Pentosan polysulfate sodium
"An absolute 10! I use to have the most awkward, painful and random pain when urinating. I could never commit to anything because I never knew if it would happen. Finally I noticed really really hot water helps and alleviates the pain so I actually carried a little campers thing with me. About a year ago, well 2 years ago, I met with this Urologist, probably the 12th for that year. He told me about Elmiron. It is expensive, but if you take it everyday I haven't had the problem since."