It is a cell cycle-specific drug that inhibits the purine synthesis pathway. Its chemical structure is similar to that of hypoxanthine, so it can competitively inhibit the conversion process of hypoxanthine. It becomes active after being converted into 6-mercaptopurine ribonucleotides by phosphoribosyltransferase in the body. It mainly works through the following mechanisms: (1) inhibiting amidotransferase through negative feedback, interfering with the initial stage of purine nucleotide synthesis; (2) inhibiting the mutual conversion between purines and reducing the generation of deoxyadenosine triphosphate (dATP) and deoxyguanosine triphosphate (dGTP), thereby preventing tumor cell proliferation. It is more sensitive to cells in the S proliferation cycle and can inhibit the synthesis of DNA and RNA. Long-term use may cause drug resistance due to mutations in leukemia cells.

Dispersed microparticles can firmly adhere to the gastric and duodenal mucosa, forming a protective film and promoting mucosal regeneration.

It is an antacid that can neutralize stomach acid and relieve stomach burning and stomach pain caused by excessive stomach acid.

It is an antacid that can neutralize stomach acid and relieve stomach burning and stomach pain caused by excessive stomach acid.

It is a laxative and can combat constipation caused by bismuth nitrate.

Azithromycin is a 15-membered macrolide antibiotic that has antibacterial effects on a variety of Gram-positive aerobic bacteria, Gram-negative aerobic bacteria, anaerobic bacteria, sexually transmitted disease microorganisms and other microorganisms. It mainly binds to the 50S subunit of the bacterial ribosome and inhibits RNA-dependent protein synthesis.

Regulating calcium and phosphorus metabolism

It must be converted by both the liver and kidneys to become biologically active vitamin D3, and its biological activity is far inferior to that of vitamin D3

Vitamin D2 must be converted by the liver and kidneys to become biologically active vitamin D3. It plays a role in regulating calcium and phosphorus metabolism. In this conversion process, only a part of vitamin D2 is finally converted into vitamin D3. Therefore, the biological activity of vitamin D2 is far inferior to that of vitamin D3.

Ganciclovir is a guanine antiviral drug. It is a homologue of acyclovir but has a stronger effect. It has a strong inhibitory effect on cytomegalovirus in AIDS patients. After entering the cell, it is rapidly phosphorylated to form a monophosphate compound, and then converted into a triphosphate compound by the action of cellular kinase. The phosphorylation process in cells infected with cytomegalovirus is faster than that in normal cells. Triphosphates can competitively inhibit DNA polymerase and are incorporated into the DNA of viruses and host cells, thereby inhibiting DNA synthesis. The inhibitory effect on viral DNA polymerase is stronger than that on host cell DNA polymerase.