When a patient experiences PONV in the PACU, don't automatically reach for an antiemetic agent. You first need to rule out other potential causes, such as abdominal obstruction or blood in the patient's stomach. Once you determine it's appropriate to administer an antiemetic agent, select an agent with a mechanism of action different from the agent you administered for prophylaxis. It's important to recognize that prophylaxis and treatment are distinct therapies. Serotonin antagonists have been extensively studied for both preventing and treating PONV. If a serotonin antagonist was administered for prevention of PONV, studies show that using it for treatment of PONV is no more effective than placebo. Also, limited literature suggests that doses of serotonin antagonists lower than those used for preventing PONV may be effective for treatment.

Andrew J. Donnelly, PharmD, MBA
Clinical Professor of Pharmacy Practice
University of Illinois Medical Center in Chicago
Chicago, Ill.
writeMail("donnelly@uic.edu")