Sodium phenylacetate plus benzoate 10%/10% intravenous (IV) injection (Ammonul) has been approved for adjunctive use in the treatment of acute hyperammonemia and associated encephalopathy in patients with urea cycle disorder (UCD). Ammonul is intended to be used as a rescue medication when a patient with UCD progresses into a hyperammonemic crisis.

Ammonul is a product of Ucyclyd Pharma, a subsidiary of Medicis Pharmaceutical Corporation.

Sodium phenylacetate plus benzoate injection works by scavenging ammonia from the bloodstream, bypassing the patient's defective urea cycle.

Adverse events associated with Ammonul include rare reports of vomiting, hyperglycemia, hypokalemia, convulsions, and mental impairment.