A huge number of medical conditions can be painful; in addition, some treatments (for example, surgical operations) can also lead to discomfort. However, pain is an enemy that we can combat – and we have wide range of options for minimising and managing pain. In this blog, we’re going to explore this essential aspect of veterinary work.
What is pain?
Pain is defined as “the emotional response to actual or potential tissue damage”. So, it is indeed technically true that pain is all in the mind… just not very helpful! However, we can divide pain states into several categories:
- Acute pain – this is the response to actual injuries, and is a sensible and protective response, to minimise further damage.
- Chronic pain – this occurs with long-lasting injuries or disease processes, and in some cases may continue after the injury has healed. It is a “maladaptive response” in that it doesn’t actually help the patient.
- Neurological pain – pain from damaged nerves is different from other types of pain because it isn’t “real”, being due to a malfunction of the pain receptor nerves. As a result, it can be very difficult to manage.
What are the consequences of being in pain?
Firstly, it’s a massive animal welfare issue! There is no good reason to leave an animal in pain nowadays – the old idea that it was somehow helpful for animals to suffer after operations, for example, is now considered to be both false and cruel.
Secondly, however, being in pain will slow down the animal’s healing, and prolong it’s recovery.
In some situations, it is in fact possible to prevent pain from starting. Obviously, avoiding injuries is one example (if not the most practical), but another is during surgery. Nowadays, we give pain relief before, not just after, an operation – because many studies have shown that the presence of pain (even if the animal is unconscious) makes subsequent pain even worse (this is sometimes known as the “Wind Up Phenomenon”).
While humans tend to jump right for painkillers as soon as they get a headache, recent studies have suggested that this isn’t necessarily the best way forward – taking a drink of water, for example, can help manage tension and dehydration headaches.
The same principles apply in animals. In particular, there are three approaches we find really helpful:
- Facilitation. Many animals (for example, after orthopaedic surgery, or those with arthritis) are unable to mobilise easily, and the effort of climbing stairs, or jumping into the litter tray, can cause an acute painful flare up. Providing ramps, controlled little-and-often exercise, and similar low level assistance can be very valuable.
- Comfort. Many people have observed that pain is often worse in cold, wet conditions. While the theory behind this is deeply contested, it does appear to be a real phenomenon! So, we recommend warm, snug bedding in a draught-free area for painful patients.
- Physiotherapy. Physio is an essential component of rehabilitation after surgery – but it is also a very potent method of pain management, by assisting with tissue circulation and even helping to “reset” the nervous system.
In addition, extra measures such as cold laser therapy can be quite effective in reducing local pain.
In most cases, the mainstay of pain control is going to be medication. There are a number of different families of drugs that we can use:
1) NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) (e.g. meloxicam, carprofen)
The most widely used painkillers are in this family, and include a wide range of injections, tablets and liquids or syrups. They work by blocking the chemical signals that cause pain and inflammation. While there are potential side effects – primarily affecting the stomach and kidneys – in most animals, most of the time, these drugs are well tolerated and very effective for mild to moderate pain. In addition, there are so many different drugs in the family available that if one doesn’t agree with a patient, another can usually be found.
This is an unusual drug, a sort of “cousin” to the NSAIDs. It has powerful pain killing activity, but is less powerful as an anti-inflammatory. However, it is also more dangerous – it is lethal to cats, and even in dogs the safe dose is much lower than in people, so it should NEVER be used except on veterinary advice (it’s also illegal to use human paracetamol in dogs).
3) Opioids (e.g. buprenorphine, methadone, tramadol).
These are a family of drugs derived from morphine. They are excellent painkillers, but because of their addictive nature are tightly controlled in law (fortunately, we almost never see addiction in our patient – the concern is more for the humans who might have access to them!). At very high doses they can cause side effects such as sedation or even difficulty breathing, but this is uncommon in veterinary practice. Unfortunately, the majority of opioids are injection-only so are only really an option for hospitalised patients (although some can be given as a liquid under the tongue). One exception is tramadol, although the evidence for its effectiveness in dogs is quite weak.
4) GABA-analogues (e.g. gabapentin)
These drugs work to “damp down” overactive nerves, and so are sometimes used in neurological pain states, although there is no license for their use in animals.