Comparison of plasma lithium levels and their interindividual variations with coated lithium carbonate tablets and a medium-slow-release lithium sulphate preparation (Lithionit Duretter).

In a cross-over study in 10 subjects, rapidly dissolving coated lithium carbonate tablets and medium-slow-release lithium sulphate tablets were compared. Both preparations were administered twice a day. They gave similar post-absorptive concentrations of lithium in plasma and similar standard deviations of these concentrations. The medium-slow-release tablets gave smaller increases of lithium in plasma, and postponed the absorption peaks. They also gave less interindividual variation of lithium in plasma during the first few hours after administration.