CCoPE
Date: 2007-10-30

Question:
My husband is taking Mercaptopurine (Purinethol) to manage his Chrohn's disease. Can you please let me know if there is any risk involved to his sperm or the baby or if he should go off the drug if we are trying to get pregnant? Thanks

Answer:

It has been shown that in male mice, mercaptopurine treatment may decrease sperm counts and fertility (Sykora I. Neoplasma 28:739-46, 1981: 26, Oakberg EF et al: Mutat res 94:165-78, 1982).

There is an inconclusive report on mercaptopurine use by men with inflammatory bowel disease concluded that use of the medication three months or less prior to conception produced an increase in adverse pregnancy outcome (Rajapakse RO, Korelitz BI, Zlantanic J, Baiocco PJ, Gleim GW. Am J Gastroenterol 2000;95:684-8.). This conclusion was based on 2 miscarriages and 2 pregnancies with birth defects occurring among 13 pregnancies fathered by men with recent mercaptopurine use compared to 1 miscarriage occurring among 37 control pregnancies fathered by men with more remote mercaptopurine use ( 3 months or greater). The birth defects consisted of thumb aplasia and growth retardation in one child and acrania with other limb malformations in an aborted fetus.

In general, there is no single example in humans of a cancer drug that has been shown to cause malformations through sperm exposure. However, cancer drugs do commonly decrease a man?s sperm count.