A 25 year old man returns to the ED, 24 hours after being released from the hospital with a new diagnosis of schizophrenia. He has recently started to take haloperidal for his psychotic symptoms. In the ED he is noted to have involuntary contractions of the muscles of the face, a protruding tongue, deviation of the head to one side, and sustained upward deviation of the eyes. Vital signs are stable, and initial labs show no electrolyte or hematological abnormalities. Of the following choices, the preferred medication for this condition is ________.
1) diphenhydramine
2) lorazepam
3) phenobarbital
4) metoprolol