Page 75 - Radiology Book

Condition
Description
INR 3-5
no signi cant bleeding
Lower warfarin dose or omit 1-2 doses, monitor more frequently, and resume at a lower dose when INR therapeutic; if only minimally above therapeutic range, no dose reduction may be required (Grade 2C).
INR 5-9
no signi cant bleeding
Omit next one or two warfarin doses, monitor more frequently and resume at lower dose when INR in therapeutic range. Alternatively, omit dose and give vitamin K (≤5 mg orally x1), particularly if at increased risk of bleeding. If more rapid reversal is required because the patient requires urgent surgery, vitamin K (2 to 4 mg orally) can be given with the expectation that a reduction of the INR will occur in 24 hours. If the INR is still high, additional vitamin K (1 to 2 mg orally) can be given (Grade 2C).
INR ≥9
no signi cant bleeding
Hold warfarin therapy and give higher dose of vitamin K (5-10 mg orally) with the expectation that the INR will be reduced substantially in 24-48 hours. Monitor more frequently and use additional vitamin K if necessary. Resume therapy at lower dose when INR therapeutic (Grade 2C).
Serious bleeding at any elevation of INR
Hold warfarin therapy and give vitamin K (10 mg by slow IV infusion), supplemented with fresh plasma or prothrombin complex concentrate, depending on the urgency of the situation; recombinant factor VIla may be considered as alternative to prothrombin complex concentrate; vitamin K can be repeated every 12 hours. (Grade 1C).
Life- threatening bleeding
Hold warfarin therapy and give prothrombin complex concentrate supplemented with vitamin K (10 mg by slow IV infusion); recombinant factor VIla may be considered as alternative to prothrombin complex concentrate; repeat if necessary, depending on INR (Grade 1C).
Acetaminophen Alcohol (binge) Allopurinol Amiodarone Argatroban Aspirin Azithromycin Bactrim
Chloral hydrate Chloramphenicol Cimetidine Cipro oxacin Citalopram Clarithromycin
Doxycycline Entacapone Erythromycin Felbamate Feno brate Fluconazole Fluorouracil Fluvoxamine Gem brozil Clo brate Danazol Diltiazem Disopyramide Disul ram
In uenza vaccine Isoniazid Itraconazole Levo oxacin Metronidazole Miconazole Moxalactam Neomycin Nor oxacin O oxacin Omeprazole Phenylbutazone Piroxicam Propafenone
Propranolol Quinidine Ritonavir Sertraline Simvastatin Sulfamethoxazole Sul npyrazone Tamoxifen Testosterone Tetracycline Vitamin E Voriconazole Za rlukast
warfarin (CouMadin) reversal
73
Notes: Vitamin K (Phytonadione, Mephyton) is available as 5 mg tablets. For doses that cannot be given with the tablets, the vitamin K injectable solution can be given PO. SC route may produce unpredictable absorption therefore the PO route is preferred due to faster absorption and more predictable effectiveness. IV route may produce an anaphylactic reaction. Chest 2004;126: 204S-233S
drugs tHat increase inr
Warfarin