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Liotrix Pregnancy and Breastfeeding Warnings

Liotrix is also known as: Thyrolar, Thyrolar-1, Thyrolar-1/2, Thyrolar-1/4, Thyrolar-2, Thyrolar-3

Medically reviewed by Last updated on Apr 9, 2020.

Liotrix Pregnancy Warnings

Use is considered acceptable.

US FDA pregnancy category: A

Animal studies have not been reported. Thyroid hormones do not readily cross the placenta. Clinical experience to date does not indicate any adverse effects on the fetus when thyroid hormones are administered to pregnant women. There are no controlled data in human pregnancy.

US FDA pregnancy category A: Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

See references

Liotrix Breastfeeding Warnings

Caution is recommended.

Excreted into human milk: Yes

-This drug is a mixture of levothyroxine (T4) and liothyronine (T3) which are normal components of human milk.
-Limited data on exogenous replacement doses of T4 show no adverse effects on nursing infants.
-Dose requirements may be increased in the postpartum period compared to pre-pregnancy requirements in women with Hashimoto's thyroiditis.

See references

References for pregnancy information

  1. "Product Information. Thyrolar (liotrix)." Forest Pharmaceuticals, St. Louis, MO.

References for breastfeeding information

  1. "Product Information. Thyrolar (liotrix)." Forest Pharmaceuticals, St. Louis, MO.
  2. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):

Further information

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