With all the talk about COX-2 painkillers in the news, you might be wondering why drugs such as Vioxx, Celebrex, and the newest COX-2 med Arcoxia increase cardiovascular risks while non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen don't.
Well, first it's important to know that COX-2s are NSAIDs, in the same general class of drugs as ibuprofen or naproxen. They're just a newer kind of NSAID. And research has shown that all NSAIDs--not just the COX-2 painkillers--raise heart risks to some degree.
The key to why COX-2 inhibitors such as Celebrex cause more of a heart risk is in the way both kinds of NSAIDs work in your body.
As MedicineNet.com explains in this overview, both older NSAIDs and COX-2s work by blocking enzymes--called COX-1 and COX-2--that are present both in your stomach and in places in your body where there's inflammation that's causing pain. Older NSAIDs block both COX-1 and COX-2, while COX-2 inhibitors block only the COX-2 enzyme, as their name suggests.
But here's a big difference between these two enzymes: COX-1 is in the stomach and in the whole body, and COX-2 is only in other parts of the body--not in the stomach.
COX-1 protects your stomach by making sure there's enough protective mucous in the stomach lining to keep the organ from being damaged. Because older NSAIDs block both COX-1 and COX-2, they stop this COX-1 in the stomach from producing that protective mucous. This can lead to ulcers and other gastrointestinal problems.
That's what's so helpful about COX-2 inhibitors. Because they only block COX-2 (which isn't in the stomach), Celebrex and other COX-2 painkillers only block the enzymes that are causing pain in your body. They don't bother the COX-1 that's protecting your stomach.
Sounds great, right? Well, unfortunately blocking only COX-2 in the body causes other risks.
As Dr. Joseph Mercola says on his Web site, COX-1 has another job besides making the stomach's protective mucous. It also controls how "sticky" your blood platelets are and it makes your blood vessels constrict or become more narrow. COX-2 balances these COX-1 effects. It keeps blood platelets from clumping together and causing clots, and it keeps blood vessels more open so blood can flow more freely.
Take away only COX-2 and you can guess what happens. Your body has too much COX-1, which means your blood could be thick and more prone to clots. And your blood vessels could be too closed, which could trap those clots. And these are major risk factors for cardiac problems such as stroke and heart attack.
