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Naproxen Poisoning in Dogs
Written By hannah hollinger
Published: 07/04/2016Updated: 01/12/2022
Veterinary reviewed by Dr. Linda Simon, MVB MRCVS
What is Naproxen Poisoning?
Naproxen is an over the counter NSAID that is used to treat pain, inflammation, and fever in people and dogs. Naproxen has typically been prescribed for dogs at a dose of 2 milligrams per kilogram of body weight every other day. Due to the side-effects, many veterinarians recommend only using naproxen if other medications are ineffective. 
Naproxen works by blocking the enzyme cyclooxygenase which helps to limit fever and inflammation responses in the body. However, cyclooxygenase also produces prostaglandins that protect the gastrointestinal tract and help with blood flow and filtration in the kidneys. Inhibition of this enzyme can result in bleeding and ulceration of the GI tract as well as reduced kidney function. 
Dogs have been known to develop vomiting, lethargy and bloody stools after only a single dose of naproxen and week-long regimens can result in signs of kidney dysfunction, especially if they don’t adequately account for the dog’s weight. 
The Animal Poison Control Center had 4,404 reported cases of naproxen poisoning from 2001-2011, both from naproxen that was prescribed to dogs and accidental overdoses of human medication. Single doses as low as 7 mg per kg can have significant symptoms, while 13-15 mg per kg will cause signs of kidney failure with increased blood nitrogen. 
Gastrointestinal symptoms will become apparent in 2-24 hours, while kidney dysfunction develops in 24-48 hours. Use of other NSAIDs can compound the problem and older dogs with prior kidney disease are also more at risk. Severe overdose can lead to fatal bleeding in the GI tract and acute kidney failure if left untreated. Most symptoms of naproxen poisoning can be resolved with treatment and kidney dysfunction is usually reversible as long as there are no complicating diseases or toxicities.
Naproxen is a non-prescription NSAID that is used to treat fever, inflammation, and pain in humans. It is also prescribed to treat these conditions in dogs, however high doses can have toxic side-effects. Naproxen poisoning in dogs can cause ulcers, gastrointestinal bleeding, and kidney failure.
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Naproxen Poisoning Average Cost
From 48 quotes ranging from $300 - $6,000
Average Cost
$3,000

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Symptoms of Naproxen Poisoning in Dogs
Get veterinary treatment as soon as possible if you notice any of the following symptoms associated with naproxen toxicosis.
  • Frequent vomiting (with or without blood)
  • Abdominal pain
  • Lack of appetite
  • Weight loss
  • Lethargy
  • Blood in the stool which may be red or black(melena)
  • Gum ulcers
  • Pale mucous membranes
  • Weakness
  • Stumbling
Types
These are the brand names for some over-the-counter human medications that contain naproxen.
  • Aleve
  • Anaprox
  • Mediproxen
  • Naprelan
  • Naprosyn
Causes of Naproxen Poisoning in Dogs
These are the most common risk factors associated with naproxen poisoning.
  • High doses of naproxen prescribed to dogs
  • Owners giving naproxen intended for humans to dogs
  • Combining Naproxen with other NSAIDs
Accidental overdose of medication for dogs or humans can occur due to :
  • Improperly stored medications
  • Bottle left open
  • Dog chewing through bottle
  • Sugar coated pills that taste good to dogs
Diagnosis of Naproxen Poisoning in Dogs
The veterinarian will physically examine your dog and take blood and urine samples. Blood tests will show regenerative anemia from blood loss as well as increases in BUN (blood nitrogen) and creatinine if kidney failure is present. The veterinarian will need a list of your dog’s current medications and a detailed description of the symptoms. In the case of accidental overdose, bring the empty container or a sample of the medication you think your dog ingested so the veterinarian can evaluate it. The veterinarian will want to know when you think the exposure took place as well as how much your dog may have ingested.
Treatment of Naproxen Poisoning in Dogs
Calling a poison helpline can be a good first step for naproxen overdose, especially if you don’t have immediate access to a veterinarian. Have the medication on hand, as well as your dog’s breed and weight. Follow the instructions the agent gives you and get in-person veterinary attention as soon as possible. Only induce vomiting if specifically directed by a professional.
If your dog is developing mild symptoms from a naproxen prescription, the veterinarian will discontinue the medication and treat the symptoms as necessary. Larger doses will require more aggressive treatment. If ingestion took place in the last 2 hours, the veterinarian will give your dog medication that causes emesis. Activated charcoal may also be given to help limit availability in the gastrointestinal tract and a cathartic medication will help to encourage excretion through bowel movements. A second dose of activated charcoal may be administered 24-48 hours later to limit recirculation from the liver.
Intravenous fluids and electrolytes will help to balance sodium levels which can rise as a result of activated charcoal administration. Various medications may be used to protect the GI tract, including sucralfate, misoprostol, famotidine, or omeprazole. If significant GI bleeding develops, blood transfusions may be necessary to reduce anemia and prevent fatal blood loss. 
If kidney failure is a possibility, the veterinarian will monitor blood and urine levels and provide fluid treatment as needed to dilute toxins that are normally filtered by the kidneys. Symptoms of naproxen toxicity can continue to increase over a 72 hour period, so the veterinarian will need to monitor your dog during that time. For severe overdose, your dog will need to stay in a veterinary hospital for 3-4 days or until all systems have returned to normal.

