Plasma levels and clinical response during treatment with clomipramine

The plasma levels of clomipramine (CI) and its major metabolite desmethylclomipramine (DMCI) may be related to clinical response during treatment of depression. Not all workers have been able to demonstrate such a relationship. The many factors which may affect clinical response include sample selection, assessment and its quantification and kinetic factors. A further investigation into the relationship between plasma levels and response was, therefore, carried out taking these into account and attempting to control them. Sixty-two patients with depressive illness were included. The plasma levels of CI + DMCI as measured on the 28th day of treatment were correlated against clinical response at the time. Patients with the highest combined plasma levels showed the best response. Patients with intermediate plasma levels showed more modest response, whilst lowest plasma levels tended to be shown by patients who exhibited an inadequate response or who relapsed during subsequent outpatient follow-up. The threshold value for satisfactory antidepressant effect appeared to be a combined CI + DMCI plasma level of 160-200 mg/ml.