[Lithium Treatment and Potential Long-term Side Effects: a Systematic Review of the Literature]

Introduction And Aim: 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.

Materials And Methods: 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.

Results: 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.

Conclusions: 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.