What you brought up here is a reminder to those who have elderly parents or relatives who are on various and usually many medications to double check on what they are taking and for what purpose. The older generations tend to follow like sheep what the doctor prescribes for them and are not mindful of generic substitutes or how that works. Your Pharmacist is supposed to be one of our first defenses against wrong medications and can be if we ASK questions.
PS: This also includes any substitutes for your dependent children.