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Question of the Week: February 11, 2000

What is the first choice prokinetic agent used in critical care?

Answer:

Metoclopramide is the preferred prokinetic agent in the critical care population.

There are three major prokinetic agents available. Metoclopramide and domperidone are dopaminergic agents which have an effect mainly on the esophagus and stomach, with minor effects on the small intestine. Cisapride is a cholinergic-like agent that also has activity on the esophagus and stomach, but has additional effects on the colon and anal sphincter.

There are a variey of reasons why metoclopramide remains the number one choice:

fewer drug interactions, specifically with erythromycin, clarithromycin, fluconazole or fluoxetine
better side effect profile (no cardiac effects)
can be used in patients with history of cardiac disease, arrhythmias or renal failure
metoclopramide is available in both an enteral and intravenous preparation
metoclopramide has less effect on the large intestine thus tends to cause less diarrhea
less expensive product

Cisapride can prolong the QT interval and cause ventricular tachycardia with torsades de pointes. There are case reports of fatalities when used in patients with a history of cardiac disease or arrhythmias. Any condition which will increase the serum level of cisapride (renal failure, use with other drugs which decrease its hepatic metabolism, use with other drugs which also prolong the QT interval such as calcium blockers, erythromycin or clarithromycin, fluconazole and fluoxetine) increases the risk of fatal or non-fatal arryhthmias. Therefore, cisapride should be used cautiously, and only in patients not responding to metoclopramide and who are free of the above mentioned risk factors.

References:

Metoclopramide Product Monograph, 1999
Cisapride Product Monograph, 1999
Drug Information, American Hospital Formulary Service, 1999