An updated review of the optimal lithium dosage regimen for renal protection.

OBJECTIVE: Despite several decades of research, there is still uncertainty regarding the optimal lithium dosage regimen associated with a decreased risk of renal effects, such as polyuria, in patients with bipolar affective disorder. We present an updated review of the literature to provide an informed dosing regimen recommendation for prescribers.

METHOD: Major databases MEDLINE and Embase were searched using terms, such as lithium, drug administration schedule, dose-response relationship, once daily, twice daily, and sustained release. In addition, the bibliographies of related publications were manually searched.

RESULTS: A total of 20 trials were included. Some trials showed a reduction in urine volume with single daily dosing (SDD), while others showed no change. The only trial evaluating patients newly started on lithium found a reduction in urinary frequency with SDD after 21 days. Trials examining renal biopsy results found that multiple daily doses were associated with more pathologic damage to the kidneys. SDD regimens were generally well tolerated, and no reduction in efficacy was noted in any of the trials.

CONCLUSIONS: The available evidence is contradictory as to whether SDD of lithium reduces polyuria; however, no trial has demonstrated any downfall of SDD in terms of prophylactic efficacy or adverse effects. Given the added benefits of SDD, such as improved compliance, we recommend patients newly started on lithium should be converted to a SDD of lithium at bedtime once an appropriate daily dose is determined.