Background Adverse drug reactions are the main cause of 2–8% of hospital admissions in Europe. Of all drug classes with important adverse reactions described, oral anticoagulants (OAC) are one of the most prevalent. From all available OACs, warfarin remains a drug of choice due to its low cost and demonstrated efficacy (reduces the risk of stroke by two-thirds and mortality by a quarter compared with controls, aspirin or no therapy). One of the main difficulties in the safe use of warfarin is to maintain the international normalised ratio (INR) between the reference ranges, with the elderly being more susceptible due to their comorbidities, polypharmacy and ageing per se.

Purpose To analyse the percentage of hospital admissions due to bleeding events associated with the intake of warfarin and the impact of these events on patients.

Material and methods Retrospective analysis of prescriptions for phytomenadione in the emergence department. All patients that received phytomenadione for treating bleeding associated with warfarin were included. The information was cross checked with patient files and laboratory results (INR). The sample analysed included 98 patients (55 men; 43 women), aged between 60 and 90 years (67% of sample). The follow-up period was from January 2016 to the end of August 2016.

Results 1.24% of all hospital admissions were due to bleeding events related to warfarin. 55 registered cases corresponding to 44 patients, of whom 21 were symptomatic. At the time of admission, 45% presented an INR >6.0. Major causes responsible for an increase in INR were acute kidney injury (27%) and infections (22%). 17 patients remained hospitalised and there were two therapeutic switches, 1 to dabigatran and 1 to rivaroxaban.

Conclusion There is a need for a closer link between primary health care services and secondary care organisms in order to guarantee better support to populations likely to suffer an adverse drug reaction.

References and/or acknowledgements Kirchhof P, et al. 2016ESC guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J2016;37(33).

No conflict of interest