Double blind cross-over trial comparing fenbufen and acetylsalicylic acid in rheumatoid arthritis.

25 out-patients with active classical or definite adult-onset rheumatoid arthritis were enrolled in a 4-week randomized, two-period double-blind cross-over study comparing gamma-oxo(1,1'-biphenyl)-4-butanoic acid (fenbufen) (1000 mg/d) and acetylsalicylic acid (ASA) (3600 mg/d). Only patients with active, flaring disease, off antiinflammatory drugs, were admitted into this study. Significant mean improvement from baseline was seen with both fenbufen and ASA after two weeks of treatment. There were no statistically significant differences between the degree of improvement from baseline between fenbufen and ASA. However, there were significant differences in patient tolerance of the two medications with more patients reporting adverse experiences with ASA than with fenbufen. The differences between treatments were statistically significant for side effects graded as moderate or severe with 6 patients experiencing drug-related side effects on ASA compared to none on fenbufen.