What is Pristiq (desvenlafaxine)? The newest antidepressant approved by the U.S. Food and Drug Administration (FDA), which will hit the U.S. market in a few months. Pristiq is a drug similar in composition to Wyeth’s existing antidepressant, Effexor XR (which loses its patent protection in 2010, 2 years from now). It is Wyeth’s hope that Pristiq, therefore, will replace Effexor XR in a few years’ time. Why? Because Effexor XR makes $3.8 billion (with a ‘b’) a year in sales.

Pristiq has shown the same level of effectiveness as many other antidepressants on the market today — about a 2 point difference in a depression rating scale, compared with a placebo. This is the same 2 point difference that research last week showed wasn’t all that clinically significant in older new generation antidepressants (SSRIs like Prozac and Paxil).

Strangely enough, lower doses (50mg) of Pristiq proved more effective than higher doses (100mg). I believe this is the first time where a drug company has shown in their own data that less of their drug works better than more of it (at regular dosing levels)!

Pristiq, compared with Effexor XR, should be seen for what it is — an evolution in an existing chemical compound, trying to address some of the concerns with the current drug. Time will tell whether the side effects are more tolerable than those associated with Effexor XR or not. Because unless Wyeth releases the drug at a lower price point than Effexor XR (which is highly unlikely), Pristiq will have to prove itself as more than just another antidepressant.

The New York Times: F.D.A. Approves Wyeth Antidepressant

Dr. Carlat’s take: Top 5 Reasons to Forget about Pristiq

Dr. John Grohol is the CEO and founder of Psych Central. He is an author, researcher and expert in mental health online, and has been writing about online behavior, mental health and psychology issues -- as well as the intersection of technology and human behavior -- since 1992. Dr. Grohol sits on the editorial board of the journal Cyberpsychology, Behavior and Social Networking and is a founding board member and treasurer of the Society for Participatory Medicine.

    Last reviewed: By John M. Grohol, Psy.D. on 4 Mar 2008
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