Co-Director Kathryn Emerick, MD
photo: Jamie Manser
Many patients are prescribed medications for anxiety and sleep before pregnancy. Two commonly prescribed PRN (as needed) medications are hydroxyzine and propranolol. You may have a patient who was prescribed these medications before they became pregnant, and they now have questions about their use during pregnancy. Since these are such common medications, we have compiled safety data on hydroxyzine and propranolol below to assist you in having a robust informed consent discussion with your patient.
Hydroxyzine
Teratogenic and development outcomes: There is no clear pattern of malformation associated with hydroxyzine, although data in humans are very limited. There have been rat studies that found an increased risk of skeletal malformations, but this may not apply to humans because of the different ways antihistamines affect rats versus humans. In humans, antihistamines dilate blood vessels, but in rats, they cause constriction. This may account for the data differences found in human and animal research for hydroxyzine.
Gestational outcomes: Hydroxyzine can decrease fetal heart rate response, but it is not clear that this decrease is clinically significant.
Neonatal outcomes: There have been two reports of seizures in infants born to mothers taking hydroxyzine throughout pregnancy for pruritus. Again, this data is extraordinarily limited, and we are unable to draw any conclusions about causation from this.
Breastfeeding: There are reports of minor adverse reactions in infants breastfed by mothers taking hydroxyzine. The most reported effects are irritability and sedation. Theoretically, because of hydroxyzine’s anticholinergic effect, antihistamines in general might reduce milk production. We have no specific data on the impact of hydroxyzine and breastmilk production, but it may be a consideration for a mom who is struggling to breastfeed and is taking high, consistent doses of hydroxyzine.
Propranolol
Teratogenic and developmental outcomes: There is no identified pattern of malformation associated with propranolol. Studies investigating the medications that babies with major malformations were exposed to during pregnancy compared to studies looking at the outcomes of propranolol gestational exposure have not detected any teratogenic effect.
Gestational outcomes: Some studies show an increased risk of intrauterine fetal growth restriction (IUFGR) with the use of beta-blockers. However, the studies showing this association have examined daily doses between 40mg and160mg. For anxiety, the range is usually between 10 and 20mg. Other studies have indicated that the risks of IUFGR are dose-dependent, which is reassuring for the doses normally used in psychiatry. This may be a consideration, however, for a mom that has other risk factors for IUFGR.
Neonatal outcomes: Propranolol exposure in late pregnancy (within about a week of delivery) has been associated with neonatal apnea, respiratory distress, bradycardia, and hypoglycemia. However, this data is complicated as propranolol is most often used for maternal hypertension which mean that the dose in most of these studies are higher than those regularly prescribed for anxiety. It is also worth noting that no cases of persistent consequences have been described in these cases. Symptoms in affected neonates consistently clear in 24 to 48 hours.
Breastfeeding: Propranolol is highly protein-bound, limiting excretion in milk. Between 0.3 and 0.4% of the weight-adjusted maternal daily dose would be ingested by a nursing infant. Nursing infants can be monitored for bradycardia and other symptoms of beta-blockade, although these adverse effects have not been associated with propranolol exposure through milk.
The above information is only about the general risks associated with these medications. It does not tell us whether it is necessary to continue this medication in pregnancy for the patient in front of us. It does not tell us if the patient has tried 10 other medications and this is the medication that has worked best for her, that without the propranolol to manage her performance anxiety – she cannot function at work, or that without the hydroxyzine to help with anxiety at bedtime – she risks damaging her relationship.
As you consider discussing the safety of medications during pregnancy with patients, please also keep in mind that all perinatal psychiatry medication discussions are highly individualized and depend on the personal history and needs of that specific patient.