Zofran, or ondansetron as it is sometimes known, was initially created in the 1980s in England. It is a serotonin 5-HT3 receptor antagonist used to prevent nausea, which essentially means that it blocks the chemicals that are responsible for nausea and vomiting. The FDA didn’t approve Zofran for use in the US until early 1991. It was only approved for the use by cancer patients undergoing therapy and patients that are recovering from surgery.
Zofran worked extremely well for cancer patients and those recovering from surgery. It quickly became popular with doctors and at one point was ranked as the 20th highest selling brand name drug in the US. As its popularity grew, doctors began prescribing it off-label to expectant mothers with violent morning sickness that was not responding to other treatments. When a doctor prescribes an off-label drug, the doctor is giving it for a reason that it has not yet been approved for. Zofran had not been approved for use by expectant mothers.
While it had not been approved, in the past there had been testing in animals, mostly rabbits and rats, to see if its use affected unborn babies. These test showed no negative effects on the babies born. However, studies done with humans have been inconclusive. Some show no negative effects while others show a minor to significant increase in certain birth defects. The defects vary but most commonly are the development of a cleft lip, cleft palate, or heart defects.
The makers of Zofran never petitioned for the approval of the drug for expectant mothers. In fact, they have since issued a warning against its use by expectant mothers and the makers of Zofran have had to pay $2 billion dollars in penalty for marketing the drug as safe for expectant mothers without approval. Lawyers are beginning to collect cases of fetal birth defects caused by the drug, and if even one Zofran lawyer begins winning cases the popularity of the drug will begin to decline.