Intensive treatment with lithium carbonate "once a day" in bipolar patients

Lithium carbonate is the treatment of choice in the prevention of recurrences of bipolar mood disorders. The aim of this study is the evaluation of the pharmacokinetics of a new lithium compound to be administered "once a day", with a half-life of 32.4 hours. The present study investigates plasma lithium levels in patients treated with the novel vs. standard preparation of lithium carbonate to assess whether the new preparation may be associated with lithium plasma accumulation. The authors studied twenty-two bipolar patients whose standard lithium treatment was replaced by the new one. The total duration of the new treatment was 57 days. During this period, lithium plasma levels were monitored 7 times, 12 hours post-lithium administration. Lithium plasma level 24 hours following administration was evaluated in seven patients. The average dose of "once a day" lithium was 821 (+/- 250) mg/day, the corresponding plasma level was 0.45 (+/- 0.11) mEq/L, and the dose (g) to plasma level ratio was 1.96 (+/- 0.66). Differences between average lithium plasma levels at time T1 and successive times were not statistically significantly. Moreover, the average lithium level at 12 hours after lithium administration was not different from that after 24 hours (0.45 +/- 0.11 and 0.47 +/- 0.0.29 respectively). These results demonstrate that the new preparation, "once a day", maintains steady lithium plasma levels during our times of observation without accumulation in body fluids and tissues. "Once a day" lithium carbonate appears to be a useful alternative to the standard preparation, and may potentially improve treatment compliance by simplifying patients' medication.