Serum drug level monitoring in affective disorders

Abstract

This study surveyed serum level monitoring of lithium and carbamazepine in three psychiatric hospitals, to determine how the service is used with respect to affective disorders. The monitoring of lithium serum levels appears to be carried out in relatively close adherence to recommended guidelines. Carbamazepine serum levels are monitored with a similar frequency to lithium, despite the lack of an established therapeutic window for indications other than epilepsy. Changes in drug therapy, which are consequent upon monitoring of serum drug levels, occurred after only 7.5% of lithium and 13.7% of carbamazepine samples. Changes were made independently of serum level results with greater frequency in carbamazepine-treated patients, although less frequently with lithium-treated patients. Adverse consequences of such changes occurred only once, involving lithium. More research is needed to determine the potential benefits of carbamazepine serum level monitoring in affective disorders because the service appears to be overutilized at present.