Serum lithium levels and the outcome of maintenance therapy of bipolar disorder

A literature review was conducted to locate studies that compared different serum lithium levels in the long-term treatment of patients with bipolar d isorder and articles about factors that may affect serum lithium levels, Pa tients with bipolar disorder on long-term treatment with lithium are typica lly maintained at serum lithium concentrations between 0.6 and 1.0 mEq/L. A lthough there are individual exceptions, serum lithium levels below 0.6 mEq /L have been shown in controlled clinical trials to be less effective in pr eventing relapses than levels within this range, whereas levels much above 1.2 mEq/L can lead to toxicity. Differences in efficacy between levels with in the accepted range have not been established. However, higher levels are associated with greater side effects, which can lead to poor compliance. I nterindividual variation in pharmacokinetics and pharmacodynamics, as well as such external factors as diet and concomitant medications, can affect se rum lithium levels.