SPRING 2015 ISSUE
EQUINE MATTERS
6
MANAGING PA IN
Managing pain in
horses
Veterinary surgeon
Aimi Duff
XLEquine practice
Scott Mitchell
Associates
Aimi Duff BVM&S MRCVS,
Scott Mitchell Associates
Physical methods of pain relief
Bandaging/splints
Simple or support bandages with splints
can be used to provide support in cases of
tendon/bone injury and this in itself can
reduce the need for analgesics.
Relieving pressure
In cases of colic caused by intestinal
obstruction the stomach and intestine leading
up to the blockage can become full of fluid
and food material. This causes the stomach
and intestinal walls to stretch, in turn causing
discomfort. By passing a long, soft plastic
tube through the nose and into the stomach
the vet can evacuate this material, making the
colic patient more comfortable.
Another example where relieving pressure has
an analgesic effect is where a horse is suffering
from a foot abscess. The build up of pus within
the hoof exerts pressure on the sensitive
structures within the foot causing intense pain
and lameness. By locating the pocket of pus
and carefully paring to provide a drainage
tract, the pressure is relieved improving comfort.
Many diseases affecting horses cause pain.
Uncontrolled pain can cause stress which in
turn might adversely affect healing. The long
term effects of chronic stress include weight
loss, muscle loss, colic, aggression, stable vices
(e.g. crib-biting, weaving), diarrhoea, immune
suppression, inappetance, and gastric ulceration.
A key aspect of veterinary care is the
provision of effective pain management and
this can be achieved in several ways; pain
relieving medications, provision of support
and relieving pressure.
‘Analgesia’ is the term used to describe
‘relief from pain’ and an ‘analgesic’ is the
drug used for this effect.
Chemical analgesia
Non-steroidal anti-inflammatory
drugs (NSAIDs)
NSAIDs are useful for reducing inflammation,
fever and pain and are commonly used in
equine practice for lameness and colic
cases. Examples of NSAIDs used in horses
include phenylbutazone ‘bute’, flunixin,
and aspirin.
Treatment with NSAIDs can be short or
long term, e.g. horses with degenerative
conditions such as arthritis. When used
long term it is recommended that the horse
be checked every 6 months and a blood
sample taken to check that the drug is not
causing unwanted side-effects.
Side-effects associated with NSAID
treatment in horses include:
●
Gastrointestinal ulceration
●
Oedema
●
Diarrhoea
●
Weight loss
●
Kidney damage
The risk of side-effects is increased in
foals, small ponies and dehydrated
animals. In these cases concurrent drugs
may be needed or hydration corrected
to prevent complications.
Opioids
As with people, opioids like morphine can
be used in horses to provide short term
pain relief.
Opioids work on the central nervous system
to reduce pain sensation in circumstances
where NSAIDs are insufficient or
contraindicated. They can be injected into
muscle, direct into joints or as epidurals.
Opioids can potentially cause excitability
and constipation so their use must be
carefully monitored and they are typically
avoided in colic cases.
Opioids are most often used to provide pain
relief for orthopaedic procedures during
anaesthesia and in the post-operative period.
This class of drugs are commonly used to
sedate horses but they do also have an
analgesic effect. This can be particularly
useful when pain is causing distress.This
class of drugs are commonly used to
sedate horses but they do also have an
analgesic effect. This can be particularly
useful when pain is causing distress.
a2-agonists
Ketamine is routinely used as an anaesthetic
drug but also has analgesic effects.
Ketamine
Local anaesthetic drugs can be used to
‘numb’ nerves supplying a painful area
such that the pain is no longer felt. By
sequentially ‘blocking’ nerves that supply
certain parts of the limb, vets can localise
the painful region before x-raying or
ultrasound scanning these areas; this is
called ‘diagnostic anaesthesia’ or
‘nerve-blocking’. Local anaesthetics might
also be used to ‘block’ the area around a
wound so that it might be stitched.
Local anaesthetic drugs
There are several medications available
for pain management in horses which
have different mechanisms of action.
