The Prevalence of Sub Optimal Anti Coagulation

Poor Drug Response

A study on warfarin administration to show whether noncompliance of the patient will affect our target (INR) during therapy or not beside its drug and dietary interactions. The study will show the prevalence of sub optimal anti coagulation among patients with prosthetic cardiac valves that will undergo warfarin therapy.

Besides the risk of infective endocarditis, thromboembolism from the foreign body structures of the prosthesis remains a major problem, which can be effectively reduced, but not inhibited by the use of oral anticoagulants in patients with prosthetic cardiac valves. Warfarin as a vitamin k antagonist is widely used to decrease risk of thromboembolism but need strict monitoring for INR to avoid warfarin failure or hemorrhage. It acts through inhibiting an enzyme called the vitamin K1 2,3 epoxide reductase complex, subunit1 (VKORC1). All patients with mechanical heart valves need the oral anticoagulation to keep the INR between 2.5:3.5 according to valve type, position and other comorbid conditions. However some patients need higher than expected doses of warfarin to get their (INR) into the target therapeutic range. Resistance to warfarin has been described as the inability to prolong the prothrombin time or raise the international normalized ratio (INR) into the therapeutic range when the drug is given at normally prescribed doses. Resistance is different than warfarin failure ,which is defined as a new thrombotic event despite a therapeutic prothrombin time and INR . The causes of warfarin resistance can be either acquired from high consumption of vitamin K or C ,decreased absorption or increased clearance of the drug ,dietary or drug interactions or hereditary by genetic factors that result either in faster metabolism of the drug (a form of pharmacokinetic resistance) or in lower activity of the drug (pharmacodynamic resistance).

No related papers found yet.