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Trimethoprim Pregnancy and Breastfeeding Warnings

Trimethoprim is also known as: Primsol, Proloprim, Trimpex

Medically reviewed on November 15, 2017

Trimethoprim Pregnancy Warnings

UK: Contraindicated
AU, US: This drug should be used during pregnancy only if the benefit outweighs the risk.

AU TGA pregnancy category: B3
US FDA pregnancy category: C

Comment:
-This drug may interfere with folic acid metabolism in the fetus; supplementation may be required.

This drug has been shown to be teratogenic in animal studies when given in doses 40 times the human dose. In other animal studies, the overall increase in fetal loss (dead and resorbed and malformed conceptuses) was associated with doses 6 times the human therapeutic dose. There are no controlled data in human pregnancy.

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 C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

See references

Trimethoprim Breastfeeding Warnings

AU, UK: A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.
US: Caution is recommended.

Excreted into human milk: Yes

Comments:
-Because of the low levels of this drug in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects.
-Because this drug may interfere with folic acid metabolism, caution should be exercised if it is administered to a nursing woman.

See references

References for pregnancy information

  1. Cerner Multum, Inc. "Australian Product Information." O 0
  2. "Product Information. Trimethoprim (trimethoprim)." Teva Pharmaceuticals USA, North Wales, PA.
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

References for breastfeeding information

  1. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT." ([cited 2013 -]):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Trimethoprim (trimethoprim)." Teva Pharmaceuticals USA, North Wales, PA.

Further information

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

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