| Pain
Management in Cats
Pharmacokinetic data developed
in other species cannot be safely extrapolated
to the cat. Feline deficiency of glucuronidation
pathways results in slow metabolism of several
NSAIDs, which prolongs the duration of effect
and may lead to drug accumulation and toxicity.
Meloxicam, a COX2 selective
NSAID, has demonstrated clinical efficacy for
chronic pain, musculoskeletal pain, and routine
soft tissue surgery with few side effects. Based
on clinical experience, Lascelles of NCSU College
of Veterinary Medicine, now recommends oral meloxicam
doses for cats that are less than previously reported
in the literature (0.1 mg/kg PO on day 1 followed
by 0.05 mg/kg PO daily for 4-6 days, then 0.025
mg/kg daily for 10 days, then lowest effective
dose).1
Five days of oral treatment
with meloxicam or ketoprofen for cats with painful
locomotor disorders provided similar analgesia2,
but meloxicam drops were more palatable than ketoprofen
tablets. Appropriately flavored preparations in
a convenient dosage form are easier for owners
to administer and allow for accurate dosing.
According to Robertson and
Taylor3, opioids have an unjustified
reputation for causing mania in cats, but with
refinements in dosing they are now used successfully
in this species. The mu-opioid agonists are generally
considered the best analgesics. Morphine (0.1–0.3
mg/kg) is effective in a clinical setting. Oxymorphone
and hydromorphone (0.05–0.1 mg/kg) are widely
used in the USA. These opioids are more potent
(up to 10 times), and longer acting than morphine
in cats. Buprenorphine (0.01–0.02 mg/kg),
a partial mu-agonist, is the most popular opioid
used in small animal practice in the UK, other
parts of Europe, Australia and South Africa. In
clinical studies it has produced better analgesia
than several other opioids and appears to be highly
suitable for perioperative pain management in
cats.
Amitriptyline (starting dose
2.5 mg/kg PO, once daily) has been used to treat
feline interstitial cystitis with few side effects,
and there are anecdotal reports of its use for
cancer and neuropathic pain management.
Some of the less conventional
analgesics including the tricyclic anti-depressants
and gabapentin may prove to play a useful role
in chronic pain management, but controlled clinical
trials are needed to establish the best doses
for maximum efficacy. Other less traditional analgesics
such as ketamine and local anesthetics are also
used for clinical pain management. The transmucosal,
transdermal and epidural routes offer novel methods
for administration of analgesic drugs and have
considerable potential for improving techniques
in feline pain management.
1www.vetmash.com/dr_duncan_lascelle04.pdf,
accessed Nov 2004
2J Small Anim Pract 2001
Dec;42(12):587-93
Click here to access the PubMed abstract of this article.
3Journal of Feline Medicine and
Surgery; 6(5), Oct 2004: 321-333
Meloxicam for Analgesia
in Dogs
A clinical trial was conducted
to evaluate the safety and efficacy of meloxicam
in dogs with chronic osteoarthritis. A scoring
system assessed specific lameness, general stiffness,
painful rise, exercise intolerance, and behavior,
and demonstrated significant reductions in clinical
signs of osteoarthritis following 4 weeks of drug
therapy. Side effects were minimal in extent and
duration. The findings of this investigation suggest
that the efficacy, tolerance, and formulation
of meloxicam oral suspension make it well suited
for the treatment of chronic osteoarthritis in
the dog.
Can Vet J 2000 Apr;41(4):296-300
Ketoprofen
is a potent anti-inflammatory and analgesic which
can be used for the management of surgical pain
or chronic pain. The drug should not be given
to animals with GI ulceration, impaired renal
or hepatic function, or coagulation disorders.
Ketoprofen should not be used preoperatively when
noncompressible bleeding may be a problem. Occasional
vomiting has been reported. When an NSAID or other
drug that is potentially irritating to the GI
tract is needed, topical preparations offer an
excellent alternative. Pharmaceutical Research,
Vol. 13, No. 1, 1996 reports (in humans)
“a topical formulation of ketoprofen has been developed for the temporary relief of
minor aches and pains of muscle and joints and
to minimize gastrointestinal side effects after
oral administration.”
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