OCCURRENCE OF NEUROLEPRIC MALIGNANT SYNDROME ON TRIHEXPHENIDYL DISCONTINUATION

The neuroleptic malignant syndrome (NMS) commonly occurs on treatment with neuroleptics, it is also reported in patients who suddenly stop drugs like levodopa, amitriptyline and imipramine. We report a case of NMS, which occurred in a patient on lithium, haloperidol and trihexyphenidyl (THP) after sudden discontinuation of THP. The cholinergic system, through its effect on the dopaminergic system, may play a role in the genesis of NMS. Alternatively, anticholinergic withdrawal may produce extrapyramidal symptoms (EPS), and the consequent alteration in food and fluid intake may produce electrolyte imbalance which increases the risk for NMS.