Issue Fifty-Six – June 2012
standards of
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CLINICAL CASE MANAGEMENT NEWSLETTER
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The Calgary Animal Referral & Emergency Centre Animal Hospital
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standards of
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Issue Fifty-Six – June 2012
NSAID Indications and Contraindications
Danny Joffe, DVM, Diplomate ABVP (Canine/Feline Specialty)
Non-steroidal anti-inflammatory drugs (NSAIDs) are very commonly utilized in
day-to-day small animal practice. NSAIDs are a very useful and very flexible
family of drugs, and can be indicated for the treatment of pain and
inflammation due to varying clinical scenarios. Acute traumatic pain, perioperative pain, and therapy of chronic pain due to osteoarthritis or any other
chronically painful clinical condition are among the most common indications
for using NSAIDs in the clinical setting. Though very commonly used, and a
valuable tool in every practicing veterinarian’s therapeutic armamentarium, the
other side of the coin is that NSAIDs are a common cause of adverse events in
small animal practice. The reason for this is that, as a family, NSAIDs have a
narrow therapeutic index. That is, there is a very thin line between safe
efficacious use and the occurrence of adverse events. Because of this, it is
important to understand the contraindications to using NSAIDs so as to help
minimize the frequency of adverse events.
Contraindications can be divided into absolute contraindications and relative
contraindications. An absolute contraindication would dictate that the drug
cannot be used at all in a patient as the chances of adverse events well
outweigh potential benefits. A relative contraindication would mean that you
would prefer not to use the drug in a certain clinical scenario, but under special
circumstances the benefits may outweigh the risks, so use of the medication can
still be considered.
Absolute contraindications for the use of NSAIDs are concomitant use of another
NSAID, concomitant use of a corticosteroid, uncontrolled hyperadrenocorticism
and gastrointestinal disease. The first two contraindications are very obvious.
Using two NSAIDs in the same patient will greatly enhance the chances of
potentially severe adverse events. The exception to this would be using
acetaminophen at the same time as another NSAID. Acetaminophen is
considered an NSAID, but it does not have the same anti-prostaglandin activity
of other NSAIDS (and therefore is not an anti-inflammatory), so in certain unique
cases (e.g. chronic pain management scenarios) it could be used along with
another NSAID. As corticosteroids inhibit the inflammatory cascade in much the
same way as NSAIDs (albeit at a different “level” of the cascade), use of these
two families of drugs together will greatly magnify the chance of adverse events.
Likewise, as a patient with hyperadrenocorticism is endogenously producing
excess corticosteroids, NSAIDs cannot be used in such patients. Theoretically, if
hyperadrenocorticism is very well controlled (that is, there is no excess of
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standards of
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Issue Fifty-Six – June 2012
endogenous corticosteroids) then NSAIDs could be considered for use, but only
with extreme caution. As prostaglandins are essential for upper gastrointestinal
health (through decreasing gastric acidity, increasing gastric mucous
production, and increasing mucosal blood flow) using anti-prostaglandins (i.e.
NSAIDs) in the setting of gastrointestinal disease will commonly lead to
exacerbation. Likewise, and for the same reasons, the use of this family of drugs
for patient’s undergoing surgery of the intestinal tract is also contraindicated.
Relative contraindications would include cases in which, in an “ideal world” you
would not use NSAIDs; but, in certain cases, for specific reasons, their use can be
considered. The most common relative contraindications for NSAIDs would be
renal or hepatic disease. NSAIDs as a family can lead to hepatotoxicity or, in
specific scenarios, renal compromise. Though it would be ideal to not use an
NSAID in a patient with elevated hepatic enzymes, there are always exceptions
where NSAIDs are needed in such a patient to maintain a good quality of life. In
such cases, if a bile acid panel is performed documenting normal hepatic
function, then NSAIDs could carefully be considered for use after an informed
discussion with the owner as to the risks, and with enhanced monitoring during
therapy. Other issues to be aware of with regards to hepatic enzymes would be
in cases in which alkaline phosphatase levels are disproportionally elevated as
compared to ALT, it would be critical in such a case to rule out
hyperadrenocorticism. It would also be important in cases with high levels of
alkaline phosphatase to ensure that a more “sinister” cause for the patient’s pain
is not present. Increased alkaline phosphatase levels can occur in patients with
osteosarcoma, so if radiographs have not been performed previously to assess a
cause of the patient’s discomfort, they would be indicated. NSAIDs can lead to
nephrotoxicity in times of renal hypotension. This is most common due to
hypotension during anesthesia or in dehydrated patients. During these times of
“renal distress” the kidneys rely on prostaglandins to help maintain renal blood
flow. Giving NSAIDs to a patient whose kidneys are reliant on prostaglandins
may lead to a sudden decrease in renal blood flow and nephron loss. In wellcompensated chronic renal failure, the kidneys are not reliant on prostaglandins
for blood flow, so NSAIDs could theoretically be used safely if deemed necessary.
Of course these patients are very prone to dehydration at which point the
kidneys would become more sensitive to NSAIDs, so use in such a patient again
requires informed consent of the owner and careful monitoring.
As practitioners we are very lucky to have several licensed NSAIDs that are all
extremely efficacious. These drugs can also be used very safely despite their
narrow therapeutic index as long as we are cognizant of the various
contraindications to their use. As a family, NSAIDs also serve as a great example
of why we should choose to use a licensed veterinary product as opposed to an
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Issue Fifty-Six – June 2012
extra-label human product Liability is greatly minimized if we use a licensed
product as per the label; whereas if one chooses to use an extra-label product
there is increased liability. There are many examples of human meloxicam
leading to many more, and much more serious, adverse events than are
typically seen with appropriate use of the licensed veterinary form of the same
molecule. Used properly NSAIDs are a very valuable family of drugs; vigilance
as far as appropriate use is critical though to try and ensure safe use.
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