Nitroflurbiprofen is a cyclooxygenase (COX) inhibitor with nitric oxide (NO)-donating properties, modulates the increased intrahepatic vascular tone in portal hypertensive cirrhotic rats. IC50 & Target: cyclooxygenase (COX)^[1] In Vivo: In vivo hemodynamic measurements (n = 8/condition) and evaluation of the increased intrahepatic resistance by in situ perfusion (n=5/condition) are performed in rats with thioacetamide-induced cirrhosis that receive either Nitroflurbiprofen (45 mg/kg), Flurbiprofen (30 mg/kg, equimolar concentration to Nitroflurbiprofen), or vehicle by intraperitoneal injection 24 hours and 1 hour prior to the measurements. Treatment with Nitroflurbiprofen, an NO-releasing cyclooxygenase inhibitor, improves portal hypertension without major adverse effects in thioacetamide-induced cirrhotic rats by attenuating intrahepatic vascular resistance, endothelial dysfunction, and hepatic hyperreactivity to vasoconstrictors^[1].