Review Question - QID 108999

A 23-year-old man presents to the emergency department. He was brought in by police for shouting on a subway. The patient claims that little people were trying to kill him and he was acting within his rights to defend himself. The patient has a medical history of marijuana and IV drug use as well as multiple suicide attempts. He is currently homeless. While in the ED, the patient is combative and refuses a physical exam. He is given IM haloperidol and diphenhydramine. The patient is transferred to the inpatient psychiatric unit and is continued on haloperidol throughout the next week. Though he is no longer aggressive, he is seen making "armor" out of paper plates and plastic silverware to defend himself. His temperature is 98.6°F (37°C), blood pressure is 115/71 mmHg, pulse is 72/min, and respirations are 12/min. The patient's treatment history is significant for failure to obtain symptom control with risperidone, haloperidol, and ziprasidone. Which of the following is the most appropriate next step in management?