Poisoning in Dogs: Symptoms and Treatments

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Poisoning in Dogs: Symptoms and Treatments

A poison is any substance harmful to the body. Dogs, being curious by nature, tend to explore out-of-the-way places such as wood piles, weed thickets, and storage areas. These environs put them into contact with insects, dead animals, toxic plants, and poison baits. It also means the exact cause of poisoning will not be known in many cases.

Drug Poisons

Unintentional overdose with veterinary medications and accidental ingestion of both human and veterinary pills are the most common causes of poisoning in pets. Veterinary products, in particular, are often flavored to encourage a dog to take them, and will be eagerly consumed if they are discovered.

Many people give over-the-counter medications to their dogs without veterinary approval, to treat a variety of symptoms; they believe that what works for people works for dogs. Unfortunately, this is not correct. Drugs given to dogs in human dosages are often toxic-and some human drugs cannot be given to dogs in any amount.

Common pain relievers such as ibuprofen (Advil) and acetaminophen (Tylenol) are a particular problem. Dogs and cats do not have the necessary enzymes to detoxify and eliminate these drugs. This can lead to the accumulation of dangerous substances in the animal that are left behind when the drugs are metabolized. As few as two Tylenol tablets can produce severe organ damage in a medium-size dog. Symptoms develop quickly and include abdominal pain, salivation, vomiting, and weakness.

Other human drugs that produce a variety of toxic effects and are commonly involved in accidental poisonings include antihistamines, sleeping pills, diet pills, heart pill, blood pressure pills, and vitamins.

Treatment: If you suspect your pet has swallowed any drug, immediately induce vomiting. Call your veterinarian for further instructions. A specific antidote may be available for the drug in question.

Rodent Poisons

Common rat and mouse poisons include anticoagulants and hypercalcemic agents. Both can be deadly if your dog ingests them.


Anticoagulant rat and mouse poisons are the most commonly used household poisons. These products account for a large number of accidental poisonings in dogs and cats. Anticoagulants block the synthesis of vitamin K, essential for normal blood clotting. Vitamin K deficiency results in spontaneous bleeding.

Observable signs of poisoning do not occur until several days after exposure. The dog may become weak and pale from blood loss, have nose bleeds, vomit blood, have rectal bleeding, develop hematomas and bruises beneath the skin, or have hemorrhages beneath the gums. The dog may be found dead from bleeding into the chest or abdomen.

Treatment: Seek immediate veterinary help. If at all possible, bring in the product container so the veterinarian can identify the poison. This is important because treatment depends on whether the poison was a first- or second-generation anticoagulant. With observed or suspected recent ingestion, induce vomiting.

Hypercalcemic Agents

Hypercalcemic agents are poisons that contain vitamin D (cholecalciferol) as their effective agent. Cholecalciferol poisons work by raising the calcium content in blood serum to toxic levels, eventually producing cardiac arrhythmias and death. They are becoming increasingly popular because rodents do not develop resistance to them and, with the rare exception of a puppy or small dog, dogs who eat poisoned rodents will not develop toxicity. In virtually all cases, the dog must eat the poison itself to become ill.

In dogs, signs of hypercalcemia appear 18 to 36 hours after ingesting the poison. They include thirst and frequent urination, vomiting, generalized weakness, muscle twitching, seizures, and, finally, death. Among survivors, the effects of an elevated serum calcium may persist for weeks.

Treatment: If you suspect your dog has ingested one of these poisons within the past four hours, induce vomiting and notify your veterinarian.


Poisoning by antifreeze that contains ethylene glycol is one of the most common small animal toxicities. Antifreeze has a sweet taste that appeals to dogs. Exposure typically occurs when antifreeze drips from the car radiator and is lapped up by the pet. Dogs may also drink from the toilet bowl in vacation homes that have been winterized by pouring antifreeze into the bowl.

Less than 3 ounces (88 ml) is enough to poison a medium-size dog. The poison primarily affects the brain and the kidneys. Signs of toxicity are dose-related, and occur within 30 minutes to 12 hours after ingestion. They include depression, vomiting, an uncoordinated “drunken” gait, and seizures. Coma and death can occur in a matter of hours. Dogs who recover from acute intoxication frequently develop kidney failure one to three days later. Death is common.

Treatment: If you see or suspect that your pet has ingested even a small amount of antifreeze, immediately induce vomiting and take your dog to the veterinarian. If treatment will be delayed, administer activated charcoal to prevent further absorption of ethylene glycol. A specific antidote (4-methylpyrazole) is available to treat poisoning. It is most effective when given shortly after ingestion and early in the course of treatment. Intensive care in an animal hospital may prevent kidney failure.

This article is excerpted from “Dog Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.

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Reviewed on 12/3/2009 11:29:52 AM

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