Pristiq is the brand-name of desvenlafaxine, a new antidepressant which is still brand-name only. Desvenlafaxine sounds a lot like venlafaxine – which is Effexor, an old antidepressant which is available in generic. In fact, desvenlafaxine is a tiny change to the venlafaxine molecule which may or may not have any interesting medical benefit over the original, and which was invented solely to have something whose patent hasn’t expired.
Wyeth, the company that makes Pristiq, says that it’s better than Effexor because it doesn’t have as many drug-drug interactions. But Effexor doesn’t really have clinically significant drug-drug interactions, and this seems to be them just saying random stuff and hoping people believe them. There are no good head-to-head studies comparing Pristiq to Effexor, but if you try to piece together a comparison from unrelated studies (not recommended, but we’ll do it anyway) Effexor actually seems better than its newer cousin. Even the data I took from drug rating databases shows patients preferring Effexor to Pristiq by quite a lot. Carlat Psychiatry, which is psychiatrists’ insider news site on pharmacology developments, has a blog post called Top Five Reasons To Forget About Pristiq. Most of the well-informed psychiatrists I know agree that Pristiq is a slightly worse version of an older antidepressant with no proven advantages.
A month’s supply of Effexor costs $20. A month’s supply of Pristiq costs $300. So let me amend the paragraph above. Pristiq is a slightly worse version of an older antidepressant with no proven advantages that also costs fifteen times as much.
It should come as no surprise to anyone familiar with the state of psychiatry that it is the second most-prescribed antidepressant in the USA, with three million prescriptions per month.
Why would this happen? The relevant study is called Pharmaceutical Industry-Sponsored Meals And Physician Prescribing Patterns For Medicare Beneficiaries, so you know it’s going to be good. It shows that doctors who often eat drug-company-sponsored free lunches are more than twice as likely to prescribe Pristiq as doctors who rarely eat such lunches. This matches my observations perfectly. Doctors prescribe Pristiq because they don’t know very much about antidepressants, but they attend free lunches by pharmaceutical companies who tell them that Pristiq is great, and they believe it. If this surprises you, be more cynical.
I’m looking at the price of Pristiq in Canada, and it seems to range around $120 to $250. So if we instituted price regulations like Canada’s, we might lower the cost of Pristiq from $300 to $150. If we convinced doctors to prescribe Effexor instead, it would be $20, plus I really do believe Effexor is genuinely better.
Pristiq is far from alone in this. I don’t have good statistics, but I bet that at least half of brand-name prescriptions in the US are more like Pristiq (attempts to rip people off) than like Harvoni (genuinely wonderful breakthroughs in medical science).
Thursday, September 8, 2016
Drug Pricing in America
Scott Alexander is in the midst of an argument with Vox about the EpiPen mess, with Vox putting most of the blame on our lack of drug price controls and Alexander blaming the regulations that make it so hard to bring in generic competition. In the course of his latest, long response, Alexander explains that the best way to control drug costs is neither price regulation nor competition, but changing the behavior of doctors: