Coumadin is a prescription medication that is commonly used as a blood thinner to prevent the formation of blood clots. The medication is also known by several other names including warfarin, Jantoven, Marevan, and Lawarin. Warfarin is the generic name for Coumadin and is widely used in the healthcare industry. Jantoven and Marevan are the brand names of warfarin that are produced by different pharmaceutical companies. Lawarin is another name given to warfarin that is specifically used in Japan. The use of these synonyms for Coumadin allows doctors and healthcare providers to communicate effectively with their patients and ensure accurate treatment.