AstraZenica’s a monster of a pharmaceutical company. If you saw our last posts (here and here) on the drugs most frequently prescribed in 2011 and the ones purchased in largest numbers, AstraZenica’s Nexium is clearly a popular drug among doctors and patients. Nexium (esomeprazole) is typically taken for gastroesophageal reflux disease aka heartburn.
You should be embarrassed if you prescribe Nexium because you’re screwing your patients and you’re screwing the taxpayers.
~Thomas A. Scully, head of Centers for Medicare and Medicaid Services
So what’s the big deal? In 1989, AstraZenica marketed the drug we know as Prilosec, the famously popular heartburn medication. In 1999, Prilosec accounted for $5.91 billion, making it the best-selling drug on the market. But in 2001, AstraZenica’s patents expired. Through strategic lawsuits and marginally related patents, they managed to suppress generic versions of their formula long enough to introduce their new drug, Nexium.
Both Prilosec and Nexium are proton-pump inhibitors that target the enzymes CYP2C19 and CYP2C9. Both drugs treat heartburn by blocking the final step in gastric acid production to reduce gastric acidity. They also share similar side effects, effective dosage levels, and delivery systems. Below is an image of what you get in Prilosec. Want a picture of Nexium? Take a look at the same image.
Technically, Nexium and Prilosec aren’t the same thing. Prilosec includes both the molecules depicted above. Nexium only includes the top one. Omeprazole (chemical name for Prilosec) is called a “chiral” molecule, from the Greek word for hand–a fitting name given that there are “left-handed” and “right-handed” versions of the molecule.
So that’s how they did it. AstraZenica patented Nexium (esomeprazole) once their patent for Prilosec (omeprazole) expired. But why is there controversy? Maybe just left-handed version (Nexium) works better than a combination of both (Prilosec). After all, the left-handed ibuprofen is over 100 times more potent than the right-handed version.
The problem is, experiments done by people besides AstraZenica say that left-handed omeprazole might not be better than just omeprazole, though it is almost twice as expensive. In fact, the right-handed omeprazole is significantly more effective in rats, though it’s less effective in canines. Research even indicates that in the parietal cells that omeprazole and esomeprazole do their work, both react with the acidic environment and are converted to same compound.