Trends of reporting of ‘serious’vs. ‘non‐serious’ adverse drug reactions over time: a study in the French PharmacoVigilance Database

• Several factors are known to influence spontaneous reporting of adverse drug reactions (ADRs). Among them, 'seriousness' of the reaction is one of the most important. • However, evolution in the reporting of 'serious'vs.'non-serious' ADRs over time for the same drug remains unknown.• Spontaneous reports mainly involve 'non-serious' ADRs during the first years of marketing and 'serious' ADRs later, particularly for drugs with non-hospital use.To investigate trends in spontaneous reporting to the French Pharmacovigilance system of 'serious' (SADRs) and 'non-serious' (NSADRs) adverse drug reactions over time.Annual SADR : NSADR ratios were calculated for each drug and their evolution tested with linear trend tests.Among the 39 new active substances commercialized in France in 2000, 16 had sufficient data to perform linear trend tests. An increasing linear relation was found for five widely prescribed drugs, a non-significant increasing trend for eight others, i.e. drugs mostly used in hospitals.ADR reports mainly concern NSADRs during first years of marketing. Reports of SADRs are proportionally more frequent later.