http://dx.doi.org/10.1160/TH14-05-0433 Thromb Haemost 2014; 112: 853–856 For the first four decades after their introduction in 1941, the clinical use of vitamin K antagonists (VKAs) was hampered by haphazard laboratory control, lack of rigorous evidence for efficacy, and bleeding complications. In this narrative historical perspective, I discuss my personal experience in providing evidence for...

BACKGROUND Vitamin K antagonists are effective in the prevention and treatment of thromboembolic disorders. Warfarin is one of the most widely prescribed vitamin K antagonists in the world [1, 2]. It has a narrow therapeutic range and a given dose may result in a large inter-individual variation of response. Insufficient dose may fail to prevent thromboembolism, while an overdose increases the ...

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to interact with the oral anticoagulant warfarin and can cause a serious bleeding complication. In this study, we evaluated the risk factors for international normalized ratio (INR) increase, which is a surrogate marker of bleeding, after addition of an NSAID in a total of 98 patients who used warfarin. Patient age, sex, body mass index, m...

BACKGROUND Obstructive sleep apnea hypopnea syndrome (OSAHS) constitutes an independent factor for high warfarin dose for patients with pulmonary embolism (PE). The aim of this study was to investigate whether the 6-month anticoagulation treatment by warfarin is enough for patients with PE complicated by OSAHS. METHODS We investigated 97 PE patients, 32 of them had OSAHS and 65 non-OSAHS. War...

BACKGROUND The activated partial thromboplastin time (APTT) is used to adjust heparin sodium dosage. However, warfarin sodium is often administered concomitantly with heparin and may also affect the APTT and, therefore, heparin dose. We performed a prospective cohort study to quantify the effect of warfarin on the APTT in patients who are being treated with heparin. METHODS Serial assays of A...

BACKGROUND AND PURPOSE Intracranial hemorrhage is the most devastating complication of anticoagulation. Outcomes associated with different sites of intracranial bleeding occurring with warfarin versus dabigatran have not been defined. METHODS Analysis of 18 113 participants with atrial fibrillation in the Randomized Evaluation of Long-term anticoagulant therapY (RE-LY) trial assigned to adjus...

OBJECTIVE The p.V433M in cytochrome P450 4F2 (rs2108622, CYP4F2*3) is associated with a higher warfarin dose and lower risk of hemorrhage among European Americans. We evaluate the influence of CYP4F2*3 on warfarin dose, time to target international normalized ratio (INR), and stable dose, proportion of time spent in target range (PTTR), as well as the risk of overanticoagulation and hemorrhage ...

AIMS The influence of CYP2C9 and VKORC1 on warfarin dose, time to target International Normalized Ratio (INR), time to stabilization, and risk of over-anticoagulation (INR: > 4) was assessed after adjustment for clinical factors, intraindividual variation in environmental factors and unobserved heterogeneity. MATERIALS & METHODS Common CYP2C9 and VKORC1 polymorphisms were assessed in 302 Euro...

Atrial fibrillation (AF) is considered as one of the most common cardiac arrhythmias worldwide and always associated with a significantly increased risk stroke thromboembolism. VKAs (Warfarin & Acenocoumarol) are highly effective in reducing patients AF, but bleeding issues disutility sparked development direct oral anticoagulants (DOACs) or NOACs (Novel anticoagulants). These drugs, offer ...

Objective: To investigate the efficacy and safety of genotype-based anticoagulant therapy with warfarin in patients with atrial fibrillation. Methods: A total of 66 patients with non-valvular atrial fibrillation treated admitted to our hospital from December 2014 to May 2015 were enrolled in this study. The patients were randomly allocated to the control group (n=33) and the intervention group ...