Long-Term Lithium Treatment Has Risks for Kidney Function, Even with Precautions
Long-term lithium use has long been associated with decreased renal function. But some Swedish researchers noticed that most long-term studies of patients with renal failure had begun in the 1960s and 1970s. In the 1980s, when it became clear that lithium could reduce renal function, doctors began to institute new safety measures for lithium users, including monitoring of blood levels of the drug and of creatinine, a substance that is excreted by the kidneys as part of normal muscle metabolism. So the researchers undertook a new study to examine whether the protocols instituted in the 1980s had reduced the renal risks of long-term lithium use. Unfortunately, they found that some reduced renal function is still common among people who use lithium for longer than 10 years, and this risk does not necessarily decrease when patients stop taking lithium.
The researchers, led by Harald Aiff, published the study in the Journal of Psychopharmacology in 2015. They identified 4,879 patients who had been prescribed lithium, and narrowed this list down to 630 adult patients who had taken lithium for at least 10 cumulative years, who had normal levels of creatinine when they began taking lithium, and on whom good data existed. About one-third of these patients had evidence of chronic renal impairment, and in 5% of these the impairment was severe or very severe.
Aiff and colleagues’ findings show that lithium treatment requires careful monitoring, especially over the long term. Patients must consider the risk/benefit ratio of lithium treatment. Since prevention of mood episodes can preserve an average ten years of life expectancy, and lithium has the best data for efficacy in preventing manic and depressive episodes, patients must weigh the risks of insufficiently treated bipolar illness against the possibility for long-term decreases in kidney function.