Selected Podcast
Exploration of a New Analgesic Drug
Elizabeth Maxwell, DVM discusses the limitations and side effects associated with current canine oral analgesic medications and how this shows the need to investigate novel pharmacologic options for the management of canine pain.
Featuring:
Learn more about Elizabeth Maxwell, DVM
Elizabeth Maxwell, DVM
Elizabeth Maxwell, DVM is a Clinical Assistant Professor.Learn more about Elizabeth Maxwell, DVM
Transcription:
Melanie Cole (Host): As oral analgesic options available on the market for companion animals have shown to have questionable bioavailability and variable efficacy, the limitations and side effects associated with current canine oral analgesic medications show the need to investigate novel pharmacologic options for the management of canine pain.
Welcome to UF Vet Med Voice with the University of Florida College of Veterinary Medicine. I'm Melanie Cole. And joining me today is Dr. Elizabeth Maxwell. She's a Clinical Assistant Professor of Surgical Oncology in the Department of Small Animal Clinical Sciences at the University of Florida College of Veterinary Medicine.
Dr. Maxwell, thank you so much. This is a great topic and really broad in the spectrum of it. Can you tell us about some of the oral analgesic options available on the market today for companion animals and what have been some of the challenges and limitations that I mentioned in the intro associated with current canine oral analgesic medications?
Dr Elizabeth Maxwell: Hi, Melanie. So, right now, the most common pain medications that we have available for dogs include anti-inflammatories similar to ibuprofen, tramadol, and gabapentin. Those are the three most common ones that we use. However, there's a lot of limitations with these, because the anti-inflammatories, for example, cannot be used with dogs that have kidney disease or liver disease. And they also increase risk of gastric ulcerations, and we can see gastrointestinal signs, such as vomiting and diarrhea. And so only certain patients can receive anti-inflammatories.
Now, with gabapentin, which is commonly used, we have very few studies that actually show its efficacy. There may be a couple of studies in dogs showing efficacy, particularly for neurologic pain and some for postoperative pain, but really very limited. And some of the side effects can include sedation or dizziness. With tramadol, which is the third most common drug used, and it's actually not even used very frequently anymore, because we have studies that have shown that it's not effective for dogs. They don't metabolize the drug the same way that people do. And so in people, tramadol is effective for managing pain, but in dogs it is not. And so we're very limited in our options for oral pain medications.
Melanie Cole (Host): That's such an interesting challenge, Dr. Maxwell. Can you tell us about kratom, a tropical plant indigenous to Southeast Asia. And despite not being recognized therapy in the US as of now, it is of particular interest in the research community. Can you tell us about that?
Dr Elizabeth Maxwell: Yes. So kratom, also referred to as KRAT-um or kra-TOM, is the common names for a plant called Mitragyna speciosa. And this plant is native to regions in Southeast Asia. And for decades, this plant is used by natives as a stimulant for laborers in the field. They would chew the leaves. And then at higher doses, we can see pain-relieving effects, as well as other effects such as it's an anxiolytic or antidepressant, has been considered anti-inflammatory and it's actually very commonly used for treatment of opioid withdrawal in people. And so that's where a lot of their research interests comes into play, particularly for its use with opioid withdrawal. But a lot of opioid users are addicted to these drugs due to chronic pain. And so this kratom has been anecdotally very helpful in the community for management of chronic pain. And so there's a lot of interest looking into its effects on pain management, as well as for treatment of opioid withdrawal.
Melanie Cole (Host): Now, you're doing some studies on this, yes? Can you tell us a little bit about this research and the significance of the papers that you're working on?
Dr Elizabeth Maxwell: So I've been very fortunate to collaborate with our college of pharmacy here. Dr. Chris McCurdy and Dr. Sharma, they are leading experts in the field, maybe in the world, regarding kratom studies. The most common chemical component of kratom that is responsible for this pain relief effects is called mitragynine. And so, they've done a lot of studies regarding mitragynine in rodents, and we wanted to take it to the next step, to again translate into human studies in the future. And so in order to do that, dogs are really great models for people in terms of they metabolize the drugs very similarly.
