Hydroxyzine
MedicationVistaril, Atarax
Antihistamine
Research strength: 3 / 5
The current US DailyMed label says hydroxyzine is contraindicated in early pregnancy because human data are inadequate; the UK product information says it should not be used during pregnancy. A CDC-funded birth-defects study included hydroxyzine exposure from 1 month before pregnancy through the first trimester and found an association with conotruncal defects, a type of heart defect (6 exposed cases and 7 exposed controls; adjusted odds ratio 3.75, 95% confidence interval 1.25 to 11.26), but the authors warned that many comparisons could produce chance findings. A Danish cohort found 5 major defects among 98 exposed live births, with a wide confidence interval (adjusted odds ratio 1.54, 95% confidence interval 0.63 to 3.80); it did not include pregnancies that did not end in a live birth. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, published 14 Sep 2026)Drug company label
- UK eMC: Hydroxyzine Hydrochloride 25 mg SmPC
- Hansen et al., Birth Defects Research 2020 (National Birth Defects Prevention Study)US government
- Broe et al., Pharmacoepidemiology and Drug Safety 2025 (Danish cohort)US government
Research strength: 2 / 5
The current US DailyMed label's formal contraindication is for early pregnancy, while the UK product information says hydroxyzine should not be used during pregnancy. The human studies located do not give a separate hydroxyzine risk estimate for the second trimester; MotherToBaby says it is unknown whether hydroxyzine alone increases preterm delivery or low birth weight. A 1997 prospective study combined hydroxyzine and cetirizine exposures and reported no significant differences in pregnancy outcomes, but it did not provide hydroxyzine-only trimester estimates. The evidence remains too limited for a second-trimester-specific conclusion. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Hydroxyzine (Vistaril, Atarax) fact sheetTeratology service
- DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, published 14 Sep 2026)Drug company label
- UK eMC: Hydroxyzine Hydrochloride 25 mg SmPC
- Einarson et al., Prospective controlled study of hydroxyzine and cetirizine in pregnancy (1997)US government
Research strength: 2 / 5
MotherToBaby reports two newborns with temporary withdrawal-like symptoms after mothers used hydroxyzine in the four weeks before delivery; one had a seizure and the other had jitteriness, jerking movements, and feeding problems. Two published case reports describe neonatal symptoms after high-dose or late-pregnancy exposure, but case reports cannot estimate how often such effects occur. The UK product information warns that sedating antihistamines in late third trimester may cause neonatal irritability, excitability, or tremor; the US label's formal pregnancy contraindication is limited to early pregnancy. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Hydroxyzine (Vistaril, Atarax) fact sheetTeratology service
- Prenner et al., Neonatal withdrawal syndrome associated with hydroxyzine hydrochloride (1977)US government
- Serreau et al., Neonatal seizures associated with maternal hydroxyzine hydrochloride in late pregnancy (2005)US government
- UK eMC: Hydroxyzine Hydrochloride 25 mg SmPC
- DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, published 14 Sep 2026)Drug company label
Hydroxyzine — Breastfeeding
Research strength: 2 / 5
MotherToBaby and LactMed say occasional doses are not expected to cause effects, but larger or prolonged use may lead to infant drowsiness or irritability and could lower milk supply. LactMed reports no published hydroxyzine levels in milk or infant serum, and a French pharmacovigilance study mentions hydroxyzine among possible causes without giving a hydroxyzine-specific count or exposure denominator. The US label says hydroxyzine should not be given to nursing mothers because milk excretion is unknown, while NHS Specialist Pharmacy Service permits cautious short-term use with infant monitoring and prefers other antihistamines. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Hydroxyzine (Vistaril, Atarax) fact sheetTeratology service
- LactMed (NIH): HydroxyzineUS government
- DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, published 14 Sep 2026)Drug company label
- NHS Specialist Pharmacy Service: Using antihistamines during breastfeedingUK government
- Soussan et al., Drug-induced adverse reactions via breastfeeding (2014)US government
Pregnancy
A 1997 prospective controlled study followed 120 women exposed to either hydroxyzine or cetirizine; 53 had hydroxyzine exposure during organogenesis. It found no significant differences in pregnancy outcomes, including spontaneous or therapeutic abortion, stillbirth, major or minor anomalies, birth weight, or gestational age. The abstract does not give hydroxyzine-only outcome counts. Hansen et al. analyzed 41,148 pregnancies in a US case-control study. For hydroxyzine exposure from 1 month before pregnancy through the first trimester and conotruncal defects, the adjusted odds ratio was 3.75 (95% CI 1.25-11.26), with 6 exposed cases and 7 exposed controls. The analysis included 340 main comparisons; the authors noted that some positive findings could have occurred by chance. The isolated conotruncal analysis was from the same dataset, not an independent replication. Broe et al. screened 743,276 singleton live births in Denmark. Among 98 hydroxyzine-exposed live births, 5 major malformations were recorded (5.1%); the adjusted odds ratio was 1.54 (95% CI 0.63-3.80) versus unexposed live births and 2.13 (95% CI 0.62-7.32) versus previously exposed live births. These estimates are imprecise. The cohort excludes pregnancies not resulting in live birth and measures filled prescriptions, not confirmed ingestion.
