Lithium effects: relation to lithium dose and to plasma peak levels.

In a 24-hour study, plasma peak lithium was determined in manic-melancholic patients who routinely had their entire lithium dose at night. A correlation analysis was undertaken of the relation of plasma peak level and the dose of lithium to a number of lithium induced changes: Increase in urine volume, weight gain, decrease in plasm phosphate, increase in plasma magnesium, decrease in plasma urea, increase in plasma alkaline phosphatase, increase in urinary pH. Only the changes in plasma phosphate and in urine pH were significantly correlated to the peak value of plasma lithium. The increase in urine volume was significantly correlated to the dose of lithium.