Zofran is a popular anti-nausea medication that has been prescribed to post-surgical and chemotherapy patients for over the past 20 years. However, Zofran has also been prescribed for the off-label purpose of treating morning sickness for just as long, which has caused the drug and its manufacturer to land in hot water because of some serious side effects.

Recently, it has been alleged that Zofran has caused birth defects in unborn fetuses after their mothers had taken the drug to treat their morning sickness. The drug’s manufacturing company, GlaxoSmithKline (GSK), has been facing the blame for this occurrence and faces legal claims for failing to warn pregnant women about the possibility of Zofran birth defects. Reported birth defects association with off-label Zofran use include: cleft lip, cleft palate, and heart defects (especially atrial septal and ventricular septal defects).

Zofran is a member of the 5-HT2 receptor antagonist drug family, which work by blocking the serotonin channels that trigger nausea and vomiting. Essentially, Zofran’s mechanism is meant to block the body’s nausea and vomiting reactions by stopping the signals from reaching the brain. For this reason, Zofran has been a popular morning sickness treatment method since its release in 1991, although many  medical experts warned against pregnant women using this drug.

Several drug studies have observed the possible link between Zofran and birth defects, with one as recently published as 2014. This Zofran birth defects study was led by Dr. Gideon Koren and was published in the December 2014 issue of the American Journal of Obstetrics and Gynecology, highlighting the risks of Zofran imposed on pregnant women. Dr. Koren also mentioned previous Zofran birth defects studies that have found conflicting results, by stating that these mismatched findings do not rule out possible risks to the fetus. His Zofran research study followed a February 2013 study, which had observed more than 600,000 Danish women who had used Zofran in order to determine a possible link between this drug and inutero birth defects.

After finding timing flaws in the study, Dr. Koren had expanded the study in August 2013 to observe 900,000 pregnancies for over a longer period of time. Dr. Koren found that women who used Zofran had faced almost double the risk of cardiac defects, as well as an overall 30 percent increased risk of birth defect occurrence. Along with observing the possible correlation between Zofran and birth defects, the study also compared the results of another common morning sickness treatment, metoclopramide. The study found no increased birth defect risk with this drug.

The conflicting studies conducted before Dr. Koren’s study had caused many experts to state that the research study’s sample size had been too small and no adequate conclusions could be drawn from them. Overall, Dr. Koren and other medical experts state that regardless of the scientific studies, pregnant women should not be exposed to a drug of “unproven maternal and fetal safety” when other drugs are available.

Despite these findings, the U.S. Food and Drug Administration recently rejected a petition to change Zofran’s drug category, saying in an October 2015 statement that these studies “do not support a determination that there is an increased risk of fetal adverse outcomes.”

Overview of Zofran Birth Defect Allegations

As stated previously, Zofran has never been officially approved to treat birth defects by the FDA despite its popularity in that particular patient population. With these looming Zofran birth defect allegations, it is unlikely the FDA will amend their decision any time soon. Additionally, due to these recent Zofran studies, healthcare providers are likely to decrease their Zofran prescription rates to pregnant women.

The recent realization that there is little scientific evidence to support the idea of Zofran being safe to use during pregnancy has many women across the country have seeking legal action on behalf of themselves and their children.

These mothers allege that GlaxoSmithKline knew about the risk Zofran presented to unborn babies, but had chosen to omit this information from the drug’s label. However, mothers and children are not the only ones who have taken this action, as federal investigators also challenging the company. The U.S. Department of Justice had sued GlaxoSmithKline for illegal advertising practices, and for failing report accurate safety data on a number of their drugs, including Zofran.

In 2012, GSK settled a federal, civil false claim lawsuit alleging GSK had promoted Zofran for the treatment of morning sickness in pregnant women despite being approved only for post-operative nausea, and that GSK had paid doctors kickbacks for prescribing Zofran. In 2012, GSK settled that lawsuit along with three similar lawsuits regarding other GSK products for $1.043 billion.

Even with this settlement, Zofran’s warning label still includes no mentioning of birth defects.