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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Last Revision: October 31, 2018.

Estimated reading time: 1 minute

CASRN: 359-83-1

Chemical structure

Drug Levels and Effects

Summary of Use during Lactation

No information is available on the use of pentazocine during breastfeeding. Maternal use of oral narcotics during breastfeeding can cause infant drowsiness, central nervous system depression and even death. Newborn infants seem to be particularly sensitive to the effects of even small dosages of narcotic analgesics. Once the mother's milk comes in, it is best to provide pain control with a nonnarcotic analgesic and limit maternal intake of pentazocine to a few days at a low dosage with close infant monitoring. If the baby shows signs of increased sleepiness (more than usual), difficulty breastfeeding, breathing difficulties, or limpness, a physician should be contacted immediately. Other agents are preferred over pentazocine during breastfeeding.[1]

Drug Levels

Maternal Levels. Relevant published information was not found as of the revision date.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Pentazocine can increase serum prolactin.[2][3] However, the prolactin level in a mother with established lactation may not affect her ability to breastfeed.


Sachs HC and the American Academy of Pediatrics committee on Drugs. The transfer of drugs and therapeutics into human breast milk: An update on selected topics. Pediatrics. 2013;132:e796-809. [PubMed: 23979084]
Manner T, Kanto J, Scheinin H et al. Meptazinol and pentazocine: effects on prolactin, growth hormone and vasopressin levels in plasma. Pharmacol Toxicol. 1987;61:301-4. [PubMed: 3438224]
Rolandi E, Barreca T. Effects of two analgesic opiates (methadone and pentazocine) on the serum prolactin levels in breast cancer. Acta Endocrinol (Copenh). 1978;88:452-4. [PubMed: 581016]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

  • Breast Feeding
  • Analgesics, Opioid
  • Narcotics
  • Narcotic Antagonists
  • Opiates

Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.


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