Use of NSAIDs in Companion Animals for OA

B. Duncan X. Lascelles, BVSc, PhD, DACVS: I’d like to get back to this question of pain control and effective pain control. Recently, I was involved in a study with Rimadyl. It used Rimadyl to help determine how many dogs suffer the clinical signs associated with osteoarthritis, and those data support the figures we were talking about—roughly half the dog population. But if we think about effective pain control and the tools that we have, and we think about diagnosing OA early in dogs, how comfortable do people feel using, for example, the nonsteroidals, like Rimadyl or Previcox in young dogs, and for how long?

Mark Epstein, DVM, DABVP, CVPP: I feel quite comfortable. You’ve got to compartmentalize a little bit because we’re talking about the early dogs with some early signs. Nobody would want to condemn a dog to have to take those medications every day for the rest of its life. However, until or unless that patient gets relieved of some of that discomfort, all these things that we’re talking about are not going to be maximized, including therapeutic exercise and so on. Furthermore, there’s a whole process. We’ve mentioned it, I think, at the very beginning of this program and maybe it’s time to bring it back up, right now. That is the issue of sensitization. With chronic inflammation, sensitization can occur for a lot of reasons, including when Bryan cuts a nerve in surgery. So, it can happen instantly, but certainly with chronic inflammation, it begins to happen both in the spinal cord and in the peripheral tissue, in the joint itself and in the synovium. And that begins to become amplified. The vernacular term is “wind-up.” We know that term, but it’s a real molecular cellular process that begins to happen, and chronic inflammation leads to it.

And so, by reducing inflammation with drugs, NSAIDs and possibly the piprant classes of drugs, as well, now you are rendering a clinical benefit not just in that immediate timeframe, but for perhaps a long period of time after that. Now, how long does a patient go on when it’s early? Only so long, as everybody is comfortable believing that we’ve reached its maximum effect. I want to point out that there are some studies, that I’m aware of, using NSAIDs for 6 months and then a year. These are more advanced cases and the dogs never stopped getting better, as a group. They were getting better up until the day that study ended. So, something is happening besides just reducing inflammation. There are other pharmacologic benefits that are occurring, and it’s probably in the realm of diminishing that central and peripheral sensitization.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: So, you see the anti-inflammatory, the analgesic component of treating young dogs, as very important to prevent these deleterious changes in the future?

Mark Epstein, DVM, DABVP, CVPP: You get the immediate benefit from its immediate analgesic effect by interrupting prostanoid production, but also, over time, decreasing sensitization as well.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Bryan, how comfortable do you feel using NSAIDs in these young dogs?

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: I agree, totally. I don’t have a problem with it, and I think one of the keys, as you just said, is getting them out of that cycle of inflammation and that cycle of pain. It really is important that we do it to prevent those chronic changes. I have always lived by the adage of “use as little as needed, but as much to be effective.” The nice thing is, with this multimodal approach, using various things in these young animals—ie, keeping weight down, dietary changes, the high omega-3 fatty acid diet—you may be able to effectively titrate that dose down of a nonsteroidal to what is effective. And that’s the key: what’s an effective dose? For each patient, it’s going to differ. It’s going to change. Each patient is an individual, and so evaluating them on a regular basis with some of these metrics that we’ve talked about is key in being able to tailor that treatment so that we are using what’s effective. If we can reduce the dose in some of these things that we’re using and use them long-term, and reduce the potential for any issues, that could be very beneficial.

Mark Epstein, DVM, DABVP, CVPP: I was just going to ask about dose reduction or reducing the frequency, or on-off treatment.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: I believe dose reduction.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: So, daily reduction on the dose?

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: If you can. I think that’s certainly possible, and I think that’s certainly something to aim for. Because with this multimodal approach—say, in the geriatric patient, if you’re using several vials or bottles of drugs you’re using—you can effectively lower the dosages of some of those and potentially have the same efficacy. But I think the key is making sure that in that patient, the pain is treated effectively and that this patient is treated as an individual.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: I absolutely agree with that because, certainly from a clinical research perspective, we looked at continued dose versus dose reduction. You can successfully reduce the dose and maintain efficacy, but it’s on an individual basis, which comes back to the whole idea of assessment and monitoring.

Mark Epstein, DVM, DABVP, CVPP: Absolutely.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Actually, in order to assess these patients, you need to get them back into the practice. So, we need to be getting them back in on a regular basis.

Mark Epstein, DVM, DABVP, CVPP: It’s for the practice, too.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: Do you think for the early OA patients, getting them back in on a more frequent basis—as you might in a geriatric patient—is the way to go? As the patients get older, the recommendation is we’re to see them more frequently. Is that something that, for these OA patients, we should follow? Should we see them on a more frequent basis as well or is it something you do over the phone?

Sheilah Robertson, BVMS, PhD, DACVAA, DACAW: Going back to the younger patients and the talk about putting them on nonsteroidals, which could be very, very long term, I think the key thing that I think a lot of people don’t understand is that we have to damp down the inflammation and the pain signaling that’s coming from the joint. Once we have, truly what we’re going to end up with is damage to the spinal cord. I think a lot of people forget that the chronic pain in the periphery actually damages the spinal cord. Once we get this sensitization in the spinal cord, and all that going on, that’s much harder to treat. So, I think once we need to improve on the understanding that there’s good reasons to give these young animals the nonsteroidals. We’re going to, then, protect what is something very difficult to deal with. And that’s probably something we can discuss a little bit more—protecting the spinal cord from what’s happening in the periphery.