KentuckyFC writes: Americans spent $14.2 billion on veterinary care for their pets in 2013—and that doesn’t even include proprietary health diets and food supplements. Put another way, pet owners pay about $850 annually in veterinary expenses per dog, and about $575 per cat. Factor in the emotional energy we invest in keeping our companion animals healthy, and you’d hope for high confidence in the end results. But when one journalist investigated the science behind the meds being used to treat his aging dog's osteoarthritis, he was in for a nasty surprise. Glucosamine and chondroitin food supplements? Next to useless. Tramadol to kill pain? It's probably just getting dogs high. The one treatment that's been proven to help, a non-steroidal anti-inflammatory drug called carprofen, is often left on the shelf because of fears—likely overblown—that it might damage dogs' kidneys. In part, you can blame this sorry state of affairs on a lack of financial incentives for drug companies to run clinical trials on animals. But often, vets aren't paying attention to the studies that have been done. If we want our dogs and cats to receive the best possible medical care, we need to ask our vets some tougher questions about why they think the drugs will work.