The cost of newer antidepressant medications is a source of concern. When physicians decide to initiate antidepressant drug therapy, they must choose an initial medication based on clinical efficacy, tolerability and cost. Available data do not resolve the question of whether the advantages of newer antidepressant medications outweigh their higher purchase prices. Results of traditional clinical trials have consistently demonstrated no difference in efficacy between newer and older anti-depressants. However, observational studies suggest that the use of newer antidepressants leads to greater adherence and more appropriate dosing. Potentially, if the use of new anti-depressant drugs leads to more effective treatment, the higher purchase prices of the newer drugs may be justified.

Simon and associates compared long-term clinical, quality-of-life and economic outcomes after initial prescriptions of fluoxetine, imipramine or desipramine for treatment of depression. Patients who were enrolled in the study were from primary care clinics of a large staff-model health maintenance organization and were beginning antidepressant therapy for depression. Patients were randomly assigned to begin treatment with desipramine, fluoxetine or imipramine. Baseline assessment conducted before randomization included a structured clinical interview for psychiatric diagnoses based on Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria, a Hamilton Depression Rating Scale, a self-rated measurement of anxiety and depression from the Hopkins Symptom Checklist, a self-reported measurement of health-related quality of life and questions concerning use of out-of-plan medical and mental health services. Each measurement was repeated after randomization at months 1, 3, 6, 9, 12, 18 and 24.

Of the 536 patients enrolled in the study, the median age was 41 years, and 72 percent of participants were women. At the baseline interview, 358 patients (66.8 percent) met DSM-III-R criteria for current major depression, 36 (6.7 percent) met criteria for dysthymic disorder and 142 (26.5 percent) met criteria for minor depression without dysthymia.

Over time, a decrease in the use of antide-pressant medication occurred. Patients beginning treatment with fluoxetine were more likely to continue taking the initial antidepressant, and the likelihood of continuing use of any antidepressant medication decreased. In comparing the three antidepressants, no significant difference in any measure of depression severity or quality-of-life outcomes was evident. For the 24 months of follow-up, antidepressant drug costs were $250 higher in the fluoxetine group, and total medical costs were essentially identical in the three randomization groups.

The authors conclude that administrative restriction on first-line use of fluoxetine will not reduce overall cost of care. Restricting flu-oxetine to second-line treatment can lead to moderate savings in antidepressant drug prescription costs but not to overall savings.