Let's move on to a different class of drugs called the
cyclooxygenase 2 inhibitors or COX-2 inhibitors.
There are several different variation of cyclooxygenase.
COX-1, COX-2, COX-3. So these are COX-2 inhibitors.
These are very effective pain medications. And the nice thing
about these pills is that they have reduced GI side effects.
They also reduce the risk of colon cancer
which is kind of a bonus.
They have a mild increased risk however
of myocardial infarction and arterial thrombosis
which is why these medications are a little bit more controversial
in the sense that there's a lot of people saying
"Are they really worth the increased cost?"
Now, we have an increased reduction in
prostaglandin 1 or prostaglandin I formation
and also we are not sure what its effect
is on thromboxane A2.
Now, prostacyclin promotes vasodilation
and inhibits platelet aggregation.
Perhaps this is a mechanism that makes this issue relevant here.
Thromboxane A2 inhibits vasodilation and promotes platelet aggregation.
We believe that perhaps thromboxane A2 activity may be the culprit
of how myocardial infarction occurs with the COX-2 inhibitors.
Suffice to say we are not really sure.
The prototypical example of this medication is celecoxib,
also sold as Celebrex. This was the first member of this new group.
Now, rofecoxib which was Vioxx and valdecoxib which was Bextra
are also both more specific to COX-2.
These two products were taken off the market
by their manufacturers.
Now the reason why these drugs were taken off the market,
in my opinion it was silly,
I think that they were just being misused by physicians
who didn't know how to use the drugs.
Suffice it to say, one physician in Australia using
8 times the regular dose of this drug and killing his patients,
ended up resulting in taking away medication
that were used all over the world.
They were relatively good drugs
but not available anymore.
And I think the only relevant drug
in this class left is Celebrex.