Why is caffiene bad for lithium patients?

Dehydration: The main concern with lithium is to keep your lithium level stable-the main way to ensure that is to take the med consistently and to keep your body's level of hydration consistent as well. One does that by drinking adequate amounts of non-caffeinated, non-alcoholic fluids and not peeing them out immediately because of diuretics or too much sweating. As a diuretic, caffeine can cause dehydration.

Caffeine and Lithium: High quantities of caffeine can increase your body's elimination of lithium, making a given dose less effective. If you're going to use caffeine, keep the quantity stable so that your lithium blood level remains stable too. http://tinyurl.com/n2mhrs5.

Caffeine/Lithium: High amount of Caffeine induces more diuresis & hence lowers Lithium levels.