Portal andsystemic haemodynamic response to acute andchronic administration oflowandhigh

Oralisosorbide-5-mononitrate (Is-5-Mn) wasgivenindosesof10and40mg acutely and chronically (twicedailyforfour weeks), allowing anitrate freeinterval to 25patients withcirrhosis. Both10mg and40mg Is-S-Mnreduced thehepatic venouspressuregradient acutely and chronically, withoutevidence oftolerance.Thiswasachieved byareduction in thewedgedhepatic venouspressure. The effect on mean azygosbloodflowwas variable withnosignificant mean change seenacutely or afterchronicusewith either dose.Thevariability was dependentnotonthedoseusedbutontheinitial azygosflow; theflowinpatients with initially lowvaluesincreased andthose withhighazygosflowsdecreased after nitrate challenge. Thedevelopment ofthe porto-collateral flowseemsanimportant parameterinpredicting haemodynamic response toIs-S-Mn. (Gut1995; 36:104-109)