Trihexyphenidyl Pregnancy Warnings
Use is not recommended unless clearly needed
AU TGA pregnancy category: B1
US FDA pregnancy category: C
There are no animal studies evaluating teratogenicity or embryotoxic potential with this drug. In a large prospective study of 2323 exposures during the first trimester, atropine-related drugs as a whole were possibly associated with minor fetal malformations. Nine of these exposures were to this drug. There are no controlled data in human pregnancy.
AU TGA pregnancy category B1: 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 not shown evidence of an increased occurrence of fetal damage.
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.
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Trihexyphenidyl Breastfeeding Warnings
Benefit should outweigh risk
Excreted into human milk: Unknown
Excreted into animal milk: Unknown
Comments:
-Anticholinergic agents may suppress lactation; a single-dose may not interfere with breastfeeding, however, observe for signs of decreased lactation with long-term use.
In animals, anticholinergic agents can inhibit lactation presumably by inhibiting growth hormone and oxytocin secretion. A woman taking 4 mg orally once a day with haloperidol through 3 pregnancies and postpartum, breastfed each child for 6 to 8 months with no clinically apparent adverse effects; developmental milestones and educational attainments were age appropriate. Caution is advised as infants may be sensitive to the effects of antimuscarinic medications; some authorities advise against use of this drug during breastfeeding.
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