BackgroundPhosphodiesterase-5-inhibitors may lower portal pressure. AimsTo investigate the effect of the phosphodiesterase-5-inhibitor udenafil on hepatic and systemic haemodynamics in liver cirrhosis. MethodsIn an open-label phase-II-study, patients with liver cirrhosis Child A/B and hepatic venous pressure-gradient ≥12mmHg received 12.5mg/day, 25mg/day, 50mg/day, 75mg/day (n=5, each), or 100mg/day (n=10) udenafil p.o. for one week. On days 0 and 6, hepatic venous pressure-gradient was measured prior to and one hour after drug ingestion. Endpoints were reduction of hepatic venous pressure-gradient from day 0 pre to day 6 post intake and reduction in the acute setting. Pharmacokinetics were measured in the two lowest dosage groups. ResultsCombining the 75 and 100mg/day groups hepatic venous pressure-gradient reduction after drug intake was 19.9% (p=0.0006) on day 0. From day 0 pre-dose to day 6 post-dose hepatic venous pressure-gradient decreased by 15.7% (p=0.040) and in 5/15 patients by ≥20% or to <12mmHg. In the 100mg/day group, mean arterial pressure decreased from 98.9mmHg by 6.2mmHg (p=0.037) from day 0 pre-dose to day 6 post-dose. Heart rates or electrocardiograms were unchanged. Udenafil was eliminated with t1/2=25h. ConclusionsOral application of 75–100mg of the phosphodiesterase-5-inhibitor udenafil lowers portal pressure in the acute setting by about 20% without relevant systemic cardiovascular side effects.