It amazes me that Nexium has held its market position despite essentially equally effective inexpensive generic competition by omeprazole. Amazingly Nexium was the #2 drug in the US in 2009 in gross sales, right between #1 Lipitor and #3 Plavix. It goes to show just how effective direct to consumer, and more likely physician detailing actually can be. In the direct to consumer ads for nexium the ads play to our desire to have the “very best” and “most powerful” medications available. In fact Nexium is really just the isomer of omeprazole. Omeprazole is a mixture of both mirror image molecules of omeprazole, the S- omeprazole and the D-omeprazole. Both isomers are metabolized into same active drug that works to prevent acid production in the stomach, but the S-isomer is absorbed into the body more readily and may be more effective. The comparison study pits 20 mg of omeprazole (i.e. 10 mg of S-omeprazole) against 40 mg of Nexium (40 mg of S-omeprazole) and shows a slightly higher cure rate for peptic ulcers at 8 weeks for Nexium ( 93% vs. 88%) but it is very likely that higher doses of the generic omeprazole would be equally effective. One more example of the need to read the fine print, and certainly not to take direct to consumer advertising for anything more than advertising to sell a product vs. using its competitors.
I’d like to think that physicians are bright enough to see through this marketing ploy. I suspect that Nexium is so successful for several reasons. First is that as physicians we feel a great deal of pressure to both see lots of patients in a short time frame, and also to “do” something they cannot do for themselves. When a patient comes to the office, or often is referred to the GI specialists office, with heartburn or acid dyspeptic symptoms that have not responded to omeprazole 20 mg which patients can buy now without our prescription as Prilosec OTC or store brand equivalents fairly inexpensively, it is much more impressive as well as much faster, to write a Rx for Nexium than it is to explain that higher doses of the inexpensive omeprazole should help. It takes no long explanation of isomers, dosing, and reassurance, just a simple Rx to write. Second it is difficult to convince patients who have already been put on Nexium, and are doing well, that they could switch back to omeprazole, which they often already know “doesn’t work for them at 20 mg dosing, if they just took a higher dose of the generic omeprazole. Third most of the time in our third party payment system, “It’s OK doc, I have good insurance so it doesn’t cost me much.”
Resource: Nexium side effects
For a more detailed outline of the data and studies involved see a nice article on Health Skepticism.