ABSTRACT
OBJECTIVE: To evaluate the effects of piroxicam patch(Trast) in rheumatoid arthritis patients with knee joint pain and swelling and to determine the concentration of plasma and synovial fluid following patch application. METHODS: Twenty-two patients with rheumatoid arthritis participated in a double-blind, placebo-controlled study. The patients were instructed to apply piroxicam or placebo patch at one knee and re-apply it every other day for 2 weeks. They had washout period for 2 weeks and then applied the other patch for 2 weeks at the same joint. The patients recorded knee joint pain using visual analog scale. Knee joint swelling and tenderness were assessed before and after application of piroxicam and placebo patch. Complete blood count, AST, ALT, BUN, creatinine, joint fluid analysis were also done. Piroxicam concentration in plasma and synovial fluid were measured by high performance liquid chromatography(HPLC) after 2 weeks of piroxicam patch application. RESULTS: Knee joint pain improved significantly after the application of piroxicam patch for 2 weeks(visual analog scale, 56. 2+5. 9m vs 48. 2+5. 7mm, p=0. 03 by Wilcoxon signed rank test). There was no significant change in white cell count of synovial fluid, peripheral blood cell count, chemistry, C-reactive protein and erythrocyte sedimentation rate. In terms of adverse effects, mild gastrointesti nal disturbance(8/21 cases, 38%) and local side effects such as pruritus and ery thema(3/21 cases, 14%) were developed, which were insignificant compared with control groups(30%, 15% respectively). Piroxicam concentrations in plasma and synovial fluid after the application of piroxicam patch were 0. 129+0. 04ug/ ml (mean+SE) and 0. 644+0. 202ug/ml respectively. CONCLUSIONS: Piroxicam patch is a safe and effective therapeutic modality for knee joint pain in patients with rheumatoid arthritis. Mild adverse effects such as gastrointestinal disturbance and local side effects were noted. Piroxicam concentration was higher in synovial fluid than in plasma following the application of piroxicam patch.