COST-EFFECTIVENESS OF THE NEWER GENERATION OF ANTIDEPRESSANTS

In the last decade or so, several new antidepressants have been introduced into practice, including the selective seroto-nin reuptake inhibitors fluoxetine (1987), sertraline (1991), paroxetine (1992), and citalopram (1998), in addition to bupropion (1985), venlafaxine (1993), nefazodone (1994), and mirtazapine (1996). Two of these medications are avail-able in delayed-release formulations: bupropion SR (1996) and venlafaxine XR (1997). Only one of these medications is currently available in a generic formulation (bupropion, 1999). Each of these medications is more expensive in terms of acquisition costs than the older generation of tricyclics and heterocyclics and monoamine oxidase inhibitors. Together, the newer generations of antidepressants accounted for ap-proximately $7.7 billion in retail sales in the United States in 1999 (1), and antidepressants are second only to antibiot-ics in prescription sales by drug category. Prices are of course subject to variation, but Table 78.1 shows that the ‘‘average wholesale price’ ’ for most of these medications is more than $2 per day, according to the 2000 Drug Topics ‘‘Red Book’ ’ (2). Actual costs to health care systems or patients can be substantially lower or higher than the figures in Table 78.1 would indicate, depending on a number of factors. Certain health care systems are able to qualify for discounted prices for certain medications, and patients can sometimes receive medications free of charge via physician samples or indigent care programs. Acquisition costs are also lowered by patient noncompliance. In addi-tion, some of the newer antidepressants are available as scored tablets (Table 78.1), so that patients taking lower doses have the opportunity to reduce costs substantially with only the modest inconvenience entailed by breaking the pills. However, higher doses of some medications lead t