Medical product information contains information about efficacy and safety for marketed pharmaceuticals.
Three studies have compared safety labelling for different therapeutic categories in different countries and detected large
variations in a number of reported adverse drug reactions (ADRs). The rapid increase in use of medications for treatment
of ADHD symptoms has created concern due to lack of information about effects from long-term use. The aim of this
study was to compare ADR information in product information (PI)/summary of product characteristics (SPC) for oral
formulations of atomoxetine, methylphenidate and modafinil marketed by the same pharmaceutical companies in
Australia, Denmark and the United States. Discrepancies in listed ADRs were defined as types of ADRs (system organ
class) not listed in all countries. For ADRs where discrepancies were detected, we extracted information about study
design (clinical trials, spontaneous report). Discrepancies in ADR labelling for the medications were found across the
three countries. A total of 75 ADR categories were listed for atomoxetine and 80% of these were listed in all three
countries. For methylphenidate, totally 101 ADR categories and for modafinil 115 ADR categories were listed. For both
substances approximately 60% of listed ADRs were found in all three countries. Discrepancies were primarily detected
for ADRs information based on clinical trials. For methylphenidate, many ADRs labelled in Australia and Denmark were
not mentioned in PIs issued in the United States. In conclusion, information about possible ADRs associated with the use
of a specific product should be made available worldwide, as the prescriber information about medicines’ safety profile
should not depend on the country in which the medication is licensed.
Keywords: Adverse drug reaction, atomoxetine, international comparison, medicines safety, methylphenidate, modafinil,
product information, summary of product characteristics.
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