Concern about mom, ER or not ER?

I called mother to check on her this morning, pretty much like I always do, but especially because she was not feeling well yesterday, when she was extremely fatigued and cold not feeling like her normal self.  Monday I had taken her to the doc for a check up and he started her on Cirpro, one-half tab every morning as preventative treatment for UTI.

What's concerning is when I called her today she was relieved that I called because she has been unable to call anyone because she has forgotten everyone's phone numbers.  She has forgotten all of the names of her medications, too.  I had my sister in law (cuz she lives a block from mom) go over there and count all of her pills.  She had taken three of the halves of the Cipro and I told her to have her stop taking that right away.  That was the only new med that she had been started on.  Also, she had not taken any of her narcotics for pain, mostly because she didn't know where she had put the newly filled Rx in the house.  I had her doc paged; I'm waiting on a return call.  Could an allergic reaction cause this level of confusion?  I'll give her until morning, then I do believe I'm getting her to an ER.