Warfarin was used in the 1950s as an anticoagulant for victims of heart attacks and strokes, but gained fame when it was used to treat President Dwight D. Eisenhower after his 1956 coronary. Ironically, Warfarin is also used as Rat Poison!
Therapeutic doses of warfarin are minuscule: 2mg to 10mg for a 100kg person. The actual dosage depends upon an individual’s diet and metabolism, as well as body weight. In fact, body weight is not a major factor. A 150kg person may require 2mg while a 75kg person may require 10mg for the same therapeutic effect.
There are very few good alternatives to sodium warfarin treatment. In some cases, a doctor may prescribe low-molecular-weight heparin (LMWH). I do not know the issues about long-term effectiveness of LMWH, but the fact that it requires two injections per day, subcutaneous, at fairly precise 12-hour intervals, precludes its use for most people. I’ve done it in the short-term (post-surgical recovery while the warfarin is ramping up). I wouldn’t want to have to do it every day.
The complementary problem for people on warfarin therapy is that it is necessary to keep a balanced intake of Vitamin K. Many foods are high in Vitamin K, including shrimp and spinach, and an unbalanced intake of Vitamin K will cause the prothrombin times to vary wildly. This is not to say that foods containing Vitamin K must be avoided; merely that the intake should be reasonably constant, so the warfarin dosage can be adjusted to compensate for it.