Promethazine

The Basics

What is Promethazine?

Used to relieve the symptoms of allergic reactions. Also used with other medications to treat anaphylaxis and the symptoms of the common cold.

Brand names for Promethazine

Phenergan

How Promethazine is classified

Antiemetics, Phenothiazines

Promethazine During Pregnancy

Promethazine pregnancy category

Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Promethazine while pregnant

Teratogenic Effects Pregnancy Category C Teratogenic effects have not been demonstrated in rat-feeding studies at doses of 6.25 and 12.5 mg/kg of promethazine. These doses are from approximately 2.1 to 4.2 times the maximum recommended total daily dose of promethazine for a 50-kg subject, depending upon the indication for which the drug is prescribed. Daily doses of 25 mg/kg intraperitoneally have been found to produce fetal mortality in rats. Specific studies to test the action of the drug on parturition, lactation, and development of the animal neonate were not done, but a general preliminary study in rats indicated no effect on these parameters. Although antihistamines have been found to produce fetal mortality in rodents, the pharmacological effects of histamine in the rodent do not parallel those in man. There are no adequate and wellcontrolled studies of Phenergan (Promethazine HCl) Suppositories in pregnant women. Phenergan (Promethazine HCl) Suppositories should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Nonteratogenic Effects Phenergan (Promethazine HCl) Suppositories administered to a pregnant woman within two weeks of delivery may inhibit platelet aggregation in the newborn.

Taking Promethazine While Breastfeeding

What are recommendations for lactation if you're taking Promethazine?

Based on minimal excretion of other phenothiazine derivatives, it appears that occasional short-term use of promethazine for the treatment of nausea and vomiting poses little risk to the breastfed infant. With repeated doses, observe infants for excess sedation. Because promethazine can lower basal prolactin secretion, promethazine might interfere with the establishment of lactation if given during labor, before lactation is well established or with a sympathomimetic such as pseudoephedrine. An antiemetic without potent histamine blocking action is preferred in nursing mothers.

Maternal / infant drug levels

Based on minimal excretion of other phenothiazine derivatives, it appears that occasional short-term use of promethazine for the treatment of nausea and vomiting poses little risk to the breastfed infant. With repeated doses, observe infants for excess sedation. Because promethazine can lower basal prolactin secretion, promethazine might interfere with the establishment of lactation if given during labor, before lactation is well established or with a sympathomimetic such as pseudoephedrine. An antiemetic without potent histamine blocking action is preferred in nursing mothers.

Possible effects of Promethazine on milk supply

Possible Effects on Lactation: Unlike most phenothiazines, promethazine usually causes a reduction in basal prolactin secretion in nonnursing women.[1][2] In one small study, women given promethazine with meperidine and secobarbital during labor, had the time to lactogenesis II prolonged by 14 hours. Women given meperidine or secobarbital without promethazine had lactogenesis II prolonged 7 hours compared to unmedicated women, but the difference was not statistically significant.[3] The effect of postpartum promethazine is not known, but it might interfere with the establishment of lactation if given in the early postpartum period.

Possible alternatives to Promethazine

Prochlorperazine.