Q. A 32-year-old woman comes to the clinic because of dizziness, headache, nausea ,and two episodes of vomiting for the past 2 hours. She has been in Mexico for the past three days and she was on the airplane when the symptoms developed. She has a history of migraine, and she uses NSAIDs to manage the attacks. Her vital signs are within normal limits. Clinical and neurologic examinations are normal. Which of the following could have been used as a prophylactic agent for this condition?