Top Ten: Toxicoses in Dogs & Cats

Tina Wismer, DVM, Diplomate ABVT & ABT

In honor of Poison Prevention Week, Dr. Wismer of the ASPCA’s Poison Control Center reviews information gathered from over 180,000 cases to name the “top ten” types of poisonings in 2012.

“Common things happen commonly” is a good adage for veterinary toxicology.

To help veterinary professionals and pet owners with poison-related emergencies, the American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center (APCC) offers a valuable resource: phone consultations with veterinary toxicologists, 24 hours a day, 365 days a year (888-426-4435).

Last year, the APCC compiled data from 180,000 cases received during 2012 to help increase both veterinary and consumer knowledge about poisoning in pets.¹

• Domestic dogs were most often exposed to toxins (79.3%), followed by cats (13.2%), birds and small mammals (ferrets, lagomorphs, rodents) (3.8%), and large animals (horses, cows) (2.13%).
• Most dogs and cats are accidentally exposed to poisons, with most exposures resulting from ingestion of human medication.
• Malicious poisonings account for less than 1% of reported situations.

Data from the calls also identified the top 10 pet toxins evaluated by the APCC in 2012.

While not all poisonings are reported to the APCC, the information gained by identification of toxins and trends associated with exposure can help veterinarians efficiently determine a differential diagnosis.

1. HUMAN PRESCRIPTION MEDICATIONS

The number one group of substances the APCC received calls about in 2012 was human prescription medications, accounting for 25,200 calls.¹ The number of people prescribed medications for chronic disease is continually growing and so are accidental ingestions of these medications by pets (such as consuming dropped pills or getting into pill organizers).

• Cardiac medications are the largest group of human medications ingested, ranging from relatively safe (ie, diuretics, ACE inhibitors) to life-threatening (ie, calcium channel blockers, digoxin) products.
• Antidepressants, thyroid, and attention deficit hyperactivity disorder (ADHD) medications are also commonly ingested. Cats are not normally attracted to large pills but they are strangely drawn to venlafaxine (Effexor, pfizer.com) capsules.

Veterinarians should counsel owners to:

• Store and take their medications in a place away from pets to prevent them from ingesting any dropped pills.
• Keep medication bottles out of reach of pets to prevent dogs from chewing on the bottles/caps and gaining access to the pills (unfortunately, child-safety caps are not pet-safe!).
• Store pet and human medications separately to avoid accidental administration of human medications to pets or vice versa.

2. INSECTICIDES

As new products have become more specific for insect physiology in the past 10 to 20 years, insecticides have become much safer for mammals. However, insecticide granules, yard sprays, and preventives used on pets can cause serious problems if not administered correctly. Eleven percent of phone calls to the APCC were in regard to insecticide exposure.¹

Veterinarians should emphasize that:

• Owners read the label and follow directions before using any insecticide
• Products labeled for dogs only should NOT be used for cats. Applying permethrin products that are labeled for dogs on cats can cause tremors and seizures, and require immediate medical intervention.²
• Cats may have taste reactions (hypersalivation) that can occur when a spray or spot-on product is applied and the cat grooms itself, ingesting the product.

Cats are over-represented in the insecticide category due to taste reactions. These reactions are not poisonings, but cats foaming at the mouth obviously make owners very concerned. The best treatment is to offer food to the cat (eg, milk, canned food, tuna), which removes the bad taste.

3. OVER-THE-COUNTER HUMAN PRODUCTS

Many pet owners do not realize that OTC medications are dangerous.

• Ibuprofen is the most common OTC medication ingested by pets.
• The toxin with the biggest gain in this category is vitamin D (cholecalciferol).¹ Many physicians are now prescribing large doses of vitamin D for patients, and manufacturers have responded by producing products with higher amounts of this vitamin (which can be available as highly palatable chocolate-flavored or gummy chews).
• Many pets are also attracted to OTC joint care products and nutraceuticals due to their animal origins.

Veterinarians need to inform pet owners that:

• OTC medications, such as ibuprofen and acetaminophen, can kill their pets.
• OTC human products should never be administered to a pet without consulting a veterinarian first.

4. VETERINARY PRODUCTS

Chewable medications are a double-edged sword in veterinary medicine. They are easy to administer to dogs or cats; however, these tasty medications can also mean that the pet, if given access, will ingest all the tablets in the bottle. Examples include veterinary NSAIDs, phenylpropanolamine, joint care supplements, and heartworm medications, which are all commonly sold in chewable formulations.

Avermectin toxicity is a concern in collie-type breeds; however, the dose of avermectin in canine heartworm preventatives is safe for these breeds. Toxicity can occur when:

• Owners use ivermectin horse dewormers, which have a much higher concentration of avermectin, for their dogs.
• A dog consumes dewormer paste that has dropped on the ground from the horse’s mouth or the tube.

Veterinarians should always make sure to:

• Remind owners to keep pet medications out of their pets’ reach.
• Recommend that pets be separated during pill administration, if there are multiple pets in the household.

5. HOUSEHOLD ITEMS

The APCC received approximately 10,000 calls about household items in 2012.¹

Paint, cleaning products, and laundry detergents are only a few types of items that pets may ingest in the home. Some household items may only cause gastrointestinal upset, while some can be deadly. Other items, such as dry wall, fire logs, and polyurethane glues, are not poisonous but can cause gastrointestinal obstructions requiring surgery.

Veterinarians can help prevent tragedies by instructing owners or providing resources on how to pet-proof homes; for example, crate training, cabinet locks, and baby gates can provide safe areas for pets. The APCC offers a helpful checklist—A Poison Safe Home—at aspca.org/pet-care/poison-control/a-poison-safe-home.

