Rimadyl, Metacam, Deramaxx, and Previcox are commonly prescribed drugs in veterinary medicine. They and related compounds (including aspirin) belong to a class of medicines called non-steroidal anti-inflammatory drugs, or NSAIDs.
NSAIDs have given new leases on life to countless pets suffering from arthritis or chronic pain. They also help to alleviate pain from surgery and trauma. They decrease inflammation and may speed healing in many syndromes. They have relieved a tremendous amount of animal suffering.
Sadly, NSAIDs are not perfect medications. Adverse effects (also known as side effects) can occur when any NSAID is used. The most common adverse effects are gastrointestinal upset, liver damage, kidney damage, and issues with blood cells. In rare instances, adverse effects from NSAIDs can lead to death. It is absolutely tragic when an animal is killed by a medicine that was intended to help it.
Sheilah A. Robertson, BVMS (Hons), PhD, MRCVS, CVA, Diplomate ECVA & ACVA (my goodness, that is the most letters I have ever seen after a person’s name) wrote a very good article in the November, 2008 issue of the NAVC Clinician’s Brief discussing adverse effects from NSAIDs in dogs. Here are some key points.
The number of adverse drug events associated with canine NSAID use reported to the U. S. Food and Drug Administration Center for Veterinary Medicine greatly exceeds that reported for other drugs used in companion animals. However, because so many dogs are prescribed NSAIDs, the actual incidence of untoward side effects would appear to be very low. Pfizer Animal Health has reported that the approximate incidence of adverse drug events is 0.009% in an estimated 1.5 million dogs treated with [Rimadyl.]
Although the percentage is low, there are groups of animals that may be at increased risk.
The most commonly affected group is dogs 10 to 15 years old, followed by 6- to 10-year-old dogs.
Many adverse drug events occur when the drug is used at doses higher than those approved, when another NSAID (including aspirin) . . . [is] used concurrently or in close temporal association, or when concurrent [for instance, liver or kidney] disease is present.
Dr. Robertson goes on to point out that
[h]owever, adverse effects can occur in dogs with no obvious risk factors and when the drug is used correctly.
So, what should veterinarians and people with pets do? In my opinion, it is important for vets to discuss the risks and benefits of the drug in question with the people living with the pets. If the benefits outweigh the risks, Dr. Robertson has several suggestions.
Veterinarians should perform a physical examination and blood tests before prescribing the medication. According to the article, most adverse effects occur within 14 – 30 days of treatment. Therefore, additional diagnostic tests should be performed 2 – 4 weeks after the onset of therapy. For pets on long-term NSAID therapy, tests should be performed every 3 – 6 months, depending on the pet’s age and health status.
People living with pets also should be alert. As Dr. Robertson points out,
[c]lients should be advised to stop administering the NSAID and call the veterinarian if they notice any changes in their pets, such as [lack of appetite], vomiting, diarrhea, lethargy, or bloody feces . . . [t]he key is to catch problems early and err on the side of caution.
NSAIDs have the potential to help millions of pets. But people with pets should make informed decisions about the use of these drugs.