Non-steroid
anti-inflammatories (NSAIDs) are the fastest growing category of veterinary
medicines. At the London Vet Clinic we use them to manage acute or chronic
pain, to reduce inflammation and to lower high fevers. (Rather surprisingly, we
also use them to slow the growth of certain forms of cancer such as bladder
cancer.)
NSAIDs are
divided into three ‘generations’. Broadly speaking, aspirin is first
generation, carprofen (Rimadyl) and meloxicam (Metacam) are second generation
and firocoxib (Previcox), mavacoxib (Trocoxil) and robenacoxib (Onsior) are
third generation.
NSAIDs can
produce unwanted side-effects, specifically stomach irritation, even
ulceration. The second and third generation NSAIDs were developed to reduce gastric
toxicity in humans. They did so but were also associated with fatal heart
complications in people, due to atherosclerosis. This condition is virtually
unknown in dogs and cats so it is not a major problem.
Our referral
orthopaedic surgeon, Gary Clayton Jones, frequently uses firocoxib (Previcox)
as his first choice NSAID for managing long term osteoarthritic pain in dogs.
In a one year study owners reported a 96% improvement rate, with a 5 % drop-out
rate before the end of the year because of gastrointestinal complications.
An
alternative that we are presently trialing is robenacoxib (Onsior). Its
mechanism of action suggests that it may have a longer duration of action and
fewer side effects than second generation NSAIDs. Its high safety index applies
to cats as well as dogs. Meloxicam (Metacam) and robenacoxib are the only
NSAIDs licenced for use in cats.
Mavacoxib
(Trocoxil) is unique in that it has an extremely long half-life. This means that
a tablet need only be given once a month. We worried that if a dog had a toxic
reaction to mavacoxib, that reaction would be prolonged because of the drug’s
very long half life but that has not proven to be the case. In reality, if vomiting,
for example, occurs it occurs for no longer than it does for other NSAIDs.
SAFE USE OF
NSAIDS
We select
NSAIDs for their safety , efficacy, ease of giving and cost. The most common
side effects are gastrointestinal although kidney and liver problems are also
possible. Unwanted side effects are most commonly associated with:
Too great a
dose for the dog or cat’s body weight
Used
together with another NSAID
Used
together with corticosteroids
Accumulation
of the drug in the body because or dehydration, kidney or liver dysfunction or
other health issues.
HOW WE USE
NSAIDs
We routinely
use NSAIDs both during and after surgery to reduce pain. This is one reason we
always give intravenous fluids to any surgical individual who may become
dehydrated.
We routinely
use NSAIDs (together with weight management, joint nutrients and controlled
exercise) for dogs and cats with osteoarthritis. We are happy to provide repeat
prescriptions but need to see your dog or cat at least once every six months,
often for a blood test for liver and kidney function and signs of dehydration,
before providing further
medication.
WHAT ABOUT
THE SLOW RESPONDER?
Each NSAID
has its own mechanism of action. It’s frustrating but if one NSAID does not
reduce your dog or cat’s osteoarthritic pain, the best course is through trial
and error to try another. We
usually like an internal of three to five days between finishing one NSAID and
starting another. If we are stopping an NSAID because your pet has experienced
an unwanted side effect we stop until we are satisfied that any pathological
changes have resolved. We provide an alternative method of pain control during
this internal.
CATS AND
NSAIDs
Kidney
disease is much more common in cats than in dogs. Osteoarthritis, on the other
hand, is equally common in both species. This means that very accurate dosing is
vital as is routine monitoring of kidney function. Because it is in liquid form
we prefer meloxicam (Metacam) as it is easiest both to dose accurately and to
give to cats.
OTHER DRUGS
WE USE FOR OSTEOARTHRITIS
For long
term management of osteoarthritic pain in dogs we use a ‘multi-mode’ approach.
In addition to weight control, nutritional supplements and controlled exercise
we initially use NSAIDs. If however this combination is not as effective as we
want we frequently add pain killers (analgesics) licenced for use in humans
that are also used extensively in dogs.
We use
tramadol when pain affects your dog’s mood or behaviour. Lameness may not
diminish but your dog seems happier even though it still limps. The most common
side effect from tramadol is mild sedation.
We use
gabapentin if we suspect neurological pain. Because it is metabolized by the
liver and eliminated by the kidneys we usually run a routine blood sample
before starting a course. As with tramadol, the most common side effect is mild
sedation. NSAIDs, tramadol and gabapentin appear safe to use alongside each
other.
Paracetemol
is generally safe for dogs BUT HIGHLY TOXIC TO CATS. On its own it is not a
very potent analgesic but when combined with an NSAID or tramadol it can be an
effective pain killer. Paracetemol should be avoided in any dog with liver
problems.
ACUPUNCTURE
Acupuncture
triggers pain control pathways in the body by triggering fibres in the skin and
muscles that affect neurotransmitters in the brain.
At the
London Veterinary Clinic we use acupuncture in conjunction with
weight control, nutritional supplements, exercise and drug therapy to manage
chronic osteoarthritic pain in dogs.
|
|