I'm on my third month of Phentermine 37.5 under a physicians supervision. My only side effects are dry mouth and, of course, no desire for food. I try to get at least 1000 calories in a day and so far I am very pleased with the results (down 35 lbs in 3 mos). I keep reading that you must drink a lot of water with this drug and I'm wondering why the water is always emphasized. I get a lot of liquids daily (coffee, iced tea, diet coke, water, etc) but want to be more informed about the emphasis on "lots and lots of water" daily. How much and why?