Naproxen, the active ingredient of Aleve(®), is a pain relief medicine not frequently prescribed for animals. When given to dogs it is most often used for the relief of pain associated with osteoarthritis or similar inflammatory conditions and belongs to the NSAID class of drugs, which is shared by aspirin as well as veterinary medicines like carprofen. Because this drug is not considered very safe (due to the high risk of toxicity and side effects, mostly as a result of accidental overdose) it is usually only used when safer alternatives have failed to provide relief.


What’s The Dosage?

Note: Never give any medicines containing naproxen to your dog unless advised to do so by your vet, and only use the drug as a last resort when other options do not provide relief from symptoms.

When used for the treatment of dogs a dosage of 0.9 mg/lb is common. This should be administered orally once every other day (every 48 hours).

Canine dosage of naproxen chart

Most tablets contain high amounts of active ingredient making it difficult to accurately give the correct amount. For example, Aleve tablets usually begin at a strength of 220 mg, over double what is required by a 100 lb dog.

Example: If your dog weighs 100 lbs they would need 90 mg once every 48 hours.

How Safe Is It?

Naproxen is not very safe, which is why it is often only used after other pain relief drugs do not work and alternate options have been exhausted. Absorption into a dog’s system after oral administration is rapid with a half life of around 34 to 72 hours (source).

Studies into the safety of this drug have given doses as high as 2.5 mg/lb to dogs for seven consecutive days. This resulted in vomiting, anemia, depression and melena. Animal poison control centers have reported blood in stools, vomiting, melena, irregular heartbeat and diarrhea in cases of overdose.

Contraindications & Drug Interactions

The medicine is associated with many contraindications, for this reason you should disclose all medical conditions your pet suffers from to your vet.

Safety Guidelines

Never administer this medicine unless a qualified vet has told you to do so. The biggest concern during treatment is the possibility of bad side effects and accidental overdose. To increase the safety of treatment you should use a strength which is easy to accurately dose and tell the vet about:

  • All medical conditions affecting your dog as well as all other medicines or supplements they are taking
  • Any prior bad reactions your pet has had to NSAID drugs

Pregnancy: The drug has not been shown to cause damage to fetuses, but studies into this matter are not yet extensive.

When Is It Used?

Naproxen is often used as a pain relief medicine for the treatment of inflammatory conditions (such as arthritis) and is reserved for use only when safer alternatives such as carprofen have failed to improve symptoms.

It should not be given to pets with stomach or intestinal ulcers.

Adverse Reactions

The risk of adverse reactions during treatment is relatively high. This may include:

  • Raised liver enzyme levels
  • Gastrointestinal ulcers
  • Stomach perforation
  • Kidney inflammation

Because of the serious sides associated with this drug many vets do not recommend its use.


An overdose can be deadly if left untreated. If your pet has ingested an overdose of this medicine you should seek immediate veterinary care. Symptoms include:

  • Pale mucous membranes
  • Blood in stools
  • Vomiting
  • Diarrhea
  • Ataxia
  • Anemia

Following an overdose pets are often given activated charcoal to absorb any drug still remaining in the stomach and you may be asked to induce vomiting with hydrogen peroxide.