Bella is your 15-year-old feline friend. She’s been with you since you adopted her at the kitty adoption clinic 14 and some odd years ago. Now, you’re starting to notice that she is slowing down a little. Things aren’t the same as they used to be, she seems reluctant to jump onto the counter for her daily treats, and sometimes she will sleep at the floor of her cat tree. This is something she has never done before. You pet her while she lies down one day and wonder what’s going on. Then you remember that you received a postcard not too long ago to bring her into the vet for her annual checkup… Maybe it’s time to do this after all.
On your appointment day, you package Bella up and bring her to your veterinarian. You mention this concern to the technician, and they pass it along to the veterinarian who comes in shortly after. What’s going on with Bella?
“My technician told me that you feel like Bella has been slowing down quite a bit?” The veterinarian leads off. You describe what you’ve been seeing and that’s when your veterinarian begins the discussion of chronic pain. Chronic pain is a condition that afflicts many of our geriatric pets. There are a variety of causes, but the one that most frequently comes to mind is osteoarthritis (OA) or degenerative joint disease (DJD). OA afflicts many animals but often worsens as they get older.
Chronic pain can be caused by essentially any organ in the body, but this blog will focus predominantly on osteoarthritic pain. There are many chronic diseases that may afflict the liver, kidneys, hearts, and various other organs of our dogs and cats that can contribute to the whole picture.
According to the Mayo Clinic (Mayoclinic.org), osteoarthritis is the most common form of arthritis in people. This develops as cartilage at the ends of bones begins to deteriorate from chronic use. The normal cartilage serves as a soft cushion to protect the ends of bones from wearing against one another. In people, it will commonly affect the hands, knees, elbows, etc. In other words, the joints that endure the most use. In dogs and cats, we often see it affecting the hips, stifles (knees), and elbows.
As a result of OA, you will often begin to see your pet start to “slow down” usually you will notice them being slower to stand up, they may not come to greet you at the door like they used to, or they may be reluctant to play with toys like they used to. This disease process can often be diagnosed with x-rays. Usually, there is degeneration or destruction of the normal bone combined with spurs of bone growth or osteophytes. Cartilage is not visible on x-rays, so a normal x-ray does not exclude OA as a potential diagnosis, as it can still be in the process of developing. How your pet acts clinically is more important than what the x-ray shows, as we want to try to manage pain earlier in the process rather than later.
Pain is an incredibly complex process that involves numerous different parts of the body, and to make it more difficult of course, our pets can’t directly tell us when something hurts. Therefore, payin=g attention to subtle changes is immensely important. Cats, like Bella, are notoriously good at hiding pain and discomfort, so mentioning subtle changes that you’ve seen at home is important to allow your veterinarian to try to help. Changes in behavior such as unwillingness to jump, play, or even eat can all be a suggestion of pain. More apparent clinical changes like limping or reluctance to use an individual limb completely are beyond a suggestion of pain and are more of a shout for help. All of these are worth bringing up to your veterinarian.
So, in Bella’s case, we’ve identified that she likely has pain, and an x-ray reveals that her hips have severe degenerative changes within them. This likely came as a result of her repeatedly jumping onto her cat tree over the years, but what can we do?
In cats, our pain management options are somewhat limited. The best long-term medication we have right now is probably Gabapentin. The mechanism by which Gabapentin works is not well understood, but it is thought to interact with calcium channels between cells which reduces the release of excitatory molecules. This helps prevent pain. Gabapentin is ideally dosed every 8 hours; however, this is not feasible for all owners, so it is frequently given twice a day. It works better if given consistently, and not on an as-needed basis.
As a side note, when I mention Gabapentin many clients ask if they can just give their own prescription to their pet because Gabapentin is commonly prescribed to people. This is not advised as the formulation for people can contain a substance, called Xylitol, which can be fatal to dogs especially in high doses. Additionally, it has a high potential to overdose a cat if giving a human formulation. To add a little additional complexity, cats frequently need the medication compounded due to their size, so this will have to be done by a compounding pharmacy. The standard capsule sizes are 100 and 300 mg which are too large for most cats. So, they should have their own prescription made rather than using one of their humans’.
For cats there are very limited additional options for long term pain control, there are certain opioid medications that can be useful, such as Buprenorphine. However, the cost of this drug in combination with its controlled status often makes it an unrealistic option.
Nonsteroidal anti-inflammatories (or NSAIDs) are the mainstay drug for dogs, and there are many products available. These drugs work to alleviate pain by decreasing inflammation. They are usually well-tolerated in dogs and can be used daily for years to help with the pain. Some dogs will have difficulty with this drug either causing gastrointestinal side effects, like vomiting or diarrhea. However, the drugs can occasionally problems with the kidneys or liver.
The potential adverse effects on the kidneys are one reason they are often avoided in cats, as geriatric cats frequently are afflicted with some level of chronic kidney disease. Currently, drugs like Rimadyl (Carprofen), Previcox (Firocoxib), and Galliprant (Grapiprant) are the most common for dogs. Rimadyl is a drug with several generics, so there are numerous names for this drug beyond what I’ve listed. These all work to block inflammation and therefore relieve pain. A drug called Onsior (Robenacoxib) is an NSAID that is FDA labeled for cats; however, it is labeled for only three consecutive days of use in the United States out of concern for the kidneys (it is approved a little longer in the UK). NSAIDs at this time are not widely used long term for cats.
