Veterinary- Tactical Canine Analgesia

[doctorrich]

Doczilla asked if I would post some information on canine analgesia in a tactical setting. We can divide veterinary pain management in the field into two catagories, chronic pain which can degrade the performance of the working dog but is not debilitating, and acute pain as a result of a sudden injury.

Chronic pain in the field can usually be managed by NSAIDs alone or in combination with mild narcotics (in more severe cases). Cases when I'd recommend these drugs are when the dog is limping occasionally in the field after strenuous exercise or after a jump or fall when the dog is not showing any acute swelling and is partially weightbearing on the limb.

First off, everything you've heard about human anti-inflammatory using in dogs is probably correct: avoid them, even as a stop-gap measure. Ibuprofen, naproxen, and acetaminophen are contraindicated in the canine patient. I have seen some dogs survive after multiple doses of ibuprofen and naproxen, but nearly all had a significant change in kidney function.

Acetaminophen is a different story. The most likely outcome of use of this drug is a severe toxic insult to the liver and the possibility of methemoglobinemia. Avoid Tylenol and don't even wave it in the direction of the dog.

Aspirin is a partial help at best, and could possibly result in gastric ulceration or clotting disorders in the field. If nothing else is available, a one-time dose of 325mg coated aspirin in a large breed dog shouldn't get you into trouble.

If you're operating in the field with a working dog, I'd recommend carrying a veterinary NSAID with instructions for use clearly printed on the label. Rimadyl (carprofen) can be administered to the dog once or twice daily depending on dosage. It's an older NSAID and long-term administration requires monitoring of hepatic enzymes (occasionally this drug causes acute hepatitis).

Metacam (meloxicam) is a once-daily NSAID in liquid form for oral administration. In my book, it has the most “bang for your buck”: great action with few side-effects. Although the drug company says that the med can be given on an empty stomach, I'd still advise to administer this drug with a meal or treat. Long-term administration is safer in my opinion than carprofen.

Deramaxx (deracoxib) is a selective COX-2 inhibitor with a mechanism of action similar to that of Celebrex or Vioxx in humans. It is, in my opinion, the strongest NSAID available in veterinary medicine today. It is a once daily pill that should always be administered with food. Overdosage will result in renal failure and possibly perforated gastric ulceration. If the dog's pain is not adequately managed with Metacam, I jump to Deramaxx. Only in rare cases do I continue this drug for long-term administration (hip dysplasia or post-surgical pain are two good indications).

It goes without saying, don't combine NSAIDs and administer them simultaneously. It would be hard to treat NSAID-induced side effects in the field, so err on the side of caution. If the dog doesn't eat, it doesn't get the med.

Tramadol 50mg tablets are safe to combine with NSAIDs in most cases. I use 50mg tabs twice daily to augment the analgesia provided by NSAIDs. In a large dog, one 50mg tab twice daily is sufficient for the management of most chronic pain. If the dog gets nauseous on NSAIDs, tramadol can be administered as a sole agent at the same dose. Avoid the formulation with acetaminophen.

Joint supplements like glucosamine +/- chondroitin +/- MSM are generally safe and can be administered with all of the previously mentioned agents. However, remember that they are supplements and not analgesics. Don't rely on glucosamine for pain relief, only for maintenance.

In severe trauma, you can utilize human narcotics so the K9 handler won't have to be tasked with carrying their dog's supply of schedule II drugs. I don't have any personal experience in administering narcotics orally... I depend on parenteral administration.

Morphine is my favorite canine narcotic, followed by hydromorphone. Morphine can be administered IM or SQ at 0.5mg/kg in combination with NSAIDs- avoid IV administration if possible. A second identical dose can be administered if 0.5mg/kg isn't sufficient to control the pain. However, dogs often get opioid dysphoria at higher doses. If you notice crying, biting, screaming, with or without mydriasis, reverse with naloxone. Titrate to effect.

Hydromorphone can be substituted for morphine at a dose of 0.1mg/kg. You can administer hydromorphone IM, SQ, and also IV.

Side effects from both drugs include transient hyperthermia and excessive panting, as well as vomiting immediately after administration. That's okay.

It's safe to induce general anesthesia with hydromorphone IV, followed by 0.2mg/kg diazepam or midazolam. If you can't intubate after a dose of both drugs IV, repeat diazepam and try again. Propofol (diprivan) is also a good choice as well as etomidate.

