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Table 5 Consensus guidelines for drug dosages for acute hyperammonemia and acute decompensations of UCDs

From: Suggested guidelines for the diagnosis and management of urea cycle disorders

Disorder

Sodium benzoate

(to be given IV in 10% glucose)

Sodium PBA/Sodium phenylacetate

(to be given IV in 10% glucose)

L-arginine hydrochloridea

(to be given IV in 10% glucose)

N-carbamylglutamate

(only oral/enteral drug)

Undiagnosed patient b

250mg/kg as a bolus in 90–120 min, then: maintenance 250-500mg/kg/d c (if >20 kg body weight, 5.5 g/m2/d)

250mg/kg as a bolus in 90–120 min, then maintenance: 250-500mg/kg/d c (1.2mmol/kg/d)

250(−400) mg/kg (1-2mmol/kg) as a bolus in 90–120 min, then maintenance 250 mg/kg/d (1.2mmol/kg/d)

100mg/kg bolus per NG tube then 25–62.5mg/kg every 6h

NAGSD

same

–

250 mg/kg (1.2mmol/kg) as a bolus in 90–120 min, then maintenance 250mg/kg/d (1.2mmol/kg/d)

same

CPS1D & OTCD

same

250mg/kg as bolus in 90–120 min, then maintenance: 250(−500) mg/kg/d c

same

–

ASSD

same

same

same

–

ASLD d

same

250mg/kg as bolus in 90–120 min, then maintenance: 250mg/kg/d c

200-400mg/kg (1-2mmol/kg) as bolus in 90–120 min, then maintenance 200-400mg/kg/d (1-2mmol/kg/d)

–

ARG1D e

same

–

AVOID

–

HHH syndrome

same

250mg/kg as bolus in 90–120 min, then maintenance: 250mg/kg/d c

–

–

  1. In severe acute decompensation both sodium benzoate and sodium PBA/phenylacetate should be given in parallel as “ultima ratio”. In less severe cases, a stepwise approach with initial sodium benzoate and if hyperammonemia persists or worsens, the addition of sodium PBA/phenylacetate can be chosen. The doses given can be used at the start of treatment but must be adapted depending on plasma ammonia and amino acids levels. Maximal daily dosages of sodium benzoate, sodium PBA and L-arginine should not exceed 12g for each of the three drugs. Grade of recommendation, D.
  2. a If citrulline is given, there is usually no need for concomitant use of L-arginine.
  3. b In undiagnosed patients, consider additional use of carnitine 100mg/kg IV, hydroxycobalamin 1mg IM/IV, and biotin 10mg IV/PO.
  4. c If on hemodialysis/hemodiafiltration maintenance doses should be increased to 350mg/kg/day (or proportional increase for body surface-based dose calculation).
  5. d In ASLD, L-arginine therapy for acute decompensations might be sufficient for some patients.
  6. e The risk for acute hyperammonemic decompensation is low in ARG1D.
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Orphanet Journal of Rare Diseases

ISSN: 1750-1172