Stravitz RT, et al. - The safety, tolerability, and pharmacokinetics of L-ornithine phenylacetate (OPA) were evaluated in patients with acute liver failure (ALF) and acute liver injury (ALI), including those with renal failure. In patients with ALI/ALF, OPA was well-tolerated and no safety signals were identified. At infusion rates of 20g/24h, target phenylacetate (PA) was achieved, leading to ammonia excretion in urine as phenylacetylglutamine (PAGN) in proportion to renal function.