Proposed guidelines for the diagnosis and management of methylmalonic and propionic acidemia

Table 7 Dosage of drugs in acute hyperammonemia

Glucose IV	L-carnitine IV	Hydroxo-cobalamin# IV/IM	Biotin IV/PO	Sodium benzoate* (to be given IV in glucose 10%)	'sodium phenylbutyrate* (to be given IV in glucose 10%)	^§L-arginine-HCl* (to be given IV in glucose 10%)	N-carbamyl-glutamate PO
Age dependent (see Table 8)	100 mg/kg as bolus, then maintenance 100 mg/kg/d	1 mg/day	10 - 40 mg/day	250 mg/kg as bolus in 90-120 min, then maintenance dose 250 mg/kg/d	250 mg/kg as bolus in 90-120 min, then maintenance dose 250 mg/kg/d	250 mg/kg as bolus in 90-120 min, then maintenance dose 250 mg/kg/d	100 mg/kg bolus, then 25-62 mg/kg every 6 h

#Vitamin B₁₂ is preferably given in the form of hydroxocobalamin; cyanocobalamin is less efficient but may be used temporarily.
*Maximal daily drug dosages: sodium benzoate 5, 5 g/m²or 12 g/d, sodium PBA 5, 5 g/m²or 12 g/d, L-arginine 12 g/day.
'sodium phenylbutyrate should only be used in urea cycle defects or when the cause of hyperammonemia is unknown. 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.
^§Arginine should only be used when the cause of hyperammonemia is unknown or when plasma arginine is low.
Grade of recommendation: D.

ISSN: 1750-1172