Using Aspirin for dogs in pain can be fairly safe provided you're very careful about getting the dosage correct, and that you don't use it as a long-term treatment.
Regular 'people' formulas shouldn't be given for more than 5 days maximum.
Even those especially formulated for dogs have a recommended duration of use.
To avoid the common side-effect of stomach irritation, choose 'buffered' or 'enteric-coated' tablets.To jump straight to the best dog aspirin choices click HERE
If you're using regular 'human aspirin' as a pain medication for dogs, the recommended dosage is..
Between 5mg and 10mg per pound of body weight (maximum of 10mg) - given twice a day - that's one dose per 12 hours.
It might help to know that a standard adult Aspirin tablet is 320mg and a baby aspirin tablet is usually 80mg. So, if you have a 40lb dog the recommended dosage would be 200mg given twice a day. 200 mg is 2 1/2 'baby' tabs.
Anything over 30mg per lb is considered toxic!
It's usually easier to get the dosage correct if you use baby aspirin, or children's liquid aspirin. It's very important to make sure that you get the dose right, especially when you're treating small/tiny dogs.
Young puppies aren't able to metabolize pain medications for dogs, or any other medicines, as efficiently as adult dogs.
Also, their liver and kidneys are immature, so they often need a lower dose per lb of body-weight than an adult dog so a large breed puppy may need less medicine than a full-grown mid sized dog of the same weight.
For most dogs there shouldn't be any appreciable side effects of giving them aspirin for a few days as long as you keep within the recommended daily dosage above.
Small or tiny dogs, and young puppies are at the biggest risk of problems and you need to be especially careful about measuring out the correct dosage (this of course applies to ALL medications) for your dog in these situations.
Seemingly minor issues such as lethargy, loss of appetite or loose stools might happen and although these aren't necessarily serious, you should definitely discuss them with your vet. These symptoms, and/or vomiting may not be anything to worry about, but they could be the first sign of serious trouble.
BUT, Aspirin can irritate the stomach lining and occasionally cause bleeding or even an ulcer. If your dog starts to vomit a dark substance (may look a bit like coffee grounds) or his poop looks black or 'tarry', then this could be a sign that there is internal irritation and bleeding - and is very serious. Get your dog to a vet right away if you notice any of these signs.
If you give too much aspirin, or doses too close together, or if for some reason your dog doesn't metabolize it quickly enough there is a risk of organ damage.
If this happens STOP giving him the medication IMMEDIATELY and get him examined by your vet.
In addition to the above side effects, there's another issue that makes it important not to use aspirin to treat chronic arthritis and other ongoing/long-term joint problems.
Aspirin is made from acetylsalicylic acid and when used for extended periods it can actually destroy cartilage and end up making joint problems much worse.
Another warning... Aspirin thins the blood (which is why it's recommended to help reduce the risk of stroke/certain heart conditions), so it's obviously not a good choice for dogs - or people- who have a clotting disorder or any other health condition that causes them to bleed easily.
It also shouldn't be given to dogs who are pregnant (it may cause birth defects) or to those who are due to have surgery in the near future.
Don't combine Aspirin with any other pain medications for dogs (otc or prescription) and don't give it to a dog who is also taking corticosteroids. Remember, if your dog is on ANY type of medication, check with your veterinarian before giving him anything else!
Instead of worrying about getting the right formula of regular aspirin, it's much easier (and safer!) to use Aspirin that has been especially designed for dogs.
Here are a couple of options that I'd recommend:
Enteric coated aspirin in 81mg tablets especially formulated for dogs.
Recommended dosage is 8 - 12mg per lb of body weight (average 10mg per 1lb of body weight to make the calculation easier here). Given only once in 12 hours, or twice a day at 12 hour intervals.
Needs to be given with a meal, or within 30 minutes of one.
Buffered aspirin in a 325mg chewable, beef flavored tablet especially formulated for dogs.
Recommended Vetrynol aspirin dosage for dogs is one 325mg tablet per 8 - 12lbs of body weight (you can average 325mg per 10lbs to make it easier to calculate this).
Given only once in a 12 hour period, ie twice per day at 12 hour intervals.