By John Nielsen, CVT, VTS (ECC, Physical Rehabilitation), CVPP, CCRP
In light of the recent opioid shortage in the U.S., veterinary rehabilitation professionals are searching for alternatives to help manage patients with significant chronic pain states. Although opioids are considered the most potent analgesics, veterinary professionals are implementing a variety of substitute therapies, often in combination, to maintain quality of life (QOL) for these patients. Regarding the following information, it is vital for the rehabilitation practitioner to remember that the best way to continuously monitor the patient’s response to any chosen therapy is to evaluate the patient utilizing a pain scoring system.
The following list of helpful resources is not meant to be all-encompassing, which would be beyond the scope of this article.
Resources for Information on the Shortage and Alternatives
When it comes to ensuring best practices and highlighting the most important information, the U.S. Food and Drug Administration has posted beneficial webpages. The following links provide recommendations on what veterinarians need to know (The Opioid Epidemic: What Veterinarians Need to Know) as well as updated information regarding drug shortages (FDA Drug Shortages). The information provided on these pages will keep the (U.S. based) rehabilitation therapist up to date on the most current information.
A secondary resource for helping with the shortage is information on alternative protocols that reduce or eliminate the need for opioids. The International Veterinary Academy of Pain Management (IVAPM) website (https://ivapm.org/) is helpful in this regard. On the home page, under the Professionals section, the very first subsection is labeled “Opioid Shortage.” In this section, there is a white paper which covers a list of recommendations for modified protocols, including opioid sparing medications and “step down” opioid (such as butorphanol and buprenorphine) usage. While the IVAPM does not generally promote the use of tramadol for pain management in dogs (cats are a different story), it will provide users with information on a variety of other medications and non-pharmaceutical options.
Reconsidering your Options
Although not necessarily a historical first-line choice, oral opioids have been considered necessary historically for severe cases of osteoarthritis. Among a series of challenges with the use of oral opioids is the amount of the first-pass metabolism that occurs with this group. The bio-availability of morphine, for example, is only 33% following oral administration. Also, the need for strict adherence to both state and federal monitor guidelines, new limitations on prescription length and the need to better recognize abuse symptoms in both staff and clients make prescribing this group of medications more burdensome.
Keeping this in mind, along with where on the mammalian pain pathway certain medications act, the IVAPM suggests reconsidering the order in which medications are chosen. Non-steroidal anti-inflammatory drugs (NSAIDs) should be considered a first-line medication, when not contraindicated due to concurrent health conditions of the patient. This class of medications acts on numerous points along the pain pathway, both peripherally and centrally. However, in patients with concurrent hepatic, renal, gastrointestinal or certain endocrine conditions, this group of medications should be used with caution.
A second medication to consider in osteoarthritic patients is gabapentin. Although not a pure analgesic when used alone, when used in combination with an NSAID it can provide a significant synergistic effect. Where the NSAID will address inflammation, gabapentin can be very beneficial in treating the neuropathic and maladaptive aspect of chronic inflammation on the CNS.
A third medication to consider in the multimodal management of osteoarthritis is amantadine. Although off label, amantadine appears to exert a pain-modifying effect as an N-methyl-D-aspartate receptor antagonist. One study demonstrated utility as an adjunct to NSAIDs in dogs with refractory DJD, and there is one case report utilizing amantadine to treat neuropathic pain in a dog. Similar in action to ketamine, it is most often used in short duration, either in a once-daily or twice-daily dosing, depending on the patient’s perceived response. However, if needed, it can be (and has been) used for more severe, chronic cases where stopping the medication results in the near immediate return of increased pain.
Further, the 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats states the following, “Polysulfated Glycosaminoglycans (PSGAGs) are parenterally administered products which have regulatory approval for the control of signs associated with noninfectious degenerative and/or traumatic arthritis of canine synovial joints. Independent studies support PSGAGs as safe and effective chondroprotectants with possible disease-modifying effects. The bioavailability and distribution of PSGAGs to inflamed joints in cats has been demonstrated with extra label subcutaneous administration. Besides, nutraceuticals and other oral nutritional supplements represent a wide spectrum of compounds either as single agents or in combinations. Anecdotal evidence for a pain-modifying effect of those products remains mixed. If nutraceuticals and/or herbal supplements are made part of a treatment plan, the Task Force suggests mindfulness towards product quality control, potential drug interactions with other medications (e.g., some over-the-counter joint products and herbal mixtures contain aspirin and some may contain herbs such as St John’s Wort that interfere with serotonin release or reuptake), and avoidance of ingredients derived from endangered species.”
Non-pharmacologic Modalities for Pain Management
Appropriate weight management greatly influences osteoarthritic patient comfort. Adipose tissue secretes a mixture of cytokines that circulate throughout the body, contributing to the pathology of many diseases, including DJD. Guiding and coaching a client to help their patient obtain a lean body condition score is central to the treatment of chronic pain.
Acupuncture offers a compelling and safe method for pain management in veterinary patients and should be strongly considered as a part of multimodal pain management plans. As it is a minimally invasive treatment, most animals tolerate treatments very well. In individual patients, it has been used as a lone pain treatment modality. There is a robust and still-growing body of evidence for the use of acupuncture for the treatment of pain in veterinary medicine to the extent that it is now an accepted treatment modality for animals in pain.
The use of pulsed electromagnetic field therapy (PEMF) treatments also have proven advantageous in reducing patient pain scores. This technology reduces inflammation by targeting the radio frequency diathermy to enhance the binding of calcium (Ca2+) to calmodulin (CaM). This binding, in turn, accelerates the nitric oxide (NO) cascade, which regulates inflammation and healing.
Beyond manual therapies such as joint mobilizations, massage and myofascial release, rehabilitation modalities such as nerve stimulation, hydrotherapy, thermotherapy, cryotherapy with and without compression, therapeutic ultrasound, therapeutic laser, and extracorporeal shockwave therapy are often successfully incorporated into an effective pain management protocol.
Environmental modifications should also be considered when formulating a protocol to improve QOL. There is strong evidence that stress inhibits healthy behaviors in animals, including eating, grooming, sleeping and elimination. Fear, anxiety, stress and distress lead to hyperalgesia in animals and strategies to mitigate hyperalgesia, therefore, include providing thick bedding and blankets, as well as ease of access to both feed and water bowls. The use of species-specific synthetic pheromones can also prove very beneficial in further reducing stress for these patients when in hospital. In their home environment, items such as throw rugs and ramps will help improve mobility.
The importance of gentle handling of patients with either acute or chronic pain cannot be overstated, especially when working with arthritic dogs and cats. Conscious avoidance of careless handling will ensure the patient’s comfort, allow for a more thorough and effective physical exam, and avoid exacerbating anxiety in the agitated, fearful or aggressive patient. A significant additional benefit of gentle handling is that it demonstrates to the pet owner that healthcare team members are compassionate and aware of the significance of pain in their patients.
Chiropractic care, homeopathy, and other integrative modalities, unfortunately at this time, don’t have enough consistent scientific studies to support their use for every patient. Anecdotally, however, this author has observed numerous patients benefit from chiropractic adjustments and herbal alternatives. The pain scores of said patients are gradually reduced at successive treatment sessions following the application of either of these treatments.
Client education is always the critical component that enables the pet owner to manage pain in the home setting. The best pain management protocols (whether with or without the benefit of opioids) should include the direct involvement of the client. Informing and educating the client regarding a fully integrated approach to pain management, including recognition, systematic assessment, and pharmacologic and nonpharmacologic methods of management, should be implemented whenever possible. This continuum of care will always provide the patient with the best QOL.