Background

BACKGROUND

In 1976, the NZ national Committee on Adverse Drug Reactions, advisory to the then Department of Health, recommended supplementing NZ’s spontaneous reporting activities (‘yellow card’ scheme) with an early post-marketing surveillance programme. The purpose was to speed up the iden-tification of previously unrecognized adverse drug reactions (ADRs) and to provide better information about risk (McQueen, 1977). The stimulus for this was the international recognition that spontaneous report-ing had proved inadequate in recognizing the serious oculomucocutaneous syndrome with the new beta-blocker practolol, even though the early symptoms were quite common (Skegg and Doll, 1977).

The additional programme, which commenced in 1977, was called the ‘Intensified Adverse Drug Reaction Reporting Scheme’ and was aimed at selected new drugs. It was to function by establish-ing patient cohorts from prescription information provided by community and hospital pharmacies and by identifying adverse events from ‘intensified’ spon-taneous reporting. For the drugs selected for study, this intensified reporting was an attempt to change the nature of reporting from that of suspected adverse reactions of recognizable clinical significance, to that of reporting all adverse events of any type or sever-ity and without any judgement on causality. Thus a high rate of reporting of all types of events was expected to provide greater opportunity for identifying signals of previously unrecognized adverse reactions. The cohorts of identifiable patients would also allow the estimation of rates or incidence of adverse events and thus provide a measure of risk.

The first drugs monitored in this way were metopro-lol, atenolol, acebutolol, labetalol, perhexiline, sodium valproate and cimetidine. Although the reporting rates for these drugs were much higher than rates in the standard spontaneous reporting programme (Coulter and McQueen, 1982), it was decided to send ques-tionnaires to the prescribers after the drugs had been on the market for at least 6 months requesting infor-mation on any adverse events noted in the patients’ records. These were called ‘event-recording surveys’, and their use was aimed at enhancing the reporting rate still further. In addition, it was possible to iden-tify when patients were no longer having their drug dispensed and specific questionnaires were then sent out asking why treatment had ceased. The use of these two questionnaires was the first endeavour at what has since been called PEM (Inman, 1981b), and the first publication resulting from the use of this methodology was the report and investigation of a new signal with labetalol (Coulter, 1979). Other findings published in this very early period concerned perhexiline (Depart-ment of Health, 1979, 1980), reasons for the cessa-tion of therapy with perhexiline, sodium valproate and labetalol (Coulter, 1981) and sodium valproate (McQueen, 1982). The early stages of the programme were reviewed after 5 years’ activity (Coulter and McQueen, 1982). In 1983, the scheme was given a more appropriate name, the Intensive Medicines Monitoring Programme.

THE INTENSIVE MEDICINES MONITORING PROGRAMME AS PART OF NEW ZEALAND PHARMACOVIGILANCE

The IMMP operates within the NZ Pharmacovig-ilance Centre (NZPhvC), which also incorporates the national spontaneous reporting programme – the Centre for Adverse Reactions Monitoring (CARM). The NZPhvC is located in the Department of Preven-tive and Social Medicine at the University of Otago. Most of the activities of the NZPhvC are under-taken under contract to the Ministry of Health, which provides the majority of the funding for the Centre. Both programmes in the NZPhvC (IMMP and CARM) report to the Ministry of Health’s medicines regulatory body (Medsafe) and its expert advisory group the Medicines Adverse Reactions Committee (MARC). This illustrates some differences to the UK PEM scheme, which is not a govern-ment funded unit and does not report directly to the medicines regulatory body or its committees. In addition, because the IMMP operates within the national pharmacovigilance centre, all spontaneous reports for monitored medicines are entered into the IMMP databases, which enhances the identifica-tion of adverse events (see IDENTIFICATION OF EVENTS).