Easing Arthritic Pain

How a supplement often used on animals is helping humans, too.

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April 10, 2000 (San Francisco) -- For more than 10 years, 72-year-old San Franciscan Ellen Arbenz was dogged by pain every time she climbed a set of stairs. Sometimes just walking across a room made her joints cry out. And though she'd always loved gardening, she had gradually come to enjoy it less and less. Kneeling to yank a weed, pushing a trowel into the dirt, or merely reaching to clip a flower had become too painful.

Arbenz's troubles are all too common: an estimated 20 million Americans suffer from osteoarthritis. Like many others with this ailment, Arbenz has long taken the standard therapy: non-steroidal anti-inflammatory drugs, or NSAIDs. The pills made her joints less achy, but they also upset her stomach.

A year or so ago, she heard of a dietary supplement called glucosamine. Indeed, if you know a lot of people with arthritis, as Arbenz does, it's hard not to hear about this substance. Again and again, fellow sufferers told her that glucosamine -- sometimes taken along with another supplement called chondroitin -- helped them. A book on these pills, The Arthritis Cure, by Jason Theodosakis, MD, was selling like hotcakes.


Six months ago, Arbenz tried glucosamine herself. "I've had very good results," she says. "I no longer take the anti-inflammatories, and the pain is still improving."

Arbenz's rebound would come as no surprise to veterinarians, many of whom have long used glucosamine and chondroitin to treat creaky horses and dogs. "We see it all the time," says Andrew Sams, DVM, a veterinary surgeon at the Madera Pet Hospital in Corte Madera, Calif. "I've had many pet owners start using these supplements for themselves after their dog began to show improvements." But after years of such anecdotal successes with only small-scale foreign studies to back them up, there's been little medical evidence of their effectiveness.

That may be about to change. The National Institutes of Health (NIH) recently allocated $6.6 million for the biggest study ever on these supplements. This eagerly awaited nine-center trial, slated to begin this summer, will assign more than 1,000 osteoarthritis patients to receive either glucosamine alone, chondroitin alone, the two substances together, or a placebo. Monthly evaluations will look at patients' levels of pain and how well they're able to manage everyday chores. Researchers will also compare X-rays of joints taken at the beginning and end of the study to look for structural changes over the four-month period.


"While this study design won't answer how the supplements work," says Daniel O. Clegg, MD, professor of medicine at the University of Utah and the NIH study coordinator, "it will be able to say with some real authority whether or not they work." This kind of clarity is needed. A review in the March 15 Journal of the American Medical Association criticized many of the past studies for possible bias and exaggeration. Even so, author Timothy McAlindon, DM, concludes that the supplements appear helpful.

How might they work? Osteoarthritis results from a breakdown of cartilage, the protective coating around the bones at the joints, Clegg says. Without this smooth and springy substance, the bones scrape against each other, which can cause chronic pain and limit range of motion.

Both glucosamine and chondroitin are synthesized by the body and are naturally found in cartilage. Clegg and other researchers theorize that glucosamine somehow helps create new cartilage, while chondroitin may slow cartilage destruction. Taken together, some experts say, the combination offers a one-two punch against the wear-and-tear of osteoarthritis. NSAIDs, in contrast, primarily mask the symptoms.

Also unlike NSAIDs, glucosamine and chondroitin don't cause symptoms such as stomach upset, nor do they carry the risk of ulcer formation. Although some people have experienced mild gas, the side effects from the supplements are negligible, according to the Arthritis Foundation's position statement. If you're thinking about trying glucosamine and chondroitin, the Foundation advises a few precautions, however. Patients who are taking the blood-thinning medication heparin -- whose molecular structure is similar to chondroitin -- should have their blood clotting activity monitored if they add chondroitin. Taking both at the same time could increase the risk of bleeding. Diabetic patients wanting to try glucosamine (an amino sugar) should consider potential effects on their blood sugar control. If you're allergic to shellfish, avoid taking glucosamine, which is made from crab, lobster, or shrimp shells. (Chondroitin is manufactured from cow cartilage.) And before you rush out to buy either of them, make sure that osteoarthritis is the cause of your pain; glucosamine and chondroitin don't seem to help other forms of the disease, such as rheumatoid arthritis. Of course, it's always a good idea to talk to your doctor first.


And be prepared: the supplements aren't cheap. A month's supply of glucosamine alone (at 1500 milligrams a day, the amount used in most studies) can run from $30 to $60 per month. And you should choose a brand that's been used in a scientific study; researchers at the University of Maryland School of Pharmacy in Baltimore recently tested several brands and found that some didn't contain as much glucosamine and chondroitin as their labels indicated. No matter the brand you purchase, insurance will not typically cover the cost, because these substances are considered to be foods, not drugs.

Arbenz, who is on Medicare, admits that she finds the cost of the supplements frustrating, but she'll continue to take her glucosamine for as long as she needs to. "Sure, I know that they don't really know if it works and all of that science stuff. But it's working for me. And for me that's enough."

To Sign Up for the NIH Study:

To be eligible to participate in the study, you should have both knee pain and X-ray evidence of osteoarthritis. Contact Diana Kucmeroski, study coordinator, at the University of Utah School of Medicine, Rheumatology Division, 50 North Medical Drive, Salt Lake City, UT 84132; or call (801) 585-6468. You will be directed to one of nine study centers (in Wichita, Cleveland, San Diego, San Francisco, Indianapolis, Philadelphia, Omaha, Salt Lake City, or Seattle).

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