tl;dr - don't need to worry about urinary tract issues unless you're using the drug (1) recreationally; (2) irresponsibly
So you feel like you need to piss regularly, but only a few drips come out. The damage can get so severe bladder gets removed.
At the lesser end of the damage is agonising stomach cramps, no idea what the cause of this is.
source: spent too long in the uk freeparty rave scene when ketamine was legal and people assumed it was completely safe due to lack of come down. Too many people ended up with severe ketamine addictions and many have to know piss through a bag
Also, it's much much cheaper on the black market than ketamine. We're talking around 1000 (recreational) doses for $20. Compared to say 10 (recreational) doses of ketamine for maybe $50?
What is it like to still be living in 2014? MXE hasn't been manufactured in any significant quantity since China banned it years ago. The stockpiles that remained have been stretched out at high prices and have significantly degraded over the years, people are reporting needing 2-3x the previous dose.
MXE does have the same bladder issues, but is taken as a smaller dose so it takes longer to happen.