NEW ORLEANS (AP) – The first head-to-head comparison of common treatments for preventing nausea and vomiting after surgery found that drugs costing a dollar or two work just as well as a more expensive medicine.

Also, a combination of two or three drugs was found to be more effective than just one at preventing people from throwing up after an operation. Some people, though, get sick to their stomach no matter what.

The study, published in Thursday’s New England of Medicine, clarifies a dismally murky area. Post-op nausea is a big problem, affecting one out of three surgery patients – about 25 million a year in the United States.

“For the first time I really feel like I understand what there is to know about preventing nausea and vomiting in the operating room,” said Dr. Allan Gottschalk, an associate professor at Johns Hopkins University.

When medical residents used to ask what to do, Gottschalk said, “I would have to say the literature was such a mess that I really didn’t have any real strong opinions. Now I think we have something.”

The study was led by Dr. Christian C. Apfel, who began the research at the University of Wurzburg in Germany and now also works at the University of Louisville. He looked at all 64 possible combinations of six nausea treatments.

Three of the treatments are drugs – the steroid dexamethasone; ondansetron, developed to avert vomiting after chemotherapy; and the tranquilizer droperidol. Droperidol costs about $1, dexamethasone $2 or less, and ondansetron $15 or so.

The group also studied two anesthetic techniques – using an intravenous anesthetic rather than gas, and using nitrogen rather than nitrous oxide – as well as use of an ultra-short acting narcotic called remifentanil.

Apfel and colleagues at 28 hospitals in seven countries used every possible combination to learn what worked best on 5,199 patients likely to have post-op stomach upsets.

The three drugs were found to be about equally effective.

Overall, 52 percent of the patients who got no anti-vomiting drug became ill after surgery. That dropped to 37 percent of those who got one drug, 28 percent of those who got two, and 22 percent of those who got all three.

The IV anesthetic propofol brought a 19 percent drop compared with use of gas, and nitrogen rather than nitrous oxide a 12 percent reduction. The painkiller change made no significant difference.

He said that people most likely to suffer post-op nausea are women, nonsmokers and those with a history of such nausea or of motion sickness. So are those undergoing surgery painful enough to need opiates afterward.

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