Arthritis: Medications for Degenerative Arthritis

 Degenerative joint disease is the number one cause of chronic pain in the dog and cat. The condition itself is the result of long term stresses and instability of a joint either as a result of old injury or of natural development of the joint in that individual. While surgery may be able to help in some situations, most of the time the degeneration of the joint cannot be reversed and treatment focuses on preventing progression of damage. Numerous products are available on the market; some are best combined with others and some cannot be combined. The following is a summary of options:

ASPIRIN

Aspirin is a non-steroidal anti-inflammatory drug or NSAID. It is effective in relieving pain due to inflammation as is occurring within the arthritic joint. It has the advantage of being readily available and inexpensive. It also has a relatively fast onset of action (other medications require at least one month of use to build up adequate levels in the joint). In some animals, however, it is simply not strong enough or it causes unpleasant side effects such as upset stomach or even intestinal bleeding. Aspirin also deactivates platelets (the blood cell responsible for clotting) and thus can promote bleeding should surgery or trauma occur.

* Cats metabolize aspirin extremely slowly and require a very low dose and a typical dosing schedule of twice a week usage. Dogs can use aspirin up to three times daily. * Because this medication is available in almost every pet-owning household, there may be a temptation to guess a dose based on the human dose. Do not be tempted to do this. Do not use aspirin or any other medication in your pet without veterinary guidance. * Enteric coating of aspirin has become popular in human products. This coating is a problem in animals and creates unpredictable absorption. This becomes dangerous when enteric coated aspirin tablets do not digest in the stomach and instead collect in the stomach until a toxic dose is reached. To avoid this disaster, use either aspirin made specifically for pets or aspirin with a powdery covering rather than the "hard candy" type enteric coating.

RIMADYL AND ETOGESIC

These medications are also NSAIDs. They were developed as an improvement upon aspirin and other NSAIDs developed for humans for which side effects have been problematic in animals. Rimadyl and Etogesic are both designed for indefinite use in dogs with minimal side effect potential. Rimadyl is given twice daily and Etogesic is given once daily.

Typically a short trial of one of these is prescribed to see if the effect is worth continuing; as with people, some individuals respond better to different NSAIDs. If the effect is good, then the medication can be continued. Some blood testing is recommended prior to long term use and every 6 months thereafter.

* Approximately one dog in 5000 will have a serious liver reaction to Rimadyl. Animals with histories of elevated liver enzymes, pre-existing liver disease, Cushing's disease, or phenobarbital use should probably not take this medication. * Neither of these medications should be used in cats.

GLUCOSAMINE AND CHONDROITIN SULFATE

These products are cartilage components harvested chiefly from sea mollusks (i.e., cartilage is made up of glucosamine and chondroitin sulfate). By taking these components orally, the patient is able to have plenty of the necessary building blocks needed to repair damaged cartilage. It is also felt that these products may have some anti-inflammatory properties separate from their structural uses. Unlike NSAIDs, these products do not produce rapid results; one to two months are needed for them to build up to adequate amounts. There are numerous products available combining glucosamine, chondroitin sulfate, assorted vitamins, creatine (a muscle building block), omega 3 fatty acids, and more.

* Because these substances are classified by the FDA as nutriceuticals (i.e., nutrients with medicinal properties) rather than as drugs. The usual rigorous testing for efficacy has not been required. As a result, the optimal dosage has not been determined and almost every product has a different dose recommendation. Some experimentation may be necessary. * These products are not likely to be helpful for spinal arthritis as the joint composition of an intervertebral disc (the joint of the spine) is totally different from those of other bones. * These products can be used in both dogs and cats. * These products often complement treatment with NSAIDs.

ADEQUAN® INJECTIONS Adequan

Adequan® is a polysulfated glycosaminoglycan, which is also a cartilage component but instead of coming from sea mollusks, adequan is derived from the windpipe cartilage of cattle. Adequan has numerous beneficial effects for the arthritis patient including the inhibition of harmful enzymes involving joint cartilage destruction, stimulation of cartilage repair, and increasing joint lubrication.

* Adequan is given as an injection and so is able to reach all joints but it seems to have a special affinity for damaged joints. * Adequan should be avoided in patients with blood clotting abnormalities as a matter of caution. (At excessive doses tested in normal patients, abnormal clotting resulted so it is best not to take a chance in an abnormal patient.) * Adequan is best given as a series of injections, twice a week or so until a response is seen but not exceeding eight injections. After an effect is seen, Adequan injections are given on an as needed basis. * Adequan is formally approved for use in dogs and horses but may also be used in cats with good results. * Adequan may be combined with NSAIDs and with glucosamine and chondroitin sulfate.

OMEGA 3 FATTY ACIDS

Certain fats have been found to have anti-inflammatory properties. While this finding has primarily been utilized in the treatment of itchy skin, many arthritic dogs and cats have also benefited from supplementation. While there are no toxic issues to be concerned with, these products require at least one month to build up to adequate amounts. Effects are not usually dramatic but can be helpful.

* Omega 3 fatty acids can be used in dogs and cats. * Omega 3 fatty acids can be combined with any of the above treatments.

MSM MSM 250

MSM stands for methyl sulfonyl methane and represents another nutriceutical anti-inflammatory agent. MSM is present in most plant and animal tissues and is a natural source of sulfur; however, for commercial sale MSM is derived from DMSO (dimethylsulfoxide), a solvent that comes in both medical grade or industrial grade. Because it is a nutriceutical and thus not required by the FDA to be subjected to tests of safety or efficacy, its effectiveness is still up in the air. There is a tremendous human market for this product, thus little motivation for manufacturers to finance expensive testing of this nature.

* MSM can be used in dogs and cats. * MSM can be combined with any of the above products.

SUPEROXIDE DISMUTASE (SOD) Comfort Tabs

The usual veterinary product for SOD is called Comfort Tabs. (There is also an injectable product called palosein.) This product is what is called an anti-oxidant, or free radical scavenger. Free radicals are molecule fragments that are unstable due to the presence of an electron that should be matched with electron as a pair. The free radical will attract electrons from other molecules thus creating biochemical chain reactions as free radical molecules steal electrons from one another. This transfer of electrons, called oxidation, is very damaging to cells and can increase the risk of cancer. The inflammatory activity in an arthritic joint is one of many sources of free radicals in the body. The body has natural anti-oxidants to curtail free radical activity but there is a great deal of thought that taking these agents as medication could be helpful in an assortment of situations (from slowing the aging process to the prevention of cancer). While proof is somewhat lacking, SOD does not appear to be harmful and should be able to combine with any of the other products listed above.

PREDNISONE AND OTHER STEROIDS

Predisone This discussion would not be complete without mention of the steroid class of drugs. These agents are strong anti-inflammatory agents but with chronic use, can lead to suppression of the immune system, excessive weight gain, and impaired cartilage healing. These are considered a last resort in most cases. See more information on prednisone.

Proper exercise is excellent physical therapy for the arthritic pet as it is crucial to maintain as much muscle mass as possible to support the abnormal joint. Massage and gentle flexion/extension of the joint may also help. Remember, treatment for joint disease is likely to involve a combination of medications in addition to physical activities.

The above is general veterinary information. Do not begin any course of treatment without consulting your regular veterinarian. All animals should be examined at least once every 12 months.

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Linda Mar Veterinary Hospital and its cat-only affiliate, Coastal Cat Clinic, are small animal practices located in Pacifica, California. To find a veterinarian or to learn more about the vet clinic and our staff, visit:[http://lindamarvet.com/]

 Wendy C. Brooks, DVM, DipABVP