BNF for Children 2011-2012

514 10.2.2 Skeletal muscle relaxants BNFC 2011–201210 Musculoskeletal and joint diseasesremedied. Skeletal muscle relaxants are effective inmost forms of spasticity except the rare alpha variety.The major disadvantage of treatment with these drugs isthat reduction in muscle tone can cause a loss ofsplinting action of the spastic leg and trunk musclesand sometimes lead to an increase in disability.Dantrolene acts directly on skeletal muscle and producesfewer central adverse effects. It is generally usedin resistant cases. The dose should be increased slowly.Baclofen inhibits transmission at spinal level and alsodepresses the central nervous system. The dose shouldbe increased slowly to avoid the major side-effects ofsedation and muscular hypotonia (other adverse eventsare uncommon).Diazepam has undoubted efficacy in some children.Sedation and occasionally extensor hypotonus aredisadvantages. Other benzodiazepines also havemuscle-relaxant properties.BACLOFENCautions psychiatric illness; respiratory impairment;epilepsy; history of peptic ulcer (avoid oral route inactive peptic ulceration); diabetes; hypertonic bladdersphincter; avoid abrupt withdrawal (risk of hyperactivestate, may exacerbate spasticity, and precipitateautonomic dysfunction including hyperthermia,psychiatric reactions and convulsions, see also underWithdrawal below); interactions: Appendix 1 (musclerelaxants)Withdrawal CSM has advised that serious side-effects canoccur on abrupt withdrawal; to minimise risk, discontinue bygradual dose reduction over at least 1–2 weeks (longer ifsymptoms occur)Skilled tasks Drowsiness may affect performance of skilledtasks (e.g. driving); effects of alcohol enhancedHepatic impairment manufacturer advises use bymouth with cautionRenal impairment risk of toxicity—use smaller oraldoses and if necessary increase dosage interval; ifestimated glomerular filtration rate less than 15 mL/minute/1.73m 2 use by mouth only if potential benefitoutweighs risk; excreted by kidneyPregnancy manufacturer advises use only if potentialbenefit outweighs risk (toxicity in animal studies)Breast-feeding present in milk—amount probably toosmall to be harmfulSide-effects gastro-intestinal disturbances, drymouth; hypotension, respiratory or cardiovasculardepression; sedation, drowsiness, confusion, dizziness,ataxia, hallucinations, nightmares, headache,euphoria, insomnia, depression, anxiety, agitation,tremor; seizure; urinary disturbances; myalgia; visualdisorders; rash, hyperhidrosis; rarely taste disturbances,abdominal pain, changes in hepatic function,paraesthesia, erectile dysfunction, dysarthria; veryrarely hypothermiaIndication and doseChronic severe spasticity of voluntary muscle. By mouthChild 1–2 years initially 300 micrograms/kg dailyin 4 divided doses, increased gradually to usualmaintenance dose of 0.75–2 mg/kg (max. 40 mg)daily in divided doses (or 10–20 mg daily in divideddoses); review treatment if no benefit within 6weeksChild 2–6 years initially 300 micrograms/kg dailyin 4 divided doses, increased gradually to usualmaintenance dose of 0.75–2 mg/kg (max. 40 mg)daily in divided doses (or 20–30 mg daily in divideddoses); review treatment if no benefit within 6weeksChild 6–8 years initially 300 micrograms/kg dailyin 4 divided doses, increased gradually to usualmaintenance dose of 0.75–2 mg/kg (max. 40 mg)daily in divided doses (or 30–40 mg daily in divideddoses); review treatment if no benefit within 6weeksChild 8–10 years initially 300 micrograms/kgdaily in 4 divided doses, increased gradually tousual maintenance dose of 0.75–2 mg/kg (max.60 mg) daily in divided doses; review treatment ifno benefit within 6 weeksChild 10–18 years initially 5 mg 3 times dailyincreased gradually; usual maintenance dose up to60 mg daily in divided doses (max. 100 mg daily);review treatment if no benefit within 6 weeksSevere chronic spasticity of cerebral originunresponsive to oral antispastic drugs (or oraltherapy not tolerated), as alternative to ablativeneurosurgical procedures—specialist useonly. By intrathecal injectionChild 4–18 years initial test dose 25 microgramsover at least 1 minute via catheter or lumbarpuncture, increased in 25-microgram steps (notmore often than every 24 hours) to max.100 micrograms to determine appropriate dosethen dose-titration phase, most often using infusionpump (implanted into chest wall or abdominalwall tissues) to establish maintenance dose (rangingfrom 24 micrograms to 1.2 mg daily in childrenunder 12 years or 1.4 mg daily for those over12 years) retaining some spasticity to avoid sensationof paralysisSafe PracticeConsult intrathecal injection product literature fordetails on dose testing and titration—important tomonitor patients closely in appropriately equippedand staffed environment during screening and immediatelyafter pump implantation. Resuscitation equipmentmust be available for immediate useBaclofen (Non-proprietary) ATablets, baclofen 10 mg, net price 84-tab pack =£1.58. Label: 2, 8, 21Oral solution, baclofen 5 mg/5 mL, net price 300 mL= £9.26. Label: 2, 8, 21Brands include Lyflex c (sugar-free)Lioresal c (Novartis) ATablets, scored, baclofen 10 mg, net price 84-tab pack= £8.67. Label: 2, 8, 21Excipients include glutenLiquid, sugar-free, raspberry–flavoured, baclofen5 mg/5 mL, net price 300 mL = £7.16. Label: 2, 8, 21By intrathecal injectionLioresal c (Novartis) AIntrathecal injection, baclofen, 50 micrograms/mL,net price 1-mL amp (for test dose) = £2.19;500 micrograms/mL, 20-mL amp (for use withimplantable pump) = £48.62; 2 mg/mL, 5-mL amp(for use with implantable pump) = £48.62