Influence of age on lithium therapy.

Contradictory information exists with respect to lithium dosage in elderly patients with affective disorders. To determine the relationship between age and lithium blood levels, we studied 66 outpatients in stable condition and receiving maintenance lithium therapy. The salient question was whether the same dosage of lithium will produce similar blood levels in both old and young adults. Our results revealed no significant correlation between age and dosage. The data suggest that the dosage of lithium required to maintain a therapeutic blood level is the same regardless of age. We therefore suggest that lithium therapy be individualized according to the total clinical picture rather than chronologic age.