New treatment options using 5-HT3 receptor antagonists in rheumatic diseases.

In vitro studies have shown that a blockade of 5-HT3 receptors brings about a reduction of tumor necrosis factor, IL-1 beta, IL-2, IL-6 as well as a decrease in prostaglandins. Clinical trials have provided evidence of pain reduction in a subgroup of fibromyalgia syndrome and, moreover, have demonstrated that tropisetron injected locally for insertion tendinoses and myofascial syndromes with associated trigger points leads to an alleviation of pain that is comparable to injections with the combination of corticosteroids and local anesthetics. The effects achieved by intra-articular injections in cases of osteoarthritis and rheumatoid arthritis paralleled those exerted by intraarticular injection of corticosteroids. In addition, the positive effects produced by systemically administered tropisetron on scleroderma need to be considered since they suggest that this therapeutic principle can also be applied systemically in immunologic processes.