An estimated 27 million adults in the United States live with osteoarthritis—the most common type of arthritis, according to NIH's National Center for Complementary and Alternative Medicine. Caused by the breakdown of cartilage, people with osteoarthritis suffer from pain, joint damage and limited motion. Many arthritis supplements contain glucosamine and chondroitin, both of which are regulated by the FDA as a food rather than a drug. Glucosamine chondroitin is used to relieve joint pain, improve joint function and lessen inflammation. Most of the side effects associated with its use are considered mild, and although there are allegations suggesting that more serious side effects are possible, there is no firm proof of this.
A 2002 NCCAM study conducted at the University of Utah School of Medicine by Dr. Daniel Clegg studied the effects of glucosamine chondroitin on 1,583 people with documented X-ray evidence of osteoarthritis. Of the 77 reports of serious adverse effects during the course of the study, only three were attributed to treatments given during the study. Most side effects were mild and related to intestinal issues that included an upset stomach. Other but less common side effects were listed in the NCCAM article as well as in a website titled nutritional-supplements-health-guide.com, and included abdominal pain, appetite loss, vomiting, nausea, flatulence or gas. Constipation, diarrhea, or softened stools were also experienced and listed on these sites but are by no means considered common.
Dr. Kate McLIntock, a physician and adviser to the Arthritis Research Campaign in Scotland, spoke with reporter Alan MacDermid about the effects of glucosamine chondroitin in an article titled "Death sparks safety concern over popular pain remedy," which appeared in the "Herald Scotland" on March 4, 2008. She was quoted in the article as stating that no serious adverse reactions are known, and that some experience reversible symptoms that include drowsiness and insomnia. Medline Plus, a website supported by NIH and the National Library of Medicine, concurs that sleep issues like insomnia and drowsiness, although rare, have occurred with people who take glucosamine chondroitin.
Glucosamine is made from the shells of shellfish, and some researchers suggest there is not enough shellfish allergen in glucosamine to prompt an allergic reaction. Nevertheless, conventional wisdom documented on both the MedlinePlus website and the "Herald Scotland" article advise people with shellfish allergies to use it cautiously or avoid it altogether.
According to MedlinePlus, extremely elevated amounts of protein were found in the urine of patients taking glucosamine and chondroitin products. While the site states that "the clinical meaning of this is unclear," it is known that glucosamine is eliminated from the body via urine, and that people with reduced kidney functioning will experience delayed glucosamine elimination. In addition, MedlinePlus makes reference to a patient who took glucosamine and experienced acute interstitial nephritis, a condition where the kidneys swell and stop working properly. Although there are no studies to corroborate the notion that people with impaired kidney functioning should avoid taking glucosamine condroitin, it nevertheless may be a wise choice.