Your veterinarian may have a suggestion for treating your arthritis! A new therapy for Osteoarthritis, glucosamine, has been used by vets for more than a decade to treat arthritic dogs and horses! The main advantage of glucosamine is that it appears to do more than just treat arthritic symptoms; it seems to address the underlying causes, with minimal side effects.

What is Osteoarthritis?

Osteoarthritis affects over 16 million people in North America. It is a chronic, progressive condition characterized by pain, inflammation, and loss of mobility. Its incidence increases with age, occurs primarily in weight-bearing joints and is closely linked to the constant wear-and-tear associated with certain occupations, sports or injuries. Over time, the cartilage, a shock-absorbing cushion, weakens and breaks down. The protein content drops while the water content increases, which softens and thins the cartilage until bone scrapes on bone, causing pain and even spur formation.

What is Glucosamine?

Glucosamine is a combination of a sugar and an amino group that is normally manufactured by the body. It is metabolized to glycosamine molecules, which are linked together to form glycosaminoglycan (GAG). Long chains of GAG are found in many of the body's tissues, including tendons, ligaments, cartilage, synovial fluid and the mucous membranes of the respiratory and gastrointestinal tracts.

Cartilage consists of a protein "backbone" with GAGs that together form the sponge-like, protective sheath for bones. As we age, our bodies produce less glucosamine, and with less of these building blocks available to make GAG, our joints are less able to regenerate damaged cartilage.

Glucosamine is tasteless, water-soluble and stable. It is a small enough molecule to be easily absorbed from the intestines and can be found in the bloodstream for several hours after ingestion. The most common form is glucosamine sulfate, but it can also be found as N-acetyl-glucosamine. Both forms are synthetic, and there is no advantage of one over the other (though rumours incorrectly persist that the sulfate form presents a problem for people with sulfa allergies).

Treating Osteoarthritis

Many therapies for Osteoarthritis treat the disease as "irreversible" or "incurable"; their goal is to decrease discomfort and manage the symptoms. The most widely used drugs are Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as A.S.A., ibuprofen, naproxen, and diclofenac. NSAIDs give almost immediate relief from the symptoms of Osteoarthritis, but patients tend to build up a tolerance to the medication in as little as 8 weeks of treatment. On the other hand, glucosamine is slower to produce a response, but the symptoms continually improve, so that by 4-6 weeks it actually exhibits greater effectiveness than the NSAIDs. In addition, its effects can persist even after discontinuation. One study demonstrated 6-12 weeks of extended response after only two months of therapy.

How does glucosamine work? There are two theories:

1. It provides the necessary building blocks to maintain healthy joint cartilage, or
2. It acts as an anti-inflammatory agent (similar to the NSAIDs).

Most literature seems to support the first theory. One study analyzed the cartilage of a patient taking glucosamine and found that the tissue appeared to be regenerating. Other studies have also shown promising results and in fact, the World Health Organization recently called for a long-term study into glucosamine's effectiveness and side effects.

Dosage

The usual recommended dose of Glucosamine Sulfate is 500mg three times daily. There are virtually no side-effects and no known contraindications or interactions; however, since the long-term effects are still uncertain, it is recommended that glucosamine be taken cyclically, e.g. three months on, and one month off. (Remember, the benefits of glucosamine appear to persist, so there should be little concern for the return of symptoms during the month off.)

Attempts have been made to produce more rapid results by giving glucosamine injections (intramuscularly or directly into the joint), but the improvements are minimal relative to the discomfort and risks associated with shots. Therefore, it is suggested that patients combine their anti-inflammatory medication with the glucosamine for the first 4-6 weeks, and then taper off as the full effects of glucosamine are established. Glucosamine can be safely combined with any of the osteoarthritis medications or herbal products like Devil's Claw.

The promising results from glucosamine studies suggest there may be help for Osteoarthritis sufferers! But glucosamine can't do the job alone: there are other valuable non-drug measures such as weight control, exercise and physical/occupational therapy that can help reduce the discomfort of Osteoarthritis. Talk to your doctor or pharmacist to find out whether glucosamine is the right solution for your osteoarthritis.

Compiled by Tracie & William Der
Island Apothecary, Gabriola Island, B.C.
Edited by Megan Stiles
Last Reviewed: September 2001