The main objective is to evaluate the effectiveness of the experimental drug to reduce plasma
ammonia concentration at a dose that is safe and well tolerated. Ammonia usually rises
significantly in the hours after gastrointestinal bleeding in patients with cirrhosis of the
liver. This increase in the concentration of ammonia facilitates the development of hepatic
The study will be divided in two parts:
Part A: Open-label, dose-escalating, single cohort study. The goal of this phase is to
confirm the tolerance and safety of the dose of OP that is being proposed for the study
according to the results of phase I and phase II studies in healthy subjects and stable
outpatients with cirrhosis.
Part B: Multi-center (2 University Hospitals), double-blind, randomized, parallel-group
trial. Assignment of treatment will be done according to a list (one at each study site) of
random numbers in blocks that will be concealed until the end of the study. The control group
will be assigned to placebo on a 1:1 ratio. The placebo and treatment will be masked.