Plasma prolactin during lithium treatment.

Plasma prolactin was determined in a longitudinal study, where -9 manic-depressive patients were examined before lithium treatment and at various times during the treatment with the aim of unravelling a possible association between initial changes in water and sodium balance during lithium treatment and changes in plasma prolactin level. No significant changes were found, nor could any correlation between serum lithium and plasma prolactin be established. Some reports have indicated association between breast cancer and prolonged elevated plasma prolactin, such as is seen during treatment with phenothiazines and reserpine. In a transversal study, determination of plasma prolactin during long-term lithium treatment in 26 patients did not reveal any elevation compared with 16 controls. Lithium is accordingly not among the drugs which produce prolonged elevation of plasma prolactin.