Review Question - QID 215098

A 33-year-old woman presents to the emergency department after not returning to work for 2 weeks. The patient is accompanied by her co-worker who went to her home and found the patient hiding inside the closet. The patient reports that she is being followed and that a group of men is plotting to kidnap her. The patient has a history of paranoid schizophrenia for which she is on long-acting injectable risperidone. However, she has not followed up with her psychiatrist for 1 month. She has no other significant past medical history and takes no other medications. The patient begins to attack the nurse and threatens the security guard. She is eventually restrained by hospital staff and is given intramuscular haloperidol. She continues to be agitated and further doses are administered. After the patient is transferred to the psychiatric floor, she becomes progressively agitated and confused over the course of 2 days. Her temperature is 102°F (38.9°C), blood pressure is 140/80 mm Hg, pulse is 120/min, and respirations are 26/min. On physical examination, the patient does not respond to questions and is looking around the room appearing afraid. Pupils are approximately 4 mm in diameter and constrict to 2 mm with light. She is profusely diaphoretic and diffusely rigid. Laboratory studies are shown:

Serum:
Leukocyte count: 15,000/mm^3

Na+: 132 mEq/L
Cl-: 99 mEq/L
K+: 5.3 mEq/L
HCO3-: 18 mEq/L
Blood urea nitrogen (BUN): 15 mg/dL
Glucose: 115 mg/dL
Creatinine: 1.3 mg/dL
Ca2+: 7.3 mg/dL
Aspartate transaminase (AST): 68 U/L
Alanine transaminase (ALT): 72 U/L

Which of the following is the most appropriate treatment at this time?