Long-term treatment with sodium phenylbutyrate in ornithine transcarbamylase-deficient patients

Ornithine transcarbamylase deficiency is a very heterogeneous urea cycle di sorder resulting in hyperammonemia with various presentations from the neon atal period through adulthood. We performed a retrospective study in nine p atients (four male/five female, age at diagnosis ranging from 6 days to 14 years) to evaluate the safety and efficacy of sodium phenylbutyrate (Ammona ps) in long-term treatment. Ah patients were diagnosed by DNA mutational an alysis and/or liver enzyme measurement. They had previously been treated wi th sodium benzoate (median dose 248 mg/kg/day; range 106-275) and low prote in diet (median 0.84 g/kg/day) and were switched to sodium phenylbutyrate ( median dose of 352 mg/kg/day) at 8.9 and 4.9 years of age (median) in males and females, respectively. We analyzed clinical and biochemical data and t he median follow-up duration was 26 months. During that time, there were no hyperammonemic episodes requiring hospitalization. Median plasma ammonia a nd glutamine levels were 30 and 902 mu mol/L, respectively. Total protein i ntake could be increased to 0.95 g/kg/day after 18 months. No side effects related to therapy were observed, Further prospective studies should be per formed to define the optimal dosage of sodium phenylbutyrate and the requir ements for protein diet at different ages. (C) 2001 Academic Press.