What Are The Side Effects Of Taking Lithium?

I am really nervous about taking Lithium for the first time tonight, The only mood stabilizer I have take is Citalopram, and I have been off of that for a while now. I don t know what to expect. They told me to take it right before I go to sleep. I am just nervous because I don t know what to expect from it. Is there anything I should be really worried about? I am starting at 150 Mg