Oral Anticoagulant Therapy—50 Years Later

Abstract

The year 1991 marked the 50th anniversary of the first clinical use of oral anticoagulant therapy as a means of preventing thromboembolic disease. Despite long-term physician familiarity with oral anticoagulants, this mode of therapy still suffers from a relatively high-risk/safety profile. This review briefly highlights important historical and pharmacokinetic points of interest but focuses predominantly on aspects of the day-to-day management of anticoagulant therapy aiming to enhance physician performance in this therapeutic milieu. Emphasis is placed on therapeutic monitoring, understanding the prothrombin time, managing complications, and assessing future innovations for the management of a growing population of patients treated with orally administered anticoagulants.

Comparison of an Anticoagulation Clinic With Usual Medical Care

“…The deterrent to warfarin use was that physicians "needlessly fear its side effects," and the suggested solution was monitoring by nurse practitioners or physician assistants. Even so, Ansell et al 5,6 questioned the benefits of ACs, and Fihn 7 noted that "There are regrettably few studies addressing such important topics as whether nurses or pharmacists operating an AC perform as well as or better than cardiologists or primary care physicians providing usual care." In fact, descriptive reports of 9 ACs 8-16 and 3 usual medical care (UMC) groups, [17][18][19] together with 7 comparative trials, [20][21][22][23][24][25][26] indicate that ACs can reduce the annual major bleeding rate from 5% to 28% in UMC to 6% or less.…”

An Audit of Management of Patients on Oral Anticoagulant Therapy With International Normalized Ratio (INR) Five or Above

“…Maintaining the international normalized ratio (INR) within the therapeutic range is a challenge for the physician to achieve maximal therapeutic benefit of oral anticoagulants in patients. Adequate anticoagulation reduces the risk of life threatening thrombosis; however there is an increased risk of bleeding complications due to over anticoagulation that may occur during the course of therapy [1]. The risk of bleeding increases with increasing INR in patients on anticoagulation [2] and most minor and major bleeds occur in patients with INR of more than 5 [3].…”

Varfarina ou Aspirina na prevenção de fenômenos embólicos na valvopatia mitral com fibrilação atrial

“…However, in spite of the better applicability of Aspirin as an anti-thrombotic in patients with RMVD with native valve or biological prosthesis associated to AF, this alternative is little explored, thus becoming a challenge 7 . The objective of the present study was to evaluate whether the Aspirin therapy can be used in patients with RMVD and AF as an effective alternative to Warfarin, in a population at risk for thromboembolic events presenting treatment adherence difficulties when submitted to Warfarin therapy.…”