Caring for dogs doesn’t mean only feeding, petting and walking them. It does mean also caring for their health and well-being, giving them the appropriate treatment for any condition or disease that may affect them and ensuring that they do not suffer from pain from any cause.
Pain relief for dogs is often overlooked by many people. Unfortunately, today there is still the misconception that animals have a high tolerance to pain and that they experience pain less intensely than humans. But this is not the case. The fact that dogs cannot tell us with words that they are in pain doesn’t mean that they don’t experience pain. Dogs use different ways for expressing their painful conditions and emotions, through abnormal postures or movements of their body and through specific vocalizations. So it is important that dogs’ owners and veterinarians learn to correctly interpret these postures, movements or vocalizations in order to detect that pets are in pain. Examples of pain behaviors include limping, stiff gait, reluctance to move, restlessness and looking, licking or chewing at the painful area.
The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage”. This universally accepted definition emphasizes the double aspect, perceptive and emotional, of the pain experience. In other words, pain is not considered merely as a sensory experience, but it also includes emotional components (anxiety, depression, behavioral changes) that are inseparable from the painful sensation. In addition, this definition stresses that pain is not always the result of a tissue damage (such as a wound or a contusion), but it can also appear without any somatic cause justifying it. From what has been said, it is clear how difficult can be sometimes detecting the cause of pain and treating it definitively.
Basically there are two types of pain, each requiring a different treatment approach: acute pain and chronic pain. Acute pain is the immediate consequence of the activation of the so-called nociceptive systems (pain receptors and nerves involved in the transmission of the painful sensation to the brain). It is usually the result of a tissue damage (to different organs and body systems such as the skin, muscles, joints and internal organs), tends to be self-limiting and often disappears with the removal of its cause. Acute pain is highly localized and has mainly a protective function, since it serves to warn the body of actual tissue damage or a potential danger. Emotional symptoms are scarcely apparent and limited to a mild anxious state.
On the contrary chronic pain has not a protective function and is not the symptom of a tissue damage. Instead, it can be considered as a disease in itself. Chronic pain has been defined as a pain that persists for at least one month after the removal of its cause and that can be perpetuated for prolonged periods of time without any apparent bodily lesion being present. Chronic pain is often refractory to various treatments, is not well localized and is associated to several emotional symptoms such as stress, depression, anxiety, fear, sleep disorders and behavioral changes, especially changes in social relationships (dog-dog and human-dog interactions). It usually develops as the result of a prolonged or repeated untreated pain condition which in turn causes an alteration to the normal pain nervous pathways. In this situation dogs can become more sensitive to painful stimuli or can even show a painful response to a non-painful stimulus.
Chronic pain as described above is more properly called pathological or neuropathic pain. It is the extreme point of a continuum that include many forms of prolonged or repeated painful conditions that, fortunately, can be effectively treated, at least as long as nervous changes in the pain-processing areas of the spinal cord and the brain have not occurred.
Although the complexity of the pain process can seem overwhelming, there are several sites of potential intervention. Intuitively pain relief for dogs should be started as soon as pain occurs and, regardless of whether pain is acute or chronic, the goals of pain therapy should be: 1) eliminating pain; 2) making the dog more comfortable; 3) suppressing pain behaviors; 4) returning the dog to its maximal function; 5) removing stress or distress. There is no universal protocol to treat pain in dogs (as well as in humans). Pain therapy should be individualized to the patient based on the mechanism of pain induction (the cause of pain), the duration of pain (acute or chronic pain), the type of pain (somatic vs. visceral pain; nociceptive vs. neuropathic pain) and the severity of pain (the perceived intensity of pain, that can vary among different dog patients).
The traditional approach to pain relief for dogs is based on the use of analgesics, that are drugs that relieve pain, combined whenever possible with the removal of the cause of pain. There are different classes of analgesics, each characterized by a different effectiveness on the treatment of acute or chronic pain and a different profile of side effects. The most used are opioids (such as morphine), local anesthetics (such as lidocaine) and alpha2-agonists (such as medetomidine) that are more effective for the treatment of acute pain, and NSAIDs (non-steroidal anti-inflammatory drugs, such as aspirin and ibuprofen) that are more effective for the treatment of chronic pain. In addition several drugs are used as adjuvant therapy especially for the treatment of chronic pain, including corticosteroids, antidepressants and anticonvulsants. Finally, complementary and alternative therapies such as acupuncture and related techniques can be effective treatment approaches for acute and particularly chronic pain in dogs, either as a supplement to conventional pain therapy or alone.
As it has been already said, there is not a single universal protocol for pain relief for dogs and the choice of the specific analgesic plan should be individualized to the patient’s needs, depending on many factors, including, but not limited to, the duration, type and severity of pain as well as the individual characteristic of patients (age, weight, sex, breed), their physical status, their medical, pharmacologic and pain history and the owner expectations. What is important is that the analgesic plan must be developed by a veterinarian that can establish the correct drugs and doses required by each individual dog and that knows well the side effects resulting from excessive doses of analgesics as well as the deleterious effects of pain resulting from undermedication of patients.