Influence of parecoxib (cox-2 inhibitor) in experimental pleurodesis

Summary Background The intrapleural instillation of a sclerosing agent produces an inflammatory process frequently followed by pain. The treatment can include the use of analgesics or anti-inflammatory drugs. Previously, it was demonstrated (experimental studies) that corticoids and nonsteroidal anti-inflammatory drugs (diclofenac) reduce the inflammation and fibrosis produced by talc but not by transforming growth factor-β or silver nitrate. The objective of this study was to determine whether parecoxib (COX-2 inhibitor) affects pleurodesis induced by talc or silver nitrate. Methods 140 rabbits received intrapleural injection (2mL) of 400mg/kg of talc or 0.5% silver nitrate. A subgroup of 70 animals received additional daily intramuscular parecoxib (1mg/kg). They were sacrificed at 4, 24, 48, 72h or 7, 14, or 28 days after the procedure. The pleural fluid was quantified; biochemical examinations (glucose, lactic dehydrogenase, and proteins) and immunologic dosages (interleukin-8, vascular endothelial growth factor, and transforming growth factor-β 1 ) were analyzed in pleural fluid and blood. Finally, macro- and microscopic pleura and lung studies were performed. Results Evaluation after 28 days demonstrated that parecoxib reduced pleural and pulmonary inflammation but not pleural adhesions. The changes were observed precociously ( ≅ 72 h ) and were more evident after silver nitrate injection. Conclusion Systemic parecoxib injection does not interfere with talc or silver nitrate pleurodesis. These results suggest that use of COX-2 inhibitors can be considered and depending of the results of other studies, recommended in human pleurodesis.