scott@vtx-cpd.com
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Replying to Felipe M. 19/07/2025 - 15:48
So helpful!
Thank you so much!
Scott 🙂
Hi Jo,
Great question and I’m really glad you brought this up. Ketamine is a fascinating drug with broad applications, and although its use as an analgesic is well established in certain contexts, its use via the subcutaneous (SC) route is still very much in an emerging phase, especially in dogs.
Traditionally, ketamine is most commonly used as an intravenous (IV) constant rate infusion (CRI) in dogs, particularly in the perioperative setting. That said, there is growing clinical interest in the SC route, particularly in chronic pain and palliative care scenarios. In my own practice, we’ve used SC ketamine at a dose of 0.5 mg/kg in dogs and cats with central sensitisation and refractory osteoarthritis. One case started with once-monthly SC injections and responded so well that we continued this protocol for over two years. As the patient’s pain progressed, we increased the frequency to every 48 hours in the final palliative phase, which subjectively helped to maintain comfort.
There is very little published evidence for SC ketamine in veterinary medicine, though that is slowly beginning to change. A recent study published in the Journal of Veterinary Pharmacology and Therapeutics (Colón et al., 2024) evaluated the pharmacokinetics of SC ketamine delivered via the Omnipod® insulin pump system in dogs following spinal surgery. Dogs received a 1 mg/kg SC bolus over one hour. Plasma ketamine concentrations ranged from approximately 42 to 326 ng/mL, with a median peak of 79.5 ng/mL at around 60 minutes. Norketamine, an active metabolite contributing up to 30% of ketamine’s analgesic effect (as shown in rodent models), was also detected, with a median peak concentration of 43 ng/mL. The study concluded that SC ketamine could be reliably delivered using this technology, offering a potential hands-free analgesic option. While this isn’t directly translatable to routine SC bolus injections, it does provide proof of concept that SC absorption and metabolite formation are clinically relevant in dogs.
In my experience, side effects at the 0.5 mg/kg SC dose have been extremely rare. Owners sometimes report that their dog seems sleepy after the injection, but we have not seen the dissociative or cardiovascular effects associated with higher anaesthetic doses (typically 3–5 mg/kg IV or IM). We use the same dose in dogs and cats, though ideally this would be refined through dose-ranging studies in future. It’s also worth noting that I have not observed any issues when using SC ketamine alongside other analgesics, including NSAIDs, gabapentin, opioids, amantadine, or even memantine. The safety margin at this dose appears to be broad, and I feel comfortable using it even in patients with concurrent heart disease, as the cardiovascular effects at such low levels are negligible.
I’ll also ask our anaesthetist for their perspective, particularly on the pharmacokinetics and practicalities of SC use, and whether they’ve observed any patient subsets where it seems especially beneficial or contraindicated.
I hope that helps!
Scott 🙂
Replying to Liz Bode 16/07/2025 - 21:13
Very interesting!
Thanks for sharing!
Scott 🙂
HAHA!
Sounds like they might still be traumatized by the physiology!
Scott 🙂
Replying to Felipe M. 13/07/2025 - 19:45
Thank you again for everything.
We are very lucky to get to work with you!
Have an amazing week.
Scott 🙂
Replying to Emma Holt 14/07/2025 - 08:47
Love seeing all the pictures of a sunny Scotland… looks amazing!
I was back in Glasgow a few weeks ago and got more sunburned there than I do here!
Hopefully see you soon.
Scott 🙂
Replying to Raquel M. 10/07/2025 - 18:53
Amazing!
Look forward to seeing you there!
Scott 🙂
Hello everyone!
Welcome to the course! Please let me know if you have any questions.
Scott 🙂
Emma!
I’m not mush use when it comes to the pulmonary hypertension… but wanted to say hi!
Was thinking of you the other day! Hope all is well.
Scott 🙂
Hello everyone!
We are so excited to bring you this course!
What amazing line up of inspiring speakers. Please let us know if you have any questions.
Scott 🙂
Replying to Liz Bode 06/07/2025 - 21:01
Hi Liz,
Thanks so much for this! Sorry for the JC spoiler! 🙂
I love your point about being pragmatic for those cases where echo just isn’t feasible. It’s that classic balance between ideal medicine and what’s actually possible in real life.
I think this study is going to make for a great journal club discussion—looking forward to hearing more!
Cheers,
Scott 🙂
Replying to Liz Bode 06/07/2025 - 21:00
Hi Liz,
Thanks so much for this! Sorry for the JC spoiler! 🙂
I also love your point about being pragmatic for those cases where echo just isn’t feasible. It’s that classic balance between ideal medicine and what’s actually possible in real life.
I think this study is going to make for a great journal club discussion—looking forward to hearing more!
Cheers,
Scott 🙂
Replying to Sybil Dryburgh 06/07/2025 - 17:23
Haha Sybil,
I wouldn’t call you a first opinion dinosaur at all—more like a first opinion legend!
And definitely not an off-topic ramble—super helpful and a good reminder for all of us to keep thinking about these nuances!
Scott 🙂
Replying to Riley D. 06/07/2025 - 15:14
Hey Riley,
I hope you are well!
That’s exactly the kind of thing I was thinking too—it’s such a tempting message (“just start pimobendan if there’s a loud murmur!”) but it risks shortcutting proper workups.
And yes, the whole treating stage B1 dogs who don’t need it is a big one for me too—cost to the owner aside, there’s that question of pushing remodelling or hypertrophy in a heart that might have stayed stable for years.
Really keen to see what Liz thinks too!
Scott 🙂
Replying to Kerry Doolin 01/07/2025 - 14:15
It is interesting indeed!
It had not crossed my mind… but it will now!
Scott 🙂
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