Drug General Information (ID: DDIBLAO8GT)
Drug Name			Azathioprine		Drug Info		Mercaptopurine		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Immunosuppressive Agents				Antineoplastics
Structure

Mechanism of Azathioprine-Mercaptopurine Interaction (Severity Level: Major)
Additive immunosuppressive effects Click to Show/Hide Mechanism Graph
Drug Name		Azathioprine				Mercaptopurine
Mechanism 1		Immunosuppressive effects				Immunosuppressive effects
Key Mechanism Factor 1
		Factor Name		Immunosuppressive effects
		Factor Description		Immunosuppression is when your immune system is not functioning as it should. The immune system is made up of cells, tissues and organs that help the body fight off infections. If the immune system is suppressed, an infection that your body was able to control may become serious or even fatal.
Mechanism Description		Additive immunosuppressive effects by the combination of Azathioprine and Mercaptopurine
Additive myelosuppressive effects Click to Show/Hide Mechanism Graph
Drug Name		Azathioprine				Mercaptopurine
Mechanism 2		Myelosuppressive effects				Myelosuppressive effects
Key Mechanism Factor 2
		Factor Name		Myelosuppressive effects
		Factor Description		Myelosuppression, also known as bone marrow suppression, is a decrease in bone marrow activity that leads to a decrease in the production of blood cells. Some blood cell disorders include: erythrocytopenia (anemia), leukopenia (neutropenia), and thrombocytopenia (thrombocytopenia).
Mechanism Description		Additive myelosuppressive effects by the combination of Azathioprine and Mercaptopurine
Increased risk of hepatotoxicity Click to Show/Hide Mechanism Graph
Drug Name		Azathioprine				Mercaptopurine
Mechanism 3		Hepatotoxicity				Hepatotoxicity
Key Mechanism Factor 3
		Factor Name		Hepatotoxicity
		Factor Description		Combination of drugs that can induce hepatotoxicity may increase the risk of liver injury. Symptoms vary depending on the level of exposure and the total extent of liver damage, and may cause few symptoms if the damage is mild, and eventually lead to liver failure in patients with severe damage.
Mechanism Description		Increased risk of hepatotoxicity by the combination of Azathioprine and Mercaptopurine

Recommended Action
Management		Concurrent use of azathioprine and 6-mercaptopurine should be avoided.

References
1	Petit E, Langouet S, Akhdar H, Nicolas-Nicolaz C, Guillouzo A, Morel F. Differential toxic effects of azathioprine, 6-mercaptopurine and 6-thioguanine on human hepatocytes. Toxicol In Vitro. 2008;22(3):632-642. [PMID: 18222062]
2	Product Information. Imuran (azathioprine). Glaxo Wellcome, Research Triangle Park, NC.
3	Product Information. Purinethol (mercaptopurine). Glaxo Wellcome, Research Triangle Pk, NC.