<<Disclaimer: Verify this information before applying it to your situation.>>

My understanding is that it is the responsibility of the pharmacist to
acced to reasonable requests regarding the compostion of the
medications.  I have never heard of this response.  Pharmacists by and
large are very customer/patient oriented.  I would probably not go back
again.

You can ask the doctor to write on the script for gluten free, but that
will not substitute for the patient making the pharmacist aware of the
specific issues involved.

The appropriate question is " Is ther any derivative of wheat , barley
Rye or oats in the pill? "  not "is it gluten free?
There is some literature on gluten reactions because of medications
contaminated.

Not medical advice
Joe Murray