kinase or cell kinase, and the drug is phosphorylated into activated acyclovir triphosphate, and then inhibits viral replication in two ways: ① Interfering with viral DNA polymerase and inhibiting viral replication; ② Under the action of DNA polymerase, it binds to the growing DNA chain, causing the extension of the DNA chain to be interrupted. This product has a special affinity for viruses, but has low toxicity to mammalian host cells.

Timolol maleate is a non-selective β-adrenergic receptor blocker with no significant endogenous sympathomimetic activity and local anesthetic effect, and no direct inhibitory effect on the myocardium. The exact mechanism of its lowering intraocular pressure is still unclear, but it may be related to reducing aqueous humor production.