The newest entry in the antidepressant market is Pristiq (desvenlafaxine). It is pharmacologically classified as a serotonin norepinephrine reuptake inhibitor (SNRI) antidepressant, a medication category that also includes Effexor XR and Cymbalta.
Wyeth Corp., maker of Pristiq, claims the medication has distinct advantages over Effexor XR (venlafaxine XR). For one, Wyeth says, patients can begin taking Pristiq at the therapeutic dose of 50 milligrams, thereby circumventing the "start low, go slow" gradual increases associated with determining the appropriate dose for an individual. Another advantage, according to Dr. Philip Ninan, a Wyeth VP for neuroscience, is that Pristiq is unlikely to interact with other medications metabolized by the liver.
It's true that Pristiq is a primary active metabolite of Effexor. This means Pristiq is the chemical compound that results after Effexor is taken and then metabolized and processed by the body. It's also true that Wyeth faces the loss of patent protection for Effexor XR in 2011, when the medication goes fully generic. This issue is not a small one: Sales of Effexor XR topped out at roughly $3.8 billion in 2007. As a result, it seems Wyeth needed a new brand to replace at least some of the revenue that will undoubtedly be lost when Effexor XR goes fully generic in a little over a year.
Meanwhile, Wyeth has been blanketing the major television networks and cable channels with information about Pristiq since June of this year. In fact, pharmaceutical companies such as Eli Lilly and Wyeth are masters at promoting the conventional wisdom that drugs are the answer to faulty brain chemistry. If only it were that simple!
Heralding antidepressants as the solution to chemical imbalances in the brain ignores the myriad other possible causes of depression. These include physical illnesses, such as heart disease, stroke, certain cancers, and hypothyroidism; prescription medications with depressive side effects, such as beta blockers and anti-Parkinson's agents; and substance abuse.
Simply put, there are a number of reasons for depressive brain function, many of which antidepressants alone cannot correct. In other words, getting brain neurochemicals to behave is only a partial solution to resolving depression. Even in the absence of other causes of depression, antidepressants have a less-than-stellar track record with patient response rates and remission of depressive symptoms.
Since 2002, the only new antidepressants to be introduced to the U.S. drug market are Lexapro, Cymbalta, the transdermal patch Emsam, and now Pristiq. A look down the antidepressant pipeline doesn't have me jumping up and down, either. This is not an attempt to disparage Pristiq. The medication is as effective as any other antidepressant. It is not special in any other way, and certainly not deserving of "novel" or "designer" drug status.
Here's the bottom line: When it comes to antidepressants, there's nothing new under the sun. The pharmaceutical companies, as part of their direct-to-consumer marketing strategy, will continue to flood TV screens with images of misbehaving brain chemicals. They will milk the chemical-imbalance theory, which is only partially true, for all it's worth. Let the consumer be aware.
