03/03/2022
The 2022 AAHA Pain Management Guideline for Dogs and Cats is now live and available for free download! Don't have time to completely digest a densely packed 20 page document? You're not alone! Here are some of the highlights:
1) Pain management in small animals is a therapeutic continuum - it involves listening and engaging with owners about changes in their pet's behavior, training staff to recognize procedures and conditions associated with pain, instituting reliable pain assessment strategies in your practice, and a willingness to change therapy over time according to the needs of the patient.
2) Proactive, preemptive, multimodal therapy is best. Treat the pain before it starts! For chronic pain, it means educating owners of breeds with a high propensity of developing chronic pain disease (like osteoarthritis) what to look for when these diseases start to emerge. Teach owners what pain looks like in dogs and cats!
Excellent YouTube video on behavioral signs of OA in cats: https://www.youtube.com/watch?v=-7hnAFNFjW0
3) Use a standardized pain assessment strategy in your hospital that is included along with your history, physical exam, clinical observation, and palpation of the painful area. Don't forget to watch your patient in the exam room - watch how the animal sits, walks, or jumps. Encourage owners to share videos of their animals at home in various stages of activity. Here are some good examples of standardized pain assessment for acute/post-op pain:
Dogs: Colorado State Pain Scale (unvalidated, but easy to use), Glasgow Pain Scale (validated, relatively easy to use)
Cats: Same as for dogs, but the Feline Grimace Scale (https://www.felinegrimacescale.com/) is probably the best way to go.
There are several chronic pain scales, especially for pets with osteoarthritis that have been validated for dogs and cats. These rely heavily on owner assessment of behavior, despite possible knowledge gaps in owner recognition of painful behaviors.
Consider performing a pain assessment along with every TPR you order for your patient in hospital for animals undergoing therapy for acute pain.
4) Analgesics used for dogs and cats will depend on several factors including whether the pain is considered acute (physiologic response) or chronic (maladaptive) and whether or source of pain is known or unknown. AAHA created a pain treatment algorithm using a tiered approach (1st tier meaning an abundance of evidence exists to support its use vs 3rd tier meaning there is minimal evidence supporting its use in small animals). See the picture below. Remember that combining Tier 1 and Tier 2 treatments is acceptable and encouraged.
5) Here are some consensus statements and recent updates on different pain medications:
Simbadol - Although labeled for cats, it can be used in dogs for 24-hour acute pain relief, but off-label
Local anesthetics - Use them as much as possible for nerve blocks, and you can add either buprenorphine or dexmedetomidine to prolong the duration of action. Nocita (slow-releasing bupivacaine) can also be used off-label to provide 3 days of analgesia when used as an incisional block for anything other than a TPLO.
Tramadol - When given orally, it does not provide effective post-operative analgesia in dogs (IV tramadol may be a different story)
Gabapentin - Sorry to say, but this drug is not effective at providing post-operative analgesia despite it's recent widespread use. Also very limited data supporting its use in chronic pain states.
Maropitant - Has VERY VERY WEAK analgesic properties, but it's a great anti-emetic
Oral opioids with or without acetaminophen - Not a good option for providing analgesia in dogs and especially not a great option in the age of the opioid crisis
Long-term NSAID use - Definitely should be used at the lowest dose tolerated, as the rate of various organ toxicosis is quite low and efficacy is quite high in both dogs and cats. However, there is no NSAID approved for long-term use in cats at least within the USA, so this type of administration is off-label. Consider using NSAIDs even in arthritic cats with chronic renal insufficiency at low doses.
Anti-NGF monoclonal antibodies - A new class of drug with some promise as an effective therapy in cats with OA.
Amantadine - No new data has come out about it's use for chronic pain in dogs, but there is a study suggesting it should be used as twice daily dosing and can be used longer than 3 weeks.
Cannabinoids - Mixed results on its use for chronic pain conditions.
6) This paper goes into a lot of detail about non-pharmacologic treatment strategies (icing, acupuncture, laser, rehab, etc.), which should be integrated alongside pharmacologic treatment modalities to augment the overall analgesic experience. If you want to know more about these modalities, I encourage you to read this section in more detail.
7) There is some emphasis in the paper that, at least in humans, we know that positive emotional experiences decrease painful responses, while negative experiences have the opposite effect. Therefore, rough handling, bad-tasting medications, and other environmental factors should be taken into account when creating a treatment modality. Factors that possibly disrupt the human-animal bond should be weighed against any benefits that a treatment provides.
The AAHA Pain Management Guidelines can be found at this link: https://www.aaha.org/globalassets/02-guidelines/2022-pain-management/resources/2022-aaha-pain-management-guidelines-for-dog-and-cats.pdf?fbclid=IwAR3iuWViHuaR0uDW0AVY9NVT09d0WW1mYpQ-TqPLYG6omyKN0cut1Jf7gbg