In looking around at the pain management options out there, it seems as though there is a fair amount of misinformation. Are there any pharmacologists in the Golden Retriever Forum? I'm familiar with human pharmacology, but appreciate there are some differences.
Arthritis pain management options for dogs include: aspirin, etodalac, ibuprofen, naprosyn, rimadyl (carprofen), deramaxx (deracoxib), tramadol (ultram), and acetaminophen.
When I read the posts on this forum, there seem to be some odd conclusions being stated that suggest dog pharmacology is wildly different than humans, which I find hard to believe. I appreciate, for instance, that cat metabolism of acetaminophen is truly different than human, but not dogs. The issues with these drugs seems to arise from safe dosing of the medicines and not specifically the safety of the medicines themselves.
Dogs have both cox-1 and cox-2 enzymes, so it would seem they are able to utilize many of the same NSAIDs humans can take. As with human pharmaceuticals, drug companies push hard on using the selective cox-2 meds (rimadyl and deramaxx for pets), because they are more expensive. Do humans have gastrointestinal bleeds less frequently on selective cox-2 antagonists than on the nonselective agents (aspirin, ibuprofen, naprosyn)? Yes. Can humans take the nonselective agents without getting gastrointestinal bleeds and/or ulcers? Yes. Where do we see the bleeds? When people take too much and/or have an underlying condition which is exacerbated by the nonselective cox antagonists. Are there allergies to nonselective agents (e.g. aspirin)? Certainly. So, care is always warranted when starting a new medicine, in people as in pets. Importantly, NSAIDs aren't used in kids under six months due to the imature kidney, so presumably something similar would be true in dogs (e.g. not starting until 3 or 4 months; purely a guess on my part).
So, if it's a safety in dosing issue, why don't people follow the pediatric methodology of medicine dosing, which is to do weight-based dosing. Pediatricians classically deliver medicines using the weight-based method, while internists and other adult physicians typically use a one-size-fits-all approach (with some exceptions, of course). I'm guessing people see so many gastrointestinal bleeds in their dogs because they're using adult human pills and not paying attention to their pet's weight. Thankfully goldens are the size of very small adults, so many adult pills can be considered.
When people talk about chronic lab testing while on pain medicines, I keep reading about checking liver function while taking the various NSAIDs, but I don't see people also mentioning kidney function. I appreciate that the site of NSAID metabolism is typically the liver, but that's not the typical site of toxicity. NSAIDs classically target the kidneys by constricting afferent arterioles, thereby limiting blood flow to the kidneys and potentially damaging them by depriving them of oxygen. So, please be sure you are also aware of your dog's kidney function while chronically taking NSAIDs. I would imagine this is probably more of a pet owner misunderstanding than a vet's lack of knowledge, but I am curious if there are known liver toxicity issues that I'm unfamiliar with.
Tramadol (ultram) is a synthetic drug that binds the opioid receptors in a similar fashion as narcotics. It has no antiinflammatory effects, but can be used in humans with kidney and/or liver disease, albeit at lower doses.
Lodine (etodolac) is an NSAID with murky pharmacology. It's metabolized in the liver, so liver function should be monitored. It's heavily excreted in the urine, so kidney function should be monitored, too.
I'm curious why acetaminophen isn't used more in dogs, as long as it's done in a weight-based methodology. Yes, acetaminophen can cause liver toxicity, but I would expect it's unlikely if you follow appropriate dosing. Yes, I would still do once or twice-yearly bloodwork to monitor liver function if the dog takes the medicine most days of the week.
Finally, if a person is on high doses of NSAIDs for a long time, they'll also typically be on a drug like famotidine (Pepcid) or omeprazole (Prilosec). This has been shown to limit gastrointestinal bleeds. Why don't I see more people talking about putting their dogs on intermittent dosing of famotidine (cheaper, but less potent than omeprazole) when they're treating the dogs for arthritis?
Another tip is that folks need to be very careful buying into the buffered and/or coated witchcraft about aspirin. The gastrointestinal bleeds that come from aspirin are due to systemic effects and not contact. There are very rare contact-based problems with aspirin, but bleeds are almost always due to the systemic effect of the drug (same in people, too). So, don't waste money on coated/buffered aspirin unless there is a very clear indication.
Bottom line: Can someone please tell me why a chronic cocktail of naprosyn or ibuprofen can't be used, as long as it's weight-based, there's intermittent use of famotidine, and there's periodic monitoring of kidney function? This is far cheaper than using rimadyl and deramaxx and should be just as effective at limiting Fido's pain/inflammation. The periodic use of famotidine would allow time for healing of minor gastrointestinal irritations. Drug companies make tons of money off of people being uninformed or underinformed, so let's improve the community knowledge.