Are the renal effects of lithium modified by frequency of administration?

It has been claimed that the unwanted effects and toxicity of lithium can be minimized by changes in the dosing schedules. Twenty consecutive psychiatrically stable patients were investigated in a cross-over study to determine whether renal function and other biochemical tests change significantly with changes from once to twice or multiple doses per day or vice versa. There were no significant differences between the 3 study conditions on the mood rating scales or a side effect scale (UKU). Urine volume, test of renal function and other biochemical and hematological indices were similar in all study conditions. We thus conclude that dosing strategy does not consistently affect renal function in lithium-treated patients.