BNF for Children 2011-2012

BNFC 2011–2012 10.2.2 Skeletal muscle relaxants 513Child up to 6 years initially 7.5 mg repeated atsuitable intervals throughout the day, total dailydose 15–90 mgChild 6–12 years initially 15 mg repeated at suitableintervals throughout the day, total daily dose15–90 mgChild 12–18 years initially 15–30 mg repeated atsuitable intervals throughout the day, total dailydose 75–300 mg (but max. most can tolerate is180 mg daily). By subcutaneous or intramuscular injection (asneostigmine metilsulfate)Neonate 150 micrograms/kg every 6–8 hours, 30minutes before feeds, increased to max. 300 micrograms/kgevery 4 hours, if necessary [unlicensed]Child 1 month–12 years 200–500 microgramsrepeated at suitable intervals throughout the dayChild 12–18 years 1–2.5 mg repeated at suitableintervals throughout the dayNeostigmine (Non-proprietary) ATablets, scored, neostigmine bromide 15 mg, netprice 140 = £56.10InjectionSection 15.1.6PYRIDOSTIGMINE BROMIDECautions see under Neostigmine; weaker muscarinicactionContra-indications see under NeostigmineRenal impairment reduce dose; excreted by kidneyPregnancy see under NeostigmineBreast-feeding see under NeostigmineSide-effects see under NeostigmineIndication and doseTreatment of myasthenia gravis. By mouthNeonate initially 1–1.5 mg/kg, increased graduallyto max. 10 mg, repeated throughout the day, give30–60 minutes before feedsChild 1 month–12 years initially 1–1.5 mg/kg/day, increased gradually to 7 mg/kg/day in 6divided doses; usual total daily dose 30–360 mgChild 12–18 years 30–120 mg, repeatedthroughout the day; usual total daily dose 300–600 mg (but consider immunosuppressant therapyif total daily dose exceeds 360 mg, down-regulationof acetylcholine receptors possible if totaldaily dose exceeds 450 mg; see notes above)Mestinon c (Meda) ATablets, scored, pyridostigmine bromide 60 mg, netprice 200 = £45.33Extemporaneous formulations available seeExtemporaneous Preparations, p. 6EDROPHONIUM CHLORIDECautions see under Neostigmine; have resuscitationfacilities; extreme caution in respiratory distress (seenotes above) and in asthmaNote Severe cholinergic reactions can be counteracted byinjection of atropine sulphate (which should always beavailable)Contra-indications see under NeostigminePregnancy see under NeostigmineBreast-feeding see under NeostigmineSide-effects see under NeostigmineIndication and doseDiagnostic test for myasthenia gravis. By intravenous injectionChild 1 month–12 years 20 micrograms/kg followedafter 30 seconds (if no adverse reaction hasoccurred) by 80 micrograms/kgChild 12–18 years 2 mg followed after 30 seconds(if no adverse reaction has occurred) by 8 mgDetection of overdosage or underdosage ofcholinergic drugs. By intravenous injectionChild 1 month–12 years 20 micrograms/kg(preferably just before next dose of anticholinesterase,see notes above)Child 12–18 years 2 mg (preferably just beforenext dose of anticholinesterase, see notes above)Edrophonium (Non-proprietary) AInjection, edrophonium chloride 10 mg/mL, net price1-mL amp = £19.50Immunosuppressant therapyA course of corticosteroids (section 6.3) is an establishedtreatment in severe cases of myasthenia gravisand may be particularly useful when antibodies to theacetylcholine receptor are present in high titre. Shortcourses of high-dose (’pulsed’) methylprednisolone followedby maintenance therapy with oral corticosteroidsmay also be useful.Corticosteroid treatment is usually initiated under specialistsupervision. For disadvantages of corticosteroidtreatment, see section 6.3.2. Transient but very seriousworsening of symptoms can occur in the first 2–3 weeks,especially if the corticosteroid is started at a high dose.Once remission has occurred (usually after 2–6 months),the dose of prednisolone should be reduced slowly tothe minimum effective dose.10.2.2 Skeletal muscle relaxantsThe drugs described below are used for the relief ofchronic muscle spasm or spasticity associated withneurological damage; they are not indicated for spasmassociated with minor injuries. They act principally onthe central nervous system with the exception of dantrolene,which has a peripheral site of action. They differin action from the muscle relaxants used in anaesthesia(section 15.1.5), which block transmission at the neuromuscularjunction.The underlying cause of spasticity should be treated andany aggravating factors (e.g. pressure sores, infection)10 Musculoskeletal and joint diseases