It works by blocking the action of substance P, found in the highest concentration in the
emetic center.11 Substance P is a neuropeptide that helps regulate mood, anxiety, stress, respiratory rhythm, pain, nausea, and vomiting.11 The receptor for substance P is NK1.11 NK1 receptors are found in both the CRTZ and the
emetic center.11
When substance P binds to the NK1 receptor, vomiting occurs.12 Blocking the binding of substance P to NK1 receptors interrupts vomiting stimuli.