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Osteoarthritis afflicts 20.7 million Americans, most over the age of 45. They spend millions of dollars on prescription and over-the-counter medications and supplements to treat it. Glucosamine is a popular nonprescription supplement some patients use to improve functional ability, often in combination with chondroitin (see "What are glucosamine and chondroitin?"). Recent research indicates that people who use glucosamine may experience less joint space narrowing and pain-which is often associated with disease progression-but more research is needed about this supplement's benefits.


Common trade names: Arth-X Plus, Bioflex, Enhanced Glucosamine Sulfate, Flexi-Factors, Glucosamine Complex, Glucosamine Mega, Joint Factors, Nutri-Joint, Ultra Maximum Strength Glucosamine Sulfate


Daily dosage, based on patient weight (note that many products combine glucosamine and chondroitin):


- below 120 lb (54 kg): 1000 mg


- between 120 and 200 lb (54 and 91 kg): 1500 mg


- over 200 lb (91 kg): 2000 mg



Adverse reactions:


Central nervous system: drowsiness, headache


Gastrointestinal: abdominal pain, constipation, diarrhea, epigastric discomfort, heartburn, nausea


Skin: rash




Interactions: none reported


Contraindications and precautions: Avoid giving glucosamine to patients who are hypersensitive to it or any of its components, pregnant or breast-feeding women, or children. Use products that combine glucosamine and chondroitin cautiously because chondroitin is chemically similar to heparin and may increase the patient's risk of bleeding, alone or in combination with anticoagulants.


Special considerations:


* Advise the patient to tell his primary care provider that he's taking glucosamine.


* Teach a patient with diabetes who's taking glucosamine long-term to monitor his blood glucose levels closely for elevation. (Using it for a short time won't affect insulin resistance, according to research.)


* Tell the patient that further research is underway for determining the efficacy and safety of glucosamine.



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*Bold italic type indicates a potentially life-threatening reaction. [Context Link]