Mrs. Smith called in the other day and reported that her dog Max has been slowing down and seems to be having a hard time getting around. He had gotten some pain medication from us before after he had injured his leg on a hike, but that stuff was awfully expensive. She just wanted to know how much Advil to give him to ease his apparent arthritis. We were all very grateful that she had called to ask instead of just giving her dog a random dose of medication because it gave us the chance to talk with her and to save Max from some medical problems that could have ranged from simply misery inducing to life threatening.
The first problem with this scenario is that although arthritis is a very common problem it is not the only reason that a pet may start slowing down and having a hard time getting around. I have seen bleeding splenic tumors, immune mediated destruction of red blood cells, ingested rat poison and pennies, bone tumors, and neurologic disease all come in the door as appointments to check arthritis. It would have been a horrible disservice to those patients to have just handed out anti-inflammatory medications without looking at them first.
More often than not the problem really is arthritis or some other orthopedic issue that would be appropriately treated with anti-inflammatory pain relievers, also known as NSAIDs (Non-Steroidal Anti-Inflammatories). Anyone who has had their dog on long term NSAIDs for arthritis knows that the veterinary formulations are considerably more expensive than aspirin, so if aspirin works well to relieve your arthritis why shouldn’t you use it for your dog too?
It turns out that dogs aren’t the equivalent of very short, furry people when it comes to the way their bodies handle many drugs. Of all the over the counter NSAIDs that people take aspirin is probably the best tolerated by dogs. However one recent study showed that 100% of dogs given a single theraputic dose of aspirin developed measurable gastrointestinal bleeding. Most NSAIDS have two major categories of effects. On the good side they relieve inflammation and pain. On the bad side they reduce blood flow to the kidneys, increase acid production in the stomach, and cause the liver to have to work to remove the drug from the system. In a human a dose of ibuprofen (Advil) or Naproxen (Aleve) is well on its way to being broken down and removed from the system in about 6 to 8 hours. In a dog that process takes about 80 hours, or more than three days. During that time the good anti-inflammatory effects are still in place, but so are all the negative effects. Give your dog a second dose the next day and another the next day and you will soon have twice and then three times the original dose floating around in your dog. The limping very well may be improved, but sometimes that is hard to determine in a dog who won’t get up off the floor because he is so sick from his liver and kidney failure and painful from his perforating ulcer.
There are several brands of veterinary NSAIDs available these days and they are all very effective for pain relief and generally very safe for dogs. They have the same sorts of negative side effects that ibuprofen and aspirin have, but at such a low rate that in almost all dogs they can used very long term without much risk of causing problems. Your veterinarian may recommend periodic blood screening to make sure that everything is still OK and that the liver and kidneys are healthy enough to be able to handle the medication. As with all medications, it is possible for certain individuals with a silent metabolic glitch to have severe adverse reactions that could be fatal. This is an exceedingly rare occurrence, so I would not let my dog live in daily pain that I could relieve with medication because less than 1 in 100,000 dogs may have a problem.
So what about cats? After all, they have pain too. Unfortunately for the feline portion of the population they don’t have most of the metabolic pathways that are essential for processing NSAIDs, which means that almost all of those drugs, including the veterinary specific ones, can be very toxic to them. Because of their quirky chemistry a single Tylenol tablet will become fatally poisonous. Don’t ever give cats over the counter medication because they are just put together differently. (as if you needed an excuse not to have to pill the cat.)