6 Jan 2026
Bekki Hill MSc(VAA), BSc(Hons), PgCert, NCert(SurgNsg), ISFMDipFN, RVN discusses physiology, pain scoring, potential treatments and modifications that can help pets
Rebecca Hill
Job Title
Image: Maria Sbytova / Adobe Stock
Pain is defined by the International Association for the Study of Pain as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage” (International Association for the Study of Pain, 2020).
In veterinary medicine, pain assessment and management represent essential components of clinical care. Effective pain management most importantly improves patient welfare.
For postoperative patients, appropriate analgesia enhances recovery, decreases complication rates and encourages earlier return to function.
In chronic pain cases, such as osteoarthritis, ongoing control of discomfort preserves mobility, maintains quality of life and strengthens the human-animal bond. Understanding the physiological mechanisms of pain and employing comprehensive assessment tools allows clinicians to intervene appropriately and tailor treatment strategies to individual patients.
Pain perception involves a complex series of neurological processes, beginning with the activation of nociceptors in peripheral tissues and progressing through transmission, modulation and perception within the central nervous system. If nociceptive input persists without adequate control, the spinal cord undergoes changes that heighten its responsiveness to painful and non-painful stimuli (Flaherty, 2013). This is a process known as central sensitisation.
“Wind-up” is a key component of central sensitisation and is a phenomenon that results in exaggerated pain responses (hyperalgesia) and sometimes pain triggered by normally innocuous stimuli (allodynia). Once established, central sensitisation can be challenging to reverse and may contribute to chronic pain syndromes. This makes early and proactive pain management vital, especially in surgical patients.
Administering analgesia before surgical stimuli, known as pre-emptive analgesia, helps to block nociceptive signalling and prevents the spinal cord from entering a hypersensitised state. By addressing pain early, clinicians reduce the risk of persistent postoperative pain and improve outcomes in animals undergoing surgical procedures.
Before pain can begin to be managed, it must first be recognised. Effective pain management depends on consistent and accurate evaluation, and because animals cannot verbalise their pain, veterinary professionals rely on structured observational tools.
Pain scoring systems are essential in both acute and chronic settings. For acute postoperative patients, validated tools, such as the Glasgow Composite Measure Pain Scale – Short Form (Reid et al, 2007) or the Colorado State University’s acute pain scale (Hellyer PW et al, 2006) enable clinicians to assess behavioural and physiological indicators of discomfort. These may include posture, response to palpation, vocalisation, mobility, heart rate, pupil dilation and overall demeanour. In cats, which often mask signs of pain, species-specific tools like the Feline Grimace Scale (Evangelista et al, 2019) provide an invaluable means of detecting subtle pain-related facial expressions.
For chronic pain, especially conditions such as osteoarthritis, quality-of-life questionnaires play a crucial role. These include instruments like the Canine Orthopaedic Index (Brown, 2014), and VetMetrica (Zoetis). VetMetrica is an online health-related quality of life instrument that allows owners to document quality of life trends and compare their responses to the typical similarly aged healthy pet.
Chronic pain often manifests as behavioural changes rather than dramatic physical signs, so owner input is essential. Owners may report difficulty with stairs, reluctance to jump, changes in grooming, disrupted sleep patterns or reduced enthusiasm for exercise. These questionnaires quantify the impact of pain on daily activities and allow clinicians to monitor long-term trends, evaluate treatment efficacy and adjust interventions accordingly.
While the benefits of these pain scoring systems are well established, it should be noted that every tool based on observation will be prone to observer subjectivity. It is often advised that the questionnaires are completed by the same person, whether this is the same veterinary nurse in a practice setting or the same member of the household in a home environment.
Pharmacological management of pain is often the first step, and current clinical practice relies heavily on multimodal analgesia. This is the strategy of combining different drug classes to target multiple points of the pain pathway (Kianian, 2024). This approach maximises effectiveness while reducing reliance on any single medication, which is particularly important in long-term therapy where side effects must be carefully considered.
Opioids such as methadone, fentanyl and buprenorphine are among the most used in acute pain management. They act primarily on µ-opioid receptors to provide strong analgesia suitable for surgical and severe traumatic pain (Kemp, 2021). While their long-term use in chronic pain is limited due to tolerance and side effects, as well as legally due to their status as controlled drugs, they remain essential for controlling acute episodes of severe discomfort.
NSAIDs such as meloxicam, carprofen and robenacoxib form the foundation of chronic pain management, especially for inflammatory conditions like osteoarthritis. They work by inhibiting cyclooxygenase enzymes (COX-1 and COX-2), reducing prostaglandin production and, therefore, decreasing inflammation and pain (Montefieori, 2014).
NSAIDs provide sustained analgesia and are often well tolerated, though patients should be monitored appropriately for long-term use. They are also used postoperatively to control inflammatory pain once surgical haemostasis is established.
Local anaesthetic agents, including lidocaine and bupivacaine, block sodium channels and prevent nerve depolarisation. They can be administered through epidurals, nerve blocks, wound-soaker catheters or regional anaesthesia techniques (Grubb and Lobprise, 2020). Their targeted action means they can provide profound analgesia with minimal systemic effects, and the long duration of action of some medications means they can be particularly valuable in the immediate postoperative period in orthopaedic patients.
Some types of pain, such as neuropathic pain, respond poorly to traditional analgesics and may require additional therapeutic classes. Gabapentin is commonly used for neuropathic pain and chronic pain syndromes (Di Cesare et al, 2023), while amantadine is an N-methyl-D-aspartate receptor antagonist that helps counteract central sensitisation and wind-up (Lascelles et al, 2008).
