Methods: We divided 42 female Wistar albino rats (aged three months; average weight 275±25 g) into three major groups of 14. Each major group was further divided into two subgroups of seven rats to be sacrificed at seven days for early changes and 21 days for late changes. We performed autologous blood pleurodesis in all rats at a dose of 3 mL/kg. Group C (control group) was administered saline, group P was administered paracetamol, and group D was administered diclofenac for the postoperative five consecutive days as a single dose intraperitoneally. We sacrificed the rats at the designated dates and removed the thoracic cages en bloc.

Results: According to macroscopical and microscopical evaluation of the specimens, paracetamol led to a similar degree of adhesions with saline, whereas diclofenac significantly reduced the intensity of the desired adhesions between the two pleural sheets (p=0.05).

Conclusion: Using anti-inflammatory analgesics following autologous blood pleurodesis may lead to unsuccessful outcome of the procedure.