Non-Steroidal Anti-Inflammatory Medications (NSAIDS) for Pets
by Shawn Messonnier, DVM
Holistic Veterinarian and Director of Paws & Claws Animal Hospital
Article used with permission.
Dr. Shawn Messonnier is the author of The Arthritis Solution for Dogs, The Allergy Solution for Dogs, the award-winning The Natural Health Bible for Dogs & Cats and 8 Weeks to a Healthy Dog (Rodale.) Check out Dr. Shawn’s Holistic Pet column each week in your local newspaper, distributed by Knight Ridder News Service.
Non-steroidal medications are another group of medications commonly prescribed for arthritic dogs. There are a number of these products, including aspirin, ibuprofen, naproxen, phenylbutazone, piroxicam, carprofen (RimadylR,) Etodolac (EctoGesicR,) and acetominophen (TyelenolR).
Note: acetominphen is not technically a non-steroidal medication even though it is often and incorrectly prescribed for this purpose; acetominophen has no anti-inflammatory properties.
Since dogs have shown greater toxicity (usually increased GI side effects) with most of the human NSAID medications, it is questionable if they should be used in dogs for any reason. As a result of this increased sensitivity towards NSAID side effects, the pharmaceutical companies are developing products which are safer for our canine patients.
Like corticosteroids, the NSAIDS work by inhibiting the chemicals (prostaglandins) that cause pain and inflammation. While they can be very useful in controlling pain and inflammation, like corticosteroids they too have side effects, some more serious and dangerous than others (see below.)
Non-steroidal medications work in something called the COX pathway. COX stands for cyclooxygenase, which is another enzyme in the pathway that break down the arachidonic acid in the cell membranes of the joint into chemicals such as free radicals and various prostaglandins that damage the articular cartilage.
There are 2 COX enzymes that have been discovered to date: COX-1 and COX-2. COX- 1 is found in various tissues such as the stomach, intestines, and kidneys and serves an important role in maintaining health. When arachidonic acid is broken down by COX-1, good, anti-inflammatory prostaglandins are produced. These prostaglandins keep the kidneys functioning normally and help protect the stomach and intestinal tract against ulcers.
When arachidonic acid is broken down by COX-2, bad, pro-inflammatory prostaglandins are produced. These prostaglandins (and other chemicals) are harmful and contribute to the side effects seen in some patients taking NSAID medications, such as GI ulcers and kidney disease. Drugs that selectively inhibit COX-2 but not COX-1 are most likely to result in fewer side effects and be safer for our patients. Right now the move is on in human medicine to find NSAIDS that inhibit COX-2 but not COX-1; hopefully our veterinary patients will benefit from this research as well.
Current NSAID medications available for veterinary patients inhibit both COX-1 and COX-2 to various degrees. Indomethacin and piroxicam have high COX-2/COX-1 ratios, and result in high incidences of GI problems (bleeding, ulcers). Naproxen, ibuprofen, carprofen (Rimadyl) and etodolac (EctoGesic) have lower COX-2/COX-1 ratios, and as a result have fewer incidences of GI problems. Aspirin has a higher ratio but an intermediate incidence of GI problems, indicating that other mechanisms are involved in causing some of the side effects we may see in patients taking NSAIDS.
As mentioned, the NSAIDS have the potential to produce a number of undesirable and potentially fatal side effects. One side effect is gastrointestinal bleeding that occurs because of prostaglandin inhibition. Other side effects include kidney disease (also due to prostaglandin inhibition,) liver disease (mild cases display elevated liver enzymes whereas more serious cases can show liver failure,) immune diseases (anemia, low platelet count, skin diseases,) neurologic signs (seizures, paralysis, unsteadiness,) behavioral problems (hyperactivity, aggression, depression, or sedation,) drug interactions (NSAIDS should not usually be used when corticosteroids are used as the potential for side effects increases,) and even death. Finally, and perhaps most importantly, as with steroids, many of the non-steroidal medications destroy cartilage, although the popular NSAIDS Rimadyl and EctoGesic appear to cause less cartilage destruction than other NSAIDS.
