The Meaning of "Safe"
Derek Lowe has some thoughts on the meaning of the word "safe":
What everyone wants to know is: are these drugs safe?
What a useless question. I mean it - we're never going to get anywhere with that line of thinking. "Safe" is a word that means different things to different people at different times, which is something you'd think any adult would be able to understand. The only definition that everyone would recognize, at least in part, is "presenting no risk of any kind to anyone." That'll stand as a good trial-lawyer definition, at any rate.
And by that one, not one single drug sold today is safe.
And if you wonder how one Celebrex study found an increased risk of complications, while another did not, he explains how the dosage regimen can affect a drug's safety profile:
There appears to have been a clear dose dependence in the elevated cardiovascular risks. At 400 mg b.i.d. (twice a day), the treatment group showed 3.4 times the risk of the placebo group. At 200 mg b.i.d., the risk was 2.5x. The average duration of treatment was 33 months - pretty substantial, but a lot of people take Celebrex for an extended period for pain relief.
Now, Pfizer has stated that another trial at a similar dose has shown no indication of cardiovascular trouble, and that's true as far as it goes - it's a 400 mg trial, but the drug is dosed q.d. (once a day). How can 400 mg act so differently, taken all at once versus split up? My industry colleagues are already nodding their heads at the probable answer. The difference is coverage.