In Switzerland, the Bayer company is now providing information on the very rare but potentially life-threatening risks of STEVENS-JOHNSON syndrome and agranulocytosis in patients receiving the oral anticoagulant rivaroxaban (XARELTO). On the basis of spontaneous reports, a reporting rate of 0.04 per 10,000 patient years for the severe skin reaction and 0.03 per 10,000 patient years for agranulocytosis is stated (1). It is our opinion, however, that the assumption can be made that there is a not insignificant number of unreported events. Patients should be informed of the possible signs and symptoms and contact their doctor if any of these occur (1).
The European Medicines Agency (EMA) overviews 34 reports of suspected cases of STEVENS-JOHNSON syndrome in patients taking the factor Xa inhibitor and 24 of agranulocytosis, 3 of which were fatal (2). In the USA, both adverse effects have been listed in the product information since the drug was approved there in 2011 (3), while to date there has been no reference to this in the summary of product characteristics (SPC) in Germany (4).