Medary.com

From Australia's ABC News:

Pfizer says the label of its Celebrex arthritis drug has been changed to add a prominent warning of possible cardiovascular risks, such as an increased chance of heart attacks, in line with new warnings on other arthritis and pain drugs.

I'm sitting here wondering about why prescription drugs need warning labels? I mean, aren't they available by prescription only because they're in some way more dangerous than non-prescription drugs?