Klin Farmakol Farm. 2008;22(1):6-10

Knowledge, perception of risks and compliance of patients using warfarin

Karel Urbánek¹, Ilona Kohlová², Jana Marečková³

¹ Ústav farmakologie LF UP a FN Olomouc

² II. interní klinika FN a LF UP Olomouc

³ Ústav ošetřovatelství a porodní asistence, LF UP Olomouc

Warfarin is one of the most effective drugs used in cardiology, but at the same time it has high risk of unwanted effects and drug interactions. Patient`s compliance, as well as the knowledge of interactions with food, can strongly affect the safety of the treatment. The objectives of this study were to explore patient`s awareness and perceptions of warfarin risks, knowledge of food influence on the warfarin effect and the compliance with treatment. Standard individual 23-item questionnaire was developed and used to assess perception of risks and compliance among patients using warfarin. Baseline information on sociodemographic characteristics, awareness of warfarin adverse effects, compliance with therapeutic regimen and knowledge of interactions with food and OTC drugs were measured. The study was performed in warfarin-anticoagulated patients of 16 general practitioners in Olomouc and Brno regions in Czech Republic.

One hundred and two patients (51 men, 51 women, 56 % of them older than 70, 61 % using warfarin longer, than one year) treated by warfarin were interviewed using a semi structured questionnaire. Eighty nine per cent of responents knew the reason of warfarin treatment, 97 % were informed about the treatment, mostly by the doctor, but only 36 % knew the risk of bleedeing. Awarenes of the risk of bleedeing was independent on usage of written information material about anticoagulant therapy (Chi-square, p = 0,308). Sixty one per cent of responders used more than 4 other drugs concomittantly with warfarin; 34 % of them used an OTC drug during last 3 months, but only 29 % of them informed the pharmacist about the fact of warfarin use. Possible affection of warfarin effects by food was deny by 62 % of asked patients. The knowledge of this risk was significantly (p < 0,01) dependent on the level of responder`s school education.

The results of our study show the necessity of improvement in education of patients treated by warfarin, not only by doctors, possibly with wider involvement of nurses and pharmacists.

Keywords: Key words: warfarin, compliance, interactions, adverse effects.

Published: April 1, 2008  Show citation