| Rob: Have you had any problems with congestive heart failure that you know of? A lot of times, people who have this problem are put on a diuretic such as HCTZ to keep fluid from building up around the heart, thus making it work harder to pump. Have you had swelling in your extremities? Also, the urology group I work for puts people with a history of kidney stones due to increased sodium levels on HCTZ to make them empty more and not have such a sodium build-up that kidney stones form.
No matter what the reason you're on it, you shouldn't be urinating that many times a day.
Also, how're your potassium levels? Losing fluid that quickly could deplete your potassium and cause problems as well (hope I didn't miss this info in a previous post). | 
