Introduction - Uppsala Monitoring Centre

new adverse event supports other data to suggest an adverse drug reaction (ADR)
then this is a signal 2 . This signal is then followed up and if on the balance of
probabilities it is considered an ADR then it is likely to be published and
communicated to all those who prescribe drugs, enabling them to use the
information for the benefit of future patients. Unless the cycle is completed
pharmacovigilance has failed.
The Pharmacovigilance Cycle
In the beginning the diameter of the cycle was small–involving only parent or
grandparent to child or family, but as tribes developed the diameter would have
increased to cover the whole tribe and a learned elder/philosopher/priest would
have entered the cycle as a pseudo ‘health professional’. When the tribes united into
a nation and a central government was formed another authoritative figure would
have taken control and issued edicts concerning the production and use of herbs
and other materials used as medicines (Figure 1), whilst after thalidomide national
2 signal = an adverse event that prompts an action , but a more formal definition is ‘information that arises from
one or multiple sources (including observations and experiments), which suggests a new potentially causal
association, or a new aspect of a known association, between an intervention and an event or set of related
events, either adverse or beneficial, which would command regulatory, societal or clinical attention, and is
judged to be of sufficient likelihood to prompt verificatory action’ (Hauben & Aronson, 2009).