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Mercaptopurine Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Mar 15, 2023.

Mercaptopurine is also known as: Purinethol, Purixan

Mercaptopurine Pregnancy Warnings

This drug should be used during pregnancy only if the benefit outweighs the risk.

AU TGA pregnancy category: D
US FDA pregnancy category: D

-This drug can harm a developing fetus.
-Adequate methods of contraception should be encouraged if either partner is receiving this drug and for at least 3 months after receiving the last dose.
-If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.
-Substantial transplacental and transamniotic transmission of 6-mercaptopurine and its metabolites from the mother to the fetus have been shown to occur.
-This drug should be avoided whenever possible during pregnancy, particularly during the first trimester.

Animal studies have shown reproductive toxicity. Abortions and prematurity have been reported after human maternal exposure. Multiple congenital abnormalities have been reported when this drug was given in combination with other chemotherapy agents. The potential hazard to the fetus must be balanced against the expected benefit to the mother.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

US FDA pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

See references

Mercaptopurine Breastfeeding Warnings

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

-This drug can harm a nursing infant.

See references

References for pregnancy information

  1. "Product Information. Purixan (mercaptopurine)." AnovoRx Distribution (2019):
  2. "Product Information. Mercaptopurine (mercaptopurine)." Mylan Pharmaceuticals Inc (2019):

References for breastfeeding information

  1. "Product Information. Purixan (mercaptopurine)." AnovoRx Distribution (2019):
  2. "Product Information. Mercaptopurine (mercaptopurine)." Mylan Pharmaceuticals Inc (2019):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.