Use of warfarin and novel oral anticoagulants (NOACS)

Abstract

Warfarin is a commonly prescribed oral anticoagulant. It has a narrow therapeutic window and requires frequent International Normalised Ratio (INR) monitoring. Warfarin doses vary according to the INR. NOACs include apixaban, dabigatran and rivaroxaban. NOACs have a predictable anticoagulant effect and therefore doses are fixed. NOACs do not require INR monitoring. NOACs have less food and drug interactions than warfarin. The main limitation of NOACs over warfarin is their high cost. Not all warfarin patients should be switched to a NOAC. Patients who are stable on warfarin and patients with a mechanical valve or valvular atrial fibrillation (AF) should not be switched to a NOAC. (Verdecchia et al., 2016) The aims of this study are to assess the level of knowledge of health care professionals (HCPs) on NOACs and to assess perception of patients on warfarin regarding adherence to treatment, awareness of NOACs and willingness to switch to a NOAC. The study is set in 8 community pharmacies, conveniently sampled from the different statistical districts. Each pharmacy analysed and identified the amount of warfarin and NOACs patients. The amount of warfarin patients was higher in all 5 districts. Three questionnaires were formulated and validated; one for general practitioners (GPs), one for pharmacists and one for warfarin patients. A total of 21 GPs, 25 pharmacists and 76 patients were interviewed. The HCPs highlighted the advantages and disadvantages of both classes of oral anticoagulants. The high cost of NOACs and need to include them in the government’s outpatients formulary list were emphasised. The results from the patients questionnaire showed that the interviewees seem to be wellcontrolled on warfarin. A few patients experienced adverse drug reactions (ADRs), 2 of which required hospitalisation. The majority of patients know about the availability of NOACs and about the differences from warfarin. Only a minority of patients are willing to switch and pay for NOACs (if suitable for them). The inclusion of NOACs in the government’s outpatient’s formulary list will increase accessibility. Nonetheless, the use of warfarin will not stop here. It is of utmost importance to keep on educating patients making use of anticoagulant treatment, particularly warfarin.