[Lithium balance in healthy volunteers]

Lithium sulphate in a sustained-release preparation was given to three healthy volunteers during 10 days. The following results were obtained: 1. The daily requirement needed for maintenance of an efficient lithium serum level from 0.7 to 0.8 mmol/l amounts to 30 mval. A steady state level of the serum lithium concentration was achieved after 4 to 5 days. 2. The mean value of lithium clearance amounts to 26.8 ml/min. 3. Approx. 98% of the ingested lithium could be recovered from the urine. 4. 6 days after drug withdrawal the lithium concentration in serum and urine was determined as 0. This result shows that the study of lithium balance can rely on renal excretion excluding other pathways. It is discussed that the simultaneous ingestion of psychortropic drugs and sodium chloride may influence the elimination rate of lithium.