Breastfeeding
LactMed reports that no published maternal milk or infant serum levels were found as of its 15 Sep 2025 revision. It says small occasional doses would not be expected to cause adverse effects, while larger or prolonged use may cause infant drowsiness or other effects or decrease milk supply. NHS Specialist Pharmacy Service reports no published breast milk levels and says low amounts are expected based on pharmacokinetics; it describes cautious, brief use with infant monitoring and prefers non-sedating antihistamines or chlorphenamine. A 2014 French pharmacovigilance study recorded 276 adverse drug reactions in 174 breastfed children across all drugs and says hydroxyzine may be implicated, but the abstract gives no hydroxyzine-specific count, symptom details, or exposed-infant denominator. LactMed's telephone-study percentages refer to infants exposed to various antihistamines, not hydroxyzine.
Hydroxyzine is a first-generation antihistamine with sedating and antimuscarinic properties. The UK product information lists use for anxiety in adults and for itching associated with urticaria and dermatitis. The listed brands are Vistaril and Atarax.
What was tested
Pregnancy evidence includes a prospective controlled study that combined hydroxyzine and cetirizine, a US birth-defects case-control study, and a Danish first-trimester prescription screening cohort limited to singleton live births. The case-control study examined 340 antihistamine-defect comparisons and reported sparse positive signals. Neonatal evidence consists of case reports rather than studies that estimate frequency. Breastfeeding evidence includes pharmacovigilance reports and clinical reviews; no published hydroxyzine milk or infant concentration study was found. No hydroxyzine-specific second-trimester estimate was located.
Pregnancy label restrictions and the human evidence
- Source A says
- The current US DailyMed label says hydroxyzine is contraindicated in early pregnancy. The UK product information says it should not be used during pregnancy. (DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, current generic record), UK eMC: Hydroxyzine Hydrochloride 25 mg Summary of Product Characteristics)
- Source B says
- Human studies are mixed. Hansen et al. reported a sparse association for conotruncal defects; Broe et al. found imprecise estimates in a Danish live-birth cohort; Einarson et al. combined hydroxyzine and cetirizine and did not report hydroxyzine-only outcomes. (Hansen et al., Use of antihistamine medications during early pregnancy and selected birth defects (2020), Broe et al., Prescription Drugs in Pregnancy and Congenital Malformations (2025), Einarson et al., Prospective controlled study of hydroxyzine and cetirizine in pregnancy (1997))
- Why they differ
- The labels state prohibitions in the setting of inadequate human data. The available observational studies have different designs and sparse outcomes; they do not establish a trimester-specific causal effect. The Hansen study tested 340 main comparisons and cautioned that some findings may have occurred by chance.
- What the evidence shows overall
- The label restrictions must remain explicit. The human evidence is limited and mixed. The Hansen association should be reported with its small exposed count and multiple-comparison context, not as established causation. The later Danish cohort does not resolve the uncertainty because its estimates are imprecise and it includes live births only.
