Risk management strategies in the postmarketing period : safety experience with the US and European bosentan surveillance programmes.

In view of the shortcomings of the current system for postmarketing drug surveillance that is based on voluntary spontaneous adverse drug reaction (ADR) reporting, new approaches are needed. We describe an approach involving a combination of limited distribution, patient and physician education, as well as a novel pharmaco-vigilance system that is capable of promoting the safe and adequate use of a new drug. Importantly, it provides the possibility of calculating true ADR occurrence rates, as the exposed population (denominator) and the number of patients with events (numerator) are known.