[Side effects and risk profile of lithium: critical assessment of a systematic review and meta-analysis]

Lithium is the only drug that obtained the highest level of recommendation for maintenance therapy in the recent German S3 guidelines on bipolar disorders. In addition it is the only drug with proven efficacy for the prevention of manic as well as depressive episodes in studies with a non-enriched design. Therefore, it is highly welcomed that The Lancet recently published a systematic review and meta-analysis on the risks and side effects of lithium. This is the most comprehensive review on this topic so far.The glomerular filtration rate and maximum urinary concentration ability are slightly reduced under lithium. More patients suffered from renal failure compared to controls; however, renal failure remains a very rare event. The review confirmed the well known suppressive effects of lithium on the thyroid. An increase of serum calcium could be observed relatively frequently, therefore, regular control of serum calcium under lithium therapy is recommended. A relevant increase in body weight is more frequent under lithium than under placebo but less frequent than under olanzapine. No statistically significant increase could be found for hair loss, skin disorders or major congenital abnormalities.Lithium treatment is a safe therapy when clinicians follow the established recommendations. Data indicate that a risk for renal failure exists especially in patients without regular monitoring or with too high lithium serum levels. A (subclinical) hypothyroidism is not an indication to stop administration of lithium but is an indication for l-thyroxin substitution therapy. In pregnancy the risks of continuing lithium should be balanced against the risks of stopping lithium together with the patient.