Knowledge is cure for curbing antiemetic use

For chemotherapy, one size doesn’t fit all

Here’s a test of your antiemetic knowledge: A patient with polycythemia vera is undergoing treatment with hydroxyurea. Vomiting ensues. The doctor writes an order to give 2 mg of the fashionable antiemetic granisetron an hour before the next dose of hydroxyurea. Is this a reasonable use of granisetron?

Reasonable, perhaps, in that granisetron will prevent vomiting. But necessary? Perhaps not. In fact, not every cancer patient who is under-going chemotherapy needs an expensive antiemetic from the "tron" class — odansetron or granisetron. Some, like the patient on the hydroxyurea, can get by just fine using an inexpensive agent such as prochlorperazine or dexamethasone. It really depends on what chemotherapeutic drug is being given and at what dose.

A friendly reminder

As part of an overall effort to streamline chemotherapy guidelines, Mercy Hospital in Miami designed an extensive and informative chart printed on the back of its chemotherapy order forms. (See chart, p. 93.)

Mike Clark, PharmD, director of pharmacy, says the chart reminds oncologists that you don’t shoot flies with a cannon.

"There’s definitely a good number who will stop and think, ‘Do I need the big guns or can I get away with a cheaper agent?’" Clark says.

There’s just one problem: a manufacturing shortage of one of those cheaper agents, prochloperazine. "In the past one or two months, we used up [all the prochlorperazine] we could get our hands on," Clark says. Mercy hasn’t been able to obtain additional prochlorperazine for a month now.

As for the chart, Clark says that while the pharmacological potential of some agents to cause vomiting is low, there’s a psychological element to chemotherapy: Patients expect they’re going to get sick, and so even when they shouldn’t, they might. On occasion that could lead to use of a higher-priced drug if prochlorperazine or dexamethasone don’t work.