Common Over-the-Counter Toxins in Dogs

Many over-the-counter medications intended for human use are poisonous to dogs. These products do not require a prescription and include anti-inflammatories; other pain medications; cold, flu, and allergy medications; vitamins and minerals; herbal supplements; and essential oils.

Exposure may occur when dogs ingest dropped medications, find medications left in bags, or are given or treated with them by their owners. Symptoms of poisoning depend on the medication and quantity ingested or applied.

What are the most common over-the-counter toxins for pets?

The following medications, supplements, and products are among the most common over-the-counter toxins for dogs.

Pain and Fever-Reducing Medications

Nonsteroidal anti-inflammatory drugs (NSAIDs): This drug class includes aspirin, ibuprofen (Advil®, Motrin®), and naproxen (Aleve®). While dogs may be prescribed specific NSAIDs by your veterinarian, some human over-the-counter NSAIDs are dangerous and have a narrow safety margin for dogs. This means that, for some medications, even a fraction of a pill may cause severe signs.

Ingestion of pills is the most common cause of poisoning, but topical ointments and creams containing NSAIDs (e.g., Voltaran®) can also cause poisoning if your dog chews on the container, licks them off your skin, or if they are transferred to your dog’s fur and your dog ingests them when grooming.

Aspirin is a compound in a group of chemicals called salicylates. These chemicals may occur in a wide range of products, including pain medications, Pepto-Bismol®, health and beauty creams, sunscreen, lip balm, and wart removers. All salicylates have the potential to cause poisoning. Symptoms occur within hours to days:

• Gastrointestinal: Decreased or no appetite, vomiting possibly with blood, diarrhea, blood in the stool, black and tarry stool, abdominal pain.
• Renal/Urinary: Increased thirst and urination, elevated kidney enzymes on blood work. In severe or prolonged cases, urine production decreases or stops completely.
• Neurologic: Lethargy, incoordination, seizures, coma.
• Bleeding: Signs of internal bleeding include pale gums, abdominal distension, difficulty breathing, weakness.

Acetaminophen (Tylenol^®, Paracetamol^®): Acetaminophen damages the liver and red blood cells. When the red blood cells are damaged, they cannot deliver oxygen to tissues normally. Acetaminophen is often found in combination with other medications such as cold medications. Acetaminophen can be prescribed for pain management in dogs; poisoning occurs at higher doses. Symptoms occur within a few hours to days and may include:

• Rapid breathing or difficulty breathing
• Bluish or muddy brown mucous membranes
• Weakness and depression
• Vomiting, lack of appetite, drooling
• Yellow discoloration of the skin or mucous membranes
• Red or brown urine
• Brown blood
• Increased liver values on blood work

Decongestants

Many over-the-counter cold, flu, and allergy medications contain decongestants such as pseudoephedrine and phenylephrine. Typically, these decongestants are combined with pain and fever relievers, cough suppressants, and other medications that can also be poisonous. Decongestants can be present in nasal sprays and eye drops that relieve redness. These medications can also be combination medications. Even small amounts of these formulations can be poisonous.

Decongestants act as stimulants. Symptoms occur within two hours and may include:

• Restlessness, agitation, hyperactivity
• Panting
• Vomiting
• Dilated pupils
• Increased heart rate and blood pressure
• Tremors, seizures, and death are possible with higher exposures

Vitamin and Mineral Supplements

Like other over-the-counter medications, vitamins and minerals can be purchased as sole active ingredients or as combination products (multivitamins).

Vitamin D (cholecalciferol [vitamin D3] and ergocalciferol [vitamin D2]): Cholecalciferol is more common and has a narrow margin of safety. It is important to distinguish which form of vitamin D was ingested. Ingestion of excessive vitamin D causes an increase in calcium and phosphorus levels. Increased calcium levels cause mineralization of tissues, including the kidneys, heart, and others. Mineralization will decrease kidney function, leading to kidney failure.

Symptoms occur within a few hours and bloodwork abnormalities occur within 72 hours:

• Increased drinking and urination
• Vomiting, diarrhea, loss of appetite
• Lethargy
• Mineralization of body tissues
• Acute kidney injury leading to failure
• Abnormal heart rhythms, internal bleeding, and breathing difficulties

Iron: This mineral is found in many multivitamin supplements. The initial clinical sign is usually vomiting, as iron irritates the stomach. Other gastrointestinal symptoms may follow, such as diarrhea and ulceration.

With an increase in dose ingested, gastrointestinal signs can be followed by a latent period of 12 to 96 hours. During this time, the dog will act normal and appear asymptomatic. The latent period is followed by recurrence of gastrointestinal signs, possibly more severe than the initial signs, lethargy, shock, severe kidney and liver damage, blood clotting abnormalities, and death.

Herbal Remedies and Supplements

The assumption that “it’s all natural so it must be safe” does not apply to many products in the home. Common supplements that can lead to poisoning include:

5-hydroxytryptophan (5-HTP): People take this supplement to treat stress, depression, and anxiety. Clinical signs occur within 10 minutes to 4 hours:

• Salivating, vomiting
• Agitation or depression
• Startles easy
• Disorientation
• Dilated pupils, blindness
• Tremors, seizures
• Fast heart rate or respiratory rate

Alpha-lipoic acid: This is an antioxidant which can improve inflammation and nerve pain and can relieve complications of diabetes and cardiovascular disease in humans. Clinical signs occur within several hours:

• Salivating, vomiting
• Low blood sugar
• Wobbly gait
• Vocalization
• Tremors, seizures
• Kidney and liver failure

St. John’s wort: This is a supplement from a plant (Hypericum perforatum) that people use to treat mild to moderate depression. Clinical signs occur within several hours:

• Salivating
• Lethargy
• Serotonin syndrome: agitation or sedation, vocalization, tremors, abnormal heart rate, increased temperature

Tea tree oil: This oil is included in many skin care products. 100% tea tree oil is extremely toxic when ingested or applied to the skin. Clinical signs occur within 2 hours and may include:

• Salivating, vomiting
• Depression, lethargy
• Wobbly gait, weakness
• Low body temperature
• Low heart rate
• Tremors

Xylitol: Xylitol is not a medication, but it is present in many non-prescription products. It is an artificial sweetener used as a flavor enhancer. It can be found in cough drops, liquid medications, gummy vitamins, quick dissolve tablets, and other supplements. Xylitol causes decreased blood sugar and liver toxicity. Low blood sugar occurs within hours and liver toxicity within two days. Signs include:

• Vomiting
• Weakness, wobbly gate, collapse
• Confusion
• Tremors or seizures

How is toxicity treated?

Call your veterinarian or Pet Poison Helpline, a 24/7 animal poison center, at 1-800-213-6680, as soon as you realize your pet has consumed a toxin. Treatment is based on the dose and type of medication or supplement. Generally, treatment consists of decontamination, antidote if available, and supportive and symptomatic care. Diagnostics may include X-rays or bloodwork, which may need to be repeated for comparison.

It is very important that all medications and supplements are kept in secure, inaccessible cabinets to avoid any accidental poisoning. With all poisoning cases, early intervention is key to successful treatment.

Pet Poison Helpline, an animal poison center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com.