Toxic to dogs · Medications

Is Naproxen toxic to dogs?

Extreme severity No safe amount — No amount is considered safe.

Yes, Naproxen is extremely toxic to dogs. Even a small amount can be life-threatening, so treat any exposure as an emergency and contact a vet immediately. No amount is considered safe.

Video explainer

Is naproxen toxic to dogs and cats?

Open the video page →

What to do right now

  1. Call your vet or an animal poison line now, even if your dog seems fine. The sooner treatment starts, the better the outcome. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435.
  2. Don't make your dog vomit at home unless a vet or poison-line expert tells you to. Doing it yourself can put your dog in more danger.
  3. Keep the packaging. Note the tablet strength, how many tablets may be missing, roughly when it happened and your dog's weight. The vet uses these to work out the risk.
  4. Tell the vet if it was a combination product such as Aleve PM, and about any medicine your dog already takes, especially a steroid or another anti-inflammatory. These drugs raise the risk of stomach and kidney damage.

Go to an emergency vet if

  • Your dog swallowed any amount of naproxen and you can't reach your vet or a poison line. As little as one tablet can cause serious harm.
  • Your dog vomits blood, passes black, tarry stools, or has pale gums or weakness. These can mean a bleeding stomach ulcer.
  • Your dog has belly pain, stops eating or is very dull.
  • Your dog has a seizure or becomes unresponsive.
  • Your dog drinks or pees more than usual. This can be a sign of kidney failure.

Symptoms to watch for

  • vomiting
  • bloody vomitus
  • black-tarry stools
  • diarrhea
  • lack of appetite
  • painful abdomen
  • weakness
  • pale gums
  • lethargy
  • sepsis
  • depression
  • seizures
  • facial twitching
  • coma

How much is dangerous

Naproxen is dangerous for dogs even in small amounts. Pet Poison Helpline says as little as one 220 mg tablet can cause very serious illness, even death, in a large dog. In ASPCA Animal Poison Control Center data, single doses of 1 to 7 mg/kg of body weight caused vomiting and lethargy. The ASPCA concludes that a single dose of 7 mg/kg or more can cause stomach and gut irritation and ulcers, and that raised kidney values on blood tests, a sign of possible kidney injury, can appear from 13 to 15 mg/kg. The Merck Veterinary Manual reports that a single dose of 35 mg/kg caused vomiting of blood and black stools. Repeated doses are also harmful: 5.6 mg/kg once a day for 7 days caused vomiting, black, tarry stools, pale gums and weakness. Older dogs with kidney problems, and dogs that also take a steroid or another anti-inflammatory, are at higher risk. Your vet works out the dose from the tablet strength, how many tablets are missing and your dog's weight.

When signs appear

Naproxen is absorbed quickly: blood levels peak 30 minutes to 3 hours after a dog swallows it, and Pet Poison Helpline says it can take effect within 1 to 2 hours. Stomach and gut signs most often appear within 2 to 24 hours, and kidney effects within 24 to 48 hours. Naproxen also stays in a dog's body for a long time. The Merck Veterinary Manual gives a half-life (the time the body takes to clear half of the drug) of 35 to 74 hours in dogs, because the drug keeps cycling between the liver and the gut. Don't wait for signs before calling your vet.

Why it's dangerous

Naproxen has a narrow margin of safety in pets, leading to severe gastrointestinal ulceration, potential intestinal perforation, and acute kidney failure.

Toxic compound: Naproxen

How vets treat it

If your dog swallowed naproxen less than 2 hours ago and shows no signs, the vet may make it vomit. Activated charcoal limits absorption. Because naproxen keeps cycling between the liver and the gut, the vet may repeat the charcoal or follow it with another medicine, cholestyramine, and checks blood sodium during this time, since charcoal can raise it. Stomach protectants are given for at least 7 to 14 days because naproxen lasts so long in dogs: sucralfate to coat ulcers, misoprostol, and an acid reducer such as famotidine or omeprazole. If the dose could harm the kidneys, your dog stays on a drip (IV fluids) for at least 72 hours, with kidney blood tests at 24, 48 and 72 hours. Liver values are checked too. Severe ulcers may need a blood transfusion, and vets have used plasma exchange for some very large ingestions.

