Ibuprofen, paracetamol: human medicines that are dangerous for dogs
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
If your dog has swallowed a tablet, capsule or syrup meant for people, or if you gave one to ease its pain, call your vet or an animal poison helpline straight away — in the US the ASPCA Animal Poison Control Center, (888) 426-4435 (a consultation fee may apply), in the UK Animal PoisonLine, 01202 509 000, in France the CNITV in Lyon, 04 78 87 10 40. Have the box in hand: the medicine’s name, the strength printed on it (in mg), how many tablets are missing, the time and your dog’s weight. Do not make your dog vomit yourself and do not give anything else to “counteract” it. And from now on, one simple rule: no human medicine without your vet’s advice, not even a common painkiller, not even “a small dose”. Treated early, most dogs recover well.
Contents · 7 sections
A very common accident
Human medicines are among the leading causes of poisoning in dogs. A review by Cortinovis and colleagues, published in 2015 in The Veterinary Journal, shows that dogs are the species most often affected, usually by accidentally eating poorly stored medicines, sometimes because an owner meant well. The classes involved: anti-inflammatory painkillers, antihistamines, heart medicines, antidepressants, sleeping pills and anti-anxiety drugs, anti-diarrhoeals, vitamin D and iron, and bronchodilators (see the study).
Non-steroidal anti-inflammatory drugs (NSAIDs) top the list. The ASPCA Animal Poison Control Center received 22,206 NSAID calls for dogs and cats between 2005 and 2010, 15,823 of them for dogs, according to Khan and McLean in a review published in 2012 in Veterinary Clinics of North America. Ibuprofen was most often involved, ahead of aspirin and naproxen (see the study).
Why these medicines are dangerous for dogs
Dogs do not clear medicines the way we do. According to the Merck Veterinary Manual, ibuprofen has a narrow margin of safety in dogs and is no longer recommended for them, because it can cause stomach ulcers and perforation; naproxen stays in a dog’s body for a very long time (a half-life of about 74 hours in dogs), so its effects drag on. NSAIDs mainly damage the stomach and kidneys. Paracetamol (acetaminophen) affects the liver and red blood cells. Doses that relieve an adult human therefore mean nothing for a dog, and a treatment can only be worked out at a consultation.
Table: the medicine cabinet from a dog’s point of view
| Medicine | What it damages in dogs | Signs to watch for | The trap |
|---|---|---|---|
| Ibuprofen | Stomach (ulcers, perforation), kidneys; nervous system at high doses | Vomiting, sometimes with blood, black stools, loss of appetite, tummy pain, lethargy | Over-the-counter painkiller, often within reach; narrow margin of safety |
| Naproxen | Stomach, kidneys | The same digestive signs, sometimes delayed | Cleared very slowly by dogs: long-lasting effects |
| Aspirin | Stomach, blood clotting, acid-base balance | Vomiting, lethargy, panting, fever, bleeding | The myth of a “gentle” medicine |
| Paracetamol (acetaminophen) | Liver, red blood cells, tears (dry eye) | Lethargy, vomiting, tummy pain, brownish or yellow gums, swelling of the face or paws | Seen as “mild” in people, which feels falsely reassuring; extremely toxic to cats |
| The dog’s own veterinary anti-inflammatory | Stomach, kidneys | The same signs as human NSAIDs | Flavoured tablets: a whole box can be chewed up |
Signs and organs affected: Merck Veterinary Manual. A vet may sometimes prescribe one of these active ingredients for a particular dog, at a dose and for a length of time worked out for that dog: that is exactly why you should never improvise.
What happens at the clinic
A study by Steele and colleagues, published in 2021 in the Journal of Veterinary Emergency and Critical Care, followed 125 dogs seen at a university hospital emergency room after an NSAID overdose. Three quarters (74.4%) had swallowed a human medicine and one quarter a veterinary anti-inflammatory, with similar outcomes. Vomiting was the most common sign (36.8%), ahead of acute kidney injury (13.6%) and suspected gut ulcers (12.8%). 96% of the dogs went home alive, and each extra day without eating raised the risk of a fatal outcome (see the study). The message is clear: seeing the vet early changes the outlook.
What to do in the first half hour
- Move your dog away and pick up whatever is left (tablets, chewed packaging).
- Count what is missing and note the strength printed on the box, the estimated time and your dog’s weight.
- Call your vet or a poison helpline, even if your dog seems fine: several effects do not show straight away.
- Give nothing by mouth (no milk, no oil, no other medicine) unless told to, and do not induce vomiting yourself.
- Take the box and the leaflet to the vet.
Prevention: store medicines as you would around a toddler
- Keep weekly pill organisers, boxes and blister packs in a closed cupboard, never on a bedside table, coffee table or in a bag on the floor.
- Pick up a dropped tablet at once: your dog is often quicker than you.
- Store your dog’s treatments separately from the family’s, to avoid mix-ups, and out of reach: they are often flavoured.
- Never give a dog a product meant for another species: our guide to flea and tick treatments for dogs also covers the reverse danger for cats. Some breeds are also sensitive to common drugs, as our article on the Australian Shepherd MDR1 mutation explains. More advice in our dog care and grooming section.
Frequently asked questions
Can I give my dog ibuprofen?
No. According to the Merck Veterinary Manual, it is no longer recommended for dogs because of the risk of stomach ulcers and perforation. If your dog is in pain, your vet has anti-inflammatories and painkillers designed for dogs.
Can I give my dog paracetamol (acetaminophen)?
Not on your own initiative. A vet may occasionally prescribe it for a particular dog, with a calculated dose and duration; given at random, it can harm the liver and the blood. For cats it is extremely toxic.
My dog swallowed just one tablet. Do I really need to call?
Yes. Depending on the medicine, its strength and your dog’s weight, a single tablet can be enough to cause trouble in a small dog. Your vet or the poison line can work it out in a few minutes.
How long before signs appear?
It depends on the medicine: vomiting can come quickly, but damage to the stomach, kidneys or liver may show later. That is why you call as soon as it is swallowed, without waiting for symptoms.
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This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
