A DOUBLE-BLIND, FIXED BLOOD-LEVEL STUDY COMPARING MIRTAZAPINE WITH IMIPRAMINE IN DEPRESSED IN PATIENTS

Antidepressant effects of mirtazapine and imipramine were compared in a randomized, double blind, fixed blood-level study with in-patients i n a single centre. Patients with a DSM-III-R diagnosis of major depres sion and a Hamilton (17-item) score of greater than or equal to 18 wer e selected. After a drug-free and a placebo-washout period of 7 days i n total, 107 patients still fulfilling the HRSD criterion of greater t han or equal to 18, started on active treatment. The dose was adjusted to a predefined fixed blood level to avoid suboptimal dosing of imipr amine. Concomitant psychotropic medication was administered only in a few cases because of intolerable anxiety or intolerable psychotic symp toms. Eight patients dropped out and two were excluded from analyses b ecause of non-compliance; 97 completed the study. According to the mai n response criterion (50% or more reduction on the HRSD score) 11/51 ( 21.6%) patients responded on mirtazapine and 23/46 (50%) on imipramine after 4 weeks' treatment on the predefined blood level. Such a dramat ic difference in efficacy between antidepressants has not often been r eported before. The selection of(severely ill) in-patients, including those with suicidal or psychotic features, may have significance in th is respect. Optimization of treatment with the reference drug imiprami ne through blood level control, exclusion of non-compliance for both d rugs, exclusion of most concomitant medication and a low drop-out rate may also have contributed. It is concluded that imipramine is superio r to mirtazapine in the patient population studied.