Neurotoxicity in elderly patients being treated with lithium: is there a reason to adjust the dosage administered?
background Neurotoxicity can occur in patients being treated with lithium. Features are cognitive dysfunctioning and motor symptoms. Some results of research performed on adults up to the age of 65 indicate that lithium can cause mild cognitive dysfunctioning. It is not clear, however, whether elderly patients are more susceptible than young adults to this form of neurotoxicity or, if this is the case, whether the dosage of lithium should be reduced.
aim To determine whether elderly patients treated with lithium run an increased risk of neurotoxicity, and to discuss the pharmacodynamic aspects of lithium use in the elderly which may cause neurotoxicity.
method Literature review in Cochrane (all ebm), Embase, Psycinfo, Medline and PubMed, with cross-checked references.
results Few studies described possible neurotoxic effects of lithium. We found no indications for cognitive dysfunctioning in elderly patients being treated with lithium. However, a lithiumassociated tremor was seen more often in elderly patients than in younger adults. Pharmacodynamic effects of aging, such as an increase in the lithium concentration in the brain with no change in the serum level, may give rise to side-effects. More research is needed into the relationship between the serum level and the neurotoxic effects of lithium in the elderly.
conclusion There are no indications that lithium causes more neurotoxicity in the elderly than in younger adults. If the use of lithium is indicated, it can be safely prescribed for the elderly, provided age-related pharmacodynamics are taken into account.