Postmarketing safety information: how useful are spontaneous reports?

UNLABELLED

From 1995 until June 1998 123 new chemical entities (NCEs) were launched in Switzerland. In this time period 250 reports of adverse reactions (ADRs) involving 56 different NCEs were reported to the Swiss Drug Monitoring Center SANZ directly by physicians within the voluntary spontaneous reporting scheme (SRS). No cases from observational or clinical postmarketing studies were included. Of the reports 88% were suspected to be drug-related and 20% of them were serious. In 64% the ADRs were unlabelled and not notified to the health professionals. Disorders of the central nervous system (CNS) were reported in 32% and cardiovascular disorders in 26% of the unlabelled and serious cases. The non-serious cases accounted for 80% of the reported NCE-ADRs and 60% of them were unlabelled. Skin reactions were reported most frequently (18%), followed by psychic (15%), gastrointestinal (10%), cardiovascular and CNS disorders (8% each). In the labelled non-serious cases gastrointestinal and skin reactions were reported in 25% and 24% respectively. The other system organ classes were involved to a much smaller extent (<8%).

CONCLUSIONS

(1) Spontaneous reports are of great value in optimizing postmarketing safety information. (2) Early reports give rise to a different ADR profile than expected from premarketing safety information. (3) Spontaneous reports have a strong signalling function especially for drugs used by general practitioners. (4) Sensitive signal detection systems are of great value in detecting non-labelled and serious ADRs in an early phase.