Ibuprofen and naproxen are both classified as NSAIDs, used in human medicine for various purposes including inflammation, pain and fever. These products are a common source of pet intoxication because well-meaning owners will give them to pets to treat ailments. Common products containing ibuprofen are Advil and Motrin, while Naproxen can be found in Aleve.

Ibuprofen

These products should not be given to animals due to the risk of toxicity. Always consult your veterinarian before giving your pet any medication. As little as one 200 mg ibuprofen tablet can toxic to cats and smaller dogs.

NSAIDs are also considered a potential toxin for horses that are not eating. Horses constantly secrete stomach acid. In the absence of food, giving a horse an NSAID greatly increases the risk of gastric erosion. This should be avoided if at all possible.

Ferrets are also indicated for this toxicity.

Signs and symptoms of toxicity: Loss of appetite or refusal to eat, abdominal pain, vomiting, diarrhea, increased production of saliva, and melena (black, tarry stool). Signs of toxicity (particularly gastrointestinal symptoms) can be seen 2-6 hours after ingestion. However, serious complications may not be seen for 4-5 days post-ingestion.

Toxic consumption:
Ibuprofen: Signs of toxicity may be seen at doses of 50 mg/kg (22 mg/lb) in dogs and 25 mg/kg (11 mg/lb) in cats. With long-term administration, toxicity has been seen in dogs with doses as low as 5-6 mg/kg (2-3 mg/lb).

Naproxen: There is no established toxic threshold for pet consumption. However, signs of toxicity have been noted in dogs that have ingested doses of 5 mg/kg (2 mg/lb) of body weight.

Dogs: Human NSAIDs Toxic Consumption
X-Small
Yorkie, Chihuahua
Small
Pug, Boston Terrier, Poodle
Medium
Beagle, Scottish Terrier
Large
Boxer, Cocker Spaniel
X-Large
Retriever, German Shepherd
XX-Large
Great Dane, St. Bernard
1 – 10 lbs.
(0.45 – 4.6 kg)
11 – 25 lbs.
(5 – 11.4 kg)
26 – 40 lbs.
(11.8 – 18.2 kg)
41 – 70 lbs.
(18.6 – 31.8 kg)
71 – 90 lbs.
(32.3 – 40.9 kg)
91 – 110 lbs.
(41.4 – 50 kg)
dog1 dog2 dog3 dog4 dog7 dog6
Ibuprofen > 22 mg > 249 mg > 589 mg > 929 mg > 1614 mg > 2069 mg
Naproxen > 2.2 mg > 24 mg > 58 mg > 92 mg > 161 mg > 206 mg

 

Cats: Ibuprofen Toxic Consumption
Most Cats

Large Cats
1 – 10 lbs.
(0.45 – 4.6 kg)
11 – 25 lbs.
(5 – 11.4 kg)
cat1 fat cat
> 11 mg > 124 mg

 

References:
– Lees P, Landoni MF, Giraudel J, Toutain PL. Pharmacodynamics and pharmacokinetics of non steroidal anti-inflammatory drugs in species of veterinary interest. J Vet Pharmacol Therapy 2004; 27:479-490.
– Osweiler, G, et al. (2011). Blackwell’s five-minute veterinary consult clinical companion. Small Animal Toxicology. [Kindle version]. Retrieved from Amazon.com