Studies of lithium pharmacokinetics in patients with affective illness.

Lithium pharmacokinetics after a single dose and pharmacokinetic prediction of optimal lithium carbonate dose in steady-state, were investigated in 15 patients with affective illness. In nine patients the course of plasma concentration after a single dose was characteristic for two-compartment and in six patients for one-compartment model. Patients fitting the two-compartment model required higher daily lithium dose to achieve steady-state therapeutic lithium level than patients fitting the one-compartment model. A significant correlation was found between plasma lithium level 12 and 24 h after a single dose and the daily dose required for achieving optimal lithium level in the course of subsequent lithium administration.