The pharmacokinetic profile of lithium in rat and mouse; an important factor in psychopharmacological investigation of the drug.

The pharmacokinetic characteristics of lithium and the profile of plasma lithium concentration at steady state in both the mouse and the rat have been determined. The half life of lithium in both rodents was shorter (3.5 h and 6 h) than that found during maintenance therapy in man. Following a loading dose (10 mmol/kg s.c.) and twice daily maintenance injections (3 mmol/kg s.c.) of lithium chloride the plasma concentration remained above the accepted human therapeutic minimum (0.4 mM) for 16 of every 24 h in the mouse and throughout the entire 24 h period in the rat. Maximum concentrations in both species were below the range at which toxic effects might be expected to occur.