Ketamine has also been described at sub-anaesthetic doses to treat chronic pain. Clinical evidence remains limited as to its use, but research suggests administering 0.5mg/kg SC can help in treating breakthrough pain (Gurney, 2024). Current anecdotes advise administering monthly to begin with, but this can be increased to every 48 hours in palliative cases with limited side effects.
Anti–nerve growth factor (anti-NGF) monoclonal antibodies (mAbs) represent an emerging class of analgesics for managing chronic pain in dogs and cats, particularly osteoarthritis-associated pain. By targeting NGF and its interaction with tropomyosin receptor kinase A receptor, which plays a pivotal role in the pain pathway, these antibodies reduce peripheral sensitisation and central pain signalling (Enomoto et al, 2018).
In veterinary medicine, species-specific anti-NGF mAbs have been developed, in the form of bedinvetmab (Librela; Zoetis) for dogs and frunevetmab (Solensia; Zoetis) for cats. These mAbs are administered via a typically monthly injection and offer targeted pain relief with fewer systemic side effects when compared to traditional NSAIDs, making them especially valuable for patients with renal, hepatic or gastrointestinal co-morbidities. Ongoing research is warranted to monitor side effects and the efficacy of their use long term.
Non-medicinal therapies play an increasingly important role in managing chronic pain and supporting postoperative recovery. They complement medications and can often reduce the required dose, lowering the risk of adverse effects.
Physiotherapy uses a range of techniques, including passive range-of-motion exercises, controlled walking, stretching and other activities, with the aim of improving strength, balance and range of motion following surgery or injury (Sharp, 2008). Rehabilitation accelerates postoperative recovery by maintaining muscle mass and joint mobility, while reducing compensatory gait changes that could lead to secondary problems. Regular visits with a veterinary physiotherapist are advised, and owners should be encouraged to also follow a home-based exercise plan.
Similarly, hydrotherapy allows animals to exercise with reduced weight-bearing forces. It is beneficial for orthopaedic postoperative patients and those with chronic musculoskeletal pain and focuses on encouraging correct movement of affected limbs (Tomlinson, 2012).
Widely used in human medicine, acupuncture is now becoming more commonly used in veterinary patients, although its mechanism of action is still not fully understood. It is thought that inserting the needle at painful trigger points relaxes the muscle, contributing to pain relief. Acupuncture also stimulates the release of anti-inflammatory and pain-relieving chemicals, such as serotonin and endorphins, leading to more generalised analgesia (Mash, 2011).
Regenerative medicine is a newly emerging treatment in veterinary medicine and represents one of the most exciting developments in long-term pain control. It uses the body’s own cells to repair and regenerate damaged tissues, helping to reduce pain and restore function in acute and chronic conditions. Stem cells, typically harvested from adipose tissue or bone marrow, can differentiate into various cell types and modulate inflammation. In osteoarthritis management, stem cells are believed to promote repair of cartilage and soft tissues, potentially slowing disease progression (El-Husseiny et al, 2022). While research is ongoing, many animals show substantial improvements in comfort and activity levels after treatment, many being able to stop daily medications completely. A full discussion of all regenerative medicine techniques is beyond the scope of this article, but other treatments include injection of platelet rich plasma and laser therapy.
Modifications made to the home environment can significantly increase the comfort and mobility of animals with chronic pain, yet they are often overlooked. Small adjustments can prevent further injury and pain flare-ups and allow pets to maintain independence (Mille et al, 2022). Clinicians should utilise regular medication reviews and physiotherapy appointments to discuss these with owners.
Supportive, orthopaedic bedding helps to distribute pressure evenly and reduces the risk of decubital ulceration.
Non-slip mats and flooring help to prevent falls and encourage patients to mobilise independently.
Ramps or pet steps enable patients to access sofas, beds or cars without jumping. This will protect painful joints and encourage the exhibition of normal behaviours, therefore maintaining quality of life.
Raised food and water bowls can assist pets with neck, shoulder or elbow discomfort by promoting a more comfortable eating posture.
Accessible litter box designs for cats with chronic pain can reduce the discomfort associated with high-sided trays. This, in turn, reduces the risks of secondary issues that can form as a result, such as inappropriate urination and defecation.
Effective pain management is crucial to ensuring the welfare, comfort and recovery of veterinary patients. Understanding the physiology of pain, including the role of wind-up and central sensitisation, is essential in appreciating the importance of early intervention and proactive analgesia. Continuous assessment using validated pain scales and quality-of-life questionnaires ensures that clinicians and owners can detect even subtle changes and adjust treatment strategies accordingly.
A multimodal approach, combining pharmacological treatments, physiotherapy and environmental modifications, provides the most comprehensive and effective way to manage both postoperative and chronic pain. As veterinary medicine evolves, such as with the continued research into regenerative medicines, patients will benefit from improved quality of life.
Bekki Hill qualified from the RVC in 2018, and is currently the lead surgical veterinary nurse in a 24 hour first opinion hospital. She has completed the Improve International certificate in surgical nursing and the ISFM diploma in feline nursing, and has recently achieved distinction in a master’s degree in veterinary anaesthesia and analgesia with the University of Edinburgh. Bekki is particularly interested in Schedule 3 procedures and all areas of anaesthesia, but specifically in mechanical ventilation and regional anaesthesia.
