Which antiemetic?

The choice of antiemetic should not be arbitrary, but should be based on knowledge of the different pathways of the various stimuli that lead to nausea and vomiting and the neuroreceptors involved. The steps to be taken in choosing an appropriate antiemetic are described. They are (a) to establish the probable cause of the nausea and vomiting, (b) to consider the afferent pathways involved, (c) to define the neuroreceptors activated at each of these sites, (d) to select the group of antiemetics that antagonizes these neuroreceptors, and (e) to choose the most potent antiemetic with the fewest side effects in that group. Causes for failure to respond to a chosen antiemetic are considered and the action to be taken is described.