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| NSAID’s
-- remain
the mainstay of therapy for chronically painful patients. Their principal
mode of action is to block prostaglandin production by binding and
inhibiting cyclooxygenase (COX). While the result of this effect is mainly
a reduction in inflammation and peripheral nociceptor sensitization, there
is some evidence that NSAID’s have a central analgesic action as well,
though the exact mechanism remains unclear.
Cyclooxygenase
occurs in at least 2 isoforms: COX1 (constitutive), which mediates
formation of prostaglandins responsible for GI mucosal protection,
hemostasis and renal blood flow, and COX2 (inducible), which catalyzes
production of prostaglandins that act as inflammatory mediators. This is a
bit of an oversimplification, as COX2 can play a homeostatic role in some
situations (ulcer healing, maintenance of renal blood flow during stress,
prostacyclin production), but in general NSAID’s that inhibit
COX2>COX1 are considered the drugs of choice in this class. These are
often referred to as COX2 preferential or selective agents.
A variety of
selective/preferential NSAID’s are available for use in dogs, including
carprofen (2.2 mg/kg BID or 4.4 mg/kg SID), etodolac (10-15 mg/kg SID),
deracoxib (1-2 mg/kg SID for chronic use), meloxicam (0.2 mg/kg on day
1, then 0.1 mg/kg SID), and tepoxalin (20 mg/kg SID on day one, then 10
mg/kg SID). Though in theory they should all be equally
efficacious, some patients appear to respond better to one over another;
thus, failure to achieve an analgesic effect with one drug does not imply
lack of response to all NSAID’s.
Caution
should be exercised when employing NSAID’s in cats. Differences in
hepatic biotransformation can lead to prolonged half-lives and the
potential for toxicity. Additionally, very few studies have been performed
examining the feline response to these compounds. One of the few NSAID’s
that appears to be well tolerated in cats is meloxicam (0.1 mg/kg SQ, PO SID
the first day, followed by 0.05 mg/kg SID for 1 to 4 days, then 0.025
mg/kg every 24 to 48 hours). Because tremendous
variation among individual cats exists in regard to metabolism, it’s
recommended they be monitored closely for adverse effects when on
long-term therapy.
In all
patients, NSAID’s should be avoided in the presence of renal or hepatic
dysfunction, coagulopathies, GI disorders, shock, hypotension/hypovolemia,
hypoalbuminemia or pregnancy. Dogs and cats on chronic therapy should be
monitored periodically for alterations in hematological or biochemical
parameters, and their owners should be instructed to watch for signs of GI
upset, alterations in appetite and PU/PD.
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Dr. Dave Thompson
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1)
CARPROFEN
a)
Classification
i)
A COX2 selective NSAID
b)
General Information
i)
Effective anti-inflammatory/analgesic generally free of significant
GI side effects
c)
Advantages/Recommended use
i)
Short term use for acute pain
ii)
Long term use in chronic pain for tolerant patients
d)
Cautionary Information
i)
As with any NSAID, GI side-effects can be substantial
(1)
Discontinue use if GI signs develop
ii)
Avoid use in:
(1)
Combination with
corticosteroids
(a)
Potentially increased ulcerogenic effect
(2)
Renal compromised patients, dehydrated or hypotensive patients,
patients with hepatic disease, pregnancy, patients with pre-existing GI
disease, coagulopathies
iii)
Monitor liver enzymes of canine patients on chronic therapy
e)
Dosage Information
i)
Dogs – 2.20 mg/kg (1.0 mg/lb) SC, PO BID or 4.4 mg/kg (2.0 mg/lb)
SC, PO SID
ii)
Cats – 1 to 2.0 mg/kg (0.45 to
0.90 mg/lb) SC one time only
f)
Cost
i)
Moderate |
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2)
DERACOXIB
a)
Classification
i)
A coxib class COX2 selective NSAID
b)
General Information
i)
Effective anti-inflammatory/analgesic generally free of significant
GI side effects
c)
Advantages/Recommended use
i)
Short term use for acute pain
ii)
Long term use in chronic pain for tolerant patients
d)
Cautionary Information
i)