6. HUMAN FOODS (Other Than Chocolate)

The most common toxicosis in this group is xylitol (a sugar substitute) toxicity.¹ Xylitol can be found in sugarless gums, candies, mints, and baked goods, and can cause low blood sugar, seizures, and liver failure in dogs.⁴ Many owners are not aware of the danger this toxin presents to their dogs.

Other food items that cause concern are grapes/raisins, onions/garlic, and avocados.⁵

• Grapes and raisins can cause kidney failure; signs may be more dramatic in animals that have concurrent illness.
• Onions and garlic can cause gastrointestinal irritation and may lead to red blood cell damage. Cats are most susceptible, but dogs that consume a large amount of these vegetables/herbs are also at risk.
• Avocados are dangerous to birds and rabbits, but only cause gastrointestinal upset in dogs and cats (the pit can become a foreign body if ingested).

Finally, moldy food can grow toxins that cause tremors and seizures if ingested.⁶ A comprehensive list—People Foods to Avoid Feeding Your Pets—can be found at aspca.org/pet-care/poison-control/people-foods.aspx.

7. CHOCOLATE

While the word has been out for a while that chocolate can be toxic to pets, it is still the number one human food that pets ingest. The APCC received 8575 calls about chocolate in 2012, about 23.5 a day.¹ The darker the chocolate, the higher the methylxanthine content and higher the risk of toxicity.³

Because cats do not have the same “sweet” taste buds as dogs and humans, dogs are the most likely species to be poisoned by chocolate. Signs of chocolate toxicosis include vomiting, diarrhea, agitation, high heart rate, tremors, seizures, and death.

8. PLANTS

About 4% of APCC phone calls were about animals that had consumed plants.¹ This is another category in which cats are over-represented. Houseplants, especially ones containing insoluble calcium oxalates (eg, Dieffenbachia, Philodendron) are the most common type ingested.

Fortunately, most cases of plant ingestion cause non–life-threatening illness and minimal clinical signs (ie, drooling, vomiting). Lilies and sago palms are probably the most dangerous to cats and dogs, respectively. The APCC offers a list—17 Poisonous Plants—at aspca.org/pet-care/poison-control/17-common-poisonous-plants.aspx.

9. RODENTICIDES

Rodenticides are designed to kill rodents, but they can be deadly for other mammals and birds. The APCC handled approximately 6965 cases of rodenticide ingestion in 2012.¹ Anticoagulants are still the primary type of rodenticide used, but bromethalin and cholecalciferol are gaining market share.

Veterinarians should counsel owners to:

• Be very careful when setting out rodent bait—the resourcefulness of pets, especially dogs that are attracted to grain-based baits, should never be underestimated.
• Keep all rodenticide labels because many baits look identical but cause very different clinical signs

10. LAWN & GARDEN PRODUCTS

Many Americans are obsessed with creating the perfect lawn and, likewise, the APCC received almost 3500 calls about noninsecticidal lawn and garden items in 2012.¹

Lawn products can range from tasty fertilizers (bone meal and blood meal) and herbicides that are only expected to cause gastrointestinal signs, to more toxic products, such as the snail and slug bait metaldehyde, which can be deadly.⁷

Veterinarians should encourage pet owners to read and follow label directions, which greatly minimizes the risk to pets.

EXPOSURE VARIANTS

Fortunately, most animal exposures to toxic agents result in no or mild clinical signs.⁸ This may be due to a small exposure dose of the toxicant or decontamination by the owner and/or veterinarian.

Exposure to toxicants can vary depending on the:

• Pet’s environment
• Time of year
• Geographical location.

For example, the APCC sees an increase in rodenticide poisoning in the northern U.S. in the fall (crop harvesting and cold weather drives rodents inside).¹

Learn more about rodenticide poisoning by reading Rodenticide Poisoning: What to Do After Exposure (March/April 2012), available at todaysveterinarypractice.com.

CLIENT EDUCATION

Educating the public about potential toxins lurking in the house and yard is a very important part of veterinary care. It is much easier to prevent poisonings than to attempt to treat them.

• Placing information in puppy/kitten packs, on your website, and in other communication with clients is a good way to start educating owners.
• Seasonal topics, such as Easter lilies and chocolate, can be included in newsletters and on websites, Facebook, and other social media outlets.
• Provide the APCC’s website link, aspca.org/home/pet-care/poison-control, to clients, which allows them to access additional information on pets and poison prevention concerns.

References

1. Data from the ASPCA APCC regarding animal poisonings in 2012.
   
2. Richardson JA. Permethrin spot-on toxicoses in cats. J Vet Emerg Crit Care 2000; 10:103-106.
3. Gwaltney-Brant S. Chocolate intoxication. Vet Med 2001; 96:108-111.
4. Dunayer EK. Hypoglycemia following canine ingestion of xylitol containing gum. Vet Human Toxicol 2004; 46(2):87-88.
5. ASPCA Animal Poison Control Center. People foods to avoid feeding your pets. aspca.org/pet-care/poison-control/people-foods.aspx.
6. Schell MM. Tremorgenic mycotoxin intoxication. Vet Med 2000; 95(4):283-286.
7. Dolder LK. Metaldehyde toxicosis. Vet Med 2003; 98:213-215.
8. Forrester MB, Stanley SK. Patterns of animal poisonings reported to the Texas Poison Center Network: 1998-2002. Vet Hum Toxicol 2004; 46(2):96-99.

Tina Wismer, DVM, Diplomate ABVT & ABT, is the senior director of veterinary educational outreach at the ASPCA Animal Poison Control Center in Urbana, Illinois. She is also an adjunct instructor at the University of Illinois and a consultant for the Veterinary Information Network. Dr. Wismer received her DVM from Purdue University. Prior to her current position, she worked in small animal practice in Michigan and emergency practice in Indiana.