Serum lithium levels and side effects during administration of lithium carbonate and two slow release lithium preparations to human volunteers

Summary Lithium carbonate, two slow release lithium preparations or placebo tablets were given to ten healthy volunteers for periods of eight days, and the lithium concentration in serum and subjective side effects were determined at various time intervals. A single blind randomized cross over design was used for the experiment. High peaks of the lithium concentration in serum occurred a few hours after administration of lithium carbonate. Slow release preparations produced more constant lithium concentrations in most subjects. — Subjective symptoms were more common after lithium preparations than after the placebo. Symptoms like nausea and general fatigue seemed to increase in frequency during the treatment periods and to be related to a high lithium level in serum. Tremor occurred in only two subjects with low serum lithium concentrations and, usually appeared from the first day of administration. One of the slow release preparations, which contained lithium sulfate, caused a high frequency of diarrhoea, which was presumably due to the release of lithium or sulfate ions in a lower part of the gastrointestinal tract.