Janie is 20 years old with severe, prolonged 2 to 3 day migraines twice per month. She also has mild chronic tension headache (CDH). She has difficulty sleeping and is mildly anxious. She occasionally utilizes an inhaler for asthma. With only two migraines per month and mild CDH, a case could be made against prevention medication. However, with the severity and length of julie's migraines (4 to 6 total days of severe migraine per month), prophylactic medications are indicated. What medication would you expect the provider to prescribe?