Warfarin Therapy: Survey of Patients’ Knowledge of their Drug Regimen

Background: Warfarin is utilised for the treatment of thromboembolic disease. Its use demands a careful and continual monitoring given its narrow therapeutic index and potentially life-threatening complications. The aim of this study was to assess the extent of patients’ knowledge of their warfarin therapy.
Methods: A total of 200 consecutive patients from a single community hospital completed an online survey questionnaire (www.eSurveysPro.com). Using the responses to the questionnaire, we recorded compliance to warfarin therapy, knowledge about drug interactions, adverse effects of warfarin therapy, complications, and resulting hospitalisation.
Results: We recruited 200 patients, 55% (109/200) women and 45% (91/200) men, among which 88% were compliant with their daily medication. Of the 200 patients, 56% were unaware of any potential drug interactions, 58% were unaware of any adverse effects, 27% had experienced adverse effects, 12% had been hospitalised because of adverse effects (33% of which were due to bleeding), and 65% kept a personal record of their international normalised ratio.
Conclusions: Despite the high level of compliance, patient knowledge of warfarin therapy was low. Given the potential drug interactions and complexities involved with warfarin therapy, it is of high importance that medical professionals educate their patients and make them aware of any impending signs of emergent medical complications.