And so, we did a couple studies actually the last year or two looking at how dogs metabolize mitragynine as well as another chemical component, 7-hydroxymitragynine, which is also of interest because it's a little bit more potent than the main chemical, mitragynine. And so we look at how dogs metabolize these drugs, and that will help us in developing clinical trials for people.
Now, after looking at how the dogs metabolize these drugs, our next step was to determine whether or not this drug would be effective for pain management. And so, a current study that we have going on is looking at how effective is kratom for management of osteoarthritis pain in dogs, because osteoarthritis pain is one of the most common forms of chronic pain that we see in our canine patients. And this will really help translate over into human medicine in the future.
Melanie Cole (Host): That's fascinating. And that was my next question, is how do you envision this research translating to care and how it could potentially change the landscape of canine pain care?
Dr Elizabeth Maxwell: That's a great question. And because we are so limited in our oral pain management options in dogs, this would potentially be a great consideration if we can show that it is effective and safe for use in dogs with osteoarthritis. I also intend to look at this drug's effect on management of post-surgical pain, which is another type of pain that we are dealing with very commonly in dogs. And as a surgeon, that is where my interests will be heading. But because we know that humans are using this to self-treat for chronic pain and other issues, this is where we're starting with our chronic pain in dogs, is the osteoarthritis study. And so far, we're seeing some pretty good things, but we won't really have results of this until probably next year. But in our pilot studies, we've started to see some efficacy of this drug for use with management of arthritis pain. And hopefully, this will give us some solid evidence for using this drug in human clinical trials in the future as well.
Melanie Cole (Host): That's terrific. And thank you so much. What a great topic. And I hope that you'll come back, Dr. Maxwell, and update us as these clinical trials and research really advance, because this is such an important topic and initiative that you're tackling. So thank you so very much. To learn more about exploration of new analgesic drug options for the management of canine pain or to listen to more podcasts from the experts at the University of Florida College of Veterinary Medicine, please visit vetmed.ufl.edu/ufachievers.
That concludes today's episode UF Vet Med Voice, brought to you by the University of Florida College of Veterinary Medicine, advancing animal, human and environmental health. I'm Melanie Cole.
Melanie Cole (Host): As oral analgesic options available on the market for companion animals have shown to have questionable bioavailability and variable efficacy, the limitations and side effects associated with current canine oral analgesic medications show the need to investigate novel pharmacologic options for the management of canine pain.
Welcome to UF Vet Med Voice with the University of Florida College of Veterinary Medicine. I'm Melanie Cole. And joining me today is Dr. Elizabeth Maxwell. She's a Clinical Assistant Professor of Surgical Oncology in the Department of Small Animal Clinical Sciences at the University of Florida College of Veterinary Medicine.
Dr. Maxwell, thank you so much. This is a great topic and really broad in the spectrum of it. Can you tell us about some of the oral analgesic options available on the market today for companion animals and what have been some of the challenges and limitations that I mentioned in the intro associated with current canine oral analgesic medications?
Dr Elizabeth Maxwell: Hi, Melanie. So, right now, the most common pain medications that we have available for dogs include anti-inflammatories similar to ibuprofen, tramadol, and gabapentin. Those are the three most common ones that we use. However, there's a lot of limitations with these, because the anti-inflammatories, for example, cannot be used with dogs that have kidney disease or liver disease. And they also increase risk of gastric ulcerations, and we can see gastrointestinal signs, such as vomiting and diarrhea. And so only certain patients can receive anti-inflammatories.
Now, with gabapentin, which is commonly used, we have very few studies that actually show its efficacy. There may be a couple of studies in dogs showing efficacy, particularly for neurologic pain and some for postoperative pain, but really very limited. And some of the side effects can include sedation or dizziness. With tramadol, which is the third most common drug used, and it's actually not even used very frequently anymore, because we have studies that have shown that it's not effective for dogs. They don't metabolize the drug the same way that people do. And so in people, tramadol is effective for managing pain, but in dogs it is not. And so we're very limited in our options for oral pain medications.
