Arthritis’ drugs glucosamine and chondroitin sulfate might no longer be prescribed as they proved inefficient in slowing the disease according to a study in the journal Arthritis & Rheumatism.

The study involved 572 arthritis patients who were followed for 18 months. They were given either glucosamine and chondroitin or placebos. At the end of the follow-up period, the researchers found that arthritis actually worsened in 24 percent of participants taking the supplements, similar to those taking placebo. More exactly, the supplements did not appear to slow the loss of cartilage.

“We don’t have good evidence that it (glucosamine and chondroitin sulfate combination) slows (disease) progression,” rheumatologist Allen Sawitzke, professor of internal medicine at the University of Utah and author of the study, said.

However, he added that more studies need to be done before labeling these supplements with a “not-working” label because they might prove valuable in future studies.

The study was an extension of the National Institutes of Health-funded Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) in which researchers followed close 1,600 patients who took one or both of the supplements, the painkiller Celebrex or placebo for six months. The study found no significant change in arthritis patients taking the supplements. Those patients suffered the same pain as patients given Celebrex or placebo.

Whether or not supplements sales would suffer loss following this study’s findings remains to be seen. According to the Nutrition Business Journal, the combination glucosamine chondroitin is the sixth-top-selling dietary supplement in the US with annual sales of $831 million in 2007.