How Does Aspirin Know Where To Go?
It is pretty amazing. You take an aspirin for a fever and the pain subsides. Then, the next week, you take an aspirin for a sprained ankle and the pain subsides. That’s two different places in the body. So, how does the aspirin know where to go in order to do it’s job?
It Doesn’t
Actually, aspirin travels all over your bloodstream and not just to the area that hurts. This is one reason why aspirin has come out in low doses and specailly coated pills. High doses of the kind our parents were encouraged to take over the years wound up wreaking navoc on the digestive system, leading to such fun side effects like peptic ulcers.
But, Meanwhile, Back In The Bloodstream…
One the aspirin pills are dissolved by digestion, the active medication acetylsalicylic acid (ASA) enters the bloodstream, looking for an enzyme called cylooxygenase-2 (mercifully shortened to COX-2). This enzyme is released by cells where the body has pain, although the body probably does quite a lot of other things to register pain.
COX-2 tells the body to make prostaglandins, which tells the brain that this particular area of the body is in pain and needs attention. What ASA does is to bind to COX-2 and stop it making prostaglandins. If there is infection, then the ASA also chemically tells the body to relase the fluid build up around the area.
Ta-Da!
Granted, science still doesn’t understand a lot about the chemistry of pain (let alone little ol’ me). But blocking prostaglandins is one way to cut down on the sensation of pain.
And that’s how aspirin knows where to go. And they all lived happily ever after.
January 8th, 2009 at 11:22 am
Thanks for this lovely explanation of how my favorite medication works. And thanks for the laugh I got when I read the title.
January 8th, 2009 at 1:20 pm
You’re quite welcome.