Classification Gastrointestinal medications antiemetics dimenhydrinate ondansetron prochlorperazine metoclopramide scopalamine promethazine Clinical Use Diabetic gastroparesis Post-surgery gastroparesis Nausea associated with chemotherapy Mechanism D2 receptor antagonist antagonist at Chemoreceptor Trigger Zone (CTZ) in Area postrema prokinetic in GERD ↑ resting tone, contractility, LES tone of esophagus does not effect colon transport time Toxicity Parkinsonian symptoms Restlessness Drowsiness/fatigue Depression Nausea/diarrhea Acute dystonic reaction treat with immediate IV diphenhydramine and benztropine Oculogyric crisis Contraindications Parkinson's Schizophrenia Small bowel obstruction References