BNF for Children (BNFC) 2018-2019

DRUGS FOR METABOLIC DISORDERS›

AMMONIA LOWERING DRUGS

Glycerol phenylbutyrate 14-May-2018

lDRUG ACTIONGlycerol phenylbutyrate is a nitrogen-
binding agent that provides an alternative vehicle for
waste nitrogen excretion.

lINDICATIONS AND DOSE

Urea cycle disorders (specialist use only)

▶BY MOUTH, OR BY GASTROSTOMY TUBE, OR BY NASOGASTRIC

TUBE

▶Child 2 months–17 years (body surface area up to 1.3 m^2 ):

Initially 9. 4 g/m^2 daily in divided doses, usual

maintenance 5. 3 – 12. 4 g/m^2 daily in divided doses, with

meals, each dose should be rounded up to the nearest

0. 5 mL. For dose adjustments based on individual

requirements—consult product literature

▶Child 2 months–17 years (body surface area 1.3 m^2 and

above):Initially 8 g/m^2 daily in divided doses, usual

maintenance 5. 3 – 12. 4 g/m^2 daily in divided doses, with

meals, each dose should be rounded up to the nearest

0. 5 mL. For dose adjustments based on individual

requirements—consult product literature

DOSE EQUIVALENCE AND CONVERSION

▶ 1 mL of liquid contains 1. 1 g of glycerol phenylbutyrate.

▶For patients switching from sodium phenylbutyrate—

consult product literature.

IMPORTANT SAFETY INFORMATION

EMERGENCY MANAGEMENT OF UREA CYCLE DISORDERS

For further information on the emergency management

of urea cycle disorders consult the British Inherited

Metabolic Disease Group (BIMDG) website at

http://www.bimdg.org.uk.

lCONTRA-INDICATIONSTreatment of acute
hyperammonaemia

lCAUTIONSIntestinal malabsorption.pancreatic
insufficiency

lINTERACTIONS→Appendix 1 : glycerol phenylbutyrate

lSIDE-EFFECTS
▶Common or very commonConstipation.diarrhoea.
dizziness.fatigue.gastrointestinal discomfort.
gastrointestinal disorders.headache.menstrual disorder.
nausea.oral disorders.peripheral oedema.skin reactions
.tremor.vomiting

▶UncommonAkathisia.alopecia.biliary colic.bladder pain
.confusion.depressed mood.drowsiness.epistaxis.hot
flush.hyperhidrosis.hypoalbuminaemia.hypokalaemia.
hypothyroidism.joint swelling.muscle spasms.pain.
paraesthesia.plantar fasciitis.speech disorder.taste
altered.ventricular arrhythmia.weight change

lPREGNANCYManufacturer advises avoid unless
essential—toxicity inanimalstudies.

lBREAST FEEDINGManufacturer advises avoid—no
information available.

lHEPATIC IMPAIRMENTManufacturer advises use with
caution—use lowest possible dose.

lRENAL IMPAIRMENTManufacturer advises use with
caution in severe impairment—no information available.

lDIRECTIONS FOR ADMINISTRATIONManufacturer advises
may be added to a small amount of apple sauce, ketchup,
or squash and used within 2 hours. For administration
advice via nasogastric or gastrostomy tube—consult
product literature.

lHANDLING AND STORAGEManufacturer advises discard
contents of bottle 14 days after opening.

lPATIENT AND CARER ADVICE

Driving and skilled tasksManufacturer advises patients and

carers should be counselled on the effects on driving and

performance of skilled tasks—increased risk of dizziness.

lMEDICINAL FORMS

There can be variation in the licensing of different medicines

containing the same drug.

Liquid

▶Ravicti(Swedish Orphan Biovitrum Ltd)A

Glycerol phenylbutyrate 1.1 gram per 1 mlRavicti 1. 1 g/ml oral

liquid| 25 mlP£ 161. 00

Sodium phenylbutyrate

lINDICATIONS AND DOSE

Acute hyperammonaemia due to urea cycle disorders

(specialist use only)

▶BY INTRAVENOUS INFUSION

▶Neonate:Initially 250 mg/kg, to be administered over

90 minutes, followed by 10 mg/kg/hour, adjusted

according to response.

▶Child:Initially 250 mg/kg, to be administered over

90 minutes, followed by 10 mg/kg/hour, adjusted

according to response

Maintenance treatment of hyperammonaemia due to urea

cycle disorders (specialist use only)

▶BY MOUTH

▶Neonate:Up to 250 mg/kg daily in 3 – 4 divided doses,

with feeds.

▶Child (body-weight up to 20 kg):Up to 250 mg/kg daily in

3 – 4 divided doses, with feeds or meals

▶Child (body-weight 20 kg and above): 5 g/m^2 daily in

3 – 4 divided doses, with meals; maximum 12 g per day

lUNLICENSED USEInjection not licensed for use in

children.

IMPORTANT SAFETY INFORMATION

EMERGENCY MANAGEMENT OF UREA CYCLE DISORDERS

For further information on the emergency management

of urea cycle disorders consult the British Inherited

Metabolic Disease Group (BIMDG) website at

http://www.bimdg.org.uk.

lCAUTIONSConditions involving sodium retention with

oedema (preparations contain significant amounts of

sodium).congestive heart failure (preparations contain

significant amounts of sodium)

lINTERACTIONS→Appendix 1 : sodium phenylbutyrate

lSIDE-EFFECTS

▶Common or very commonAbdominal pain.anaemia.

appetite decreased.constipation.depression.headache.

irritability.leucocytosis.leucopenia.menstrual cycle

irregularities.metabolic acidosis.metabolic alkalosis.

nausea.oedema.renal tubular acidosis.skin reactions.

syncope.taste altered.thrombocytopenia.

thrombocytosis.vomiting.weight increased

▶UncommonAnorectal haemorrhage.aplastic anaemia.

arrhythmia.gastrointestinal disorders.pancreatitis

lCONCEPTION AND CONTRACEPTIONManufacturer advises

adequate contraception during administration in women

of child-bearing potential.

lPREGNANCYAvoid—toxicity inanimalstudies.

lBREAST FEEDINGManufacturer advises avoid—no

information available.

lHEPATIC IMPAIRMENTManufacturer advises use with

caution.

BNFC 2018 – 2019 Urea cycle disorders 615

Blood and nutrition

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