Story at-a-glance

• • A team of veterinary researchers recently revealed a complete cure for metaldehyde toxicity in dogs; it’s called hemodialysis-hemoperfusion — a procedure used to remove kidney toxins from the blood
  • Metaldehyde is a chemical found in many snail and slug baits and is highly toxic to dogs, cats and wildlife; metaldehyde poisoning in dogs is common worldwide and about 25% of affected dogs don’t survive
  • A 10-pound dog can show signs of poisoning after eating as little as 1 ounce of a slug/snail bait containing 3% metaldehyde
  • Dogs who receive early, aggressive and appropriate supportive treatment for metaldehyde toxicity can fully recover within a few days, however, treatment is difficult and costly

Dogs explore the world with their noses and often, their mouths. In addition, most are indiscriminate eaters. This combination can lead to all sorts of challenges for dog parents — some funny, some gross, and unfortunately, some that are potentially deadly.

The latter category includes a long list of toxic substances found both indoors and out that most dogs will sniff and perhaps taste, given the chance. One of these poisons goes by a name many of you have probably never heard of: metaldehyde, a chemical used to kill slugs and snails.

Metaldehyde is highly toxic to mammals and birds and is the sixth most common substance veterinarians ask about when they call the 24-hour Veterinary Poisons Information Service, a worldwide emergency hotline. There is no known antidote for metaldehyde toxicosis, and supportive treatment is complicated and costly. Death occurs in approximately 25% of poisoning cases involving dogs.

Veterinary Research Team Uncovers a Complete Cure

Lucky for us, a team of veterinarians at the University of Munich became concerned about the number of poisonings and the prognosis for dogs with metaldehyde toxicity. They did some outside-the-box thinking and decided to see if a technique called hemodialysis-hemoperfusion — a procedure used to remove kidney toxins from the blood — might be an effective treatment.

The Morris Animal Foundation funded a grant that allowed the researchers to test their theory on plasma samples contaminated with metaldehyde. They were able to successfully reduce concentrations of the toxin in the samples, so the next step was to see if the technique would work on an actual dog.

Enter Jimbo, a Jack Russell Terrier who sampled slug bait containing metaldehyde. By the time he was brought to the university research team, Jimbo was having one seizure after another, without fully regaining consciousness. The team quickly performed hemodialysis on the dog, and within 24 hours he was back on his feet and on his way home.

As of this writing, the veterinary team has treated 10 dogs with their novel therapy and all 10 had a complete recovery. Their research findings will be published in the not-too-distant future for use by the global veterinary community.

Common Brands of Bait Sold in the US

As I mentioned earlier, metaldehyde is a chemical most commonly found in slug and snail baits. The baits usually come in granule form, but can also be found in liquid, powder, meal, gel/paste or pellet form. The baits are designed to release metaldehyde for about 10 days to two weeks under moderately moist conditions.

Bran or molasses is usually added to the baits to make them more attractive to snails and slugs, which also makes them appealing to dogs. Baits sold for home use in the U.S. generally contain between 2% and 5% metaldehyde. According to veterinarian Dr. Ahna G. Brutlag of the Pet Poison Helpline, the products most commonly reported to the hotline in this country include:¹

• • • Ortho Bug-Geta Snail & Slug Killer and Ortho Bug-Geta Plus Snail, Slug & Insect Killer
    • Corry’s Slug & Snail Death
    • RainTough Deadline Slug & Snail Killer
    • Force II Deadline Slug & Snail Killer
    • Lilly Miller Slug, Snail & Insect Killer Bait

Other U.S. brands include Antimilace, Cekumeta, Meta, Metason, OR-CAL, Slugger Snail & Slug Bait, Ortho Metaldehyde 4% Bait, Slug Pellets, Slugit Pellets and Slug-Tox. Surprisingly, in Europe, slug and snail baits can contain up to 50% metaldehyde. The chemical is also used in small heating systems (e.g., camping stoves) and lamps. The Japanese use metaldehyde in color flame tablets that are ignited for entertainment purposes.

Signs of Metaldehyde Toxicity

Dogs typically eat slug bait either off the ground or from a container. We don’t yet know how metaldehyde causes toxicity, only that it’s extremely deadly. A 10-pound dog can show signs of poisoning after eating as little as 1 ounce of a typical bait containing 3 metaldehyde.² The chemical is also toxic to cats, though cases of poisoning are rare. It can also affect wildlife.

If your pet ingests bait containing metaldehyde, signs of toxicity will develop quickly, typically within the hour. The first sign is usually vomiting, because the toxin irritates the lining of the stomach. Next come neurologic signs, which can include anxiousness, increased heart and respiratory rates, excessive drooling, a stiff or drunken gait, and in some cases, hypersensitivity to touch.

As the toxicity progresses, there are muscle tremors that often trigger a high fever that can lead to organ failure. Nystagmus (rapid back-and-forth movement of the eyes) may also occur.

Symptoms of metaldehyde toxicity continue to progress for several hours after the bait is ingested, ultimately resulting in lethargy and weakness, continuous muscle tremors or seizures, loss of consciousness and death if the dog doesn’t receive aggressive, appropriate treatment in time.

Diagnosis and Treatment

Diagnosis of metaldehyde toxicity is most often based on clinical signs and suspected exposure to slug bait. It’s possible to test the stomach contents for the presence of metaldehyde, but the results won’t be back quickly enough to be of any benefit in saving the dog.

Veterinarians typically run a number of diagnostic tests (i.e., complete blood cell count, serum chemistry profile, urinalysis, etc.) to rule out other possible causes for a pet’s symptoms, as well as to find possible complications resulting from the poisoning that also require treatment.

Veterinarians will induce vomiting in dogs brought to them within an hour of ingesting metaldehyde who aren’t showing any neurologic signs. They’ll also be given activated charcoal to bind the metaldehyde still in the intestines, decreasing further absorption. If you can’t get your dog to a clinic within an hour, your veterinarian may instruct you to induce vomiting at home before leaving.

In dogs whose conditions aren’t stable enough to safely induce vomiting, the stomach can be emptied using gastric lavage, a procedure requiring anesthesia and a tube that is passed through the esophagus to the stomach. The tube is used to drain the contents of the stomach, flush it with fluids and place activated charcoal in there to bind whatever metaldehyde remains.

Dogs who undergo gastric lavage will need to stay in the hospital for several hours to receive additional doses of activated charcoal and be closely monitored for signs of toxicity. If signs develop, a longer hospitalization will be required. Supportive care while hospitalized can help keep your dog comfortable and deal with certain effects of the toxin such as tremors, seizures and blood abnormalities. Intravenous (IV) fluids will be given and your pet’s body temperature will be closely monitored.

Prognosis and Prevention

Most dogs with metaldehyde toxicity who receive early, aggressive, appropriate treatment recover fully within two to three days. However, treatment can be expensive, especially in severe cases requiring sedation or anesthesia. Since the cost of treatment can be prohibitive, and since metaldehyde poisoning isn’t something any loving pet parent wants their dog to endure, prevention should always be the goal.

My recommendation is to avoid using slug and snail baits containing metaldehyde and/or other toxic chemicals. If you want to protect your garden from the critters, consider using broken shells, lava rock or other alternatives to snail and slug bait.

Veterinarian Dr. Catherine Barnett of VCA Hospitals also suggests using copper bands around plants, or adding lavender, mint or rosemary plants to your garden. You can also fill shallow cans with beer to attract and drown slugs.³ You can find additional nontoxic solutions at this link.

– Sources and References

• • • ¹ ScienceDirect