A husband and wife filed a birth defects lawsuit against the makers of Zofran, alleging the drug caused their son to die from heart birth defects.

Plaintiffs Stephanie E. and Martin E., filed their Zofran wrongful death lawsuit in a Kentucky court against drug giant GlaxoSmithKline (GSK).

Zofran is an anti nausea drug, approved to treat severe cases of nausea from radiation treatments and chemotherapy. It was only approved by the U.S. Food and Drug Administration to treat those conditions.

However, this lawsuit alleges that the drug’s makers have promoted Zofran for other, so-called off-label uses. Under U.S. law, while it is acceptable for a doctor to prescribe a drug for reasons beyond what has been approved by the FDA, it is illegal for a drug maker to promote the drug for other such uses.

The couple alleges that off-market promotion led to their doctor to prescribe Zofran for morning sickness. The makers of Zofran have not gotten their drug approved for this use, and therefore have not followed FDA protocols to test its efficacy and safety for this use.

The lawsuit alleges that the company has been marketing Zofran off-label since at least 1998, resulting in it becoming the most prescribed drug for morning sickness in the 2000s. The Zofran lawsuit says that Stephanie E. would have never used the drug had she known it was not tested or approved for morning sickness.

The lawsuit further alleges that the makers of Zofran had reason to suspect the drug was not safe, but did not warn the public about the risk of birth defects. As far back as the 1980s, laboratory tests on animals revealed that Zofran could cross the placental barrier of mammals and cause death and malformation of a nonhuman fetus.

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.”

Additionally, since 1992, there have been post-market reports of women taking Zofran who gave birth to children with birth defects. 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.

The couple’s lawsuit alleges that their child was born with severe heart defects caused by Zofran use during pregnancy. The defects include the right side of the heart not developing enough to adequately pump blood to the lungs, and problems with the blood supply to the right half of the heart. The child died eight days after birth in 2012.

The Zofran Birth Defects Lawsuit is Case No. 0173, filed in the U.S. District Court for the Eastern District of Kentucky, London Division.