Toxic to cats · Medications

Is Naproxen toxic to cats?

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

Yes, Naproxen is extremely toxic to cats. 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.

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Is naproxen toxic to dogs and cats?

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What to do right now

  1. Call your vet or an animal poison line now, even if your cat seems fine and even if it swallowed only a small amount. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435.
  2. Don't try to make your cat vomit at home.
  3. Keep the packaging. Note the tablet strength, how many tablets may be missing, roughly when it happened and your cat's weight.
  4. If you gave your cat naproxen yourself, tell the vet how much and how often. Also mention any steroid or other anti-inflammatory your cat takes: these raise the risk of stomach and kidney damage.

Go to an emergency vet if

  • Your cat swallowed any amount of naproxen and you can't reach your vet or a poison line. Cats may be even more sensitive than dogs, so don't wait for signs.
  • Your cat vomits blood, passes black, tarry stools, or has pale gums or weakness.
  • Your cat's face twitches, or it has a seizure or becomes unresponsive.
  • Your cat has belly pain, stops eating or is very dull.
  • Your cat drinks or pees more than usual. This can be a sign of kidney damage.

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

Cats may be even more sensitive to naproxen than dogs, because their liver has a limited ability to process it, according to the Merck Veterinary Manual. The ASPCA says cats in general have a low tolerance for NSAIDs and that most exposures need aggressive treatment. Pet Poison Helpline says just one tablet can cause poisoning, even death, in a large pet. Merck and the ASPCA give no mg/kg figures for naproxen in cats. Don't use the dog figures to judge your cat's risk: treat any amount your cat swallows as an emergency.

When signs appear

Pet Poison Helpline says naproxen can take effect within 1 to 2 hours after it is swallowed, and that it stays in the body for a long time. Merck and the ASPCA give no separate timeline for cats. 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 cat swallowed naproxen less than 4 hours ago and hasn't vomited yet, the vet may make it vomit, then give activated charcoal. To prevent stomach ulcers, cats get an acid reducer such as famotidine or omeprazole, plus sucralfate and misoprostol, for 7 to 10 days. A drip (IV fluids) runs for at least 48 hours to protect the kidneys, with kidney tests to follow progress, and the vet watches for signs of stomach bleeding.

Outlook

Most exposures in cats need aggressive treatment, because cats tolerate NSAIDs so poorly. The sooner treatment starts, the better the outcome. A severe ulcer can break through the gut wall and lead to sepsis, which can be fatal.

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.

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