When Medicine is Poison
- Mary Malucci
- Aug 4, 2023
- 5 min read
Updated: Jan 29, 2025
There are a variety of ways our pets gain access to medications their human housemates use. Many of these medications pose a threat to dogs and cats, especially if they eat a large dose. Some medications are so toxic to our pets, one dropped pill or capsule can be life threatening.
In my experience, accidental exposures occur when pet owners underestimate the inquisitiveness of their pets. The label child proof does not mean dog proof. Even a small dog can chew through a plastic bottle in a short time. Medicines left on countertops and nightstands can be readily retrieved by larger dogs. Also medicine bottles or vials can be knocked to the floor, making them accessible to small dogs. Cats may not be inclined to chew through a plastic bottle but would easily be able to chew through a plastic baggie. While most people will not go through someone else's purse, most pets are not so polite. Many people who take several different kinds of medicine will organize them in weekly planner containers. These containers are easily opened by our pets, which complicates the situation because of the variety of medications contained. Discarding unused medications in the trash can result in accidental ingestion because the pet was tempted by something else.
The best advice is to store all medications in a cabinet or drawer that can be secured against curious pets. To avoid mix-ups between human meds and pet meds, it's best to have separate secure spaces for them. If all meds must be stored together, find ways to clearly identify human versus veterinary medicines. Many veterinary clinics use different colored medicine containers, blue or green, to help distinguish veterinary meds from human meds in amber bottles. Try to take medicines over a sink or open drawer so dropped meds can be readily retrieved or cleaned up.
Sometimes, pets are given a dose of human medication by well meaning pet owners, usually in an effort to alleviate pain. I frequently tell pet owners there are no over the counter human pain medications that are safe to give to our pets.
In fact, NSAIDs or Non Steroidal Anti Inflammatory Drugs are the class of medications named first on Pet Poison Helpline's List of 10 Human Medications most frequently ingested by pets. These include all of the over the counter, or OTC, pain relievers we buy for ourselves. NSAIDs can be broken up into three categories.
NSAID Ibuprofen is an NSAID commonly marketed as Advil or Motrin. Naproxen is usually marketed as Aleve or Naprosyn. Both of these medications, even in small doses, can cause stomach or intestinal ulcers and kidney failure.
Acetaminophen is an NSAID marketed as Tylenol. While safe for humans, one regular strength tablet can alter a cat's red blood cells, rendering them incapable of carrying oxygen. A large enough dose in a dog will lead to liver failure and the same alteration to their red blood cells.
Aspirin is the original NSAID. Although it is marketed in low dose 81 mg tablets as canine aspirin, chronic use can lead to stomach ulcers and impact the liver. High doses of aspirin can put our dogs at risk for vomiting, racing heart rates and kidney failure. Preparations such as Pepto-Bismol contain an aspirin compound that can be particularly toxic to cats.
NSAIDs used in veterinary medicine often come in chewable forms. Carprofen was originally marketed as Rimadyl; it now comes in a variety of generic forms. Deramaxx is the trade name for deracoxib. Given in the prescribed dosage, these medications are safe. The problem comes when a pet eats a large number of these chewable tablets. Or a pet gets hold of a prescription not meant for them.
Tramadol is commonly prescribed as pain medication in veterinary medicine. Tramadol is not an NSAID but a mild opioid. In appropriate doses for a short time, it's safe enough. An acute overdose in most pets will produce symptoms like profound sedation, wobbliness and disorientation although some pets will become agitated instead. A large enough overdose can lead to vomiting, tremors and possible seizures.
Antidepressants This increasingly popular class of medications are sold under the trade names of Effexor, Cymbalta, Prozac and Lexapro among others. Some of these drugs are prescribed in very low doses to address anxiety in our pets. However, large doses can lead to neurologic symptoms like agitation, vocalization, tremors, loss of coordination and seizures. Large doses also dangerously elevate heart rates, blood pressures and body temperatures. For reasons no one can explain, cats are attracted to the smell and taste of Effexor.
ADD/ADHD medications Marketed as Adderall, Ritalin and Concerta, these medications contain powerful stimulants. Low doses of these medications can cause tremors and seizures and elevate heart rate and body temperature life threateningly high.
Decongestants like Pseudoephedrine or Phenylephrine are also stimulants. They can cause vomiting, high blood pressure, abnormal heart activity, tremors and seizures.
Benzodiazepines are used to reduce anxiety and help people sleep. Marketed under the names Ambien, Xanax, Lunesta and Klonopin, most pets will get sleepy and wobbly. Large doses can cause blood pressure, heart rate and respiration rate to become dangerously low. Some pets will experience the opposite effect, getting inconsolably agitated instead.
Birth control medications usually contain some form of estrogen. In small doses, it's not usually a problem. In large doses, these medications can cause bone marrow suppression, especially in birds and intact female pets.
ACE inhibitors are commonly prescribed to treat high blood pressure in people. They are occasionally prescribed for pets in low doses. Large doses can cause low blood pressure, dizziness, weakness and possible kidney injury.
Beta-blockers are also used to treat high blood pressure in people. However, these drugs are potent enough that small doses can cause a pet's blood pressure and heart rate to drop to dangerously low levels.
Thyroid hormones are often prescribed for dogs with under active thyroids. However, large acute doses in dogs or cats can cause nervousness and aggression with symptoms like panting, muscle tremors and rapid heart rate.
Cholesterol lowering agents are commonly called "statins". One time overdoses usually cause only mild vomiting and diarrhea. More serious consequences come from chronic ingestion.
Topical medicated ointments can cause toxicity in two ways. Chronic ingestion, as in a cat or dog licking the ointment off the owner's skin, can cause cumulative poisonings. For instance, a pet allowed to lick estrogen cream off their owner's skin everyday may eventually develop signs of estrogen toxicity. Acute poisonings can come from dogs chewing up a tube of cream. What's safe enough applied to human skin as a thin smear can be lethal when the whole tube is ingested. In some cases, like triple antibiotic ointment and cats, the risk is a severe anaphylactic response to one of the ingredients.
If you know or even suspect your pet ingested potentially harmful medications, contact either the ASPCA Poison Control or Pet Poison Helpline for advice on whether to seek veterinary care. Be aware that both of these services ask for a fee up front that can be paid with a credit card. If your pet is symptomatic in any way, head to the nearest veterinary emergency room as soon as possible.
ASPCA Poison Control (888) 426-4435
Pet Poison Helpline (855) 764-7661
Top 10 Human Medications Poisonous to Pets
Human Medications That Aren't Safe for Dogs by Dr. Sam Gilbert
10 Poison Pills for Pets
Top 10 OTC and Prescription Medications Toxic to Cats
by Justine Lee DVM, DACVECC, DABT
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