BNF for Children 2011-2012

BNFC 2011–2012 9.8.1 Drugs used in metabolic disorders 493Child 1 month–12 years or under 50 kg initiallyone-sixth to one-quarter of the expected maintenancedose, increased gradually over 4–6 weeks;maintenance, 1.3 g/m 2 (approx. 50 mg/kg) daily in4 divided dosesChild 12–18 years or over 50 kg initially onesixthto one-quarter of the expected maintenancedose, increased gradually over 4–6 weeks; maintenance,2 g daily in 4 divided dosesCystagon c (Orphan Europe) ACapsules, mercaptamine (as bitartrate) 50 mg, netprice 100-cap pack = £70.00; 150 mg, 100-cap pack =£190.00. Label: 21Note For child under 6 years at risk of aspiration, capsulescan be opened and contents sprinkled on food (at a temperaturesuitable for eating); avoid adding to acidic drinks(e.g. orange juice)Eye dropsMercaptamine (Non-proprietary)Eye drops, mercaptamine 0.11%, 10 mLAvailable from ‘special-order’ manufacturers or specialistimporting companies, see p. 809Pompe diseaseAlglucosidase alfa, an enzyme produced by recombinantDNA technology, is licensed for long-term replacementtherapy in Pompe disease, a lysosomal storagedisorder caused by deficiency of acid alpha-glucosidase.ALGLUCOSIDASE ALFACautions cardiac and respiratory dysfunction—monitorclosely; monitor immunoglobulin G (IgG) antibodyconcentrationInfusion-related reactions Infusion-related reactions verycommon, calling for use of antihistamine, antipyretic, orcorticosteroid; consult product literature for detailsPregnancy toxicity in animal studies, but treatmentshould not be withheldBreast-feeding manufacturer advises avoid—noinformation availableSide-effects nausea, vomiting, diarrhoea; flushing,tachycardia, blood pressure changes, cold extremities,cyanosis, facial oedema, chest discomfort; cough,tachypnoea, bronchospasm; headache, agitation, tremor,irritability, restlessness, paraesthesia, dizziness,fatigue; pyrexia; antibody formation; myalgia, musclespasms; sweating, rash, pruritus, urticaria, injectionsitereactions; hypersensitivity reactions (includinganaphylaxis); severe skin reactions (including ulcerativeand necrotising skin lesions) also reportedIndication and dosePompe disease (specialist use only). By intravenous infusionNeonate 20 mg/kg every 2 weeksChild 1 month –18 years 20 mg/kg every 2weeksAdministration For intravenous infusion, reconstitute50 mg with 10.3 mL Water for Injections to produce5 mg/mL solution; gently rotate vial without shaking;dilute requisite dose with Sodium Chloride 0.9% togive a final concentration of 0.5–4 mg/mL; givethrough a low protein-binding in-line filter(0.2 micron) at an initial rate of 1 mg/kg/hourincreased by 2 mg/kg/hour every 30 minutes to max.7 mg/kg/hourMyozyme c (Genzyme) TAIntravenous infusion, powder for reconstitution,alglucosidase alfa, net price 50-mg vial = £356.06Urea cycle disordersSodium benzoate and sodium phenylbutyrate areused in the management of urea cycle disorders. Both,either singly or in combination, are indicated as adjunctivetherapy in all patients with neonatal-onset diseaseand in those with late-onset disease who have a historyof hyperammonaemic encephalopathy. Sodium benzoateis also used in non-ketotic hyperglycinaemia.Gastro-intestinal side-effects of sodium benzoate orsodium phenylbutyrate may be reduced by giving smallerdoses more frequently. The preparations containsignificant amounts of sodium; therefore, they shouldbe used with caution in children with congestive heartfailure, renal insufficiency and clinical conditions involvingsodium retention with oedema.The long-term management of urea cycle disordersincludes oral maintenance treatment with sodium benzoateand sodium phenylbutyrate combined with a lowprotein diet and other drugs such as arginine or citrulline,depending on the specific disorder.Carglumic acid is licensed for the treatment of hyperammonaemiadue to N-acetylglutamate synthase deficiency.ARGININECautions monitor plasma pH and chlorideContra-indications not to be used in the treatment ofarginase deficiencyPregnancy no information availableBreast-feeding no information availableSide-effects intravenous injection only: nausea,vomiting; flushing, hypotension; headache, numbness;hyperchloraemic metabolic acidosis; irritation atinjection-siteLicensed use injection and tablets not licensed inchildren; powder licensed for urea cycle disorders inchildrenIndication and doseAcute hyperammonaemia in carbamylphosphatesynthetase deficiency, ornithine carbamyltransferase deficiency (specialist use only). By intravenous infusionNeonate initially 200 mg/kg over 90 minutes followedby 8 mg/kg/hourChild 1 month–18 years initially 200 mg/kg over90 minutes followed by 8 mg/kg/hour9 Nutrition and blood