[Lithium treatment and potential long-term side effects: a systematic review of the literature]

Lithium is recommended by all treatment guidelines for bipolar disorder (BD) as a first-line maintenance treatment. However, the potential side effects and risks associated with long-term lithium use may at times make the implementation of these recommendations in daily practice challenging. The aim of the study is to review available literature on potential long-term side effects of lithium.

A PubMed/Medline search was performed on papers dealing with long-term treatment with lithium and side effects. Articles published from January 1980 to February 2013 were selected.

Long-term lithium treatment is associated with a reduced urinary concentrating ability, with subsequent polyuria and polidypsia and nephrogenic diabetes insipidus (in 10-40% of patients). Lithium also reduces glomerular filtration rate, and increases risk of renal failure, although the absolute risk is small (0.5% of patients). Lithium treatment is associated with significant higher TSH levels, with a 6-fold greater risk of hypothyroidism in lithium-treated than in control subjects. Less known is the increase of PTH and calcium levels induced by lithium. An exacerbation of psoriasis is also frequently associated with lithium treatment.

Lithium remains a fundamental tool for the treatment of BD. Clinicians should know potential side effects (renal, endocrine and dermatological) associated with long-term treatment with lithium, for a correct management of the patient. A specialist referral is often necessary; the question is how to deal with long-term side effects more than whether or not withdrawing lithium. This decision should remain a psychiatrist's competence.