Remember that you can use buprenorphine 1mL/20 pounds or butorphanol 0.2mg/kg IV to reverse profound sedation from the heavy narcotics while preserving most of the analgesia. Do this only as a last resort. I'm not a fan of either of these drugs as primary analgesics. In dogs, they're just not as effective as morphine or hydro.

I shouldn't have to put a disclaimer on a post in this forum, so let's just say that I can't see your dog and prescribe drugs over the Internet. Proceed with due caution and seek competent care as soon as feasible.

Hope this helps, guys! Any questions?

[adal]

Doc,
Great input! This happens to have perfect timing. My wife and I help with a Cattle dog rescue in AZ and see many different dogs over the course of a year. As the always concerned former 18D, I am always looking out for the dogs. This helps us sound more educated when we talk with our vet about the fosters we bring in. Thanks again and hope to see more stuff here in the future.

adal

[Doczilla]

Outstanding info! I've got to remember that dogs take such whopping doses of narcs, far above what I would administer by weight in humans in a single dose for the morphine and dilaudid.

Any recommendations on sedation of the K9 that needs restraint for treatment but must maintain their own airway, perhaps to suture something? Meds typically carried on our side may include:

diazepam
midazolam
etomidate
ketamine
propofol
diphenhydramine

Any dose difference here for dogs vs. adults?

Thank you!

'zilla

[doctorrich]

Originally Posted by Doczilla

Outstanding info! I've got to remember that dogs take such whopping doses of narcs, far above what I would administer by weight in humans in a single dose for the morphine and dilaudid.

Any recommendations on sedation of the K9 that needs restraint for treatment but must maintain their own airway, perhaps to suture something? Meds typically carried on our side may include:

diazepam
midazolam
etomidate
ketamine
propofol
diphenhydramine

Any dose difference here for dogs vs. adults?

Thank you!

'zilla

Okay, Doc. If you've got IV access, you have a few good choices that are superior to IM anesthesia.

IV anesthesia

- propofol is my drug of choice at 4-6mg/kg. In dogs, administer half of the calculated volume at low end, the titrate the rest to effect. For a single dose, you've got five good minutes (sometimes longer, but don't count on it). Watch for apnea. Excellent fast recovery.

Ketamine and valium is my alternate. 1mL of equal parts ketamine and valium by volume per 20 pounds of weight. No need to titrate, just give the entire dose in 20-30 seconds. You get a longer duration of action than with propofol (probably 15 minutes or so of deep anesthesia). Recovery is rougher than propofol.

We've recently been experimenting with ketamine/valium: Instead of a 50:50 mix, we're decreasing the ketamine and increasing the valium and getting better recoveries. Last week I gave a patient a 75% valium/25% ketamine IV induction and got a great, quiet recovery. Still maintain the total volume of 1mL mix per 20 pounds of weight.

Etomidate is getting wider and wider use. I haven't used it personally, but I believe that it has to be administered with a benzo to smooth it's induction. I'll try to do some more digging if there's interest... I just haven't personally gotten the stones and the cash to get a supply and start playing.

IM anesthesia-

Straight ketamine will work if you've got nothing else. They've been doing it for forty years, but it's a nasty recovery. I wouldn't recommend it unless you've got nothing else and you're in a hurry and screaming doesn't bother you. 5mg/kg straight IM into the deep muscles of the back, about 1 inch away from the spine (midway between the wing of the ilium and the last rib). Recovery takes 20-30 minutes and the dogs vocalize the entire time due to dysphoria.

Ketamine/midazolam is a slightly better IM alternative. 2-3mg/kg ketamine mixed with 0.25mg/kg midazolam IM will smooth out your recovery a bit more... add a second identical dose of midazolam about 30-45 minutes after induction and you'll have a prolonged but slightly better recovery.

Hydromorphone/midazolam is good for a analgesic dose of sedation if you're going to do a lidocaine local wound repair. 0.1mg/kg hydromorphone/0.25mg/kg midazolam IM, wait 20 minutes, then clip/clean/infiltrate with lidocaine. I love doing this protocol, personally. Usually the dog is still ambulatory (after a fashion) and you don't have to wait hours for recovery.

[Doczilla]

Thanks doc! Great info!

'zilla

[Red Flag 1]

if it worth saying, it will be quoted.