Introduction: Information regarding adverse drug reactions (ADRs) of new medications is based on clinical studies of selected populations. The reporting of ADRs from real-life use following the marketing of new active substances is instrumental for the continuous evaluation of their benefit-risk balance. The aim of this study was to determine the number and nature of ADR reports in Iceland and compare with other Nordic countries.

Materials and methods: Reports of ADRs from 2013 to 2016 were examined using the Icelandic Medicines Agency´s database. The total number and seriousness of ADRs by ATC-classification of drugs were compared with data published in the 2013 to 2015 annual reports from the Swedish, Danish and Norwegian Medicines Agencies. Comparison of sales between countries was examined.

Results: The number of ADR reports in Iceland was between 36 to 104 per 100 thousand inhabitants/year, with less than 10% defined as serious. This compares to 58 to 133 ADR reports per 100 thousand inhabitants in the other Nordic countries, with 38% to 64% of ADRs classified as serious. In Iceland, ADR reports were more common for medications in ATC-class A and less common for classes B, J and L compared to the other Nordic countries. Sales of medications were comparable between these nations.

Conclusion: There is great variability in the number of ADRs reported annually in Iceland. The drugs reported are within different ATC-classes and the proportion of serious ADRs is low compared to the other Nordic countries. This is not explained by different sales volumes.

Table I ATC classification of drugs.

Table II General information regarding the adverse drug reactions reported in 2013 to 2015 to The Icelandic Medicines Agency.

Figure I The number of ADR reports per 100 thousand inhabitants in Iceland, Sweden, Denmark and Norway for the years 2013 to 2015. The color of colomns indicate the number of ADRs that are serious (red), not serous (blue) and unknown if serious or not (grey).

Figure II The number of ADR reports in each ATC class of drugs per 100 thousand inhabitants in Iceland during the years 2013 to 2015). The upper graph (A) indicates the number of serious and non-serious ADRs, whereas the lower graph (B) indicates the number of ADRs due to lack of efficacy (blue) compared to drugs with efficacy

Figure III The number of ADR reports and sales of medication in each ATC class in Iceland (IS), Norway (NO) and Sweden (SE) for the year 2014. A) Number of ADR reports per 100 thousand inhabitants B) The number of defined daily doses (DDD) sold per 1000 inhabitants.