In 1948, Warfarin was introduced to stamp out the rat menace under the brand name Coumadin. Rats are known to be hosts of diseases especially their urine, in addition, they can cause a lot of structural damage and fire to property and buildings by gnawing at the insulation of electrical cables, leaving them exposed. This is in addition to being an eyesore and can ruin reputations of homes and business as when spotted; one thinks of filth and an unkempt environment. In a nutshell, nothing good comes out of rats, they are pests. But, what was once used to control these pests, has been discovered to be a big help in the medical field. What was once Coumadin, is now known as Warfarin and has been introduced in many types of therapy for people.

History of discovery

A set of mysterious cow deaths in the Northern United States and Canada in the 1920’s, adjusts the pace for the discovery of Warfarin. Hundreds of cows bled to death after undergoing minor common procedures like dehorning and castration, much to the chagrin of farmers. It was Canadian Veterinarian Frank Schofield, who came up with the connection to the cow deaths. Apparently, all the dead cows had consumed moldy silage which had originated from a sweet clover plant.

An interspecies disease

The disease was aptly named ‘sweet clover disease‘,  and in experimenting with a rabbit, Schofield fed it good silage that did not affect it, and then the moldy silage which killed the rabbit as well.

Nobody knew what chemical in the clovers was killing the cows until years later when Dr. Karl Paul Links’ student, Harold Campbell, managed to isolate the anticoagulant dicourmarol. Dicourmarol was formed when courmarin, which is found in sweet smelling plants or freshly cut grass, combines with certain fungi to devastating results. Armed with that knowledge, the search for a cure began in earnest, and it was found soon after that in Warfarin.


It was used on the remaining affected cows and later in humans to great results.

Anticoagulant: Therapy for bloodclots

Six years after it was introduced to get rid of rats, scientists discovered that Warfarin had other uses. It had the ability to help blood clots in a condition medically known as Thrombosis. Warfarin did this by inhibiting the production of Vitamin K which is produced in the liver, which in turn makes a person’s blood thinned, therefore, to take longer to clot. This was a big break- through in the medical field, and today, Warfarin is America’s most prescribed oral anticoagulant.


Although Warfarin is highly effective, it has a few problems.  Warfarin has to be used in the exact right dosage. If too little is prescribed, the clotting will not be taken care of, and if too much is administered, the bleeding won’t stop. Continuous testing has to be carried out often to attain the right therapeutic target, as doses required vary from patient to patient. Hence the need for a careful balancing act when using Warfarin. The test that takes care of this problem of Warfarin is called the international normalized ratio.

Warfarin has other side-effects, although they are not considered serious like diarrhea, vomiting and inability to eat during the first 24 hours after Warfarin has been administered, bleeding of gums after brushing teeth, heavier than normal menstrual flow or bleeding in between flows, swelling or pain at the injection spot and fever.

Who would have thought that something used to control rat populations is now a therapy for blood clots and savings lives?




Please enter your comment!
Please enter your name here