Safety profile of non-vitamin K oral anticoagulants (NOACs) from a patient perspective: a web-based cohort event monitoring study.

: Non-vitamin K oral anticoagulants (NOACs) are a relatively new group of anticoagulants. Characteristics of adverse drug reactions (ADRs) as experienced by patients in everyday use have not yet been fully clarified. The aim was to gain insight into the safety profile of NOACs from a patient's perspective. : This was a prospective, observational web-based cohort event monitoring study among first-time users of NOACs. Patients were recruited between July 2012 and April 2017. They were invited to complete four web-based questionnaires 2 weeks, 5 weeks, 3 months and 6 months after starting treatment. Information was collected about patient characteristics, drug use, and characteristics of ADRs. : 1748 NOAC users were included. 661 (38%) experienced at least one ADR. The reported ADRs were comparable with the information described in the Summary of Product Characteristics and generally occurred within 1 week after the start. In 59% of ADRs the patients recovered. These ADRs had no impact on the use and dosage of the NOAC in 68%. In total, 9% of the patients discontinued the NOAC because of ADRs. : Overall NOACs were well tolerated by the participants. Most reported ADRs occurred within 1 week after the start. Patients recovered from most ADRs without changes to the use of the NOAC.