Anticoagulant-associated adverse drug reactions in 2013-15

The aim of this study was to obtain a better insight into the adverse effects profiles of the new direct-acting oral anticoagulants (DOACs).

A review was undertaken of all reports of adverse effects for warfarin, dabigatran, rivaroxaban and apixaban reported to the regional medicines information and pharmacovigilance centres (RELIS) in the period June 2013-May 2015.

Approximately 65 000 persons used direct-acting oral anticoagulants and 80 000 used warfarin in the period of the study. A total of 409 reports of adverse effects were included. Altogether 55 % of the reports applied to men. In 76 % of the reports for direct-acting oral anticoagulants and 85 % for warfarin, the patients were more than 70 years of age. The most common adverse effects were haemorrhages (48 % for direct-acting oral anticoagulants and 75 % for warfarin), most of which were cerebral haemorrhages (91 for direct-acting oral anticoagulants and 92 for warfarin). Blood clots (therapeutic failure), cognitive effects, headache and hair loss were some of the other adverse effects. The highest comorbidity was among the patients who died. The number of reported deaths was highest for rivaroxaban (1.1 deaths/1000 users) with a declining incidence for apixaban (0.9 ‰), dabigatran (0.7 ‰) and warfarin (0.6 ‰). There were different degrees of reporting for these medications, and the spontaneous reporting system cannot therefore be used to compare the incidence of adverse effects for the drugs.

Adverse effects, including serious effects, may occur when using all anticoagulants. Factors that may increase the risk of adverse effects are advanced age, high comorbidity, reduced renal function, and polypharmacy.