that hurts – part 2: managing chronic pain in pets
Proper pain management has become an important specialty area in veterinary medicine, just as it has in human medicine. There are as many different types of pain as different ways to treat it. This blog, the second in a two-part series, will discuss chronic pain specifically (we talked about acute pain in the last blog).
Chronic pain has traditionally been defined by its duration (pain that persists for weeks to months). If left untreated, chronic pain can lead to a variety of syndromes. In veterinary medicine, common causes of chronic pain include osteoarthritis, cancer pain and neuropathic pain (commonly a result of procedures such as amputation of a digit, limb, or tail; “phantom limb” syndrome post-amputation; and chronic IVDD).
Every animal experiences pain in a unique way, so just because your dog or cat does not display a pain related behavior, does not mean that he or she is not in pain. Some common indicators of pain in dogs and cats include: decreased social interaction, reluctance to move, loss of appetite, aggression, and biting.
There are many ways your vet can treat chronic pain. The most important aspect of managing chronic pain is to work with a multi-modal treatment protocol. This means using medications combined with physical therapy to target several different steps of the pain pathway, allowing more effective pain control with fewer side effects.
Drug therapies include:
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs remain the mainstay of therapy for chronically painful patients. They work mainly by blocking prostaglandin production by binding and inhibiting cyclooxygenase (COX). The result of this effect is mainly a reduction in inflammation.
These drugs are useful in a variety of chronically painful conditions (though they may have limited effectiveness in some forms of neuropathic pain). Opioids may be particularly useful for chronic pain management, as they are available in oral and transdermal versions that are delivered through the skin.
NMDA receptor antagonists
This is a class of anesthetics often used as “adjunctive drugs” (meaning in combination with other analgesics) to improve the control of pain. Intense and/or chronic painful stimuli result in changes in the central nervous system, leading to an increase of pain intensity. NMDA receptor antagonist drugs help to control and treat this amplification.
This drug has been used for many forms of chronic pain, though its best application may be for neuropathic pain. Gabapentin is commonly used in conjunction with opioids for treatment of post- amputation patients.
Tricyclic antidepressants (TCAs) act to inhibit serotonin and norepinephrine reuptake, though they may have other analgesic effects as well.
Physical therapies for chronic pain management include:
Acupuncture and electroacupuncture
Pulsed magnetic field therapy
Hydrotherapy (useful for patients with IVDD or osteoarthritis)
If you have a pet in constant pain, you may want to ask if your veterinary practice has an IVAPM (International Veterinary Pain Management) member on staff, or find a vet practice that does. IVAPM members can work toward certification in the management of animal pain. After they obtain this certification, they will be known as a CVPP or certified veterinary pain practitioner, and they can be a good resource for developing a comprehensive pain-management plan for your pet.
To find a CVPP or IVAPM member in your area, visit the IVAPM website at www.IVAPM.org