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Nafcillin Pregnancy and Breastfeeding Warnings

Brand names: Nallpen, Unipen

Medically reviewed by Last updated on Feb 8, 2024.

Nafcillin Pregnancy Warnings

This drug should be used during pregnancy only if clearly needed.

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.

Animal studies have failed to reveal evidence of impaired fertility or fetal harm. There are no controlled data in human pregnancy.

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

Nafcillin Breastfeeding Warnings

Use is considered acceptable; caution is recommended.

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

-No data available on use of this drug during breastfeeding.
-Other penicillins are excreted into human milk in small amounts.
-Penicillins generally not expected to cause harmful effects in the nursing infant.
-Disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) reported occasionally with penicillins, but such effects have not been adequately evaluated.

See references

References for pregnancy information

  1. Product Information. Unipen (nafcillin). Wyeth-Ayerst Laboratories. 2002;PROD.

References for breastfeeding information

  1. Product Information. Unipen (nafcillin). Wyeth-Ayerst Laboratories. 2002;PROD.
  2. United States National Library of Medicine. Toxnet. Toxicology Data Network. 2013.

Further information

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