Polyuria/polydipsia was always an issue for me on Lithium. It never eased, unfortunately. As annoying as these things seem to be, it's not a good idea to try to limit your beverage consumption. Drinking a lot of liquids, preferably a lot of water, is good for keeping the kidneys healthy. Kidney issues on Lithium are not that common, but they are a known possible problem for some. I ended up having to go off of Lithium because of kidney damage. My creatinine level, which should be tested periodically along with Lithium levels, was getting high.

Some people say that they have few, if any, side effects from Lithium, especially at low doses. However, many of us have a number of them, especially at therapeutic levels. I took either 1200 mg or 900 mg for all of the time I was on it (a total of 6.5 years or so). I put up with the side effects, but I really experienced many. I didn't have weight gain or water retention, like some people, but I did end up with 8 different side effects total, including the polyuria/polydipsia. Though other medications' side effects might have been even worse, no other medication gave me so many as Lithium. Note: Some of my Lithium side effects were eased by adding medications for them, or just getting through adjustment periods. Others were unstoppable. Compared to other people I've encountered on bipolar support groups, I was extremely tolerant and patience when it came to side effects.