This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pharmacology
Drug given for metaclopramidr induced dystonic reaction is: 
Select and explain. 
A. Pheniramine, B. Promethazine, C. Chlorpropamide, D. Prochlorperazine
B: Promethazine
Answer: B: Promethazine 
Explanation: Acute muscle dystonia caused by antiemetic-antipsycotic drugs is promptly relieved by parentral promethazine or hydroxyzine.this is based on central anti cholinergic action of the drugs. Promethazine is an first generation anti histaminic which has maximum anticholinergic activity.(ref: KDT 6/ep157)