Study finds FDA warning against antinausea drug droperidol unnecessary

A Mayo Clinic review of patients' responses to a drug used to control nausea and vomiting during anesthesia for general surgery questions a U.S. Food and Drug Administration (FDA) warning against the drug's use.

This study appears in the current issue of the journal Anesthesiology.

The FDA warning against droperidol was prompted in 2001 over concerns that the drug contributed to potentially fatal heart rhythm abnormalities. Mayo Clinic compared 139,932 patients' responses before the warning was issued (and droperidol was used) and found no proven cases of complications directly attributable to droperidol. In comparison, after the FDA warning, two of 151,256 patients had poor heart rhythm while receiving other, more expensive medication alternatives. The percentage of patients who received droperidol was 12 percent prior to the warning and 0 percent after placement of the warning.

Based on their findings, Mayo Clinic anesthesiologists conclude that the FDA warning against droperidol is unnecessary. They call for other investigators to study the topic to determine if further inquiry supports that conclusion.

“In our study, we obtained results that were just the opposite of what the FDA action would predict. We actually had fewer complications with droperidol,” explains Gregory Nuttall, M.D., the lead Mayo Clinic anesthesiologist on the study. “In our experience, low-doses of droperidol used by a skilled team are the safer and more effective agent for controlling nausea and vomiting, which is why we are making plans to resume its low-dose use in select patients in the cardiac Intensive Care Unit.”

The Mayo Clinic study is the first large, statistically well-controlled study of patient responses to droperidol at a single medical center over a long time (three years) that included treatment before and after the FDA warning. As such, it provides the strongest scientific evidence to date for the performance of droperidol and alternatives.

Since the FDA warning about droperidol was issued in 2001, reports in medical literature have questioned its accuracy and usefulness. It has been well established that all drugs used to prevent or control nausea prior to anesthesia use in general surgery also can have the negative side effect of prolonging a particular kind of abnormal heart rhythm known as long QT. Practitioners didn't understand why just one drug was singled out for a warning.

Dr. Nuttall explains: “There is a basic question: Is droperidol really that bad when compared to all the other drugs" I worked with droperidol, and I never saw a problem at the low doses we are talking about. After the warning, we all went to the more expensive drugs. Then we encountered the problem that none address rescue therapy well — that means once you're sick, you're stuck; the drugs don't work well. In addition, the data upon with the FDA based its decision came from case reports. Statistically, these are not as strong as controlled, systematic reviews of a large number of patient experiences at a single medical center using the same protocols.”

The Mayo Clinic team hopes another large controlled study will determine if the Mayo results can be validated. If they are validated, it might then prompt the FDA to revoke the warning against droperidol.

In the meantime, Dr. Nuttall recommends that each institution approach low-dose droperidol use with caution in a heart-monitored setting and only with advice from highly trained and experienced anesthesiologists. “Our only interest here is in seeing that patients get the safest and most beneficial treatment,” Dr. Nuttall says.