Vioxx, like Celebrex is a selective cyclooxegenese 2 enzyme inhibitor (COX-2). This enzyme manifests itself in inflamation associated with rhumitoid arthritis (sp). Compounds that selectivly inhibit COX-2 are better than non-steroidial anti-inflamatory drugs (NSAIDs) like apirin which also inhibit the COX-1 enzyme which maintains healthy lining of stomach and intestines (thats why things like aspirin lead to upset stomachs and ulcers when used over the long term). There are better choices for muscle relaxers (cheaper ones too).