Glucosamine is a chemical found in the fluid surrounding joints. A dietary supplement that is made from natural sources such as shellfish shells or made in laboratory may help treat conditions such as joint pain associated with osteoarthritis, according to MedlinePlus. Glucosamine tablets may help increase the amount of fluid and cartilage in an affected joint. In addition to the desired effects of glucosamine, the supplement may cause adverse reactions. If you take glucosamine, report any severe or bothersome side effects to a physician.
Gastrointestinal Distress
Possible side effects of glucosamine tablets include mild gastrointestinal distress. You may experience heartburn, constipation, diarrhea and nausea. With the continued use of glucosamine, the side effects may decrease or disappear. Rarer possible adverse reactions to glucosamine include abdominal pain, vomiting, flatulence and a loss of appetite, according to MayoClinic.com.
Increased Blood Sugar Levels
Glucosamine tablets may cause an increase in blood sugar levels in individuals with diabetes but will probably not cause a significant change, according to RxList.com. The risk of increased blood sugar levels occur more often with an injectable form of glucosamine, not from the tablets. Close monitoring of your blood sugar levels when using glucosamine will help determine any changes in your blood sugar levels.
Rarer Effects
Rarer side effects of glucosamine tablets include symptoms such as a headache, drowsiness and reddened skin rashes. Glucosamine tablets may cause an increased risk of bleeding if you have a blood clotting disorder. Taking glucosamine along with medications that thin the blood, such as warfarin, may further increase the possibility of bleeding and bruising. Adjusting the dosage may become necessary to prevent the risk of bleeding. Talk to your doctor about possible interactions before you start taking glucosamine supplements.
Allergic Reaction
Some individuals may have an allergic reaction to glucosamine tablets. Tablets made from natural sources, such as the shells of lobster, shrimp and crabs, may cause an allergic reaction in people with a shellfish allergy. Symptoms of an allergic reaction that you might experience include difficulty breathing, increased heart rate, swelling of the airway and hives. These symptoms signify an emergency and require immediate medical attention to prevent complications such as death.



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