Outlook

Stomach irritation and ulcers usually heal with the right treatment, and kidney effects are generally reversible when they are found early and treated aggressively. Dogs that develop ulcers are at risk of a tear in the gut wall and can die from bleeding or sepsis, a life-threatening infection. Dogs with existing stomach or kidney disease are at higher risk. The sooner treatment starts, the better the outcome.

Where pets are exposed

  • Naproxen is sold under brand names such as Aleve, Anaprox and Naprosyn, and some Midol products contain it. It belongs to the group of drugs called NSAIDs (non-steroidal anti-inflammatory drugs).
  • Over-the-counter naproxen comes as tablets, capsules and gel capsules, and the tablets contain 220 mg of naproxen sodium. Prescription tablets come in 250, 375 and 500 mg, extended-release tablets in 750 mg, and there is also a liquid.
  • Combination products such as Aleve PM, which also contains diphenhydramine.
  • Medicine cabinets and pill bottles. Dogs are curious and can get into them.
  • A dose given for pain or stiffness. Most published cases in dogs involved naproxen given over several days, for example for joint stiffness. Cats are more often poisoned by NSAIDs their owners give them than by tablets they find themselves.

Prevention

  • Never give naproxen (Aleve) to a dog or cat. The same goes for any human pain reliever your vet hasn't prescribed.
  • Ask your vet about pain relief made for pets. Vets can prescribe anti-inflammatories made for dogs, such as carprofen, deracoxib or meloxicam.
  • Keep medicines put away where pets can't reach them. Dogs can get into the medicine cabinet.
  • If your pet takes a prescribed anti-inflammatory or steroid, never add another pain reliever without asking your vet. Combining them raises the risk of stomach and kidney damage.

Good to know

As little as one 220mg tablet can be fatal even to a large dog. Cats may specifically exhibit facial twitching.

Common questions

Can I give my dog Aleve for pain?

No. Never give naproxen (Aleve) to a dog or cat on your own. Pet Poison Helpline says as little as one 220 mg tablet can cause very serious illness, even death, in a large dog, and the Merck Veterinary Manual says dogs are extremely sensitive to it because it stays in their body so long. Most vets now prescribe pain medicines made for dogs, so ask yours for one.

How much naproxen is toxic to a dog?

A small amount can be dangerous. Pet Poison Helpline says one 220 mg tablet can cause very serious illness, even death, in a large dog. ASPCA data suggest that a single dose of 7 mg/kg of body weight or more can cause stomach and gut ulcers, and that signs of kidney injury are possible from 13 to 15 mg/kg. Repeated small doses are also harmful. Your vet works out the dose from the tablet strength and your dog's weight, so call with the packaging to hand.

My dog ate one Aleve. What should I do?

Call your vet or a pet poison line now, even if your dog seems fine. As little as one 220 mg tablet can cause very serious illness in a large dog, and kidney effects can develop 24 to 48 hours later. Don't make your dog vomit unless a vet tells you to, and keep the packaging so the vet can check the tablet strength.

Is naproxen dangerous for cats?

Yes. Cats may be even more sensitive to naproxen than dogs, because their liver has a limited ability to process it, and cats in general tolerate NSAIDs poorly. Signs can include vomiting, black stools and, more rarely, twitching of the face. Treat any amount your cat swallows as an emergency and call your vet straight away.

How long does naproxen stay in a dog's system?

The Merck Veterinary Manual gives naproxen a half-life of 35 to 74 hours in dogs, which means it takes that long for the body to clear half of it. The drug keeps cycling between the liver and the gut. This is why vets often keep stomach protectants going for 7 to 14 days and a drip running for at least 72 hours. Don't wait for signs: call your vet as soon as you find out.

Sources

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

· How we prepare our guides

More substances toxic to dogs

Acetaminophen High severity Camphor High severity Lunesta High severity Methylphenidate High severity Everything toxic to dogs →

Barcode food checks, now on iPhone.

Scan a product's barcode with StrawPaw to spot ingredients that can harm dogs and cats. The app is free to download.

Download on the App Store