Still, vets could make better use of the available scientific knowledge. Today, most doctors treating human patients accept the principles of evidence-based medicine, where best practice is based on data from multiple scientific studies. But many vets are reluctant to jump on that bandwagon, arguing that there’s not enough data on animals to justify this approach. “A lot of vets think that it will undermine client confidence,” says Brennen McKenzie, president of the Evidence-Based Veterinary Medicine Association and a vet at the Adobe Animal Hospital in Los Altos, California.

Think about what he’s saying: Some vets are reluctant to delve into what science has to say, out of fear that they’ll have to admit that they don’t know for sure how to make our pets well. A comment added to one of McKenzie’s blog posts, from a vet who had learned that glucosamine does little for osteoarthritis, underlines the point. “I can tell you it was hard for me to stop selling the stuff,” the vet wrote. “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.”

My own journey of discovery about Kaleb’s treatment began at a website called BestBETs for Vets, where the Centre for Evidence-based Veterinary Medicine at the University of Nottingham helps vets to ask the right questions—and shows them how to find answers in the scientific literature. Its examples include one relevant to Kaleb, considering the effectiveness of glucosamine and chrondroitin versus an NSAID called carprofen in treating dogs with osteoarthritis. The bottom line: “Carprofen is superior to glucosamine/chrondroitin supplements in reducing the clinical signs.”

Out and about: Regular short walks with our other canine companion, Posie, should help

So are Kaleb’s supplements doing anything at all? He started taking glucosamine and chrondroitin in 2007, advised by vets in Ithaca who hoped that they might help stave off joint damage. But now that he’s already arthritic, there’s little evidence that they will help, according to a recent systematic review of available studies. (In this case, human medicine provided a good guide to the likely effects in dogs: A huge clinical trial concluded in 2006 that the supplements don’t reduce arthritic knee pain.) If we want to work on Kaleb’s diet, the same review suggested, we might try formulas rich in fish oils, which have promising results in placebo-controlled trials. (And if you’re wondering why placebo controls are needed in veterinary studies, read the note to the right.)

So much for glucosamine and chondroitin. Now I needed to find out about tramadol, the painkiller that we add to Kaleb’s breakfast. I turned to Steve Budsberg of the University of Georgia, who specializes in canine osteoarthritis. “That’s too bad,” he responded, when I told him that Kaleb was taking the drug. “I think it just gets the dogs high.”

Digging into the scientific literature, I learned why Budsberg is skeptical. Tramadol is an opioid—essentially a synthetic version of morphine—and its painkilling effects in people depend largely on its conversion in the body to a substance called M1. But dogs don’t seem to convert tramadol to M1 as well as humans. I found just one controlled trial comparing carpofren and tramadol to treat dogs with osteoarthritis. The drugs were given for only a couple of weeks, and the main conclusions were that placebo effects are large, and that findings vary depending on how you measure a dog’s symptoms.

Why is tramadol widely prescribed to dogs with Kaleb’s condition, when the best evidence indicates that NSAIDs like carpofren are the most effective option? Fear of liver and kidney damage, two known dangers of NSAIDs, seems to be the main reason. But Budsberg believes this concern is overplayed, and worries that the vogue for tramadol has achieved little apart from reassuring vets and dog owners that they aren’t risking side effects. “They’re treating themselves,” he says.

As you can imagine, Nadia and I aren’t feeling so good about ourselves right now. Each of us has a PhD in biology, and yet we’d failed to ask all of the right questions about Kaleb’s treatment. We plan to get some fresh tests to see how stable his kidney function is, and talk to our current vet in San Francisco about whether it’s time to try carprofen. (Warning: asking more questions may mean spending more money.)