Factors affecting drug absorption: Immunosuppressive drugs such as cyclosporine A (CsA), plerixifor (FK506) and rapamycin (RPM) are mainly absorbed by the intestine after oral administration, and changes in gastric emptying speed and intestinal peristalsis can affect drug absorption, leading to changes in the bioavailability of drugs and thus affecting blood concentration. As the gastric emptying and intestinal peristalsis speed up when eating, it affects the absorption of the drug by the intestine and leads to the decrease of blood concentration. Therefore, immunosuppressants such as Proscar should be taken orally 1 hour before or 2 hours after eating. 2.Factors affecting drug metabolism: Cyclosporine A, Pulcolcolax and Rapamycin are all metabolized by the cytochrome P450 3A (CYP3A) enzyme system in the liver through demethylation and hydroxylation. Therefore, any drug that affects the activity of cytochrome P450 3A enzymes can affect the metabolism of immunosuppressive agents such as cyclosporine A. Drugs that reduce the activity of CYP3A enzymes can inhibit the metabolism of cyclosporine A and increase its blood concentration. For example: Hepesin (Tenelxin, Hepesin), Nicardipine, Isoptin, Pentamidine, Ketoconazole, Clotrimazole, Erythromycin, etc. Conversely, drugs that increase CYP3A enzyme activity can promote the metabolism of cyclosporine A and so on, thus reducing its blood concentration. For example, rifampicin, phenobarbital, carbamazepine, sodium barbiturate, etc. Since many drugs can affect the metabolism of immunosuppressants such as cyclosporine A and pramipexole, resulting in changes in their blood concentrations. Therefore, when adjusting the dose of immunosuppressants, the influence of other drugs on blood concentration should be taken into account to develop an individualized dosing regimen.