Neuroleptic Malignant Syndrome (NMS) is a rare but life-threatening reaction to antipsychotic (neuroleptic) drugs, characterized by severe muscle rigidity, high fever, altered mental status, and autonomic instability such as irregular blood pressure and heart rate. It is most commonly associated with dopamine receptor blockade in the central nervous system and may develop shortly after starting or increasing the dose of neuroleptic medications. Immediate medical discontinuation of the causative drug and supportive intensive care are essential for management.