Doxylamine and Breastfeeding

Summary of use during lactation

Small occasional doses of doxylamine would not be expected to cause any adverse effects in breastfed infants. Larger doses or more prolonged use may cause drowsiness and other effects in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine or before lactation is well established.

Drug levels in milk and infant serum

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 on doxylamine was not found as of the revision date. In one telephone follow-up study, mothers reported irritability and colicky symptoms 10% of infants exposed to various antihistamines and drowsiness was reported in 1.6% of infants. None of the reactions required medical attention.[1] A mother was taking doxylamine and levothyroxine. She reported that her 28-month-old infant who was 25% breastfed experienced somnolence. The reaction was rated as possible or probable, but mild.[2]

Effects on lactation and breastmilk

Antihistamines in relatively high doses given by injection can decrease basal serum prolactin in nonlactating women and in early postpartum women.[3,4] However, suckling-induced prolactin secretion is not affected by antihistamine pretreatment of postpartum mothers.[3] Whether lower oral doses of antihistamines have the same effect on serum prolactin or whether the effects on prolactin have any consequences on breastfeeding success have not been studied. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

References

1. Ito S, Blajchman A, Stephenson M, et al. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal medication. Am J Obstet Gynecol 1993;168:1393-9.8498418 PubMed
2. Morze K, Szałek E, Waszyk-Nowaczyk M. Minding the gap. Drug-related problems among breastfeeding women. Front Pharmacol 2025;16:1542269.40183105 PubMed
3. Messinis IE, Souvatzoglou A, Fais N, et al. Histamine H1 receptor participation in the control of prolactin secretion in postpartum. J Endocrinol Invest 1985;8:143-6.3928731 PubMed
4. Pontiroli AE, De Castro e Silva E, Mazzoleni F, et al. The effect of histamine and H1 and H2 receptors on prolactin and luteinizing hormone release in humans: Sex differences and the role of stress. J Clin Endocrinol Metab 1981;52:924-8.7228996 PubMed