09 March 2017

Zofran Leads Competition In Morning Sickness Drug Market

Despite widespread concerns over the nausea drug’s safety, pregnant women continue to be prescribed staggering amounts of Zofran, according to a new report from researchers at the US Food & Drug Administration and Harvard Medical School.

Ondansetron In Pregnancy: Prescription Rates Skyrocket

Analyzing a wide range of data collected in the Mini-Sentinel Distributed Database, a system designed by FDA to gather electronic health data, the team of public health researchers discovered that around 30% of pregnant women had been prescribed an anti-nausea drug at some point during pregnancy between 2001 and 2015.

One drug in particular overshadowed its competitors. The analysis, which included data from over 2.3 million American pregnancies, showed a rapid and dramatic increase in the use of a powerful drug known as ondansetron, which has never been approved for use during pregnancy. Sold under the brand name Zofran, ondansetron was prescribed to less than 1% of women in 2001, the first year considered in the study. Thirteen years later, nearly 1 in 4 of the women were being prescribed the medication, despite its questionable safety.

Pill Question Mark

The prescription rate for Zofran exploded in 2006, the researchers say, simultaneously pushing competing drugs out of the market. As ondansetron became increasingly popular, the rate of prescription for other anti-nausea drugs, including promethazine and metoclopramide, declined sharply. The antihistamine promethazine took a particularly hard hit. It was prescribed to around 13.8% of pregnant women in 2001, but only 3.2% of women by 2006.

FDA-Approved Diclegis Lags Far Behind

The study’s most troubling conclusion, however, becomes apparent after considering Diclegis, which remains the only FDA-approved drug for morning sickness in the United States. Only 1.8% of insured pregnant women were prescribed the combination of doxylamine and pyridoxine in 2014. Around 12 times as many women received Zofran, a drug linked to major birth defects in multiple recent studies.

In light of these facts, the researchers’ conclusion is not earth-shattering, though it does call for increased vigilance:

“We observed a marked increase in ondansetron use by study year, prescribed to nearly one-quarter of insured pregnant women in 2014, occurring in conjunction with decreased use of promethazine and metoclopramide. Given the widespread use of ondansetron in pregnancy, data establishing product efficacy and methodologically rigorous evaluation of post-marketing safety are needed.”

The study, Antiemetic use among pregnant women in the United States: the escalating use of ondansetron,” was published on February 21, 2017 by the journal Pharmacoepidemiology & Drug Safety. Their research was funded by a grant from the US Food & Drug Administration.

Why Researchers Want Closer Look At Zofran’s Safety

Ondansetron is a powerful anti-nausea drug, developed by British multinational GlaxoSmithKline for sale under the brand name Zofran. The medication has been approved for the treatment of nausea and vomiting in cancer and surgical patients for decades, but was never even tested during pregnancy.

Notwithstanding an utter lack of pregnancy-related safety data, the medication quickly became a popular choice of obstetricians and gynecologists, who have long struggled to manage their patients’ morning sickness symptoms. As we’ve seen, “popular” may be an understatement, with nearly one-quarter of all insured pregnant women receiving the drug by 2014.

Linked To Birth Defects, Zofran Inspires Litigation

Recent medical research, however, has found a potential link between ondansetron, especially when prescribed during the first trimester, and a range of major birth defects. A Harvard study, performed in 2012, suggested that the drug could nearly double the risk for cleft palate. In Denmark, scientists discovered that women who took ondansetron in early pregnancy were between 200% and 400% more likely to deliver children with congenital heart defects, a result substantiated by subsequent research conducted in Sweden.

Beyond significant medical controversy, these findings have spurred a wave of litigation. Hundreds of families have filed lawsuits, accusing Zofran’s manufacturers of concealing the drug’s link to fetal harm for years. Their claims have been consolidated in the US District Court of Massachusetts, where they will progress through pre-trial proceedings as a group.