While the pharmacovigilance system in Europe is different from that the U.S., it is not necessarily better, and the experience with Vioxx rofecoxib is a case in point. European pharmacovigilance experts had a close look at COX-2 inhibitors as they received a continuous flow of adverse drug reaction reports tied to both Vioxx and the COX-2 class as a whole. However, they were never able to conclude whether there was an increased cardiovascular risk associated with Vioxx.
The European pharmacovigilance system is designed to detect side effects that are very rare events, but it is less able to detect signals pointing to an increase in the incidence of common events, such as heart attacks or stroke. There is a historical reason for the imbalance, as the system was designed in the 1960s