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Phenelzine Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Feb 21, 2023.

Phenelzine is also known as: Nardil

Phenelzine Pregnancy Warnings

Animal studies at doses exceeding the recommended human dose showed a significant decrease in the number of viable offspring and growth retardation. There are no controlled data in human pregnancy. Epidemiological studies suggest an increased risk of congenital abnormalities with antidepressant use during pregnancy as well as an increase in pre-term delivery. Neonates exposed to antidepressants late in the third trimester have shown drug withdrawal symptoms such as dyspnea, lethargy, colic irritability, hypotension or hypertension, and tremor or spasms.

To monitor maternal-fetal outcomes of pregnant women exposed to antidepressant therapy, a National Pregnancy Registry for Antidepressants has been established. Healthcare providers are encouraged to prospectively register patients. For additional information:

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.

This drug is only recommended for use during pregnancy when there are no alternatives and the benefit outweighs the risk.

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

Risk Summary: No data available on use of this drug in pregnant women to inform a drug-related risk.

-Safety has not been established during pregnancy.
-Some authorities recommend avoiding use during pregnancy, especially during the first and last trimesters, unless the benefit outweighs the risk to the fetus.
-Withdrawal symptoms, respiratory depression and agitation have been reported in neonates whose mothers had taken this drug during the last trimester of pregnancy.
-A pregnancy exposure registry is available.

See references

Phenelzine 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

-Based on the molecular weight and moderately long elimination half-life, this drug likely is excreted in breast milk.
-Some authorities recommend monitoring breastfed infants for serious adverse effects (e.g., constipation, dry mouth, dizziness, drowsiness, edema, fatigue, headache, hyperreflexia, myoclonic movements, sleep disturbances, tremors, twitching, weakness).
-Due to the lack of data, some experts recommend using other antidepressants (e.g., nortriptyline, paroxetine, sertraline) during breastfeeding.

See references

References for pregnancy information

  1. "Product Information. Nardil (phenelzine)." Parke-Davis (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

References for breastfeeding information

  1. "Product Information. Nardil (phenelzine)." Parke-Davis (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. United States National Library of Medicine "Toxnet. Toxicology Data Network." (2013):
  5. Briggs GG, Freeman RK. "Drugs in Pregnancy and Lactation." Philadelphia, PA: Wolters Kluwer Health (2015):

Further information

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