For the past year, the patient has had episodes of severe nausea, vomiting, headache, and abdominal pain separated by weeks of feeling quite well.
A 23-year-old woman is referred for intermittent episodes of nausea and vomiting she has experienced for the past year. She cannot relate her symptoms to anything in particular, although at times she wonders if food may be a trigger. She states that the nausea appears to start abruptly, followed by hours of vomiting. On occasion, she also describes generalized moderate to severe abdominal pain without any change in her stools. After these episodes, she reports feeling well for several weeks. Her examination is unremarkable and resutls of her basic chemistry lab studies are normal.
Further inquiries should be made into the patient’s use of which of the following drugs because it is associated with her condition?