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Perhaps this speaks to the kinds of TV shows I watch (I neither confirm or deny that I am in a betting league for The Bachelor), but I am often disturbed by the pharmaceutical commercials that run. Too afraid to read more about the lash-growing product Latisse whose possible side effects include respiratory compromise and blindness, I decided to fact-check the commericals for the anti-depressant Pristiq. Given the extreme side effect warnings that include worsening of high blood pressure and suicidal thoughts, it is important that Pfizer is not just manipulating us into think Pristiq is effective. The manipulations include employment of “common people” and glittering generalities.

The central claim I wanted to investigate was the one that Pristiq was a key in helping treat depression. The Pfizer website claims that according to 8-week studies, 50mg Pristiq yielded “significant improvement” in depression symptoms. On the 17-point Hamilton Rating Scale for Depression, patients reported a 52% improvement from the baseline (-12 adjusted score) as opposed to a 43% reported change from using a placebo (-10 adjusted score) [1]. For large n this can be significant improvement over a placebo [2]. Something to watch out for, however, is that this commercial suggests that Pristiq is useful for treating depression of all severities. According to this 2010 Wall Street Journal article about a study in the Journal of the American Medical Association, researchers at the University of Pennsylvania found that antidepressants seemed to help the severely depressed (improving them as much as 4 points) while having little effect on the mildly depressed over a placebo.

In fact-checking the effectivness of Pristiq, a point of concern was the eight-week period of the study: there is a bit of media buzz about the “poop out” effect (antidepressant tachyphylaxis). According to a 2011 article in the Journal for Psychiatry and Clinical Neuroscience [4] as well as a Johns Hopkins Health Alert [5], this tends to be observed in selective serontonin reuptake inhibitors (SSRIs) rather than serotonin-norephinerphine inhibitors (SNRIs). According to PubChem, Pristiq’s major active ingredient desvenlafaxine is a selective serotonin and noreprinephrine reuptake inhibitor [6]. Thus Pristiq seems less likely to lose effectiveness and the short trial period should not decrease our confidence in the long-term advantages of Pristiq.

The reported side effects of Pristiq, which include suicidal thoughts and the worsening of high blood pressure, seemed alarming. It seems, however, that these side effects are common to SNRIs [7][8][9][10].

In conclusion, it seems valid to tell TV audiences to talk to their doctor about this drug.

[1] Pfizer description of Pristiq.
[2] E-mail exchange with Adeeti Ullal, Ph.D. candidate at Harvard-MIT.
[3] Effectiveness of Antidepressants Varies Widely, WSJ, January 2010.
[4] Katz, Gergory, MD. Tachyphylaxis/tolerance to antidepressants in treatment of dysthymia: Results of a retrospective naturalistic chart review study. Journal for Psychiatry and Clinical Neuroscience, August 2011.
[5] Johns Hopkins Health Alert: Antidepressant Medication “Poop Out.”
[6] PubChem: Pristiq – Substance Summary.
[7] “Pristiq Prescription Information”. Wyeth Pharmaceuticals Inc. April 2011. Retrieved March 12, 2013.
[8] “Effexor XR Prescription Information”. Wyeth Pharmaceuticals Inc. November 2011. Retrieved March 13, 2013.
[9] “Cymbalta Prescription Information”. Eli Lilly and Company. September 2011. Retrieved March 13, 2013.
[10] “Savella Prescription Information”. Forest Pharmaceuticals Inc. December 2009. March 13, 2013.

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Commercial transcript
Woman: Depression is a serious medical condition that can take so much out of you. I feel like I have to wind myself up just to get out of bed. And, well, I have to keep winding myself up to deal with the sadness, the loss of interest, the trouble concentrating, the lack of energy.
Male voiceover: If depression is taking so much out of you, ask your doctor about Pristiq. Pristiq is a prescription medicine proven to treat depression. Pristiq is thought to work by affecting the levels of two chemicals in the brain, serontonin and norepinephrin. Tell your doctor right away if your depression worsens or if you have unusual changes of mood, behavior, or thoughts of suicide. Antidepressants can increase suicidal thoughts and behaviors in children, teens, and young adults. Pristiq is not approved for children under 18. Do not take Pristiq with MOAIs. Taking Pristiq with NSED pain relievers, aspirin, or blood thinners may increase bleeding risk. Tell your doctor about all medications, including those for migraine to avoid a potentially life-threatening condition. Pristiq can cause or worsen high blood pressure, high cholesterol, or glaucoma. Tell your doctor if you have heart disease or before you reduce or stop taking Pristiq. Side effects may include nausea, dizziness, and sweating.
Woman: For me, Pristiq is a key in helping to treat my depression.