ANALGESIA FROM VETERINARY ASPECT
July 20th, 2017 | Ammar Ahmad | No Comments
The issue of management of pain in animals was given negligible importance in past, but in last two decades this issue has been recognized and continuous progress can be seen in this regard. The abrupt and strong increase in recognition, management and control of animal pain is mainly seen towards the post-operative and muscular pain in pets or precious horses. On the other hand pain management in animals fighting with cancer like deadly diseases is very poor, similar to this, the knowledge of pain management and control in farm animals and laboratory research animals should be refined. In past years there was uncertainty about the degree of pain in animals, so analgesic drugs were not used commonly, due to the fear of unknown side effects. But as it is said earlier, in the last two decades the importance of analgesia in animals, progressed to the new height but still very low.
Pain is actually a sensory as well as emotional experience due to the unpleasant stimulus, and generally there should be a complete sensory network in body to detect that noxious stimulus. it’s a proven fact that all vertebrate animals possess a completely developed sensory mechanism in their body to identify and deal with any kind of unpleasant stimulus, so It is very much obvious that the pain mechanism in animal and human is of similar type and there should be similar kind of management and control in animals and humans. In past years there was great dilemma about the animal’s emotions and sensations that whether they feel the pain in similar manner as humans or not, major issue was with the caretakers or owners, most of them compared the consciousness of animal with self-consciousness and pain bearing ability of animals with their own pain bearing ability, but in recent researches this issue has been overwhelmed to some extent by accepting that consciousness developed systemically during the period of evolution and each specie has its own different degree of consciousness. Besides all this, there is need of new research work on these areas that will ultimately progress towards the major achievements in our understanding of quality and classification of the pain in animals.
FACTORS AFFECTING ANALGESIC USE IN VETERINARY
There is a long list of factors that influence the use of analgesic drugs in veterinary patients, but the main thing is that, there comparative importance in different species is different. Among these factors some major ones could be discussed here for the betterment of the patients.
A major concern that hampers the use of analgesics in animals is research project, for example any scientist working on a research base project using laboratory animals for tests would never use any analgesic drug in addition, because the use of analgesic drug may alter the goals of that particular research project, keeping this thing in mind scientist let the animal to bear pain rather using analgesics.
- Economy of a farm
Another hurdle that restricts the use of analgesics is economy of a farm, every farm manager wants to increase the profit margin of farm by keeping the expenditure as low as possible, by purchasing medicines for life threatening issues only, so they do not bother about the animal pain other than a serious issue, this behaviour and mind set should be changed. If a farmer don’t let animal to bear any kind of pain ultimately animal will be healthy and it will produce more output resulting into increased profit.
- Dose rates
Medicine companies mostly provide the safe drug dose rates for farm animals, small ruminants and pets only but they don’t provide any information about the safe range of drug dose in wild and exotic animals, so analgesics are not used in routine in wild animals.
- Behaviour of Animal
Expression of pain varies greatly from specie to specie, and sometimes it becomes so difficult to observe the pain feelings by the behaviour of animal, moreover in some species pain expression or response may be masked by animal’s etiquette, those animals are called expressionless animals for example sheep doesn’t show pain expressions, so it becomes obvious to assume that no significant pain is present and effective pain management is compromised.
Prior to recent studies, pain estimation and management was primarily based on the clinical outlook without any authentic validation, but satisfactory pain scales have been introduced in more recent studies for the identification and assessment of post-operative pain in small animal operations like castration and tail docking and in large animal dehorning surgeries. These applications helped a lot in determining dose rates and safety index of analgesics in animals, further practical applications will help in determining the analgesic needs of individual animals.
It is the common practice of veterinary surgeons that they use analgesics to manage pain effectively after surgeries because they simply suppose that animal suffering from pain. Mostly non-steroidal anti-inflammatory drugs (NSAIDs) or opioids are being used by veterinary surgeons as a post-operative pain management. As it is common practice in veterinary clinics or hospitals that patients are being discharged from clinics shortly after the surgery so that use of long acting analgesics has been increased. Management of chronic pain also gained importance, special analgesics which are selectively COX-2 inhibitors are being used. Recently new NSAIDs have been prepared which are selective COX-2 inhibitors and blocks the pain sensations without any side effects, previously used NSAIDS were not selective and they block COX-1 as well.
Basically COX is an enzyme which causes inflammatory pain response by producing prostaglandins, and it is of two types COX-1 and COX-2, It is very important to keep in mind before using NSAIDs as analgesic that inhibition of COX-2 is sufficient to block pain sensation, and COX-1 should not be inhibited because it is very important enzyme that lines the stomach and protects it from digestive enzymes it is also actively involved in normal kidney function, so inhibition of COX-1 enzyme has serious side effects like gastric ulcers and renal failure, so only use selectively COX-2 inhibitor NSAIDs.
Pain management is chief to veterinary practice, not adjunctive. Relieving pain is not only a professional obligation but also a key contributor to successful case outcomes and enhancement of veterinarian-client-patient relationship. Allegiance to pain management identifies a practice as one that is committed to compassionate care; injury or surgery; optimum recovery from illness, and enhanced quality of life.
Ammar Ahmad and Yasra Syed*
DVM 6th semester, Faculty of Veterinary Science, University of Agriculture, Faisalabad
*Pharm-D 8th Semester, Institute of Pharmacy, Physiology & Pharmacology, UAF
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