December 15, 2016 — Zofran should be a last-resort when other medications have failed to treat morning sickness, according to a review of how to manage nausea and vomiting during pregnancy
Experts analyzed several studies investigating the use of Zofran for morning sickness, and published their conclusions in the Journal of Obstetrics and Gynaecology Canada.
Many studies that were reviewed had serious flaws, or showed that Zofran was no better than Reglan (metroclopramide) or the first-line treatment for morning sickness, Diclegis (doxylamine and pyridoxine). Diclegis is a “Pregnancy Class A” drug, whereas Zofran is “Class B.”
Experts also pointed out several cases of bowel obstruction — a rare but serious side effect of Zofran — and noted that Zofran is significantly more expensive per dose than other cheap, safe, and effective treatments for morning sickness.
Zofran (ondansetron) is not approved for use during pregnancy, but its manufacturer — GlaxoSmithKline (GSK) — paid a $3 billion settlement after the Justice Department said it was marketed to pregnant women.
The problem is that studies have linked Zofran with higher rates of birth defects. In 2014, a study associated Zofran with a 62% increased risk of heart defects, and a doubled risk of “hole in the heart” defects. In 2012, a study published in Birth Defects Research associated Zofran with a 2.4-fold increased risk of cleft palate.
In Canada, the label for Zofran clearly states that “the safety of ondansetron for use in human pregnancy has not been established,” and “the use of ondansetron in pregnancy is not recommended.” These warnings are not on the label in the U.S. Instead, the label states that Zofran should be used during pregnancy “only if clearly needed.”
As of mid-December 2016, there were 362 lawsuits involving Zofran birth defects pending in a Multi-District Litigation (MDL No. 2657) in the U.S. District Court for Massachusetts. All of the lawsuits accuse GlaxoSmithKline of failing to warn pregnant women about the risk of birth defects.