Drug information of Warfarin

Warfarin

Drug group: Anticoagulants

Warfarin is an anticoagulant (blood thinner). Warfarin reduces the formation of blood clots. Warfarin is used to treat or prevent blood clots in veins or arteries, which can reduce the risk of stroke, heart attack, or other serious conditions.

Mechanism of effect

Warfarin inhibits vitamin K reductase, resulting in depletion of the reduced form of vitamin K (vitamin KH2). As vitamin K is a cofactor for the carboxylation of glutamate residues on the N-terminal regions of vitamin K-dependent proteins, this limits the gamma-carboxylation and subsequent activation of the vitamin K-dependent coagulant proteins. The synthesis of vitamin K-dependent coagulation factors II, VII, IX, and X and anticoagulant proteins C and S is inhibited. Depression of three of the four vitamin K-dependent coagulation factors (factors II, VII, and X) results in decreased prothrombin levels and a decrease in the amount of thrombin generated and bound to fibrin. This reduces the thrombogenicity of clots.

Pharmacodynamic

Warfarin, a coumarin anticoagulant, is a racemic mixture of two active isomers. It is used in the prevention and treatment of thromboembolic disease including venous thrombosis, thromboembolism, and pulmonary embolism as well as for the prevention of ischemic stroke in patients with atrial fibrillation (AF).

Pharmacokinetics

Rapidly absorbed following oral administration with considerable interindividual variations. Also absorbed percutaneously. 99% bound primarily to albuminMetabolized stereo- and regio-selectively by hepatic microsomal enzymes. Very little warfarin is excreted unchanged in urine. The metabolites are principally excreted into the urine; and to a lesser extent into the bile.

Dosage

Usual Adult Dose for Deep Vein Thrombosis - Recurrent Event
Initial: 2 to 5 mg orally or intravenously once a day for 1 to 2 days, then adjust dose according to results of the International Normalized Ratio (INR) or prothrombin time (PT).
Maintenance: the usual maintenance dose ranges from 2 to 10 mg orally or intravenously once a day.

Interactions

Atorvastatin , Atomoxetine , Azathioprine , Azithromycin , Alteplase , Allium- S , Blonanserin , vorapaxar , vortioxetine , Venetoclax , Roxithromycin , tropisetron , Ipilimumab , tibolone , Aminophenazone , bazedoxifene/conjugated estrogens , Netonal , Oxaprozin , Vorinostat , Urokinase , Triphasic , norfloxacin , Secobarbital , Edoxaban , Rofecoxib , Cordyceps , Lorlatinib , Troleandomycin , Butabarbital , Urokinase , icosapent , Betrixaban , Drotrecogin alfa , Ramucirumab , Cefditoren pivoxil , Cefdinir , Cefoxitin , Cefotetan , Milnacipran , Grepafloxacin , Tositumomab , Ibritumomab tiuxetan , Dabrafenib , Ardeparin , Estropipate , Cefpodoxime , Efavirenz , Esmolol , Aceclofenac , Acemetacin , Chitosan , Tinzaparin , Parecoxib , Dalteparin , Glucagon , Methohexital , Telmisartan , Chloral hydrate , novafen , Ginkgo biloba , Etidronic Acid , Cefadroxil , Tigecycline , Peginterferon alfa-2b , Rosiglitazone , Tirofiban , Dexmethylphenidate , chlorpropamide , L-Carnitine , Felbamate , Phenindione , Desirudin , Argatroban , Mifepristone , Quinine , Indinavir , teriflunomide , Ethinyl Estradiol , ritonavir , saquinavir , Zileuton , Apixaban , Econazole , Influenza vaccine , Fluoxymesterone , Dabigatran , fluvastatin , methylene blue , Rifabutin , Carbenicillin , Vancomycin , ethacrynic acid , Aspirin , cefepime , Sofosbuvir , ledipasvir and sofosbuvir , escitalopram , miconazol , sulfinpyrazone , Cefalotin , Curcuma , Rivaroxaban , Disulfiram , Rucardin , Cratagol , Rosuvastatin , Soyagol , valirest , Enzalutamide , Digester , Lithorex-B , Bicalutamide , Clofibrate , Cloxacillin , Contraceptive DE , Cotrimoxazole , Cholestyramine , Tranquival , Carbamazepine , Ketorolac , Chloramphenicol , Chlorpromazine , Chlordiaze poxide , Clopidogrel , Nalidixic acid , Nervoxin , orlistat , Vitamin E , Vitamin C , Capecitabine , Medroxyprogesterone , Mesna , Melatonin , Moxifloxacin , Milrinone , acitretin , Leflunomide , Levamisole , Lovastatin , Levofloxacin , Metronidazole , Methyl salicylate , Phyto arthrit , Finasteride , Glucosamine , Gliclazide , Lansoprazole , Letrozole , Citalopram , Flutamide , Fluticasone propinate , Fluvoxamine , Fluoxetine , Phenytoin , Ceftriaxone , Cefixime , Sorafenib , Sevelamer , Sulfasalazine , Ciprofloxacin , Rowachol , Cod liver oil , Royal jelly , Royal jelly+Ginseng , Sawpalmatto , Sawpalmatto complex , Tolmetin , Tinidazole , Danazol , Disopyramide , Digoxin , Rowatinex , Pneumovax , Penicillin G , Piascledine , Piroxicam , Tanacetum parthenium , Feverfew , Tolterodine , Propafenone , Propofol , Propyl thiouracil , Protamine sulfat , Primidone , pentoxifylline , Imatinib , Indomethacin , Ivermectin , Bosentan , Achillea millefolium , Paroxetine , Olanzapine , Omeprazole , Oxandrolone , Oxymetholone , Ibuprofen , Ifosfamide , Ezetimibe , Esomeprazole , Acetaminophen , Stragol , Estramustine , Ofloxacin , ampicillin , Amoxicillin , Amitriptyline , Aprepitant , Erlotinib , Erythromycin

Alerts

1-Warfarin sodium can cause major or fatal bleeding. Warfarin sodium can cause major or fatal bleeding. Bleeding is more likely to occur within the first month. Risk factors for bleeding include high intensity of anticoagulation (INR > 4.0), age greater than or equal to 65, history of highly variable INRs, history of gastrointestinal bleeding, hypertension, cerebrovascular disease, anemia, malignancy, trauma, renal impairment, certain genetic factors, certain concomitant drugs, and long duration of Warfarin therapy.
2-Drugs, dietary changes, and other factors affect INR levels achieved with Warfarin sodium therapy

Points of recommendation

1- Perform regular monitoring of INR in all treated patients
2-Instruct patients about prevention measures to minimize risk of bleeding and to report signs and symptoms of bleeding

Pregnancy level

X

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