Drug companies will get approval for a drug for one disease, then later get approval for more diseases by doing additional post-market studies. I think it was with Celebrex that they found the problems during a study to get approval for Celebrex to be indicated for treatment of COLON POLYPS. The dosage was 2x that for arthritis.
Arthritis dosage is 100 mgs, sometimes 200 mgs. They were using 400 and 800 mg. dosing. The cardiac effects were a bit more pronounced at the 800 mg dosing, but still a very small number of people.
What they need to learn is why some people have this effect.