What is this medication?
Anticoagulant; Vitamin K Antagonist
Warfarin, Coumadin/Jantoven is officially indicated for atrial fibrillation, myocardial infarction, cardiomyopathy, mechanical valve replacement, venous thromboembolism, thromboprophylaxis, hip arthroplasty, hip fracture surgery, knee arthroplasty, and heparin induce thrombocytopenia. (may be used for conditions not listed)
“ALERT: US Boxed Warning
Warfarin can cause major or fatal bleeding. Perform regular monitoring of international normalized ratio (INR) on all treated patients. Drugs, dietary changes, and other factors affect INR levels achieved with warfarin therapy. Instruct patients about prevention measures to minimize the risk of bleeding and to report immediately to their health care provider signs and symptoms of bleeding.”
How does this medication work?
Vitamin K is involved in the synthesis of many coagulation factors (II, VII, IX, X), protein C and protein S. Normally the active form of vitamin K is oxidized into an inactive form to activate these clotting factors and the inactive form is reactivated by vitamin K epoxide reductase complex 1 (VKORC1) to be used again. Warfarin/Coumadin/Jantoven inhibits subunit 1 of the multiunit VKORC1 complex thereby depleting active vitamin K stores. This reduces the synthesis of active clotting factors which in turn decreases coagulation.
How should I take this medication?
Generally dosed once daily in an individualized manner, the amount of which is dependant on patient’s INR, normally falling between 2 and 10mg for most patients. INR target is normally 2-3 or 2.5-3.5 when high levels of anticoagulation are required. When starting warfarin, it may take days for vitamin K levels to deplete followed by coagulation factors depletion, therefore bridging therapy with a parenteral anticoagulant is common for high risk patients.
How to Take: Follow instructions provided by physician/pharmacy label, take consistently at same times each day unless otherwise directed, store at room temperature. Diet should be consistent as foods rich in vitamin K can decrease the effects of warfarin. If a high vitamin K diet is normal, then your dosage will end up higher however if this suddenly changes you make become over anticoagulated.
You Need to Avoid: Alcohol may raise INR so use cautiously. Do not stop this medication suddenly or without involvement of your physician. Prematurely stopping this medication can cause increased risk of a thrombotic event such as stroke so generally if changing medications, a bridging schedule is required. If the medication is to be discontinued follow your physician’s instructions, the exception to this is if a major bleed is occurring in which case it must be stopped immediately, and emergency medical attention is required. If a dosage is missed the general recommendation is to take the dosage as soon as you remember and then to continue your normal dosing schedule the following day. Confirm with your physician if you are wanting to use any NSAIDs such as ibuprofen, ASA or naproxen. Do not self-select over the counter items such as these without asking a medical professional due to risk of ulceration and a severe hemorrhage.
What should I watch for while using this medication?
Before starting Warfarin/Coumadin/Jantoven make sure your physician is aware of any allergies or medications you currently take, if you have kidney disease, if you have liver disease, if you have had bariatric surgery, if you have a bleeding disorder or active pathological bleed (such as an ulcer), if you have thyroid disease, an active infection, a dietary insufficiency (vitamin k deficiency), or if you are pregnant or breastfeeding
What if I miss a dose?
If you miss a dose of medication, try to take it as soon as possible. However, if it is almost time for your next dose, take only that scheduled dose. Do not take double or extra doses.
How should I store this medication?
Keep out of the reach of children at all times. Store at room temperature, 59 to 86° F (15 to 30° C). Protect from light. Keep the container tightly closed. Properly dispose of any unused medication after the expiration date.
What are the possible side effects of using this medication?
The main side effects are bruising and hemorrhage (bleeding) both minor and major. Patient should monitor for weakness, dizziness, unexplained edema, black tarlike stool, what appears to be coffee grounds in vomit, major unexplained bruising, minor cuts that do not stop bleeding, blood when brushing teeth etc. These are signs of over anticoagulation or an internal bleed in which case immediate medical attention is required.
Note this is not a complete list of side effects, only common ones
- Choosing a selection results in a full page refresh.
- Press the space key then arrow keys to make a selection.