A 72-year-old woman who has smoked 20 cigarettes daily for the past 38 years begins using eye drops for glaucoma. Three days later, she has a marked increase in shortness of breath while walking up…

A 72-year-old woman who has smoked 20 cigarettes daily for the past 38 years begins using eye drops for glaucoma. Three days later, she has a marked increase in shortness of breath while walking up a flight of stairs. Which of the following drugs is the most likely cause of the development of shortness of breath in this patient?