If you're a pharmacist or pharmacy technician, this will make perfect sense to you.
People, for whatever reason, feel the need to add extra words to their request or statement. Example:
"Where's the non-drowsy Claritin-D?"
Sometimes they feel the need to stress the "non-drowsy" part of their sentence. And when you try to explain to them that there isn't a drowsy version, they just look at you like you're pulling a fast one on them. I think it might be the power of advertising... a TV ad which tells the views to "Ask for the non-drowsy Zyrtec-D at your pharmacy counter!" so that's exactly what they do. Have we become so dumb-downed in our society that everything must have a clarifying adjective added?
It just sounds stupid on our end. It would be like asking:
"Where's your pain-relieving Tylenol?"
Oh, that's right next to the non-pain-relieving Tylenol.
"Do you have any vitamin-containing supplements?"
Yes, it's on the aisle with the placebo vitamins.
"Where are your sterile band aids?"
We keep them separate from the non-sterile band aids to prevent contamination.
And all this makes perfect sense... until you get this question, which I did yesterday:
"Where's the non-drowsy Benedryl?"