Britannica Sources used in this answer

How does azathioprine help prevent transplant rejection?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Kidney transplant — transplant British surgeon Andrew Ready flushing a donated kidney during a transplant at Queen Elizabeth Hospital, Birmingham, England, 2006.

Azathioprine helps prevent transplant rejection by acting as an immunosuppressive drug that inhibits the body's immune response to a foreign organ.12

Its primary mechanism involves inhibiting several enzymatic pathways essential for the synthesis of deoxyribonucleic acid (DNA). By interfering with DNA synthesis, the drug effectively suppresses the proliferation of lymphocytes—the white blood cells responsible for identifying and attacking foreign tissues. Because it is particularly effective against dividing cells, it reduces the number of these immune cells that can migrate to the site of the graft, thereby helping to maintain coexistence between the host and the transplanted organ.123

Due to its potential to damage bone marrow and cause side effects like leukopenia, patients require careful monitoring of blood cell counts to ensure the dosage remains safe and effective.13