Analysis of the pharmacokinetics of lithium in man

Summary

An analysis of the single and multiple dose pharmacokinetics of lithium in 7 healthy volunteers is presented. A solution of lithium chloride was administered in single dose experiments and the same solution and a sustained release preparation were employed in multiple dose experiments, which were carried out at steady state. A fixed dose of 24 mmol was used in the single dose experiments and in the subsequent multiple dose experiments in the same subjects the same dose was administered once daily for a week. Distinct two-compartment characteristics were found, with a mean disposition rate constant (β) of 0.035 h⁻¹±0.010 SD, corresponding to a mean biological half-life of about 19.8 h. The mean half-time of the distributory α-phase was about 1.15 h. The absorption of lithium from an orally administered solution took place with a half-time of about 0.15 h in the single dose experiments. The apparent volume of distribution of the central compartment (V_c) was 0.307 1 kg⁻¹±0.046 SD, less than half that of V_de at equilibrium. V_dβ (V_darea) was 0.8291 kg⁻¹±0.184 SD and mean total body clearance was 27.6 ml kg⁻¹ h⁻¹±4.7 SD.