PHARMACOECONOMIC ANALYSIS OF VENLAFAXINE IN THE TREATMENT OF MAJOR DEPRESSIVE DISORDER

We conducted a cost-effectiveness analysis of acute major depressive d isorder (MDD) using serotonin-norepinephrine reuptake inhibitors (SNRI s; venlafaxine), selective serotonin reuptake inhibitors (SSRIs; fluox etine, fluvoxamine, sertraline, paroxetine), or tricyclic antidepressa nts (TCAs; amitriptyline, imipramine, desipramine, nortriptyline). A d ecision-tree model over 6 months was constructed using an expert panel . The analytic perspective was that of the Ontario Ministry of Health as payor for all direct costs, which were derived from standard lists and included the cost of the drug as well as those for medical care, l aboratory services, hospitalisation and managing adverse events. Succe ss and dropout rates were determined from a meta-analysis of published randomised controlled trials. Medline, Embase, and International Phar maceutical Abstracts were searched from 1984 to 1996, as were referenc es from retrieved articles and reviews. Inpatients and outpatients wer e analysed separately. SSRIs were used as backup therapy for patients receiving venlafaxine and TCAs, and SNRIs were used as backup therapy for patients receiving SSRIs. Pharmacoeconomic outcomes were expected cost per success, expected cost per symptom free day (SFD), and increm ental cost per success and per SFD. The meta-analysis identified 56 tr eatment arms from 36 randomised controlled trials involving 2953 patie nts (2380 outpatients and 573 inpatients). SNRIs had the highest succe ss rates. The respective costs (in 1996 $Can; $Canl = $US0.74) for out patients and inpatients are given below. The expected costs per succes s were $6044 and $17 234 for venlafaxine, $6634 and $20 874 for SSRIs, and $9035 and $20 459 for TCAs in outpatients and inpatients, respect ively. The respective expected costs per SFD were $45.92 and $127.31 f or venlafaxine, $51.64 and $157.04 for SSRIs, and $70.71 and $152.43 f or TCAs. Venlafaxine was dominant for all incremental pharmacoeconomic analyses. Sensitivity analyses indicated that the results were robust for outpatients but somewhat sensitive for inpatients. In conclusion, venlafaxine is a cost-effective drug for the treatment of MDD in adul t outpatients and inpatients.