Zofran (also known as ondansetron) is commonly used to treat nausea and vomiting associated with cancer chemotherapy, anesthesia or use of narcotics. Zofran is the first member of a group of drugs that all work the same way to reduce nausea and vomiting. Kytril and Anzemet are two other members of the 5-HT3 antagonists that can be taken by mouth. These drugs are very expensive, ranging in price from about $20 for 4 milligrams (mg) of Zofran to almost $50 for 1 mg of Kytril.

Nausea and vomiting of pregnancy is a relatively common problem affecting up to 90 percent of expectant women. Although it has been studied extensively, the cause of the nausea and vomiting is unknown, and most treatments provide only partial success. I am not aware of any clinical studies that have shown that Zofran and the other 5-HT3 antagonists work for morning sickness. We would need to know whether other 5-HT3 antagonists worked and at what dose in order to make any recommendations about alternatives.

The American College of Obstetrics and Gynecology recommends the use of vitamin B6 (also known and pyridoxine) alone or in combination with an antihistamine called doxylamine as the first-line treatment for morning sickness. In the past, a pill containing pyridoxine and doxylamine and an antispasmodic called dicyclomine was available as a product called Bendectin. Unfortunately, Bendectin was removed from the American market in 1983 by the manufacturer, due to accusations that is caused birth defects. No linkage was ever found between use of the drug and an increase in birth defects.

The usual dose of Bendectin was two tablets at bedtime (each tablet contained 10 mg of pyridoxine and 10 mg of doxylamine). Doxylamine is available over the counter (Unisom Tablets), as is vitamin B6 (pyridoxine). One Unisom tablet along with 25 to 50 mg of pyridoxine is used by many obstetricians as a replacement for Bendectin. The cost is about 30 cents a day.