This morning at 5:00AM the telephone rang. "This is Billy. Roxxi just ate some rat poison. What should I do?" My usual answer when awakened in what passes for the middle of the night is: "..Unnhh?!" In other words, I do not awaken rapidly, in full possession of my faculties. In one of Edgar Rice Burroughs' Tarzan novels, he notes that the ape-man does not awaken slowly, and gradually become aware of his surroundings in the manner of "civilized" man. No, indeed, he awakens fully and instantly, like the sleeping dog who, upon feeling the touch of the cart-wheel, awakens fast enough to escape injury. Frankly, I've seen plenty of dogs who didn't wake up fast enough to keep from getting run over, and I know darn well that I wouldn't. But, I digress.
I soon became awake enough to ask "Billy who? How big is Roxxi? What kind of poison did she get into?" It transpired that Roxxi weighed about forty pounds and may have eaten half a tray of D-con. Now, while it is bad to eat poison just as a general rule, this is the best kind to eat. It is slow-acting, so you have time to administer an antidote. You should still try to induce vomiting to get rid of it (oral hydrogen peroxide usually works), but there is a good, safe, effective antidote. The poison is an anti-coagulant, meaning that it interferes with the body's ability to produce blood-clotting proteins. Vitamin K will counteract it, but it needs to be administered in large doses for about three weeks. For more details on the treatment of this type of poison, I refer you to VeterinaryPartner.com.
While the upside of this stuff is that it is slow-acting, that is often a down-side as well. People see the dog consume the poison, expecting rapid convulsions or something. When nothing happens, they assume that he didn't get enough to hurt him. Three days or so later, he runs out of blood-clotting proteins and begins to hemorrhage (often internally, where you don't realize it until it's too late). WHOOPS! Fortunately, you can still administer the antidote and stop the bleeding if the pet is not too far gone. You've lost your cushion, though.
There is another type of rodent poison that is completely unrelated. It monkeys with the blood calcium levels and works much faster. It has no specific antidote other than supportive care with IV fluids and symptomatic treatment. It has a lousy prognosis.
My beef with this is that it should never happen in the first place, no matter what time of day (or night) I get the call. People just stuff the poison in a corner, or behind the water heater or something, and forget about it. If you don't have to use tools to get to the spot, the dog can and will get there and eat it. For that matter, toddlers are at risk, too. When you use poisons, use a little judgment about where you put them. A dog only uses one criterion to judge whether or not he should eat something: "Can I get it in my mouth?" If the answer is "yes", then you know he's going to eat it.
So use some judgment in these matters. When an exposure occurs, be sure that you have the details on what kind of poison it is, what brand, what name, what the active ingredients are, and how much there was. In addition to your veterinarian, your best resource is the Animal Poison Control Center. Wake up and smell the coffee instead of waking me up.