Coumadin

Warfarin

Clinical data
Pronunciation	/ˈwɔːrfəˌrɪn/ WORF-ə-rin
Trade names	Coumadin, Jantoven, Marevan, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682277
License data	US FDA: Warfarin
Pregnancy category	AU: D US: X (Contraindicated)
Routes of administration	By mouth or intravenous
ATC code	B01AA03 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	79-100% (by mouth)
Protein binding	99%
Metabolism	Liver: CYP2C9, 2C19, 2C8, 2C18, 1A2 and 3A4
Biological half-life	20-60 hours (mean: 40 hours)
Excretion	Kidney (92%)
Identifiers
IUPAC name (RS)-4-Hydroxy-3-(3-oxo-1-phenylbutyl)- 2H-chromen-2-one
CAS Number	81-81-2 Y
PubChem CID	54678486
IUPHAR/BPS	6853
DrugBank	DB00682 N
ChemSpider	10442445 Y
UNII	5Q7ZVV76EI
KEGG	D08682 Y
ChEBI	CHEBI:10033 Y
ChEMBL	CHEMBL1464 N
ECHA InfoCard	100.001.253
Chemical and physical data
Formula	C19H16O4
Molar mass	308.33 g/mol
3D model (Jmol)	Interactive image
SMILES CC(=O)CC(C\1=C(/O)c2ccccc2OC/1=O)c3ccccc3
InChI InChI=1S/C19H16O4/c1-12(20)11-15(13-7-3-2-4-8-13)17-18(21)14-9-5-6-10-16(14)23-19(17)22/h2-10,15,21H,11H2,1H3 Y Key:PJVWKTKQMONHTI-UHFFFAOYSA-N Y
NY (what is this?)

Warfarin, sold under the brand name Coumadin among others, is a medication that is used as a blood thinner. It is commonly used to treat blood clots such as deep vein thrombosis and pulmonary embolism and to prevent stroke in people who have atrial fibrillation, valvular heart disease or artificial heart valves. Less commonly it is used following ST-segment elevation myocardial infarction (STEMI) and orthopedic surgery. It is generally taken by mouth but may also be used by injection into a vein.

The common side effect is bleeding. Less common side effects may include tissue death and purple toes syndrome. Use is not generally recommended during pregnancy. It is recommended that the effects of warfarin typically be monitored by checking prothrombin time every one to four weeks. Many other medications and dietary factors can interact with warfarin, either increasing or decreasing its effectiveness. The effects of warfarin may be reversed with phytonadione (vitamin K1), fresh frozen plasma, or prothrombin complex concentrate.

Warfarin decreases blood clotting by blocking the enzyme vitamin K oxide reductase that reactivates vitamin K₁. Without sufficient active vitamin K₁, clotting factors II, VII, IX, and X have decreased clotting ability. The anticlotting protein C and protein S are also inhibited but to a lesser degree. A few days are required for full effect to occur and these effects can last for up to five days.