As a retail pharmacist, I agree this can be an annoying problem. I try to encourage single-ingredient generic products as much as possible. And yes, "brand extension" as they call it has rendered popular names like Mucinex and Robitussin useless or even downright harmful. I think many people just look for something with "severe cold" or whatever without even considering what's in it.

It's not just patients either. Some OTC products are covered by some insurance plans. I've had prescribers change from one OTC product to another that shared none of its ingredients with the first. Not sure what they were treating other than "patient wants a prescription".

And don't get me started on homeopathic products. I had a man come in once with the box of a homeopathic product looking to buy more for his wife. I looked around, showed him a similar product, and asked if this was OK. He said it was as long as it worked as well. That I could guarantee!

I do try to dissuade such purchases, but when the customer comes in knowing what they want, it's often a losing battle. The one time homeopathic products can be useful is when someone just has to have something to treat their two-year-old's cold.