Antihistamine
PREGNANCY RECOMMENDATION: Limited Human Data—No Relevant Animal Data
BREASTFEEDING RECOMMENDATION: Limited Human Data—Probably Compatible
PREGNANCY SUMMARY
In general, antihistamines are considered low risk in pregnancy. However, exposure near birth of premature infants has been associated with an increased risk of retrolental fibroplasia.
FETAL RISK SUMMARY
The Collaborative Perinatal Project monitored 50,282 mother–child pairs, 65 of whom had 1st trimester exposure to brompheniramine (1, pp. 322–325). Based on 10 malformed infants, a statistically significant association ( p <0.01) was found between this drug and congenital defects. This relationship was not found with other antihistamines. For use anytime during pregnancy, 412 exposures were recorded (1, p. 437). In this group, no evidence was found for an association with malformations.
The use of antihistamines in general (specific agents and dose not given) during the last 2 weeks of pregnancy has been associated with an increased risk of retrolental fibroplasia in premature infants (2). Infants weighing <1750 g, who had no detectable congenital anomalies and who survived for at least 24 hours after birth, were enrolled in the multicenter National Collaborative Study on Patent Ductus Arteriosus in Premature Infants conducted between 1979 and 1981 (2). After exclusions, 3026 infants were available for study. Exposures to antihistamines and other drugs were determined by interview and maternal record review. The incidence of retrolental fibroplasia in infants exposed to antihistamines during the last 2 weeks of gestation was 22% (19 of 86) vs. 11% (324 of 2940) in infants not exposed during this interval. Adjustment for severity of disease did not change the estimated rate ratio.
BREASTFEEDING SUMMARY
A single case report has been located describing adverse effects in a 3-month-old nursing infant of a mother consuming a long-acting preparation containing 6 mg of dexbrompheniramine and 120 mg of d-isoephedrine (3). The mother began taking the preparation on a twice-daily schedule about 1 or 2 days before the onset of symptoms in the infant. Symptoms consisted of irritability, excessive crying, and disturbed sleeping patterns, which resolved spontaneously within 12 hours when breastfeeding was stopped. One manufacturer considers the drug to be contraindicated for nursing mothers (4). The American Academy of Pediatrics noted the above adverse effects observed with dexbrompheniramine plus d-isoephedrine, but classified the combination as usually compatible with breastfeeding (5).
References
1.Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA: Publishing Sciences Group, 1977.
2.Zierler S, Purohit D. Prenatal antihistamine exposure and retrolental fibroplasia. Am J Epidemiol 1986;123:192–6.
3.Mortimer EA Jr. Drug toxicity from breast milk? Pediatrics 1977;60:780–1.
4.Product information. Dimetane. AH Robins Company, 1990.
5.Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001;108:776–89.