I have a 44oz cup that I use for mine. Otherwise measuring would be impossible... but I had to ask my pdoc if it was possible I could be unintentionally flushing with all that water... he said if you're thirsty, drink it. I know at work, the water pitcher is constantly empty... so we're not alone. I think most of these meds do it to most of us. Especially the ones that alter the endocrine system or are processed by the kidneys...