A federal judge in Massachusetts has denied a motion by drug maker GlaxoSmithKline to dismiss cases alleging that the drug Zofran (ondansetron) caused birth defects on the grounds that federal law preempts state failure-to-warn claims.
Federal law is the “supreme” law of the land and when a federal law conflicts with a state law, the federal law will trump, or “preempt”, that state law. In the decision, Judge F. Dennis Saylor wrote, “the issues presented in defendant’s motion are not ripe for decision on the present record and at this stage of the litigation.”
In October 2015, the Judicial Panel on Multidistrict Litigation transferred twelve Zofran cases to the Court for consolidated pre-trial proceedings. Additional cases have since been added, according to court documents.
Zofran received Food and Drug Administration (FDA) approval in 1991 for the prevention of post-operative nausea and vomiting associated with anesthesia, and for nausea and vomiting caused by radiation and chemotherapy. But in addition to the approved uses, GlaxoSmithKline (GSK) is alleged to have marketed Zofran “off-label” for pregnancy-related nausea and vomiting—morning sickness.
About 80 percent of women experience nausea and vomiting in pregnancy and for about 15 percent of pregnant women, the problem is serious enough to require medication, according to Medscape Multispecialty. Nausea and vomiting peak during the first trimester and this is when there is the greatest danger that a drug will have teratogenic— harmful—effects on the development of the fetus. Research findings suggest the need for caution in prescribing Zofran.
In 2004, research from Canada and Australia compared rates of miscarriage, stillbirth, and major birth defects among pregnant women taking ondansetron, other antinausea drugs, or no antinausea medication (176 women in each group). The women who received ondansetron were in the first trimester of pregnancy. The researchers saw no significant differences among the groups for adverse pregnancy outcomes; however, this industry-sponsored study was powered to detect only a 3.5-fold or greater increased risk in major birth defects. A larger, case/control study associated ondansetron with a significantly increased risk for cleft palate. The odds of cleft palate were 2.4 times higher with exposure to ondansetron during the first trimester. Australian researchers who compared 251 pregnant women exposed to ondansetron from 2002 to 2005 with 96,717 women who were not exposed found a 20 percent increased risk for a major birth defect among infants exposed to ondansetron during the first trimester.
A Danish study, using the Medical Birth Registry and National Patient Register, evaluated the teratogenic effects of ondansetron exposure during the first trimester using 1997-2010 data. Of 897,018 births, prescription records indicated that 1248 women were exposed to ondansetron. The odds of fetal heart malformation were two times higher in infants of women exposed to ondansetron compared with women not exposed to the drug.
Under current guidelines in the U.S. and Canada, Zofran is not recommended as the first-line option for treating nausea and vomiting in pregnancy, Medscape Multispecialty reports. Lifestyle and dietary modifications should be the first steps. If medication is required, doxylamine/pyridoxine (Diclegis) is FDA-approved for treating nausea and vomiting in pregnancy. Given current evidence, ondansetron should be avoided in the first trimester of pregnancy unless other treatments are ineffective.