Definition of "Ondasetron is Unavailable"

The phrase “if Ondansetron is unavailable” is included to address practical situations where the medication is not accessible, most commonly due to supply shortages or stocking issues. It is not suggesting a change in preference, but rather clarifying what to do if you do not have it on hand (i.e., you're out of stock on your ambulance). 

Ondansetron remains the preferred first line antiemetic. It works by blocking serotonin receptors involved in triggering nausea and vomiting and is generally more effective with fewer side effects than alternatives. It also causes less sedation, which makes it a better option in most patients.

If Ondansetron is not available, Dimenhydrinate can be used as your first line antiemetic instead. While effective, it tends to cause more sedation and anticholinergic effects, so Ondansetron remains the preferred agent when accessible.

This wording simply ensures continuity of care when supply limitations occur, while maintaining Ondansetron as the standard choice whenever possible.