[Adverse events related to substitution of generic products in Norway 2005].
BACKGROUND
The Norwegian Medicines Agency has since 2003 encouraged health professionals to report adverse events (AEs) related to generic substitution through the spontaneous reporting system. Goals of this study were to evaluate the quality of these reported AEs and to assess whether there were signals of altered efficacy or AEs related to substitution of such products.


METHODS
The World Health Organisation's (WHO) tool for documentation grading was used to evaluate the AE reports. Signals of AEs were identified based on WHO's signal definition.


RESULTS
423 spontaneous reports concerning substitution of generic products were identified; 232 (55 %) of these reached documentation grade 1?-?3 and could be used to detect signals of AEs. The AEs were mostly common symptoms that also appear in the general population not treated with drugs. Only two of the 423 reports were classified as serious AEs. Signals of dizziness and muscle pain were identified after substitution of the original product Norvasc with the generic product Amlodipin Ratiopharm. Amlodipine was the substance associated with most AE reports; i.e. 79 (19 %) reports.


CONCLUSIONS
About half the spontaneous reports regarding substitution of generic products could be used for signal detection. The substitution of generics does not seem to represent a safety problem.
Reppe
Linda Amundstuen
LA
RELIS Midt-Norge Avd. for klinisk farmakologi St. Olavs Hospital 7006 Trondheim. linda.reppe@legemidler.no
Stenberg-Nilsen
Hanne
H
Harg
Pernille
P
Hegge
Anne Bee
AB
Lillefloth
Anna Karine
AK
Buajordet
Ingebjørg
I
D016907:Adverse Drug Reaction Reporting Systems / Q000592:standards; D004282:Documentation / Q000592:standards; D064420:Drug-Related Side Effects and Adverse Reactions; D016568:Drugs, Generic / Q000009:adverse effects*; D006801:Humans; D009664:Norway; D011358:Product Surveillance, Postmarketing / Q000592:standards; D011785:Quality Assurance, Health Care
D016568:Drugs, Generic