Hydroxyzine during breastfeeding
- Source A says
- DailyMed and the UK product information say hydroxyzine should not be given to nursing mothers; both note that milk transfer or infant effects are unknown. (DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, current generic record), UK eMC: Hydroxyzine Hydrochloride 25 mg Summary of Product Characteristics)
- Source B says
- LactMed says occasional small doses would not be expected to cause adverse effects. NHS Specialist Pharmacy Service says it can be used with caution, preferably occasionally or briefly, with infant monitoring. Neither reports published hydroxyzine milk levels. (LactMed (NIH): Hydroxyzine, NHS Specialist Pharmacy Service: Using antihistamines during breastfeeding)
- Why they differ
- The labels take a restrictive position when milk excretion or infant effects are unknown. LactMed and NHS SPS weigh limited clinical reports and pharmacokinetic expectations, while acknowledging that direct milk-level information is absent.
- What the evidence shows overall
- There are no published hydroxyzine milk or infant levels in the reviewed sources, and infant symptoms have been reported without a denominator that would estimate frequency. The conflicting label and clinical-service positions support a guidance rating rather than broad reassurance or a claim that an infant effect is certain.
- NHS Specialist Pharmacy Service says hydroxyzine can be used with caution during breastfeeding, preferably occasionally or for a short time, with infant monitoring; it prefers a non-sedating antihistamine or chlorphenamine. (NHS Specialist Pharmacy Service)
- LactMed prefers other agents, especially while nursing a newborn or preterm infant, and lists cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine as alternatives to consider. (LactMed (NIH))
General research, not specific to pregnancy.
DailyMed reports post-marketing cases of QT prolongation and Torsade de Pointes, most often in patients with other risk factors, and contraindicates hydroxyzine in patients with a prolonged QT interval. It also warns of drowsiness and increased effects with alcohol or central nervous system depressants.
- DailyMed reports cases of QT prolongation and Torsade de Pointes and contraindicates hydroxyzine in patients with a prolonged QT interval. EMA's 2015 referral advised the lowest effective dose for the shortest possible time and restricting use in patients at high risk of heart rhythm problems. (DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, current generic record), European Medicines Agency: Hydroxyzine referral)
- DailyMed warns that hydroxyzine may cause drowsiness, may increase the effect of alcohol, and can potentiate central nervous system depressants. (DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, current generic record))
- MotherToBaby: Hydroxyzine (Vistaril, Atarax) fact sheetTeratology serviceSecondaryPage dated 2025-05-01
- LactMed (NIH): HydroxyzineUS governmentSecondaryPage dated 2025-09-15Independent check
- DailyMed: Hydroxyzine pamoate capsule label (RemedyRepack, current generic record)Drug company labelTertiaryPage dated 2026-09-14
- DailyMed: Atarax hydroxyzine hydrochloride label (Roerig, older brand record)Drug company labelTertiaryPage dated 2006-09-21
- UK eMC: Hydroxyzine Hydrochloride 25 mg Summary of Product CharacteristicsTertiaryPage dated 2025-06-16
- NHS Specialist Pharmacy Service: Using antihistamines during breastfeedingUK governmentSecondaryPage dated 2026-02-05Independent check
- European Medicines Agency: Hydroxyzine referralEU agencySecondaryPage dated 2015-03-27Independent checkEuropean guidance
- Hansen et al., Use of antihistamine medications during early pregnancy and selected birth defects (2020)US governmentPrimaryIndependent check
- Broe et al., Prescription Drugs in Pregnancy and Congenital Malformations (2025)US governmentPrimaryPage dated 2025-07-28Independent check
- Einarson et al., Prospective controlled study of hydroxyzine and cetirizine in pregnancy (1997)US governmentPrimaryIndependent check
- Prenner et al., Neonatal withdrawal syndrome associated with hydroxyzine hydrochloride (1977)US governmentPrimaryIndependent check
- Serreau et al., Neonatal seizures associated with maternal hydroxyzine hydrochloride in late pregnancy (2005)US governmentPrimaryIndependent check
- Soussan et al., Drug-induced adverse reactions via breastfeeding: a descriptive study in the French Pharmacovigilance Database (2014)US governmentPrimaryIndependent check
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.