Ondansetron Linked to Birth Defects in Canada

Several pregnant women in Canada experiencing morning sickness have been prescribed an anti-nausea medication to help control their symptoms. However, reports indicate that the medication Ondansetron may be responsible for creating serious, life-threatening birth defects.

Ondansetron is a medication approved by Canada’s Health Board to treat patients undergoing chemotherapy who experience vomiting and nausea. The drug is not approved for pregnant women, yet several physicians have been prescribing it to them regardless, using an off-label, even though the manufacturer of the medicine advises against prescribing it to expectant mothers. 

So far, at least 20 women have come forward after taking the nausea medication, stating their infants now have severe side effects, including heart defects, kidney malformations, and even infant death. Although the information has been disclosed by the Health Board, local reporters and investigators uncovered the details in the United States Food and Drug Administration’s (FDA) “Adverse Event Reporting System” (FAERS).

Unfortunately, ondansetron is only one of the off-label medications used in Canada. In fact, there isn’t even a law that prohibits doctors from prescribing medications that haven’t been approved. 

In 2012, Canada’s Health Board was told by the Senate that there was concern about monitoring pregnant women who were prescribed off-label drugs. Health Canada admitted that pregnant women were not being properly monitored, even after a 2011 poor auditing report that stated there was poor medication monitoring by physicians.

Although the women’s name were removed from the FDA’s report on ondansetron, the research indicates that the side effects for pregnant women consisted of:

  • Infant musculoskeletal anomaly
  • Mouth deformity
  • Jaundice
  • Heart murmurs
  • Heart defects
  • Cleft palate

Since most pregnant women experience nausea most often during the first trimester of pregnancy, the medication is taken during the most sensitive time period for infants, when the most crucial parts of development begins. Around 10 to 15% of pregnant women in Canada were prescribed ondansetron.

GlaxoSmithKline, the maker of the drug’s brand name, Zofran, made a statement after the findings of birth defects, stating that “the safety of ondansetron for use in human pregnancy has not been established. The company monitors and reports all adverse event reports and works closely with regulatory authorities in Canada to include relevant safety information for physicians and patients within our product labels.”

Other generic manufacturers of the medication refused to make comment.

Several studies have been conducted regarding the dangerous effects of ondansetron, yet it is still prescribed to pregnant women in Canada. Although the research produced mixed results, a 2011 study suggested that cleft palate was a concern and a study that researched 900,000 births indicates that an infant’s chance of developing heart defects almost doubles if the mother takes ondansetron during pregnancy.

The Hospital for Sick Children in Toronto’s Motherrisk program provides a number for pregnant women to call for questions and concerns. In 2012, staff members received 194 calls from expectant mothers regarding the safety issues surrounding ondansetron. 

“Here is a drug not meant for pregnancy, given in pregnancy, with no data. So how do you know it’s safe for a baby? It’s an extrapolation that doctors do. They think it’s the last chance for your patient. They think that there’s an edge for that drug compared to other drugs,” Motherrisk director Dr. Gideon Koren said.