Warfarin Part II
Dear Bloggers, Shalom
I'm back with the second part of my blog, I entitled Warfarin Part II.
In this part, I will share mainly three aspects: Warfarin interactions, its adverse Effect and Its Reversal.
O Warfarin Interactions.
As I already pointed out, warfarin is a common simple and complex anticoagulation drug due to the fact that it has been used for decades (simple) and due to the several factors which interact with its pharmacokinetics and pharmacodynamics proprieties.
u Drug-drug interactions 
High protein binding, Cytochrome P450 dependant metabolism and a narrow therapeutic range are three unfavorable proprieties which give warfarin a potential life threatening drug-drug interactions. Having a concomitant drug therapy/regimen always makes hard to predict the response of the anticoagulation control in a patient. That's why it's recommended to monitor the INR (International Normalized ratio) every 2days. Some drugs such as antibiotic (Macrolides, quinolones), Fluconazole, SSRIs, antiplatelet agents, antiarrhythmics, anti-inflammatory agents, phentoin through different mechanism of action can increase INR and others drugs such as Rifampicin, carbamazepine and phenobarbitone also through certain mechanism of action can decrease INR.
u Drug-food interactions 
As we might know that food with high intake of vitamin K (which is largely sourced from green vegetables) can/will influence anticoagulation response from Warfarin. The administration of warfarin increases the sensitivity of people to small fluctuation in their vitamin K intake. We should also know that smoking causes enzyme induction and therefore potentially lowers the INR. Mustard, chard, Turnip, Parsley constituent foods high in Vitamin K. As foods moderate in vitamin K we can have Avocado, beans, Tofu, Lettuce and Spinach. And in foods low in Vitamin K we have asparagus, carrots, potatoes, meat, fish and poultry.
u Drug-herb Interaction [3-5]
Herb-drug interactions are based on the same pharmacokinetics and pharmacodynamics mechanism as drug-drug interactions.
Herbs that are potentially increasing INR and/or the risk of bleeding are: Boldo, Ginger, Ginkgo, and Garlic. Those that are potentially decreasing INR and/or the risk of bleeding are: Ginseng and Green tea.
u Drug-disease Interaction [6-7]
Certain sickness or concomitant diseases are crucial factors that can influence the INR. Hepatic dysfunction potentiates warfarin responsiveness through impaired synthesis of coagulation factors.
Diseases like Cancer, Collagen vascular, vitamin K deficiency, Heart failure and Hyperthyroidism increase warfarin effect while others illness such as Hypothyroidism, Edema and Nephrotic syndrome decrease Warfarin effect.
O Warfarin Adverse Effect.
As any others drugs, warfarin has some complications. The Common adverse effects are bleeding , skin Necrosis , purple toes syndrome , fetal warfarin syndrome and other rare adverse effects are alopecia, osteoporosis and rush.
O Warfarin Reversal
Warfarin therapy is a quite problematic due of its wide inter-individual and intra-individual variation in dosage requirements. Therefore the connection between warfarin sensitivity and serious bleeding is inevitable. Then if warfarin reversal is required, the method chosen should reflect the clinical seriousness of bleeding and balance against the thrombotic risk of temporary suspension or reduction of anticoagulation.
According to the serious of the bleeding, the warfarin reversal is categorized as Rapid, Fast, Prompt, Slow and Ultra slow options. But regardless the options for warfarin reversal, the UK and US guidelines for reversal of warfarin mention a potential role for FFP (Fresh Frozen Plasma) and PCCs (Prothrombin Complex Concentrate) in major bleeding.
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This Blog does not contain Any Plagiarized Materials.
This Blog does not contain Any Plagiarized Materials.