A 45-year-old male, Sanjeev was brought to the emergency with severe agitation and aggressive behavior. He was staed on haloperidol and the patient became responsive and cooperative. After 8 days of treatment, he developed high grade fever, diarrhea, confusion and muscle rigidity. Which of the following should be used for the treatment of this condition?

(Ref: Katzung 11/e p499) Diagnosis in this patient is neuroleptic malignant syndrome (NMS). It is an adverse effect caused by typical antipsychotic drugs like haloperidol. It presents clinically with four primary features: (1) hypehermia, (2) extreme generalized rigidity, (3) autonomic instability, and (4) altered mental status. Dantrolene is drug of choice for this condition.