In my opinion, adverse drug reaction is a real public health issue. We're talking populations. Even though a drug may have a small risk, if you have 10% of the population exposed, it's going to result in a very large absolute number of cases.
Eventually the serious effects will be picked up by the pharmaco-vigilance. My problem here is that it's not timely enough. If additional measures could be introduced right at the time of marketing, the adverse effects could be picked up sooner.