Safety and Efficacy of NSAIDs for Canine Arthritis

A common justification for the use of alternative therapies, with or without evidence concerning safety and efficacy, is that they are appropriate when conventional medicine does not have an established effective treatment for the problem. This is a legitimate argument in that there is always a balance to be struck between the degree of uncertainty about whether a treatment works or is safe and the urgency of treatment. For mild, self-limiting diseases there is little excuse for using therapies of uncertain safety or efficacy. And when there is ample evidence a therapy is ineffective (such as homeopathy) or unsafe (such as cervical chiropractic treatment or some herbal remedies), there is no justification for its use.

But if there is a significant clinical problem for which science has not yet found a safe or effective therapy, there is some justification for accepting the risk and uncertainty of using an unproven approach, so long as the patient/client understands the degree of uncertainty and the unpredictability of the outcome. Despite the assumptions and accusation of some alternative medicine proponents, those of us dedicated to science and evidence-based medicine don’t object to trying unproven approaches when there is little else available. What we object to is offering these approaches with unjustified claims about their safety and efficacy based on anecdote, personal experience, of scant and sloppy research. Whether it is ostensibly “scientific” treatment like adipose-derived stem cell therapy or clearly unscientific approaches like “energy medicine” and the like, there is an ethical duty on the practitioner offering the unproven method to provide honest, objective disclosure to the client or patient about the state of the evidence so they can make an informed decision balancing the needs of the patient and the potential risks and benefits of treatment.

Far more often, however, this argument is used to justify the use of alternative therapies when there really are established, science-based treatments available. In the case of arthritis in dogs, for example, there is a long list of unproven or disproven alternative therapies available, such as acupuncture, fish oil supplements (and here), electromagnetic devices, fat-derived stem cell injections, and of course the ubiquitous glucosamine, which seems to be taken by nearly every dog I see as a preventative of therapy for arthritis despite the voluminous evidence that it has no benefit (c.f. 1, 2, and 3). These therapies range from safe but useless (such as glucosamine) or safe but with little demonstrated benefit (acupuncture), to truly uncertain long-term safety and efficacy (such as stem cell therapy and most herbal approaches). But apart from the evidence against the claims that these treatments help, the argument for their use is further weakened by the existence of safe and effective conventional treatments for arthritis in dogs.

Much arthritis in dogs is related to congenital or developmental diseases, such as hip and elbow dysplasia, which can be prevented through aggressive testing and breeding programs and proper nutrition for puppies. Arthritis secondary to such problems can also be prevented by timely surgical treatment (and here) of affected animals.

A prime factor in the development of arthritis and its symptoms, for both humans and dogs, is obesity. There is good evidence that controlling weight is a very effective therapy for canine arthritis (1, 2).

And, of course, there are many effective medications for the treatment of osteoarthritis in dogs. The best among these are the non-steroidal anti-inflammatory drugs (NSAIDs), though drugs such as tramadol, gabapentin, amantidine, and other can be of benefit. In every study or review of arthritis treatment for dogs, nothing comes close to the effectiveness of NSAIDs (c.f. 1, 2, 3).

Of course, as I have often said, there is no free lunch in physiology. The body is a complex system with innumerable interactions, and anything that has a beneficial effect on one element of the system is going to have effects on others as well, and not always beneficial effects. Despite the claims of something for nothing often made by proponents of alternative therapies, anything that helps will have some risk of harm. Unfortunately, proponents of alternative therapies for arthritis frequently downplay the benefits and exaggerate the risks of conventional therapies, and NSAIDs in particular seem to generate a lot of unjustified fear and hysteria.

A recent paper reviewed the literature concerning the safety and efficacy of these drugs in dogs:

Innes JF, Clayton J, Lascelles BD. Review of the safety and efficacy of long-term NSAID use in the treatment of canine osteoarthritis. Vet Rec. 2010 Feb 20;166(8):226-30.

As usual, the quantity and quality of the veterinary research on the subject is less than ideal. However, a number of studies have been conducted, and they show unequivocal efficacy. Most subjective measures by owners or veterinarians improve by close to 90%, and when objective measures are used they almost always show clear benefit. Certainly, these results are far stronger than the equivalent results in studies claiming positive effects for glucosamine and many other alternatives to NSAIDs. And there is even some limited evidence that these drugs may reduce the development or progression of arthritis, though the findings are only preliminary and may or may not turn out to be clinically relevant (1, 2)

And what about the risks? The quality of the data on this subject was often poor, especially given that placebo controls were not used in many studies, which would tend to exaggerate the appearance of harm done by the drugs. However, the rate of adverse events ranged from 0 to 0.31 with no significant difference in the rate of adverse events between the NSAID and placebo when placebos were used. out of 1589 dogs in the studies reviewed, only 1 experience a severe reaction requiring hospitalization for treatment.

Other evidence, including trials used to gain FDA approval, show that dogs on NSAIDs can experience minor problems, such as self-limiting vomiting and diarrhea, or potentially more severe problems such as stomach bleeding, worsening of pre-existing kidney disease, or liver failure. However, the rates of these problems are extremely low, and they must be balanced against the life-limiting pain caused by arthritis, the clear efficacy of NSAIDs in relieving this pain, and the great deal of uncertainty about the safety or benefit of alternative treatments.

Owners can only evaluate the risks and benefits of treatment options if they have accurate information about these. It is a disservice to our clients and our patients to guide them towards unproven therapies, at the risk of unexpected side effects or continuing, unrelieved pain, on the basis of inaccurate or exaggerated assessments of the risk of established therapies such as NSAIDs. These are very effective and very safe medications which literally save the lives of thousands of animals who would be euthanized due to pain and unacceptable quality of life without this treatment.

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