A COST-EFFECTIVE APPROACH TO THE USE OF SELECTIVE SEROTONIN REUPTAKE INHIBITORS IN A VETERANS-AFFAIRS-MEDICAL-CENTER

In light of the tremendous expansion in the number of selective seroto nin reuptake inhibitors available to the clinician, the Pharmacy and T herapeutics Committee of the Denver Veterans Affairs Medical Center co nsidered the advantages and disadvantages of fluoxetine, paroxetine, a nd sertraline, to determine which agent or agents would be carried on the formulary. The committee recommended sertraline as the preferred a gent for the treatment of depression, panic disorders, and obsessive-c ompulsive disorders. The purpose of this retrospective study was to as sess the economic outcome of that decision. The study population consi sted of patients at the medical center who were receiving selective se rotonin reuptake inhibitors during January through March of 1994 and t hose who were receiving these agents between September 1995 and Januar y 1996. The expanded collection period in 1995-96 was due to a relativ ely new medical center policy to offer 90-day fills on medication to r educe costs. The extended collection period assured a 100% sample of p atients receiving these agents. The 1994 fluoxetine to sertraline dosa ge equivalency ratio was 20 mg:55.6 mg, based on average daily doses o f fluoxetine and sertraline of 32.7 and 90.9 mg, respectively. The cos t to the medical center for an average daily dose of fluoxetine was $1 .86; sertraline cost $1.22 per day. The 1996 fluoxetine to sertraline dosage equivalency ratio (20 mg:51.3 mg) had not changed significantly since 1994, indicating that a dose of 20 mg of fluoxetine remained ve ry close to a 50-mg dose of sertraline. The average daily doses of flu oxetine and sertraline (34.9 mg and 89.7 mg, respectively) were not si gnificantly different than the 1994 doses. Only 33 patients had been p rescribed paroxetine (average daily dose, 32.4 mg). On the basis of th ese values, the average daily cost of fluoxetine to the medical center was $2.01, compared with $1.18 for sertraline and $1.24 for paroxetin e. This $0.83 per patient per day drug acquisition cost difference bet ween fluoxetine and sertraline results in a drug cost reduction of $30 2,647 per year.