Evaluating the relationship of high-dose venlafaxine prescribing to treatment-resistant depression

Abstract

Aims and Method Prescribing of venlafaxine in The South London and Maudsley NHS Trust was found to account for over 50% of the antidepressant costs, but only 15% of the prescriptions. There is evidence to suggest that higher doses of venlafaxine may be effective in treating treatment-refractory depression. We aimed to discover if higher doses of venlafaxine used in the trust were related to prior failure to respond to antidepressant treatment. Hospital in-patients being treated with venlafaxine during a 1-week period in October 2001 were identified and case notes were reviewed to determine patient demographic data and prior history of antidepressant therapy. Results There were 38 patients identified as being prescribed venlafaxine (18 of whom had a primary diagnosis of depression). Twenty-five were classed as non-treatment-resistant and 13 were classed as treatment-resistant. Doses of venlafaxine were statistically significantly higher in patients considered treatment-resistant (245 mg v. 180 mg daily, P=0.03). All other recorded patient characteristics were similar. Clinical Implications Higher doses of venlafaxine were prescribed to patients who were retrospectively defined as treatment-refractory. Further studies should address the reasons for this prescribing practice.