Thanks for the supportive replies folks.
It's now been almost 2.5 days since having my first (and hopefully last) TURBT that included the intravesical instillation of Mitomicyn-C (MMC). I was prescribed phenazopyridine as needed for pain and cyprofloxacyn, an antibiotic. The phenazopyridine was especially helpful, especially during the first 36-48 hours. Urinating went from an excruciatingly painful experience (on all 4s at one point) to being barely tolerable during that period. Otherwise I felt perfectly fine. I've been drinking water as if I were being paid for each ounce consumed and I'm happy to report that today the burning has subsided considerably and I almost welcome the experience. Only a few small flecks of blood are visible as as my bladder is being flushed with each visit to the toilet.
As I wrote recently, I awoke from surgery to find, or be told of, a clamped catheter preventing the instilled MMC from going anywhere but where it needs to be (in my bladder). The rigid resistance of a clamped catheter was most painful. I did some reading today and learned of a novel technique purported to improve patient comfort during intravesical instillation of MMC. By elevating the urine bag above the supine patient, MMC can be retained in the bladder by hydrostatic pressure. Has anyone else experienced painful instillation or experienced the process using the "hey, why don't you unclamp the tube and lift the bag" technique?
My best to all.