Editorial Post-marketing Drug Surveillance—How Far Have We Got?

The early recognition of serious adverse effects of drugs is clearly important for ensuring optimum health care. Since only about 3000 patients will receive a new drug prior to licensing, it is essential that systems exist to monitor their safety thereafter. Within the United Kingdom, the corner-stone of this post-marketing surveillance has been the yellow card system of reporting adverse drug reactions to the Committee on Safety of Medicines. Now over 25 years old, this mechanism is generally highly successful, even though under-reporting is known to occur. In reviewing the future requirements for adverse drug reaction monitoring (in the aftermath of the Opren affair), the Second report of the Working Party on Adverse Drug Reactions [1] concluded that there was a need for other independent systems to monitor new drugs, although they recognized the difficulty of creating, maintaining and funding such enterprises. Apart from Prescription Event Monitoring [2], no other system has been developed in this country. The ideal resource should not only be able to detect adverse reactions with new drugs but also to examine specific drug toxicity issues that arise. Such an issue, raised initially on the theoretical grounds that a reduction in intragastric acidity increases nitrosamines [3], is whether taking the H2-receptor antagonist, cimetidine, migh