A patient with acute psychosis, who is on haloperidol 20mg/day for last 2 days, has an episode characterized by tongue protrusion, oculogyric crisis, stiffness and abnormal posture of limbs and trunk without loss of consciousness for last 20 minutes before presenting to casualty. This improved within a few minutes after administration of diphenhydramine HCl. The most likely diagnosis is
High-Yield Explanation
DOC for acute muscular dystonia is one of the central anticholinergic. Diphenhydramine has anticholinergic property, therefore the patient in question had improved after administration of diphenhydramine.