how we can predict the side effects of a drug before it is launched in to the market?

Question

especially in case of duract

Answer 1

That is done by the drug company conducting tests on humans who have volunteered to participate in a blind drug study. They already pretty much know that the drug is safe but, still need to study the effects before the FDA will approve it to market.
It is not fool proof though, look at viiox.

Answer 2

pass them out @ a rave 4 free & see who ends up @ emerg