Introduction
Chemical composition
Dosage
Effectiveness
Side Effects
Osteoarthritis is a common disease among the elderly and is often associated with significant disability. Treatment for osteoarthritis includes both non-pharmacological and pharmacological methods. Among the pharmacological methods, glucosamine compounds have attracted much attention, particularly in the lay press.
Glucosamine, a complex amino sugar, is a normal constituent of the glycosaminglycans that are normally found in joint cartilage and synovial fluid. Therefore glucosamine is considered a type of “nutraceuticals” for treating osteoarthritis. The exact mechanism by which glucosamine works on osteoarthritis remains unknown. However, with an excellent safety profile and the claim by the pharmaceutical industry that it may slow down cartilage degeneration, it is one of the most commonly used over-the-counter alternative remedies for osteoarthritis.
As an oral preparation, glucosamine compounds are well absorbed by the small intestine. Once absorbed, it is transported to the liver and metabolised significantly on first pass. A typical dosage of glucosamine salt is 1,500mg per day for adults over 18. No specific maximum dosage recommendation is available in literature. The treatment should be reviewed if the patient has found no benefits after two to three months.
Glucosamine is available in either a sulphate or a hydrochloride form. In the United States, glucosamine has not been evaluated by the Food and Drug Administration (FDA) as a pharmaceutical product and is therefore not approved for medical use. They are classified as a dietary supplement, meaning that strict evidence of safety, purity and efficacy are not required as long as it is not advertised as a form of treatment for a medical condition. On the other hand, in Europe, it is approved as a drug and is sold in the form of glucosamine sulphate. It is subject to the usual quality controls for pharmaceuticals.
The efficacy of glucosamine for osteoarthritic symptoms has been studied in a number of controlled clinical trials. There were specific weaknesses with these studies. Most of the studies were small and the follow-up period was short, with variable methods of administration and dosages. The types and sites of osteoarthritis evaluated were also different.
So far, glucosamine has not been studied in children, pregnant women or lactating women. Therefore, glucosamine compounds are not recommended for these patients. Also, patients with allergy to shellfish should not take such compounds as they may contain trace amounts of shellfish.
Side effects of glucosamine are uncommon and mild; most of the reported adverse effect is gastro-intestinal in nature. Nausea, abdominal pain, indigestion, diarrhoea, constipation, headache, fatigue, flushing, rash, skin itchiness and increase in circulating cholesterol have been reported.
Your orthopaedic surgeon will be able to give you a proper assessment and medical advice on the treatment of osteoarthritis