Claritin Cleared of Birth Defect Hypospadias
By Barbara
K. Hecht, Ph.D. and Frederick
Hecht, M.D.
Medical Authors and Editors, MedicineNet.com
The allergy drug Claritin has been found not to cause
the birth defect hypospadias. Claritin (loratadine) is a
popular non-sedating antihistamine.
Hypospadias is a relatively common congenital malformation (birth
defect). It affects one boy in every one to two hundred born in
the US. In hypospadias, the urethral opening is located along the
underside of the penis, scrotum, or perineum. Hypospadias is classified
in order of increasing severity as first, second, or third degree. The
condition often requires surgery.
The Fear of a Birth Defect
The fear that Claritin might cause hypospadias dates to 2002. That year a Swedish
study reported that the prevalence of hypospadias was twice normal
among boys whose mothers had taken Claritin during pregnancy.
However, insufficient data were available to determine the severity of the
hypospadias, and the study did not control for confounding variables such as a
family history of hypospadias.
In 2003, a small prospective study failed to confirm the association of
Claritin with hypospadias. The study done in 4 countries indicated that 5 of
142 pregnancies in women exposed to Claritin resulted in infants with major
malformations, a prevalence consistent with that of the general population.
None had hypospadias.
New Study by the CDC
To further assess a possible association between exposure to
Claritin and the occurrence of hypospadias, the CDC (Centers for Disease
Control and Prevention) have analyzed data from their National Birth
Defects Prevention Study. Exposure to Claritin was defined in this study as
any maternal use of the drug from a month before pregnancy through
the end of the first trimester (through the third month of pregnancy).
All cases of second- or third-degree hypospadias were recorded in the study.
(First-degree hypospadias is so slight that it is not considered a
major malformation.) In the study there 563 boys born with
hypospadias. Among the 1,957 mothers of infants with hypospadias and control
babies, 33 (1.7%) reported using Claritin during the exposure period.
Reassuring Findings
Analysis of the data showed no association between the use of Claritin
and hypospadias. The analysis determined specifically that no increased risk
for second- or third-degree hypospadias existed among women who used Claritin
in early pregnancy. Furthermore, the use of nonsedating antihistamines
(including Claritin) and of sedating antihistamines also were not associated
with hypospadias.
Antihistamines in Pregnancy
During 1998 and 1999, Claritin was the drug that was most advertised directly
to consumers in the US. It was used by 3% of women of childbearing age. Since late in 2002, Claritin has been available in the US without a
prescription.
Antihistamines such as Claritin are used widely by consumers, including
women of childbearing age, 20-30% of whom have allergic conditions, primarily
rhinitis (eg, hayfever) and sinusitis.
Because an estimated 50% of all pregnancies in the US are unintended,
women frequently are exposed inadvertently to medications before learning they
are pregnant.
Limitations of the Study
The CDC report is subject to at least two limitations. First, the
National Birth Defects
Prevention Study does not track all birth defects.
Because first-degree hypospadias is excluded, the potential association between
this mildest form of hypospadias and Claritin could not be assessed.
Second, women in the study were interviewed about their pregnancy
exposures after delivery, and the ability to recall drug use might be different
among mothers of infants with major birth defects compared with mothers of
infants without major birth defects.
Caveat
These results are very reassuring but they do not provide definitive
information on the overall safety of Claritin. All women should continue to
consult their health-care providers before using any medications during
pregnancy.
Source
Evaluation of an Association
Between Loratadine and Hypospadias --- United States, 1997--2001. Morbidity and
Mortality Weekly, March 19, 2004.
Related Links
Antihistamines
Birth Defects
Last Editorial Review: 4/6/2004
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