When you first start taking lithium, you may experience tiredness, thirst, urinating more frequently, drowsiness, weight gain or mildly shaking hands. As your body adjusts to lithium, these should go away, but if they continue or get worse, talk to your doctor and pharmacist as soon as possible.

Less common side effects can be serious. Tell your doctor immediately if you experience diarrhea, fever, dizziness, vomiting, confusion, blurred vision, slurred speech, severe trembling of the hands, or...