Cost effectiveness of venlafaxine compared with generic fluoxetine or generic amitriptyline in major depressive disorder in the UK.

OBJECTIVE

To estimate the cost effectiveness of venlafaxine compared with generic fluoxetine and generic amitriptyline used in major depressive disorder in primary care in the UK.

METHODS

A decision-tree model for the treatment of major depressive disorder was constructed using a Delphi panel. The tree was populated with clinical success rates from a pooled analysis of fluoxetine compared with venlafaxine and a clinical trial of amitriptyline compared with venlafaxine using remission as the key endpoint. Where there was insufficient data from clinical trials, the Delphi panel was used. Costs within the tree were taken from contemporary UK sources. Six-monthly costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios were then estimated.

RESULTS

Treatment costs for 6 months were pound1530 for venlafaxine, pound1539 for fluoxetine and pound1558 for amitriptyline (year of costing 2006). Cost effectiveness as assessed by incremental cost per QALY ratio at 8 weeks was pound20 600 for venlafaxine compared with fluoxetine, with fluoxetine dominating (being less costly and more effective than) amitriptyline. To test the robustness of the model a Rank Order Stability Assessment was performed that showed that even if fluoxetine and/or amitriptyline were given away free, a scenario starting with venlafaxine would still be the least costly treatment over a 6-month period.

CONCLUSION

In this model, venlafaxine was shown to be a cost-effective alternative to generic fluoxetine and amitriptyline when used as a first-line therapy. Thus, cost of therapy should not be a barrier to use of venlafaxine as a first-line option in treating major depressive disorder in primary care in the UK.