Objectives: The use of rapid lithium dosage administration, a strategy that could lead to rapid improvement in mania, has been largely unexamined. In this open-label, pilot, acute-treatment study, we sought to determine the safety and tolerability of lithium administered at 20 mg/kg/day. A secondary aim was to provide preliminary data regarding the efficacy of this strategy in ameliorating manic, depressive, and psychotic symptoms.
Methods: Fifteen patients hospitalized with DSM-IV bipolar disorder, manic or mixed, and who provided written informed consent, received lithium 20 mg/kg/day for up to 10 days. Patients were evaluated for adverse effects daily. Lithium levels were obtained on days 2, 3, 4, 5, 7, and 10 or at study termination. Electrocardiograms (EKGs) were performed at baseline and on days 1–5, 7, and 10 or at study termination. Symptomatic improvement was assessed daily using the Young Mania Rating Scale, 24-item Hamilton Depression Rating Scale, and the Scale for Assessment of Positive Symptoms (SAPS).
Results: Five of the 15 patients completed the 10-day study period. Two patients dropped out due to adverse events. Seven patients did not complete the inpatient trial because of improvement sufficient to allow hospital discharge. All patients achieved serum lithium concentrations ≥0.6 mEq/L after 1 day of treatment; the mean±SD concentration on day 5 was 1.1 (±0.1) mEq/L on day 5. There were significant reductions from baseline to endpoint on all rating scales, except the SAPS bizarre behavior subscale.
Conclusions: These pilot data suggest that lithium 20 mg/kg/day was well tolerated and that this strategy may produce rapid improvement in affective and psychotic symptoms. These impressions require confirmation in double-blind, randomized trials.