Carglumic Acid (Ureidoglutaric acid) is an orphan drug used to treat hyperammonemia in patients with N-acetyl glutamate synthase absence. This rare hereditary disease results in elevated blood levels of ammonia, which can eventually cross the blood-brain barrier and lead to neurologic problems, coma, cerebral edema, and death. Carglumic acid was approved by the U.S. FDA on 18 March 2010.