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Recovery of Naproxen Poisoning in Dogs
Dogs often make a complete recovery after treatment for naproxen poisoning, but there is always a risk of fatal bleeding complications or kidney failure. If your dog is prescribed naproxen, discuss the risk of side-effects with your veterinarian and make sure your dog is on the lowest possible dose. Never give dogs any medications intended for humans. 
Keep all medications in your house on a high shelf or in a closed medicine cabinet that your dog cannot access. Close all bottles and avoid leaving them around since dogs may be able to access the pills by chewing through the bottle. Sugar coated pills can be an incentive, especially if your dog is already familiar with the taste.
Naproxen Poisoning Average Cost
From 48 quotes ranging from $300 - $6,000
Average Cost
$3,000
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Naproxen Poisoning Questions and Advice from Veterinary Professionals
Pit Bull
eleven months

16 found this helpful

16 found this helpful

My pet has the following symptoms:
None
Was able to chew the top of the bottle off and chewed the top. Found a couple 250mg pills that were halves not sure how much or if any was consumed. Dog doesn't show any signs as of yet happened in the last hour.
Nov. 9, 2020
Answered by Dr. Linda S. MVB MRCVS
16 Recommendations
Doses over 10mg/kg can be toxic. So, for example, we would be concerned if a 20kg dog ate 200mg or more. From your description it is quite likely this amount has been ingested so I would seek immediate vet care. They can induce vomiting, give activated charcoal, start him on a drip and monitor his vitals and bloodwork. This drug is dangerous and can cause ulcers, kidney failure and even death. We may not see any signs initially but this does not mean the dog is safe so a vet visit is essential.
Nov. 9, 2020
Was this question and answer helpful?
English Bulldog Terrier
Two Years

6 found this helpful

6 found this helpful

My pet has the following symptoms:
Noisy Breathing
Ate 1 pill of naproxen.Will he live?
Aug. 1, 2020
Answered by Jessica N. DVM
6 Recommendations
Hello- Thank you for your question. Naproxen is very toxic. He does need immediate medical care. For toxin ingestion my first recommendation would be to call pet poison helpline at 855-764-7661. They will be able to tell you based on the amount of medication he received the toxic effects and can make a treatment plan for your veterinarian. I would also recommend seeing a veterinarian immediately or going to a veterinary ER. Good luck and take care.
Aug. 1, 2020
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Dachshund terrier
7 + 1/2

2 found this helpful

2 found this helpful

My pet has the following symptoms:
None
Look up medication and found out it is toxic to dogs
July 9, 2020
Answered by Dr. Michele K. DVM
2 Recommendations
That is a lot of human medication for a small dog, and it would be best to seek Veterinary Care as soon as possible. That drug can cause kidney failure, GI ulcerations, and other problems. Having your dog seen by a veterinarian, they will be able to treat any signs that are happening, and help make sure that your dog is okay. I hope that all goes well.
July 9, 2020
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Dachshund terrier
6 + 1/2

