Carglumic acid

How it works

It is a structural analogue of N-acetylglutamate that activates carbamoyl phosphate synthetase 1, the first enzyme of the urea cycle, restoring ammonia detoxification and lowering plasma ammonia.

Prescribing in practice

• Acute hyperammonaemia is a medical emergency requiring prompt treatment and specialist metabolic input, with carglumic acid used alongside measures to control plasma ammonia rather than in isolation.
• It is given orally (dispersed in water), often divided across the day and titrated to the plasma ammonia response.
• Treatment should be initiated and supervised under the guidance of a physician experienced in the management of inherited metabolic disorders.

Monitoring

Monitor plasma ammonia and the patient's clinical and neurological status to guide dosing, with additional metabolic monitoring as directed by the specialist team.

Counselling the patient

• Disperse the dose in water and take it as instructed, immediately before feeds or meals where advised.
• Continue any prescribed protein-restricted diet and supportive treatment.
• Seek urgent medical help if vomiting, drowsiness or behavioural change occurs, as these may signal rising ammonia.

Evidence & guidelines

Its use is supported by clinical experience and studies in N-acetylglutamate synthase deficiency and related causes of hyperammonaemia.