Small, occasional doses of hydroxyzine are generally considered acceptable while breastfeeding, but regular or higher doses raise more concern. The drug has been linked to sedation and other side effects in some nursing infants, making it one of the antihistamines that warrants extra caution during lactation.
What the Evidence Shows
The NIH’s Drugs and Lactation Database (LactMed) states that small occasional doses of hydroxyzine “would not be expected to cause any adverse effects in breastfed infants.” The risk increases with larger or more frequent doses. In a review of 174 adverse event reports, hydroxyzine caused reactions in 8 infants and was flagged as one of the antihistamines most often suspected in serious adverse reactions, with sedation being the primary concern.
A separate telephone follow-up study found that about 10% of infants exposed to various antihistamines through breast milk showed irritability and colic-like symptoms, while 1.6% showed drowsiness. These numbers reflect antihistamines as a class, not hydroxyzine alone, but hydroxyzine is a first-generation antihistamine with stronger sedating properties than many alternatives.
How It Can Affect Your Baby
Hydroxyzine crosses into breast milk and can cause several noticeable effects in a nursing infant. The most commonly reported is sedation: your baby may sleep longer than usual, not wake to feed on their own, or fall asleep during feedings. Some infants show the opposite pattern, becoming unusually irritable or fussy.
Other signs to watch for include dry mouth (which can make feeding difficult), poor feeding, and inadequate weight gain over time. These effects are more likely with daily or repeated dosing than with a single dose taken once.
Impact on Milk Supply
Hydroxyzine has anticholinergic properties, meaning it can interfere with the hormonal signals that drive milk production. Larger doses or prolonged use may decrease your milk supply. This risk is higher in two specific situations: during the early weeks postpartum before your supply is well established, and when hydroxyzine is combined with a decongestant like pseudoephedrine, which independently suppresses milk production. If you’re still building your supply in the first few weeks after birth, even occasional use deserves extra consideration.
Reducing Risk if You Do Take It
If you and your provider decide hydroxyzine is the right choice, a few strategies can limit your baby’s exposure. Using the lowest effective dose and taking it as infrequently as possible keeps the amount reaching your milk to a minimum. Timing the dose right after a feeding session, rather than right before one, gives the drug more time to clear your system before the next feed.
Hydroxyzine’s effects in adults typically peak about two hours after an oral dose, and the drug has a half-life of roughly 14 to 25 hours (meaning it takes that long for half of it to leave your body). Because of this relatively long half-life, the drug doesn’t clear quickly, which is part of why repeated doses can build up and cause more infant exposure than a single dose would.
Watch your baby closely after you take a dose. If your infant seems unusually sleepy, is harder to wake for feedings, feeds poorly, or becomes unexpectedly irritable, those are signals to stop and reassess.
Alternatives Worth Discussing
If you need an antihistamine for allergies, hives, or itching, second-generation options like cetirizine (Zyrtec) and loratadine (Claritin) are generally preferred during breastfeeding. They cause less sedation overall and have more safety data in lactating women. Loratadine in particular is widely considered one of the best-studied antihistamines for nursing mothers.
If hydroxyzine was prescribed specifically for anxiety or sleep rather than allergies, the conversation with your provider may look different, since the alternatives depend on what you’re treating. But it’s worth knowing that hydroxyzine’s sedating profile is exactly what makes it riskier during breastfeeding compared to newer antihistamines, so exploring other options is a reasonable step.