Aspirin is also technically an NSAID drug that has been used for many years in dogs and cats for anti-inflammatory processes. It is not labeled as a drug to be used for dogs and cats by the FDA and so its use is actually “off label.”
Unfortunately, many drugs that we use in veterinary medicine are not well studied in dogs and cats and so many of them are off label. There are numerous reasons specific label indications are not sought for drugs including, but not limited to, the cost of approval, obtaining large enough sample sizes for approval, and duration of study requirements. Once a drug has FDA approval for a single-use the company may not seek approval for additional uses based on these factors and more. Aspirin can be used daily to twice daily for dogs for pain, and usually will be dosed two to three times per week for cats. Aspirin may be more likely in some animals to cause gastrointestinal upset, especially if accidentally dosed too high, so its use should be judicious.
Aspirin also affects platelets which are clotting cells in the body. So, some cats or dogs will be placed on aspirin to disrupt excessive clotting of blood or what is called a pro-coagulant state. These patients may have heart disease, certain immune-mediated disorders, or certain hormone-based disorders. Dosing regimens for these conditions may vary from what I’ve presented here at the discretion of the clinician you are working with.
Another option for OA in dogs is a drug called Tramadol. Tramadol is an opioid type drug that works by blocking mu receptors in the central nervous system. It also inhibits the reuptake of serotonin and norepinephrine which potentially contributes to its pain relief and sedative effects. This drug has been used for quite a long time in dogs for chronic pain control; however, more recent research is suggestive that it may not be quite as effective as once thought. A 2018 study published to the Journal of the American Veterinary Medical Association available in NCBI evaluated a large sample of dogs and found Tramadol to be ineffective for pain relief. Anecdotally for some dogs; however, Tramadol seems to provide quite a bit of benefit, so it is still somewhat commonly used for long term indications.
The final thing I’ll say about Tramadol is that it has a bitter taste which can make administration difficult. There is little research on the use of Tramadol in cats for pain relief, but the bitter taste alone is probably sufficient to avoid the use of this drug in pain management for most cats.
Glucosamine and Chondroitin Sulfate
Glucosamine and Chondroitin Sulfate are two nutritional supplements that have been widely used together as adjunctive treatments for OA in dogs, cats, and humans. These appear to be very safe; however, like with many of our pain control options, their efficacy is unclear. These drugs are not direct pain medications; they seek to help the cells within joints produce protective products and inhibit pro-inflammatory ones. With long term use, we can often see a positive response from patients in combination with other pain medications. There is a wide body of research surrounding these supplements, so I will not cite them all in this article, a google scholar search on these compounds will reveal all the reading you could desire on these products.
There are numerous supplements available nowadays for the management of a wide variety of conditions. Since research is extremely variable on these substances I will not cover individual ones in this article beyond Glucosamine and Chondroitin Sulfate and an injection that can be helpful for dogs with OA called Legend.
This injection contains hyaluronic acid which is an important component to joint health. It is given by intravenous injection monthly and was developed for use in horses. This drug requires a trip to the veterinarian every month to receive the injection which is not feasible for all owners, but it can be useful for canine companions that are hurting. The drug is thought to be most beneficial before degeneration of the joint progresses to more severe stages.
Beyond some of these standard medications discussed above, there are a few alternatives that warrant mentioning as well.
Acupuncture can be anecdotally useful for some animals. Acupuncture has large bodies of research about it both for and against its efficacy, so I will not review all the literature here. I mention it to say that it does seem useful in certain patients, and it is an option to explore with your vet if you are interested.
Additionally, laser therapy can be used to help with osteoarthritic pain. Laser therapy uses a beam of light (laser) to inhibit inflammation in body tissues. It can be helpful to some patients and is becoming more widely available.
Depending on your area you likely already have a veterinarian nearby with the ability to do this. There are two main types of laser, the type that helps manage pain is often referred to as cold laser or low-level laser. The “high powered” laser is used for surgical procedures, not for pain management. There is a trove of studies both for and against the use of laser, so the full extent of the benefit of this procedure is not well known, but many patients seem to have a good response to it. The laser experience itself is nonpainful causing mild warming to the tissue and light pressure. You and your pet will have to wear eye protection when they are receiving laser therapy. The veterinarian or technician performing the procedure will be able to explain this to you at the time of treatment. Laser and acupuncture can be administered to both dogs and cats.
Well, what happened to Bella? After your visit, you were given a prescription for Gabapentin to take to your nearest compounding pharmacy. They are familiar with making this product for cats and ask whether you would like chicken or liver flavoring. You may ponder this question longer than you need to, but decide that Bella likes chicken more than liver. She seems to agree. You’ve been giving this three times per day to Bella, and she has seemed to become more comfortable. Her ability to get up to her favorite perches is still decreased, but you perceive a general increase in her day to day quality of life. This is often the best-case scenario for our feline friends with chronic pain.
As you can see, the world of chronic pain in dogs and cats is not a straight forward one. There are many options and quite a bit of variability in terms of how patients will tolerate medications and how effective said medications will be. The complexity should not discourage one from trying to get pain managed as adequately as possible. Pain is one of, if not the largest, source of diminished quality of life in our furry friends. I hope that you enjoyed reading this article. The world of pain management changes rapidly, so the views expressed here may change as new information becomes available.
This citation will take you to the article I discussed on Tramadol.
Budsberg SC, Torres BT, Kleine SA, et al. Lack of effectiveness of tramadol hydrochloride for the treatment of pain and joint dysfunction in dogs with chronic osteoarthritis. J Am Vet Med Assoc 2018;252(4):427–432.