Melanie Cole (Host): That's such an interesting challenge, Dr. Maxwell. Can you tell us about kratom, a tropical plant indigenous to Southeast Asia. And despite not being recognized therapy in the US as of now, it is of particular interest in the research community. Can you tell us about that?
Dr Elizabeth Maxwell: Yes. So kratom, also referred to as KRAT-um or kra-TOM, is the common names for a plant called Mitragyna speciosa. And this plant is native to regions in Southeast Asia. And for decades, this plant is used by natives as a stimulant for laborers in the field. They would chew the leaves. And then at higher doses, we can see pain-relieving effects, as well as other effects such as it's an anxiolytic or antidepressant, has been considered anti-inflammatory and it's actually very commonly used for treatment of opioid withdrawal in people. And so that's where a lot of their research interests comes into play, particularly for its use with opioid withdrawal. But a lot of opioid users are addicted to these drugs due to chronic pain. And so this kratom has been anecdotally very helpful in the community for management of chronic pain. And so there's a lot of interest looking into its effects on pain management, as well as for treatment of opioid withdrawal.
Melanie Cole (Host): Now, you're doing some studies on this, yes? Can you tell us a little bit about this research and the significance of the papers that you're working on?
Dr Elizabeth Maxwell: So I've been very fortunate to collaborate with our college of pharmacy here. Dr. Chris McCurdy and Dr. Sharma, they are leading experts in the field, maybe in the world, regarding kratom studies. The most common chemical component of kratom that is responsible for this pain relief effects is called mitragynine. And so, they've done a lot of studies regarding mitragynine in rodents, and we wanted to take it to the next step, to again translate into human studies in the future. And so in order to do that, dogs are really great models for people in terms of they metabolize the drugs very similarly.
And so, we did a couple studies actually the last year or two looking at how dogs metabolize mitragynine as well as another chemical component, 7-hydroxymitragynine, which is also of interest because it's a little bit more potent than the main chemical, mitragynine. And so we look at how dogs metabolize these drugs, and that will help us in developing clinical trials for people.
Now, after looking at how the dogs metabolize these drugs, our next step was to determine whether or not this drug would be effective for pain management. And so, a current study that we have going on is looking at how effective is kratom for management of osteoarthritis pain in dogs, because osteoarthritis pain is one of the most common forms of chronic pain that we see in our canine patients. And this will really help translate over into human medicine in the future.
Melanie Cole (Host): That's fascinating. And that was my next question, is how do you envision this research translating to care and how it could potentially change the landscape of canine pain care?
Dr Elizabeth Maxwell: That's a great question. And because we are so limited in our oral pain management options in dogs, this would potentially be a great consideration if we can show that it is effective and safe for use in dogs with osteoarthritis. I also intend to look at this drug's effect on management of post-surgical pain, which is another type of pain that we are dealing with very commonly in dogs. And as a surgeon, that is where my interests will be heading. But because we know that humans are using this to self-treat for chronic pain and other issues, this is where we're starting with our chronic pain in dogs, is the osteoarthritis study. And so far, we're seeing some pretty good things, but we won't really have results of this until probably next year. But in our pilot studies, we've started to see some efficacy of this drug for use with management of arthritis pain. And hopefully, this will give us some solid evidence for using this drug in human clinical trials in the future as well.
Melanie Cole (Host): That's terrific. And thank you so much. What a great topic. And I hope that you'll come back, Dr. Maxwell, and update us as these clinical trials and research really advance, because this is such an important topic and initiative that you're tackling. So thank you so very much. To learn more about exploration of new analgesic drug options for the management of canine pain or to listen to more podcasts from the experts at the University of Florida College of Veterinary Medicine, please visit vetmed.ufl.edu/ufachievers.
That concludes today's episode UF Vet Med Voice, brought to you by the University of Florida College of Veterinary Medicine, advancing animal, human and environmental health. I'm Melanie Cole.