The typical stance of a laminitic horse exhibits just how painful the disease is: The affected horse rocks back onto his hind legs, trying to remove weight from painful front feet, and/or shifts his weight side-to-side.
The severe pain associated with the breakdown of the hoof’s fragile laminae is one of the leading reasons laminitis treatment fails, said Alonso Guedes, DVM, MS, PhD, of the University of California, Davis, School of Veterinary Medicine. To address the issue, Guedes presented a lecture on the topic at the 2013 American Association of Equine Practitioners’ Convention, held Dec. 7-11 in Nashville, Tenn.
While veterinarians still have a lot to learn about laminitis, research results now show that the disease involves both neuropathic (having to do with the sensory system) and inflammatory (heat and swelling) pain. This, Guedes said, means laminitis requires a multimodal pain management approach that addresses both types of pain.
Veterinarians frequently use non-steroidal anti-inflammatory drugs (NSAIDs), such as phenylbutazone (Bute) and flunixin meglumine (Banamine), to manage horses' laminitis pain. However, Guedes suggested that the additional use of tramadol (a narcoticlike pain reliever), ketamine (a dissociative drug used to treat severe pain in horses), or gabapentin (a drug originally used to treat neuropathic pain and seizures in humans, but now also being used to treat laminitic horses) might help modulate neuropathic and pathologic pain states in horses. These pain states are characterized by hyperalgesia (exaggerated response to painful stimulus) and allodynia (pain response to a normally nonpainful stimulus).
In one study Guedes described, the use of tramadol alone produced a significant, but limited, improvement in off-loading (shifting side-to-side) frequency in horses that had not previously received medication to manage their laminitis-related pain. In the same study, veterinarians also administered intravenous ketamine for the first three days of treatment and demonstrated that this intervention significantly improved off-loading and forelimb load during and after tramadol therapy.
“It’s possible, although it needs to be demonstrated, that co-administration of tramadol with NSAIDs could result in greater modulation of inflammatory responses and superior pain management than when each drug is used alone,” Guedes said. Veterinarians should consider introducing these additional modalities as soon as they perceive the current treatment protocol isn’t producing the desired pain control for the horse, he said.
“Neuropathic changes can occur very early in the disease and, in these cases, NSAIDs alone may not be able to provide sufficient pain control,” he noted.
Because poorly controlled pain can be a deciding factor for euthanizing laminitic horses, Guedes said an appropriate and timely approach to pain therapy is critical for proper case management.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.