Can NSAIDS be safely used in the treatment of arthritis? I believe NSAIDS can be safely and effectively used short-term (5-7 days) in pets not taking any other medications and in pets without other diseases. This means a careful history, examination, and laboratory testing will be needed in most pets. For long-term use (which is rarely necessary as most pets do very well on complementary therapies as discussed in Part III,) I only use NSAIDS if ALL OTHER TREATMENTS HAVE FAILED, AND IF THE OWNER HAS BEEN WARNED OF POTENTIAL SIDE EFFECTS. These patients are frequently (every 2-3 months) monitored for side effects, and GI protective medications (see below) may be used to decrease GI side effects. In effect, we try to make the patient comfortable and have a good quality of life at the risk of causing side effects and even death in that pet.
As I mention in The Arthritis Solution for Dogs (Prima Publishing) “Blanket therapy with anti-inflammatory drugs is a poor substitute for a well-designed program of management.”
Complementary Therapies for Pets with Arthritis
While conventional therapies can be useful for short-term pain relief in pets with arthritis, most dogs and cats will improve significantly when treated with complementary therapies. This final article will provide a brief overview of the most popular complementary therapies available for treating arthritis.
Homeopathy uses diluted substances to help the body heal itself. Individual remedies are selected based upon a careful history and physical examination of the arthritic pet. Several remedies can be combined in solutions such as those made by HomeoPet that are available for short-term use of mild lameness. Common individual remedies include: Caulophyllum, Lithium Carb., Rhus Tox., Bryonia, Hecla Lava, and Actaea Rac.
Traditional acupuncture involves the placement of tiny needles into various parts of a pet’s body. These needles stimulate acupuncture points which can effect a resolution of the clinical signs. Other forms of acupuncture involve laser therapy, aquapuncture (tiny amounts of vitamins are injected at the acupuncture site for a more prolonged effect,) and electroacupuncture (a small amount of non-painful electricity stimulates the acupuncture site for a more intense effect.)
As a rule, results from acupuncture compares quite favorably with traditional therapies. Side effects from acupuncture are rare. Accidental puncture of a vital organ can occur. Infection can occur at the site of needle insertion. Occasionally, the needle can break and surgery may be needed to remove it. Some pets require sedation in order to allow insertion of the acupuncture needles. In some animals, signs may worsen for a few days before they improve.
Many owners worry that acupuncture is painful and that their pets will suffer. Usually acupuncture is not painful. Occasionally, the animal will experience some sensation as the needle passes through the skin. Once in place, most animals will relax and some may become sleepy. Fractious animals may require mild sedation for treatment.
The number of acupuncture treatments that a pet will require varies from pet to pet. Usually, we try at least 8 treatments (2-3/wk) to assess if acupuncture will work. On average, treatments last about 15-30 minutes for needle acupuncture, and 5-10 minutes for aquapuncture or electroacupuncture. If the pet improves, acupuncture is done “as needed” to control the pet’s signs.
In recent years, therapy using magnets has gained a following among some doctors and pet owners. It is seen as a safe a simple method of treating various disorders, often producing positive results without side effects or much expense.
Doctors theorize that magnets work by means of magnetic lines of force; units called gauss measure the strength of the magnetic field. The higher the gauss number the stronger the magnet (a 1000 gauss magnet is stronger than a 100 gauss magnet.) Magnets are used either as permanent magnets, also called static magnets, or as pulsed electromagnetic field magnets (PEMF). Static magnets come in bars, beads, or strips. PEMF uses pulsing current flow through a wire coil to create a magnetic field around the wire: the greater the amount of current flow, and the greater the number of turns of the wire, the greater the magnetic field that forms. In people PEMF is approved for treating nonunion fractures (fractures that have failed to heal) by the FDA. Other uses include avascular necrosis of the hip, osteoarthritis, and rotator cuff injuries. No toxic effects have been reported using magnetic therapy.
In our Western view of healing, magnets appear to heal the body by removing inflammation and restoring circulation. By increasing blood flow to a diseased site, increased nutrients are available for healing. In the Eastern view of healing, magnets help restore the energy flow of the body to allow healing and proper metabolism. This is similar to one of the theories used to explain the positive effects of acupuncture as well.
While usually safe, magnets should not be used in acute infectious conditions, on cancerous growths (although some doctors do find them useful in treating cancerous tumors), in acute injuries, pregnant animals, or in dogs with cardiac pacemakers.