Review Question - QID 109010

A 32-year-old man presents to his primary care provider for a headache. He reports that he has headaches at night several times a week. He first developed these headaches over 1 year ago, but they started up again 3 weeks ago. The episodes start suddenly and feel like a stabbing, electrical pain over his left eye. He also reports tearing of the left eye during these episodes. The headaches self-resolve over the course of 2-3 hours, but the patient complains that he is avoiding going to sleep for fear of waking up in pain. His medical history includes type 1 diabetes mellitus and an episode of herpes zoster on his right flank 1 year ago. His only home medication is insulin. His temperature is 98.6°F (37°C), blood pressure is 112/69 mmHg, pulse is 61/min, and respirations are 14/min. On physical exam, his extraocular muscles are intact and his eyes are not injected. A CT of the head and sinuses shows no acute abnormalities. Which of the following is most likely to prevent future episodes of headache in this patient?