3 found this helpful

3 found this helpful

My pet has the following symptoms:
None
What should I do look up medication is toxic!!!
July 9, 2020
Answered by Dr. Michele K. DVM
3 Recommendations
That is a lot of human medication for a small dog, and it would be best to seek Veterinary Care as soon as possible. That drug can cause kidney failure, GI ulcerations, and other problems. Having your dog seen by a veterinarian, they will be able to treat any signs that are happening, and help make sure that your dog is okay. I hope that all goes well.
July 9, 2020
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Siberian Husky
Darcy
3 Years

6 found this helpful

6 found this helpful

My pet has the following symptoms:
Vomiting
Hi our husky has eaten 6 naproxen and they are 250mg each we have only just found the remains of the box so this may of happened 2days ago she keeps being sick she weighs 25kg please help with any advice
June 17, 2018
6 Recommendations
Naproxen is highly toxic to dogs with just a single tablet sufficient to cause serious illness, there isn’t anything I can recommend you can do at home but you should visit an Emergency Veterinarian immediately for a check of kidney function and for fluid therapy. Regards Dr Callum Turner DVM www.petpoisonhelpline.com/poison/naproxen/ http://veterinarymedicine.dvm360.com/toxicology-brief-naproxen-toxicosis-dogs
June 17, 2018
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Miniature Schnauzer
Maggie
15 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Vomiting
I unintentionally gave my dog (mini schnauzer) an Equate version of Aleve last Friday. She’s vomited several times and doesn’t have much of an appetite. I just Googled this morning that it can be toxic to dogs (I should’ve looked before I gave her one 🤦🏻‍♀️). What can I do now? It’s been a week... she seems to be feeling better, but still isn’t eating. Do I really need to take her to a vet? Or is there something I can do at home?
Standard Poodle
Cha-Cha
20 Months

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Didn'T See Any
Came home to find a chewed-up naproxen bottle on the floor. Culprit was our nearly two year old 50 pound standard poodle. She seemed normal, but it had only been a couple of hours, and this med progresses slowly, apparently. Were advised to take her to an emergency vet, and took her to a nearby clinic, where they made her throw up (yes, it had a blue-ish color), and also gave her charcoal. She subsequently had terrible black diarhea, but I think this is part of the "purging" process. Fortunately the clinic and hospital had to deal with that--not us--and they actually taped up her long tail to make it easier for cleaning! With the lengthy half-life of this medication, the idea is to flush it out of the system as thoroughly as possible, to try to prevent the liver and kidneys from having to deal with it. That required also "flushing" her circulatory system via IV (saline solution, essentially), for THREE SOLID DAYS, so we ended up shuttling her between the daytime clinic and the emergency pet hospital that could administer all this 24 hours (the daytime clinic was cheaper, plus it was nice to see her each evening and morning). She had a VERY close call, particularly, I believe, with her GI tract, which fortunately did NOT rupture or ulcerate right through, which would have required surgery. It appeared that the Chinese herb yunnan baiyao was particularly (amazingly, actually) helpful with that. She was finally discharged, along with a regimen of six medications. She now seems to have fully recovered, but it was scary, and it will take a bit longer for our finances to recover. So please DO pay attention to the vets' responses in this thread to take your dog to an emergency clinic IMMEDIATELY, as it's a VERY serious situation. Seems as though the fields below are limited in number of chars, strangely, so will elaborate here: Meds: (along with Chinese herb),benamarin, carafate, omeprazole, misoprostol , metronidazole
Border Collie
Montana
9 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Diarrhea
Weakness
Vomiting
Stumbling
A bottle of Aleve fell on the floor about a week ago and my dog ate one of them. I didn't think anything about it or know that they were toxic to dogs. Three days ago Montana started showing some signs of leaning to one side, slipping, falling, and having difficulty getting up. Yesterday she vomited twice. After reading this article I see these could these be signs of poisoning. What can I do now that it may have been at least a week ago that she gotten a hold of the pills? I'm very worried and scared.
Labrador Retriever
Fiji
1 Year

1 found this helpful

1 found this helpful

My pet has the following symptoms:
Vomiting
I was on my way out this morning and my 86lb dog busted through a bottle of naproxen, i don't know how much he ate. I don't know what his symptoms are my mom found out when she got home.What do I need to do? I am placing an unkown symptom seeing as how I currently dont know his shape
Naproxen Poisoning Average Cost
From 48 quotes ranging from $300 - $6,000
Average Cost
$3,000

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