Pharmacoeconomic analysis of venlafaxine in the treatment of major depressive disorder

We conducted a cost-effectiveness analysis of acute major depressive disorder (MDD) using serotonin-norepinephrine reuptake inhibitors (SNRIs; venlafaxine), selective serotonin reuptake inhibitors (SSRIs; fluoxetine, fluvoxamine, sertraline, paroxetine), or tricyclic antidepressants (TCAs; amitriptyline, imipramine, desipramine, nortriptyline). A decision-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, laboratory services, hospitalisation and managing adverse events. Success and dropout rates were determined from a meta-analysis of published randomised controlled trials. Medline, Embase, and International Pharmaceutical Abstracts were searched from 1984 to 1996, as were references from retrieved articles and reviews. Inpatients and outpatients were 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 incremental cost per success and per SFD. The meta-analysis identified 56 treatment arms from 36 randomised controlled trials involving 2953 patients (2380 outpatients and 573 inpatients). SNRIs had the highest success rates. The respective costs (in 1996 $Can; $Canl = $US0.74) for outpatients and inpatients are given below. The expected costs per success were $6044 and $17 234 for venlafaxine, $6634 and $20 874 for SSRIs, and $9035 and $20 459 for TCAs in outpatients and inpatients, respectively. The respective expected costs per SFD were $45.92 and $127.31 for venlafaxine, $51.64 and $157.04 for SSRIs, and $70.71 and $152.43 for 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 adult outpatients and inpatients.