A 30 year old woman arrives at the ER with intermittent pain on one side of her fact, near her jaw, brought on when brushing her teeth. She has a history of facial pain buth says that today it was like being stabbed with a dagger over and over for a full minute. She has no dental issues and reports no injury that would account for the pain. She struggles visibly when speaking and asks for opiod therapy. Which medication would most likely improve her discomfort?