Glucosamine is an amino sugar typically classified as a dietary supplement that, while not approved by the FDA for medical use, is often used for treating osteoarthritis.1 The compound can be produced synthetically or derived from shellfish and certain vegetables, and is needed by the body to manufacture glycoproteins, glycolipids, and glycosaminoglycans.2 These compounds, in turn, make up many structures in the body, such tendons, ligaments and cartilage, synovial fluid, mucous membranes, various structures found in the eye, blood vessels, and heart valves. The compounds are also a major component of joint cartilage; thus glucosamine may help treat arthritis by helping to rebuild cartilage.
Glucosamine is generally well-tolerated in most patients, with drowsiness, sedation, or insomnia as the most common side effects.5 Some patients may not be suitable candidates for these supplements, however, including those with
Patients who need to restrict potassium intake, are at high risk for cataracts, or who are on medications that increase urine flow should avoid this supplement. Patients who experience an allergic reaction (hives, trouble breathing, swelling of the face, lips, tongue, or throat) or anorexia, back or neck pain, changes in levels of creatine, constipation, coughing, diarrhea, dizziness, dry mouth, ear inflammation, heaviness or pain in the stomach, fluid accumulation, gas, headache, heartburn, increased blood lipids, increased growth rate or toughness of fingernails, indigestion, liver problems, muscle problems, nausea, upper abdominal tenderness, or vomiting should contact their physician immediately. Patients taking glucosamine for extended periods of time, in high doses, or who are taking the supplement via intramuscular injection should monitor their health and blood chemistry regularly.
Patients who are sensitive allergic to glucosamine and its parts, such as shrimp, crab, and other shellfish, or to iodine should not take this drug. Glucosamine should be taken cautiously in pregnant or nursing patients, and in patients who are under 18 years of age. Use of this supplement with methylsulfonylmethane should be avoided in children due to a possible link to autism.
Glucosamine dates back to the 1970s, when it was first used in veterinary medicine.6 Although the supplement has been a part of the human health market since the 1990s, there are many contradicting statements made about the drug. One place to look for quality information about glucosamine is The Cochrane Collaboration, a global, non-profit organization that relies on an independent network of researchers, professionals, patients, caregivers, and people interested in health to produce credible, accessible health information that is free from commercial sponsorship and other conflicts of interest. According to their latest study, glucosamine may provide patients some pain relief and improvement in physical function with low probability of side effects.7 However, placebo medications had almost the same effect as the drug itself.
The National Institutes of Health’s National Center for Complementary and Integrative Health conducted the first large-scale, multicenter clinical trial in the United States to test the effects of the dietary supplements glucosamine and chondroitin chondroitin sulfate for the treatment of knee osteoarthritis.8 Known as the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT), the study looked at whether or not the two supplements, alone or in combination, reduced pain in just over 1,500 patients. The results were mixed. In the overall population, no significant differences were seen in patients taking placebo pills versus glucosamine alone or with chondroitin. However, a subset of participants with moderate-to-severe pain did find that glucosamine combined with chondroitin provided significant pain relief.
The Natural Medicines Comprehensive Database has also found glucosamine to be effective in reducing pain in some patients with osteoarthritis, but not all.9