by Elisa F. Cascade and Amir H. Kalali, MD
Ms. Cascade is Vice President, Strategic Research and Safety, Quintiles Inc., Falls Church, Virginia; and Dr. Kalali is Vice President, Global Therapeutic Group Leader CNS, Quintiles Inc., San Diego, California, and Professor of Psychiatry, University of California, San Diego.
Abstract
In this article, we investigate the penetration of generic selective serotonin reuptake inhibitors (SSRIs) in the US market and the implications for patient out-of-pocket expense. The data suggest that generic penetration into the SSRI market has grown from approximately nine percent in 2000, the year that the patent for Prozac® expired, to 72 percent in 2007. For December, 2007, the difference in patient out-of-pocket expense for branded vs. generic agents was, on average, $55.42 for patients paying by cash (i.e., they had no prescription drug insurance) and $22.39 for patients with insurance coverage.
Key words
SSRI, generic, trade, prescription, out-of-pocket expense
Introduction
Since the introduction of generics in 2001 for Prozac® (fluoxetine), three additional major selective serotonin reuptake inhibitors (SSRIs) have experienced generic competition: Paxil® (paroxetine), Celexa® (citalopram), and Zoloft® (sertraline). In fact, today, there is only one major SSRI that doesn’t have generic alternatives on the US market, namely Lexapro® (escitalopram). In this article, we investigate the penetration of generic SSRIs in the US market and the implications for patient out-of-pocket expense.
Methods
We obtained data from Verispan’s Vector One National (VONA), which captures nearly half of all retail prescription activity in the US. VONA includes data on prescriptions paid by third-party payers and cash. We also analyzed information from Verispan’s Vector One Payer, which provides data on patient-out-of-pocket expense.
Results
Data from Verispan indicate that total prescriptions for SSRIs grew from 80 million in 2000 to 150 million in 2007. Figure 1 displays the share of generic SSRIs over this timeframe. As seen in Figure 1, penetration of generics has grown from approximately nine percent in 2000, the year that Prozac’s patent expired, to 72 percent in 2007. In other words, branded SSRIs (primarily Lexapro) accounted for only 28 percent of SSRI prescriptions dispensed in 2007.
Figure 2 presents average patient out-of-pocket expense for branded vs. generic SSRIs. As seen in Figure 2, for patients paying by cash (i.e., they have no prescription drug insurance), the average out-of-pocket expense per prescription was $34.75 for generics and $90.17 for branded products. Thus, the price premium for a cash-paying customer is $55.42 per prescription (typically a one-month supply). The difference in out-of-pocket expense for a patient with third-party drug insurance coverage, however, was significantly less, only $22.39 ($32.15 per branded prescription and $9.76 per generic prescription).
