The U.S. patent expiry of Eli Lilly's Prozac (fluoxetine) on August 2, 2001, and the subsequent approval of several generic competitors will dramatically alter the competitive landscape for selective serotonin reuptake inhibitors (SSRIs).

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In response to the question of whether and to what extent sales of other SSRIs will be adversely impacted by the release of generic fluoxetine, Decision Resources, Inc., announces the results of a June 2001 survey of 72 U.S.-based primary care physicians (PCPs) who are high-volume prescribers of antidepressants. This survey addresses issues such as whether PCPs are likely to acquiesce to the cost control efforts of HMOs and other managed care organizations, or whether their prescribing patterns are more likely to be influenced by other factors (e.g., patient requests, financial incentives).

What Influences Physicians to Prescribe Generics?

The survey responses indicate that 20-25% of the physicians in this influential group will initially retain their loyalty to branded Prozac rather than turning to the newly available generic fluoxetine for newly diagnosed depression patients. Preference for the branded product drops dramatically for existing patients, for whom weekly Prozac is another option. Prescribing patterns will be heavily influenced by potential formulary restrictions, as shown by physician responses when considering various managed-care-mandated treatment scenarios.

Will Diagnosis Drive Selection?

The extent to which sales of other SSRIs (Pfizer's Zoloft, GlaxoSmithKline's Paxil, Solvay's Luvox, Forest Laboratories' Celexa) will be adversely impacted by the availability of generic fluoxetine is highly dependent on the patient diagnosis and brand of SSRI. The survey finds that the remaining branded SSRIs will not be on a level playing field in terms of generic erosion. Survey results show the specific patient subgroups and individual brands that will be the most vulnerable.

The Formulary Factor

Formulary restrictions will influence significantly physicians' generic fluoxetine prescribing patterns, particularly when physicians are considering switching patients' medications. Results of interviews with seven pharmacy directors of national HMOs showed them to be surprisingly consistent in their opinions of the future positioning of generic fluoxetine in their formularies and potential treatment directives that would be forthcoming.

The results of this survey will be published in PhysicianForum: The Impact of Generic Fluoxetine, due in September 2001.

Decision Resources, Inc., is a world leader in pharmaceutical research publications, advisory services, and consulting designed to help clients shape strategy, allocate resources, and master their chosen markets. Founded as a subsidiary of Arthur D. Little, Inc., the company has provided strategic information services for 30 years. Visit the Decision Resources Web site at

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SOURCE: Decision Resources, Inc.

Contact: Alice Von Loesecke of Decision Resources, Inc., +1-781-296-

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