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
A drug given for metoclopramide induced dystonic reaction is : 
Select and explain. 
A. Pheniramine, B. Promethazine, C. Chlorpromazine, D. Prochlorperazine
B: Promethazine
Answer: B: Promethazine 
Explanation: "Acute muscle dystonia caused by antiemetic-antipsychotic drugs is promptly relieved by parenteral promethazine or hydroxyzine." This is based on the central anticholinergic action of the drugs.
Promethazine is a first-generation anti-histaminic which has a maximum penetration of blood-brain barrier and maxi­mum anticholinergic activity.