Cetirizine / Zyrtec® in Pregnancy and Breastfeeding

Cetirizine (Zyrtec®)
CATEGORY: B
Antihistamine. Metabolite of hydroxyzine. Molecular weight: 461.82.
"In mice, rats, and rabbits, cetirizine was not teratogenic at oral doses up to 96, 225, and 135 mg/kg, respectively (approximately 40, 180 and 220 times the maximum recommended daily oral dose in adults on a mg/m 2 basis)".

In a prospective, controlled, observational study of women exposed to either hydroxyzine or cetirizine during pregnancy 39 women were exposed to cetirizine during organogenesis. Most of the women had been treated with cetirizine for rhinitis or urticaria. There were no significant differences found between the cetirizine group and a control group in the rates of major or minor anomalies, spontaneous abortions, stillbirths, mean birth weight, mode of delivery, gestational age, or presence of neonatal distress.

In an observational study of newly marketed drugs prescribed in England cetirizine was taken during the first trimester in 20 pregnancies. One patient chose to have an elective abortion. There were 4 spontaneous abortions. The remaining mothers delivered 16 normal infants (one set of twins).

The American College of Obstetricians and Gynecologists (ACOG) and The American College of Allergy, Asthma and Immunology (ACAAI) recommend chlorpheniramine and tripelennamine as the antihistamines of choice for pregnant women. Cetirizine and loratadine may be considered (preferably after the first trimester) in patients who cannot tolerate or do not respond to maximal doses of topical therapy.

BREAST FEEDING: Excreted into human milk. Not considered compatible with breast feeding by the manufacturer.