As with any NSAID, GI side-effects can be substantial
(1)
Discontinue use if GI signs develop
ii)
Avoid use in:
(1)
Combination with
corticosteroids
(a)
Potentially increased ulcerogenic effect
(2)
Renal compromised patients, dehydrated or hypotensive patients,
patients with hepatic disease, pregnancy, patients with pre-existing GI
disease, coagulopathies
iii)
Monitor liver enzymes of canine patients on chronic therapy
e)
Dosage Information
i)
Dogs – 1 to 2 mg/kg PO SID for general pain management
(1)
3 to 4 mg/kg PO SID for up to 7 days for acute surgical pain
ii)
Cats – use of deracoxib is not
recommended at this time
f)
Cost
i)
Moderately high |
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3)
ETODOLAC
a)
Classification
i)
A COX2 selective NSAID
b)
General Information
i)
Effective anti-inflammatory/analgesic generally free of significant
GI side effects
c)
Advantages/Recommended use
i)
Short term use for acute pain
ii)
Long term use in chronic pain for tolerant patients
d)
Cautionary Information
i)
As with any NSAID, GI side-effects can be substantial
(1)
Discontinue use if GI signs develop
ii)
Avoid use in:
(1)
Combination with
corticosteroids
(a)
Potentially increased ulcerogenic effect
(2)
Renal compromised patients, dehydrated or hypotensive patients,
patients with hepatic disease, pregnancy, patients with pre-existing GI
disease, coagulopathies
iii)
Monitor liver enzymes of canine patients on chronic therapy
e)
Dosage Information
i)
Dogs – 10 to 15 mg/kg (4.8 TO 6.8 mg/lb) PO SID
ii)
Cats – use of etodolac is not recommended
at this time
f)
Cost
i)
Moderately low |
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4)
KETOPROFEN
a)
Classification
i)
An NSAID
b)
General Information
i)
Effective anti-inflammatory/analgesic with significant GI side
effects if used long term
c)
Advantages/Recommended use
i)
Long acting analgesic injectable for single
dose post-op use
(1)
Duration of effect is 12 to 18 hours
(2)
Single dose post-op usage has been shown to be free of any
side-effect concerns in normal dogs and cats
d)
Cautionary Information
i)
Avoid long term use
(1)
GI side effects can be substantial
ii)
Avoid use in combination with corticosteroids
(1)
Potentially increased ulcerogenic effect
iii)
Avoid in renal compromised patients
iv)
Avoid in dehydrated or hypotensive patients
e)
Dosage Information
i)
Dogs – 2.0 mg/kg (0.9 mg/lb) SC one time only
ii)
Cats – 2.0 mg/kg (0.9 mg/lb) SC one time only
f)
Cost
i)
Very low |
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5)
MELOXICAM
a)
Classification
i)
A COX2 selective NSAID
b)
General Information
i)
Effective anti-inflammatory/analgesic generally free of significant
GI side effects
c)
Advantages/Recommended use
i)
Short term use for acute pain
ii)
Long term use in chronic pain for tolerant patients
(1)
This NSAID appears more suitable for longer term use in cats
(a)
Cats, even more so than dogs, need to be monitored closely during
therapy
d)
Cautionary Information
i)
As with any NSAID, GI side-effects can be substantial
(1)
Discontinue use if GI signs develop
ii)
Avoid use in:
(1)
Combination with
corticosteroids
(a)
Potentially increased ulcerogenic effect
(2)
Renal compromised patients, dehydrated or hypotensive patients,
patients with hepatic disease, pregnancy, patients with pre-existing GI
disease, coagulopathies
iii)
Monitor liver enzymes of canine patients on chronic therapy
e)
Dosage Information
i)
Dogs – 0.2 mg/kg (0.1 mg/lb) IV, SC, PO SID on day one then 0.1
mg/kg (0.05 mg/lb) IV, SC, PO SID
ii)
Cats – 0.1 mg/kg SC,
PO SID the first day, followed by 0.05 mg/kg SID for 1 to 4 days, then
0.025 mg/kg every 24 to 48 hours
(1)
The injectable Metacam® product is currently labeled
for a one time dose of 0.3 mg/kg (0.14 mg/lb) SC. Oral dosing following this
injectable dose is not recommended
(2)
For accurate dosing it is recommended that a Tb or insulin syringe
without needle be used to draw up the exact drug volume
(3)
Exercise great caution when using NSAIDs long term in cats.
f)
Cost
i)
Moderate |
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Dave Thompson & Bob Stein
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