Zofran (odansetron) was approved by the US Food and Drug Administration in 1991 for the prevention of nausea and vomiting resulting from chemotherapy and radiation and for prevention of postoperative nausea and vomiting.
Studies of Zofran have never been done in pregnant women, so the label warns the consumer that although studies of the drug in pregnant rats and rabbits did not result in impaired fertility, “There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used in pregnancy only if clearly needed.”
In the years since it was approved for other uses, the makers of Zofran, GlaxoSmithKline (GSK), are aware that this drug has been prescribed to millions of pregnant women for morning sickness, even in the presence of mild symptoms. Zofran is prescribed to many of the approximately ten to fifteen percent of pregnant women who receive drugs for treatment of morning sickness. In fact, the manufacturer of Zofran has settled a lawsuit that alleged it actively promoted this use of Zofran in pregnant women, a violation of FDA regulations.
The first trimester of pregnancy is typically when women experience morning sickness, and it is also an important period of fetal development. Studies suggest that women who took Zofran during the first trimester of pregnancy have had a 30 percent higher rate of birth defects. Children who were born to mothers who took Zofran for morning sickness have an increased incidence of cleft palate, cleft lip, atrial septal defect of the heart, and kidney development abnormalities.
Zofran is currently rated “Pregnancy Category B,” which means that there are no adequate studies to determine the safety of the drug in pregnant women. This classification was based upon a sample of less than 200 women. Before Zofran was approved by the FDA, GSK had already confirmed in several studies that Zofran is transferred to the fetus through the placenta in significant amounts. Although a study in the New England Journal of Medicine concluded there was no increased risk of birth defects with Zofran, half of the women in the study only took Zofran after 10 weeks gestation, when the developing fetus was no longer at risk for cleft lip or palate or atrial septal defect. A subsequent study showed that Zofran doubled the risk of a birth defect after fetal exposure, resulting in a birth defect of approximately 5% in fetuses exposed to Zofran, compared to a 3.5% risk of birth defect in fetuses not exposed to Zofran. Another study of 1349 infants born to mothers who had taken Zofran in early pregnancy revealed that there was a significantly increased risk of a defect of formation of the cardiac septum, or wall between the chambers of the heart.
There is a reason that the “off-label” use of a drug is risky – when a drug is approved for a certain indication by the FDA, the manufacturer must provide evidence of efficacy and human safety.
Most pregnant women are very careful to stay healthy and to avoid anything that would endanger fetal development, which is why it is discouraging to see poor prescribing habits and drug company equivocation result in birth defects that negatively impact a child’s opportunities in life. The costs of congenital defects affects the infant, the family, and society. It’s important to discourage unsafe off-label prescribing habits. If you are a pregnant woman, you should carefully consider the potential risks against the potential benefits of taking this medication. There is a tremendous amount of uncertainty around its use in early pregnancy.
If you have taken Zofran (odansetron) during pregnancy and subsequently gave birth to a child with congenital malformations like cleft lip, cleft palate, or heart abnormalities, you may be entitled to legal recourse. Call us today for a review of your case by an experienced medical malpractice attorney at 312-527-4500.