Dissimilar effects of lithium and carbamazepine on erythrocyte lithium transport in vivo: clinical implications.

The effect of lithium (Li) and carbamazepine (CBZ) on erythrocyte lithium transport in vivo was investigated in 28 patients with affective or schizoaffective illness (14 given Li and 14 given CBZ). In 12 of them, Li or CBZ were added to current psychotropic treatment. The activities of erythrocyte lithium-sodium countertransport (LSC), lithium-potassium cotransport (LPC) and passive lithium diffusion (PLD) were assayed before and after 28 days of treatment. The administration of Li caused a significant decrease of LPC as well as PLD activity. The administration of CBZ resulted in a significant increase of the activity of LPC system. No systematic relationship was observed between Li or CBZ-induced alterations in erythrocyte transport and changes in clinical state of patients. The possible clinical implications of the dissimilar effect of Li and CBZ on erythrocyte lithium transport are discussed.