Mercaptopurine Pregnancy and Breastfeeding Warnings

Brand names: Purinethol, Purixan

Medically reviewed by Drugs.com. Last updated on Mar 17, 2025.

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: Not assigned

Risk summary: This drug can cause fetal harm when administered to a pregnant woman, exposure during pregnancy may cause miscarriage and stillbirth. It has been shown to be embryolethal and teratogenic in animal studies.

Comments:
-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 Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

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

Comments:
-This drug can harm a nursing infant.

See references

Further information

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

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