Reducing Pain During Pre-Euthanasia Sedative Injections

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Pain has no place during euthanasia. By popular demand these days, pet patients are being given sedation medications to relax them into deep sleep before the administration of euthanasia solution, to both relieve chronic or acute pain that may have led to the decision to euthanize, and to ensure that death itself is not painful.  What many veterinary professionals have found, however, is that the injection of these pre-euthanasia medications themselves can be pain-inducing and downright tricky to manage.

For many years now, I’ve been fortunate to learn wonderful ways to reduce pain during pre-euthanasia sedative injections in pets (typical drugs include opioids, alpha-2 agonists, dissociatives, benzodiazepines, and phenothiazines). Veterinarians love to share what they’ve come up with to keep their patients more comfortable during the procedure. Thanks to such generosity of information, I’m happy to share some of the ones leading to reduced pain and stress. 

While we don’t have much in the way of published data on the following methods, they are still worth sharing, and worth a try in your own patients.  The overarching theme appears to be go slow, use small needles and dilute low pH drugs (ketamine and tiletamine which have a pH close to 3). Note that while pet sedative and anesthetic pre-euthanasia drugs are different from each other, I’m referring to everything as sedatives for simplicity in this blog. And I’m including only Dr. Maslanka’s drug volume because it is important as it relates to the volume of dilution.

  1. The Marchitelli Protocol – Dr. Beth Marchitelli adds liquid sodium bicarbonate to neutralize the pH of dissociatives like tiletamine or ketamine. She uses 2 syringes – one larger syringe to hold Plasmalyte and bicarb, and one to hold her drug combination (Marchitelli prefers Telazol, acepromazine, and butorphanol). The goal is to increase the pH to 6.75 or even 7.

~ 1st syringe holds 0.5ml Plasmalyte with 2-3 drops of bicarb in a 3 or 6 ml syringe.

~ 2nd syringe holds the Telazol combo (or any dissociative combo you prefer).

~ Right before it’s time to give the injection to the patient, add the 2nd syringe contents to the 1st. You may see some brief fizzing.

~ Give subcutaneous (SC) in the neck region with a 27-gauge needle.

  1. The Vitamin B12 Protocol – I was unable to locate exactly where this protocol got its start, but the goal is to dilute dissociatives (ketamine or tiletamine) with liquid B12 perhaps in an effort to increase the pH to a more neutral 7.  Most veterinarians report adding anywhere from 0.5 -1 ml of B12 to their syringe right before injection.  In my experimentation with this, the pH never went above 4, so if it does reduce painful injections, it may be due to some other reason besides pH.  Perhaps it blocks discomfort from an alcohol in the mix. Whatever the reason, many veterinarians swear by B12 as the answer to more comfortable injections.  I prefer to use 1 ml of saline to dilute my drug combinations.  Seems to work just as well and isn’t the unpleasant red color.
  2. The Maslanka Protocol – Dr. Patti Maslanka has been perfecting her approach for many years. It takes calm and steadiness, which is what we are trying to achieve in end-of-life work. No need to rush a good thing. The goal with this one is to give SC fluids before the drugs and after, to dilute the whole area and reduce sting. Note that a large amount of tiletamine is used for complete anesthesia.

~ Warm fluids by immersing a saline fluid bag in hot water to increase it to body temp. Test a few drops on your arm.

~ Distract the patient with food or gentle body touches.

~ Give fluids using a 23-gauge butterfly catheter in the neck/shoulder blade region where SC fluid boluses are normally given (administer 15 mls of saline for felines, 25 mls for canines).

~ Into the fluid bubble using the same butterfly catheter, inject Telazol (1 ml for felines, 3 mls for dogs under 50 pounds, and 5-10 mls for canines over 50 pounds).

~ Following the Telazol injection, inject an additional 1 ml of saline to flush the catheter.

 Want to learn more about Dr. Maslanka’s full protocol description? Click here or watch this video.

4. The Hinsch Protocol – Dr. Brett Hinsch has found a unique way to reduce the amount of tiletamine given to patients.  He reconstitutes the bottle with 2.5ml sterile water rather than the labeled 5ml, making the drug more concentrated than the label suggests. This does not change the pH, it just reduces the amount given to effect. Dr. Hinsch also administers ketamine and acepromazine to his patients with 0.1ml lidocaine to the syringe before injecting into the epaxial region.

5. The Hendrix Protocol – I’m giving Dr. Lynn Hendrix the credit on this one since she is the one I hear instructing on it most often.  The goal is to administer 2 sets of injections. 

~ Combine butorphanol and acepromazine into one syringe and give SC. 

~ Wait until noticeable patient relaxation (5 minutes common), then give a second injection containing a dissociative to induce deeper unconsciousness. Patient should not notice the second injection.

…Regardless of the protocol, the general rule of thumb is to inject slow and steady, with the smallest needle possible.  Many use 25 or 27 gauge needles.  Ask clients if their pet is painful anywhere you can avoid. Distract with food if the patient is still eating and desensitize the area with touch/rubbing if they are receptive.

Want to learn more about reducing pain during pre-euthanasia sedative injections? Consider taking our Peaceful Euthanasia Certification, available for all members of the veterinary team.

References and Resources

Cooney, K. et al. (2012) Veterinary Euthanasia Techniques: A Practical Guide. 1. Aufl. Newark: Wiley-Blackwell. Print.

Hendrix, L. (2022) Animal Hospice and Palliative Medicine for the House Call Veterinarian. Philadelphia: Elsevier. Print.

Marchitelli, B & Shearer, T. (2020). Small Animal Euthanasia: Updates on Clinical Practice. The Veterinary Clinics of North America. Small Animal Practice, 50(3), i–i.

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Dr. Kathleen Cooney

DVM, CHPV, CPEV, DACAW resident Founder, Senior Director of Education for the Companion Animal Euthanasia Training Academy

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