Bromadiolone is a toxic rodenticide used in products to kill mice and rats. An anticoagulant, this poison works by stopping the body’s ability to clot blood, which causes internal bleeding and a host of other symptoms that lead to death within days.

Bromadiolone poisoning in dogs occurs when a dog accidentally ingests the poison meant for the mice or rats. Since bromadiolone is highly toxic, an exposed dog can begin to show signs of toxicity in a just few days. There is an antidote, however, but time is of the essence in treating bromadiolone poisoning before it becomes fatal. 

The signs of bromadiolone poisoning relate to the inability to stop bleeding, and generally appear within 3 to 5 days of exposure, which can sometimes be too late to reverse its toxic effects. While veterinary treatment should be sought before symptoms appear, pet parents are often unaware their dog has ingested the poison until they show physical signs that relate to internal bleeding. These can include:

Bromadiolone directly affects the body’s ability to clot blood by inhibiting the recycling of Vitamin K, a needed nutrient in the production of proteins that cause blood clotting. Once exposed to bromadiolone, the recycling of Vitamin K stops, but the body continues to use its current stores of Vitamin K. Signs of bromadiolone exposure appear within 3 or more days when the body has run out of Vitamin K, which in turn means the coagulation proteins are not present to stop bleeding, resulting in uncontrolled bleeding which can be fatal.

With over 130 registered products that contain bromadiolone, most rodenticides come in granules, pellets and bait blocks. Often left near places rats and mice infest, such as garages, basements, attics, and sheds, children and pets can easily be exposed to this toxin. Luckily, many products also contain a red or blue-green dye that can help pet parents identify what their dog has eaten.

Bromadiolone poisoning can occur if:

If you have witnessed or suspect your dog has eaten bromadiolone in rodenticide bait, you’ll need to take them to a veterinary or emergency clinic immediately. Bring the bait and/or the box it came in with you, and be sure to relate any signs you’ve noticed in your dog, when you think they might have ingested the poison, and how much may have been ingested.

More often, you won’t know something is wrong with your dog until 3 to 5 days after exposure when signs of internal bleeding begin to appear. At this time, your dog’s condition is critical, and they should be rushed to your veterinarian or emergency clinic. If your veterinarian does not know the cause of your dog’s symptoms, they’ll likely ask you if your dog has eaten anything unusual, or possibly been exposed to different types of toxins. If your dog’s stool has a red or blue-green color to it, or contains blood, this will be helpful in coming up with a diagnosis of anticoagulant rodenticide poisoning.

After a physical exam, your veterinarian may run blood tests, an anticoagulant screen, analyze your dog’s stomach contents, or run imaging tests, such as X-rays or ultrasounds. A diagnosis of bromadiolone poisoning can be confirmed by a prolonged blood clotting time measured through a prothrombin time (PT) test.

In the case of a bromadiolone poisoning, there is an antidote, but treatment must begin right away.

Since bromadiolone works by inhibiting the body’s supply of vitamin K, the resultant lack of coagulation proteins directly causes uncontrolled bleeding. Replacing that vitamin K back into the body can counteract the affects of bromadiolone poisoning.

In a case of poisoning, over the counter vitamin K supplements or foods containing vitamin K are not strong enough to treat bromadiolone poisoning. Rather, your veterinarian will give your dog an injection or oral dose of vitamin K1 right away, then prescribe your dog vitamin K1 to take over the next several weeks. As vitamin K is replenished, and coagulation proteins are made, your dog’s clotting time, or PT, will be tested regularly to see how treatment is working.

If your veterinarian in unsure what is poisoning your dog, or if they think there is still rodenticide in your dog’s stomach, they may administer medication to induce vomiting. They may also administer activated charcoal to absorb the poison. However, if ingestion occurred over 8 hours before treatment, such therapies may not be effective.

Due to the uncontrolled bleeding caused by bromadiolone poisoning, your dog may have lost a lot of blood and plasma. It may take up to 6 hours for blood to clot after starting vitamin K therapy. Plasma or blood may be administered to replace those fluids and clotting proteins. Oxygen may also be given to your dog. If your dog’s condition is severe, they may be hospitalized until their condition is more stable.

Recovery from bromadiolone poisoning depends on several factors, including how much poison was ingested, if the dog is a puppy or elderly, or is suffering from a pre-existing liver or gastrointestinal disease. Most importantly, though, is how quickly treatment is administered. Dogs have a better chance of recovery if treatment begins within hours of bromadiolone ingestion. As days go by, and bleeding remains uncontrolled, recovery rates go down, which is why you should seek veterinary help as soon as you discover something is wrong with your dog.

When your dog returns home, you will need to continue to give them vitamin K for 4 to 6 weeks. Your veterinarian will check your dog’s PT to keep an eye on progress, and to know when your dog has fully recovered and can discontinue taking vitamin K. Vitamin K is given orally with a fatty meal, generally twice daily. Limit your dog’s activity while they recover to minimalize bleeding, especially in the first week, and give them a quiet place to rest.

To prevent bromadiolone poisoning, do not place rodenticides containing it in or around areas your dog frequents or has access to. Or consider using live traps rather than poisonous bait to control rat and mice populations.