At the 2018 American Association of Equine Practitioners Convention, held Dec. 1-5 in San Francisco, California, Lori Bidwell, DVM, Dipl. ACVAA, described how practitioners—particularly ambulatory vets—can manage laminitic horses’ pain levels during the acute and chronic phases of disease.
The immediate acute phase causes a physiologic pain that, if not dealt with, can become chronic, she explained. The chronic phase is neuropathic, meaning the nerves have become the pain source. Human patients have described this type of pain as burning, shooting, tingling, and electric.
Bidwell said immediate treatment of acute laminitis includes:
- Icing the feet for the first 48 hours;
- Administering non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone (Bute) or flunixin meglumine (Banamine), noting that 2 g of Bute daily is her drug of choice in this scenario;
- Removing the horse’s shoes and protecting the soles with pads or padded boots;
- Putting the horse on deep, soft footing such as sand or deep shavings; and
- Giving ¼ tube daily of omeprazole to protect the stomach lining from acid if the horse doesn’t have much appetite; ingesta such as hay normally helps buffer this acid.
Bidwell said she might administer other pain-relieving drugs if a horse doesn’t tolerate or respond to NSAIDs and is in severe pain. These include Traumeel tablets (a homeopathic medication you can find in most pharmacies) off-label; the sedative detomidine; the opioid butorphanol; or lidocaine patches.
Lidocaine patches help relieve prickly pain and work locally, not systemically, over blood vessels in the lower limb, she said. Veterinarians can cut the patch to size and apply it to the horse’s pastern and fetlock, then cover and secure it with a bandage. Pain relief should be evident within about 30 minutes and can last up to 11 hours. Swap it out for a new patch every 12 hours. (She cautioned that these are toxic to dogs.)
Another way to relieve pain in these horses, said Bidwell, is to place an abaxial nerve block (at the base of the proximal sesamoid bones, which are located at the back of the fetlock) to numb everything below the fetlock. But she doesn’t always recommend it because she doesn’t want the horse to feel so good that he moves around. Rather, she recommends using sarapin, a plant extract distilled from Sarracena purpurea, better known as the pitcher plant, as a block to help relieve pain without numbing the nerve completely.
For extremely painful horses, she said she might place a perineural catheter along the digital nerve branches and infuse lidocaine through it for about 12 hours.
During the first week of caring for an acutely laminitic horse, be very involved and evaluate his pain levels daily, said Bidwell. You can do this using a pain scale that factors in the horse’s heart rate, gastrointestinal motility (movement—i.e., is he defecating normally), appetite, mobility, and attitude.
“Alter pain control protocols based on your findings,” she said.
Chronically laminitic horses have entered the recovery phase and are dealing with neuropathic pain.
“Treating chronic laminitis pain involves developing a balance between budget restraints placed by the owner, analgesic options, and patient drug tolerance,” said Bidwell.
Along with NSAIDs, she said veterinarians can reach for drugs such as the nerve pain medication gabapentin, the opioid methadone, and the analgesic tramadol for long-term care. Drugs like gabapentin help quiet excitable nerves and allow other drugs, such as NSAIDs, to work better, Bidwell explained.
She also recommended veterinarians consider alternative ways to manage these horses’ pain and anxiety, such as acupuncture and calming supplements.
“Every patient has a different response to pain,” said Bidwell. “It is dangerous to think that every patient will respond the same way to analgesics. Be aggressive with treatment in the early phase of disease, and find a balance with long-term care that is suited to each patient.”
If the horse is in uncontrollable pain or owner resources are limited, she added that humane euthanasia is often the best option.