Coumadin is rat poison? Really?

In a note I transcribed this evening, the doctor dictated that the patient refused to take Coumadin (warfarin), because it is a rat poison. Is that true? How would that work, Coumadin is a blood thinner, right? So, what, the rats eat the stuff and we hope they get a cut and bleed to death?

Coumadin, which is used as a blood thinner is also effective in poisoning rats (by causing them to bleed to death internally). So it doesn’t poison them.

From the Wisconsin Alumni Research Foundation (WARF) site:

It’s not uncommon for biologically active compounds to have a variety of uses.

That’s really interesting. Thanks!

I should point out that humans on warfarin are usually closely followed for bleeding problems. Usually, they go in for bloodwork every week or two.


As with many things, “the dose makes the poison.”

Chlorine and Fluorine are poisons, but we put them in our drinking water. Tylenol is a great fever reducer and pain reliever, but take too much and it kills you. Just about everything you might take as medicine would be poisonous at higher doses.

I was listening to The People’s Pharmacy, a call-in show on public radio, and a man called and complained that his wife’s doctor had prescribed Coumadin, which is a rat poison, and he sounded pretty ticked off about it. The hosts of the show effectively did a big “duh!” and explained that the dose makes the poison. Since your doctor’s patient had heard the same thing about Coumadin, there might be some wacko conspiracy circles that circulate this BS… Yep, I just did a web search, and the wackos responsible for this one are the alternative medicine people. Here’s a quote: “I would no more put coumadin in my body than Rat Poison. Why? They are the same thing. Coumadin is one of the main ingredients in rat poison. If you need to thin your blood, please find a Naturopath who can help you by using natural blood thinners, like high doses of vitamin E, for example.”

Yeah, it’s essentially watered-down rat poison; my dad takes it, and he was the first to point that out. He goes in for blood tests every now and then, but has been fine for years.

My father in law is now in a nursing home because he was bleeding internally from taking this poison and was incapacitated for a few weeks. It has weakened his muscles so much that he must now go through rehabilitation because he can’t stand on his own two feet. I wouldn’t touch this “medicine aka poison” with a ten foot pole…

Not only can Warfarin kill small rats, it’s thought to have killed some mighty big rats as well! There’s a not very far fetched theory that it was used to kill Stalin.

I’m sure 2001 is suitably distraught.

We’ve been Stalin for time.

Does it kill zombies? 12 year old zombies more specifically?

Did you not read the posts above?

Like they said, the dose determines the poisonousness. A little salt is poisonous to bacteria, but not to us, and is actually necessary.

Yet, when you eat salty foods, you’re eating a disinfectant of sorts.

The reason they prescribe coumadin/warfarin for preventing and treating strokes and heart attacks is the EXACT SAME reason that it is lethal to rats. It’s beneficial in the small amounts used as an anticoagulant, and lethal to rats in the dosages they eat as a poison. I suspect with the right dosage, it would be an effective anticoagulant in living rats as well.

What’s more, any sort of anticoagulant will work in much the same way, unless it’s human-specific. Even the large doses of vitamin E someone mentioned above would likely either kill or mess up the rat.

This thread is so old, it’s probably going to have a stroke any minute.

dangit - I usually notice Zombie threads… Would Warfarin be effective against zombie Stalin??? I’d pay good money to see a cage match between zombie Stalin and zombie Hitler. Who would win?

Never trust anything made by John Warfarin at Yoyodyne.

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Welcome to the Straight Dope Message Board, inquisitive_blee. Please note that the thread you are replying to dates back to 2001. We tend to refer to old threads like this that have been revived as zombies (hence, all of the zombie jokes in the replies). While we do permit zombies here, we also ask that you do not revive old threads unless you have new information or something substantial to contribute to the thread. Also, please note that due to this thread’s extreme age, many of its participants may no longer be around to read or comment on your reply.

Because of this thread’s extreme age, and because its revival is getting more zombie jokes than actual comments, I am going to put this poor zombie back into his grave.

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