Americans spend about around $60 billion on their pets annually. We love our pets and consider them to be members of the family and, naturally, we want to help them when they’re sick or aging. In many cases we administer whatever pharmaceuticals and food supplements that our vets recommend. But what if the drugs don’t work?

Journalist and Biology PhD Peter Aldhous conducted his own investigation into this subject after reading a study on feline osteoarthritis and two food supplements – glucosamine and chondroitin – ingredients used to manage feline osteoarthritis. Aldhous’s interest was sparked when he recognized that the same supplements examined in the study were also part of his dog’s osteoarthritis regimen.

It turns out that neither supplement did much to help cats with disintegrating joints, so Aldhous questioned whether the supplements were doing anything to help his dog. After some research, he found that there is little evidence that painkillers do much to ease the suffering of aging pets with hip dysplasia or arthritis, for example. Non-steroidal anti-inflammatory drugs (NSAIDs) may be more helpful in addressing these issues, but are prescribed less, possibly due to fears of kidney damage.

In 2013, Americans spent over $14 billion on veterinary care for their pets, $12.65 billion of which went to supplies and over-the-counter medicine, according to the American Pet Products Association. Aldous points out that if a medicine is on the FDA-approved list for animal drugs, it most likely does what it claims to do. For example, most flea and worming medications have been more extensively tested and are helpful with eliminating parasites from pets.

But things “get murky with many commonly prescribed drugs, including antibiotics and painkillers, which have not specifically been approved for use in animals and where practice is based on extrapolations from human medicine,” Aldhous says.

Vets may not be entirely to blame because they have relatively few options of FDA-approved drugs to prescribe and “most of what we know about whether drugs work and are safe comes from clinical trials conducted by pharmaceutical companies to win marketing approval.”

Yet, Brennan McKenzie, the president of the Evidence-Based Veterinary Medicine Association told Aldhous that vets, unlike other doctors, may be reluctant to dig too deep into scientific research for fear they may discover that they’ve been prescribing useless medications or don’t know how to really help make our pets well again.

One vet commenting on a blog post on McKenzie’s website wrote, “I can tell you it was hard for me to stop selling the stuff. I was making money, the clients thought it was working… and I did not want to fess up and tell them they had bought something from me that was a waste of money.”

Ultimately, Aldhous used a website called BestBETs for Vets, which helps vets find answers to their customers’ concerns in available scientific literature. There he discovered that an NSAID called carprofen is superior to treating osteoarthritis in dogs than are glucosamine and chondroitin supplements.

More scientific research is needed in understanding pet diseases and infections. “It would help if professional bodies [like the American Veterinary Medical Association] took a strong evidence-based stand,” Aldhous says. But pet owners can make a difference “by pressing vets to consider the evidence that does exist… So ask your vet why they think the drugs your animal is being given will work.”

“If all you get from your vet is a bland assurance that they’ve been doing this for years, and see great results, get them to talk you through the scientific evidence,” he continues. “If they can’t do so, that should be a warning sign: It might be time to look for another vet.”

It is important to be a prudent consumer of medication and supplements for your pet, as well as for yourself,” said Emmie Paulos, an attorney with the Levin, Papantonio law firm who is active in the BP Oil Spill litigation. “Remember, advertisements for a particular medication are designed to entice you to want to use that medication and pharmaceutical companies will always paint the prettiest picture when describing the benefits of a particular medication.”

Alisha is a writer and researcher with Ring of Fire. You can follow her on Twitter @childoftheearth.