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.

Dr. Dave Thompson

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

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

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

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

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

Dave Thompson & Bob Stein