Comparison of Two Different Techniques Of Warfarin Dosing Determination - A Chemometrics Study.

A high prevalence of genetic polymorphisms increases sensitivity to warfarin therapy. In this study, we investigated 47 patients with effective long-term therapy by warfarin well-controlled by monitoring of International Normalised Ratio (INR). All patients were tested for gene polymorphisms VKORC1, CYP2C9*C2, and CYP2C9*C3, which were used for a dose calculation employing a program www.WarfarinDosing.org. The main goal was to investigate whether the warfarin doses determined by INR are in accordance with the doses calculated according to the pharmacogenetic algorithm. For this purpose, several chemometric tools, namely principal component analysis, cluster analysis, correlation analysis, correspondence analysis, Passing-Bablock regression, Bland-Altman method, descriptive statistics, and ANOVA were used. We also analysed the relationship between the dose of warfarin determined by INR and several constitutional and genetic factors. Statistically significant association between clinically optimized warfarin dose and indication for the treatment, age, and warfarin sensitivity determined by VKORC1, CYP2C9 gene polymorphisms were confirmed. Finally, we confirmed a good concordance between the INR determined warfarin doses and pharmacogenetic approach.

[Warfarin - its synthesis and properties in a twenty-year retrospective*]. / Warfarín - jeho syntéza a vlastnosti v dvadsatrocnej retrospektíve*

The review paper deals with some aspects of warfarin history and its use, at the beginning as a rodenticide and later as an anticoagulant. It describes its principal physical-chemical properties and it analyzes schematically the possibilities of its preparation by both selective and non-selective synthesis from coumarin derivatives. A survey of syntheses and its results are tabulated, including the literary references, and the paper is concluded with an evaluation of the prospects of this agent in comparison with alternative anticoagulants and its advantages, disadvantages and prospects.

A severe renal bleeding as a complication of coumarin therapy in Behçet's disease.

Behçet's disease is a systemic inflammatory disease, which predisposes patients to venous or arterial thrombosis. We report a case of 41-year-old patient who presented for several years with recurrent fevers, arthralgias, episodes of skin eruptions and recurrent bilateral deep venous ileofemoral thromboses, extending into the inferior vena cava, despite the oral anticoagulant therapy. Additionally, he also reported recurrent aphthous oral and genital lesions, and eye problems. A laboratory picture of chronic inflammation, normocytic anaemia and a finding of lupus anticoagulant/antiphospholipid antibodies were observed. PET raised a high suspicion of vasculitic PTT-lupus anticoagulant process, involving the large vessels. During an anticoagulant therapy by warfarin (dose in upper limit of therapeutic range), the left kidney had to be removed because of acute retroperitoneal haemorrhage. On histologic examination, the picture of nephritis was described. A detailed retrospective reevaluation of complex history as well as other clinical findings strongly raised the suspicion of a systemic vasculitic syndrome, such as Behçet's disease, accompanied by antiphospholipid syndrome. The patient responded well to the combination of colchicine and anticoagulant therapy by low-molecular-weight heparin. The episodes of fever, skin eruptions and other symptoms disappeared. We assume that this is a case of an unusual course of Behçet's disease presenting with a rare kidney involvement. Kidney disorder complicated the oral anticoagulant therapy for recurrent venous thromboses and led to the excessive renal bleeding, requiring nephrectomy. Recognition that nephritis is associated with Behçet's disease may be useful to prevent severe renal bleeding in relation to anticoagulant therapy.