Visiting Veterinarian : Pets can't describe pain, so how do vets treat for it?
My husband and I always laugh at those TV advertisements for prescription medications. You know, the ones for arthritis, psoriasis, or erectile dysfunction. Happy people leap effortlessly through fields of flowers, climb mountains, play football, gaze romantically at one another, as an upbeat voice lists devastating possible side effects, usually including death. The dissonance is bizarrely funny. "Who would ever take these drugs after hearing the ads?" I wonder. The reality is that many medications can potentially, albeit rarely, cause serious, even fatal, side effects. How does one decide when benefits of a particular treatment outweigh the risks? It's a dilemma, even more so in veterinary practice than in human medicine, where at least patients can speak for themselves.
The quandary is particularly troublesome in the realm of pain management for cats. When I first began practicing, the whole notion of painkillers for animals was really in its infancy. We prescribed "Bute" for lame horses and dogs, even gave hurting cows huge aspirin boluses, but whether an animal was suffering from trauma, surgery, or chronic diseases like cancer or arthritis, sophisticated use of analgesics was uncommon. Because animals tend to hide the fact that they are hurting, many people thought they didn't feel pain the same way we do. Wrong. Animals feel pain. Veterinarians also conjectured that if convalescent animals took painkillers, they might move around too much, while withholding analgesics would result in restricted activity and improved healing. Wrong again. Animals, like people, heal better when not in pain.
Over the past 30 years, analgesic options for dogs have increased dramatically. In addition to new injectable medications for surgical and hospital cases, many oral non-steroidal anti-inflammatory drugs (NSAIDs) such as Rimadyl®, Deramaxx®, and Metacam® are approved for long-term use in dogs. Although side effects do occur occasionally, these drugs are sufficiently safe and efficacious for routine usage. Owners notice when Whiney the Weimaraner whimpers and are happy to have painkillers for him. It's good that when Bouncy, the bichon, goes home after her spay, I can send along medication to keep her pain-free as she recuperates. It's wonderful when a client tells me that Achy, the arthritic Airedale, has a new lease on life since starting daily NSAIDs. With long-term NSAIDs, dogs should have preliminary blood tests to assess liver and kidney health, follow-up tests soon after starting medication, then every two to six months thereafter.
Then there are...cats. Gotta love 'em. Typically more stoic than dogs, it can be hard to tell when cats are in mild to moderate pain. Owners may notice reluctance to move, jump, or groom, or a change in temperament such as increased irritability. These are all clues. Take Zeno, a 15-year-old kitty who has sustained multiple traumas during her long life and is, well, kind of cranky. " I think she may be uncomfortable," her mom said, asking about pain medication. Now if this had been Whiney, the Weimaraner, after baseline blood work I could have grabbed any of a number of products off my shelf. But this was a cat. Gotta love 'em.
Quirky not just in temperament but in biochemistry, cats are notorious for unusual reactions to medications, and since owners have historically spent less on cats than dogs, to date pharmaceutical companies have invested significantly less on research for them. I picked up a bottle of Metacam ® Oral Suspension and paused thoughtfully.
Metacam® is the brand name for the NSAID meloxicam made by Boehringer Ingelheim Vetmedica, Inc. (BIVI). In Canada, Australia, the United Kingdom, and much of Europe, Metacam ® has been licensed for use in dogs and cats since the 1990s. It was introduced in the United States in 2003, and the oral form is licensed for dogs only. Based on the experience of veterinarians abroad, many American doctors prescribed oral Metacam ® to cats "off label," advising owners that it is not FDA-approved for cats, but getting "informed consent" to use it anyway. I liked Metacam®. It seemed safe, effective, and easy to administer.
But in September 2010, in the wake of numerous reports of adverse side effects in cats in the United States, BIVI had to add an FDA "black box warning" to the label: "Warning: Repeated use of meloxicam in cats has been associated with acute renal failure and death. Do not administer additional doses of injectable or oral meloxicam to cats." Oddly, vets in other countries were not getting reports of these dire adverse effects, and continued to use it routinely.
Some wondered if American veterinarians were dosing improperly (since packaging here does not include feline dosage information) or that our litigious society has something to do with it and international controversy persists about the risk of using Metacam in cats. Although many have completely eliminated it from their feline pharmacies, other veterinarians still use it, believing it to be reasonably safe when dosing conservatively and monitoring kidney function carefully. This puts U.S. veterinarians in a dicey legal position. After all, it now says right on the label in a big black box. "Do not..." Why not just pick another NSAID? Simple. There are no others currently approved for use in cats.
I ran preliminary blood work on Zeno and offered alternative treatments — everything from fish oil to glucosamine to acupuncture. We discussed other options. Very few officially approved for use in cats. None extensively tested for efficacy. None without risk. I corresponded with British veterinarians who routinely prescribe meloxicam and with American veterinarians who wouldn't touch it with a ten-foot polecat. I looked again at that box on my shelf and thought " Do no harm." The first tenet of medicine.
But isn't denying Zeno effective pain control harmful? Is the potential for dramatically improving quality of life worth the risk? I don't know. Zeno's owner and I will decide together what path to take...and I may make a video of cats leaping effortlessly onto kitchen counters, pouncing on mice, and happily shredding upholstery while I mellifluously read the black box warnings aloud.