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Mechlorethamine topical Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Jul 11, 2022.

Mechlorethamine topical is also known as: Valchlor

Mechlorethamine topical Pregnancy Warnings

In animal reproduction studies, administration of a single subcutaneous injection of this drug during organogenesis resulted in embryofetal mortality, alterations to growth, and structural abnormalities. Reports in pregnant women receiving this drug IV state that it causes major birth defects when a pregnant woman is systemically exposed.

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

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.

Use should be avoided.

AU TGA pregnancy category: B3
US FDA pregnancy category: Not assigned.

Risk Summary: Based human data, findings in animal reproduction studies, its mechanism of action, and genotoxicity findings, this drug can cause fetal harm when administered during pregnancy.

-This drug can harm a developing fetus.
-Adequate methods of contraception should be encouraged. A barrier method of contraception should be used to avoid direct exposure of reproductive organs to this drug.
-Verify negative pregnancy status in females of reproductive potential prior to initiating therapy.
-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.
-Based on animal data, this drug may impair fertility in both males and females. The reversibility of the effect on fertility is unknown.

See references

Mechlorethamine topical Breastfeeding Warnings

Use should be avoided.

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

-The effects in the nursing infant are unknown.
-Because of the potential for topical or systemic exposure to this drug through exposure to the mother's skin and the potential for serious adverse reactions in the breastfed child, advise patients not to breastfeed during therapy.

See references

References for pregnancy information

  1. "Product Information. Valchlor (mechlorethamine topical)." Ceptaris Therapeutics (2013):

References for breastfeeding information

  1. "Product Information. Valchlor (mechlorethamine topical)." Ceptaris Therapeutics (2013):

Further information

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