This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
All are antiemetic except ? 
Select and explain. 
A. Ondansetran, B. Metoclopramide, C. Chlorpromazine, D. Bismuth
D: Bismuth
Answer: D: Bismuth 
Explanation: Ans. is 'd' i.e., Bismuth Antiemetic drugs Anticholinergics - Hyoscine, Dicyclomine. H1 antihistaminics - Promethazine, cyclizine, Cinnarizine, etc. Neuroleptics (D2 blockers) - Chlorpromazine, Haloperidol, Droperidole etc. Prokinetics drugs - Metoclopramide, Domperidone, cisapride, Mosapride, Tegaserod. 5-HT3 antagonists - Ondansetron, Granisetron. Adjuvant antiemetics - Dexamethasone, BZDs, Cannabinoids, Clonidine & ephedrine.