Drug given for metoclopramide dystonic reaction is-
Ans. is 'b' i.e., Promethazine o We all know, blockade of D2 receptors in brain produce extrapyramidal side effects (as caused by antipsychotics), and acute muscular dystonia (dystonic reaction) is one of them. o Treatment of choice for acute muscular dystonia is central anticholinergic. o But, in given options, they have not given typical central anticholinergics. All options are typical antihistaminics. o As we also know that antihistaminics have anticholinergic propeies. So, amongst the given options we will have to choose the drug which has maximum central anticholinergic propey. First generation antihistaminics : i) Have maximum anticholinergic propey ii) Have maximum penetration of blood brain barrier For these two reasons, first generation antihistaminics have maximum central anticholinergic propey. o Amongst the given options, only promethazine is first generation antihistaminic. o Following statement of KDT will clear all doubts: "Acute muscle dystonia caused by antiemetic-antipsychotic drugs is promptly relieved by parenteral promethazine or hydroxyzine." Remember o DOC for antipsychotic induced acute muscle dystonia central anticholinergic o If central anticholinergic is not given in the options --> antihistaminic with maximum central anticholinergic propey is the DOC.
Phenaramine
Promethazine
Chlorphenaramine
Prochlorperazine