Lithium has been standard drug therapy for bipolar disorder over the last 25 years. It is an alkali methal that shares many properties with sodium and potassium. Adverse effects involving multiple organ systems are common and require careful patient monitoring throughout treatment. Mild gastrointestinal upset, fine hand tremor, and muscle weakness may occur transiently during initial therapy, but they usually subside and are generally tolerated. Cognitive dulling and weight gain may be more problematic. Other adverse events associated with chronic lithium treatment (e.g., thyroid and renal dysfunction, toxic serum levels) can be serious but are usually prevented by vigilant monitoring and appropriate intervention.

        Key words: lithium, bipolar disorder, alkali metal, cognitive dulling, weight gain.