What is best antibiotic to treat 4th ecoli UTI in 90 year old with slight kidney problem (elevated bun when dehydrated)? Is cipro (ciprofloxacin) ok?

Bacteria have to be sensitive to the antibiotic used or the medication will be ineffective.

Cipro (ciprofloxacin) will be fine if the bacteria are sensitive to it, this can be checked by getting a culture and sensitivity test. Your 90 year old should also be hydrated. She hopefully is not retaining urine, or having an indwelling catheter, both of which would make UTI elimination very difficult. Would you like to video or text chat with me?

Many antiobiotics (including cipro) need to have the dosing adjsuted based on kidney function.

Your doctor will be able to determine the best antibiotic and its dose based on many criteria including allergies, drug-drug interactions, renal and liver function, and bacterial sensitivity. Remember that not every UTI needs to be treated for example - asymptomatic bacteriuria. Would you like to video or text chat with me?

At this point, i'd definitely obtain a culture of urine prior to deciding on the antibiotic choice.

If your e.Colt has not cleared after 3 antibiotic treatments and no culture has been done, it's imperative to get one prior to further treatment. Ciro may be a right choice, but will need to be adjusted to your kidney function. Would you like to video or text chat with me?