What Causes Frequent Urination On Being Diagnosed With Dementia?

My wifes age is 74, and she's between years 7- 8 with dementia or short term memory challenges. She has occasionally struggled with frequent urination, mostly during morning hours, but sometimes throughout the day. Such has been the case the last 5 to 7 days. Her PCP has twice prescribed meds after urinalysis to remove a bacteria found during the test. My question: Is there something we can buy (non-prescribed) that would help promote getting past this untimely interruptive problem? Thanks for your help.