High level of lithium exposure linked to kidney damage

ACUTE kidney damage may develop among people with bipolar disorder receiving lithium treatment, according to a new research from the University of East Anglia (UEA) and Norfolk and Suffolk NHS Foundation Trust. 

The recent finding highlights the need for careful monitoring of these patients. Lead researcher Emma Kirkham from UEA’s School of Pharmacy said that the analysis shows for the first time that a single exposure to a lithium level greater than 1.0mmol/L is linked to an increased risk of kidney function impairment in the following three months. She added that the higher the level of lithium given, the greater the effect on the kidney.

Regular monitoring should then be undertaken at least every three months. It should not be reduced until the impact of more than one high-level of lithium has been fully established. 

A mainstay treatment for bipolar disorder, the lithium drug is known to cause a loss of kidney function. The new research establishes the link between short-term exposure to high levels and potential damage to the kidneys. The impact on kidney functions of more than a single exposure to high levels of lithium is still unknown, and the Norfolk team is currently studying the effects of multiple exposures to high lithium levels.

The study involved an analysis of 699 Norfolk people registered on the Norfolk SystemTDM database who have received lithium over the past 10 years. Researchers from UEA's School of Pharmacy and Norwich Medical School and pharmacists at Norfolk and Suffolk NHS Foundation Trust undertook a retrospective analysis of the data. Norfolk’s county-wide lithium database and register, which has been active since 2002, has significantly improved rates of lithium testing and monitoring. It has enabled NHS services in the county to exceed national standards of care for people taking lithium. 

The study measured kidney function in the three months following detection of greater than 1.0mmol/L of lithium compared to people who received lithium levels not exceeding 0.8mmol/L. The findings show that a single high level of lithium (greater than 1.0mmol/L) leads to a substantial decrease in filtration by the kidneys. The effect on kidney function lasted up to nine months after exposure to a high level of lithium. 

Professor Steve Bazire, consultant pharmacist at Norfolk and Suffolk NHS Foundation Trust, said that the recent findings challenge the safeness of less frequent testing of lithium. He said the level of care provided in Norfolk to patients taking lithium should be the norm across the country rather than the exception.