We already know the frequency with which reactions to most drugs are experienced. ADRs are detected at the pre-marketing stage precisely because they occur frequently. We therefore have a good idea of the frequency at which they occur. Mandatory post-marketing reporting would not simply reproduce information available at the pre-marketing stage. It is adverse reactions that have not been detected at the pre-marketing stage that have to be reported at the post-marketing stage. These sort of reactions, although rare, are often potentially deadly.
In Quebec, we are 10% short of the number of pharmacists that we require. Some hospitals only have locum pharmacists, people who fill in for a week or so before moving on. If you ask pharmacists to report adverse reactions, or even if you require them to do so, you will be simply wasting your time, as it would do nothing to improve their scientific knowledge or change the way in which they treat their patients.
The focus should be on developing a culture whereby professionals report the more serious ADRs they are not familiar with, and where these reports are met with feedback. Feedback is important, as it allows pharmacists to treat their patients appropriately. At the moment, however, there is no feedback.