Studies also suggest that an over-the-counter supplement called glucosamine sulfate is safe and may help people with osteoarthritis in the knees. A study published in 2001 described improvement over three years for patients taking 1,500 milligrams of glucosamine a day compared with a placebo (an inactive pill). A newer study in 2006 found that glucosamine seems to work better when combined with chondroitin for moderate to severe osteoarthritis. However, there is no compelling evidence that joint deterioration can be slowed or stopped by treatment with glucosamine. The issue continues to be studied. Over-the-counter creams containing capsaicin applied to the skin over painful joints also may help.
The most commonly reported side effects were: oral thrush , nausea , headache , and pain in the pharynx or larynx . More rarely reported side effects (occurring in <1% of patients during the clinical trial) include: tachycardia , palpitations , dry mouth , allergic reaction ( bronchospasm , dermatitis , hives ), pharyngitis , muscle spasms , tremor , dizziness , insomnia , nervousness , and hypertension . Patients experiencing an allergic reaction or increase in difficulty breathing while using this medication should immediately discontinue its use and contact their physician.