BNF for Children 2011-2012

BNFC 2011–2012 5.1.9 Antituberculosis drugs 293Contra-indications epilepsy, depression, severeanxiety, psychotic states, alcohol dependence, acuteporphyria (section 9.8.2)Renal impairment reduce dose and monitor bloodcycloserineconcentration; avoid in severe impairmentPregnancy manufacturer advises use only if potentialbenefit outweighs risk—crosses the placentaBreast-feeding present in milk—amount too small tobe harmfulSide-effects mainly neurological, including headache,dizziness, vertigo, drowsiness, tremor, convulsions,confusion, psychosis, depression (discontinue orreduce dose if symptoms of CNS toxicity); rashes,allergic dermatitis (discontinue or reduce dose);megaloblastic anaemia; changes in liver functiontests; heart failure at high doses reportedPharmacokinetics blood concentration should notexceed a peak concentration of 30 mg/litre (measured3–4 hours after the dose); penetrates CNSLicensed use licensed for use in children (age rangenot specified by manufacturer)Indication and doseTuberculosis resistant to first-line drugs, usedin combination with other drugs. By mouthChild 2–12 years initially 5 mg/kg (max. 250 mg)twice daily, adjusted according to blood concentrationand response up to 10 mg/kg (max.500 mg) twice dailyChild 12–18 years initially 250 mg twice daily for2 weeks adjusted according to blood concentrationand response to max. 500 mg twice dailyCycloserine (King) ACapsules, red/grey cycloserine 250 mg, net price100-cap pack = £333.80. Label: 2, 8ETHAMBUTOL HYDROCHLORIDECautions test visual acuity before treatment and warnpatients to report visual changes—see notes above;young children (see notes above)—routine ophthalmologicalmonitoring recommendedContra-indications optic neuritis, poor visionRenal impairment reduce dose; if creatinine clearanceless than 30 mL/minute/1.73 m 2 , monitorplasma-ethambutol concentration; risk of optic nervedamagePregnancy not known to be harmful; see also p. 291Breast-feeding amount too small to be harmful; seealso p. 291Side-effects optic neuritis, red/green colour blindness,peripheral neuritis, rarely rash, pruritus, urticaria,thrombocytopeniaPharmacokinetics ‘peak’ concentration (2–2.5 hoursafter dose) should be 2–6 mg/litre (7–22 micromol/litre); ‘trough’ (pre-dose) concentration should beless than 1 mg/litre (4 micromol/litre); for advice onlaboratory assay of ethambutol contact the PoisonsUnit at New Cross Hospital (Tel (020) 7771 5360)Indication and doseTuberculosis, used in combination with otherdrugs see notes aboveEthambutol (Non-proprietary) ATablets, ethambutol hydrochloride 100 mg, net price56-tab pack = £12.00; 400 mg, 56-tab pack = £44.18.Label: 8Extemporaneous formulations available seeExtemporaneous Preparations, p. 6ISONIAZIDCautions see Monitoring in notes above; also slowacetylator status (increased risk of side-effects); epilepsy;history of psychosis; alcohol dependence,malnutrition, diabetes mellitus, HIV infection (risk ofperipheral neuritis); acute porphyria (section 9.8.2);interactions: Appendix 1 (isoniazid)Hepatic disorders Children and their carers should be toldhow to recognise signs of liver disorder, and advised todiscontinue treatment and seek immediate medical attentionif symptoms such as persistent nausea, vomiting, malaise orjaundice developContra-indications drug-induced liver diseaseHepatic impairment use with caution; monitor liverfunction regularly and particularly frequently in thefirst 2 months; see also Hepatic Disorders aboveRenal impairment reduce dose if estimated glomerularfiltration rate less than 10 mL/minute/1.73 m 2 ;risk of peripheral neuropathyPregnancy not known to be harmful; see notes aboveBreast-feeding monitor infant for possible toxicity;theoretical risk of convulsions and neuropathy; prophylacticpyridoxine advisable in mother and infant;see also p. 291Side-effects nausea, vomiting, constipation, drymouth; peripheral neuritis with high doses (pyridoxineprophylaxis, see notes above), optic neuritis, convulsions,psychotic episodes, vertigo; hypersensitivityreactions including fever, Stevens-Johnson syndrome,purpura; blood disorders including agranulocytosis,haemolytic anaemia, aplastic anaemia; hepatitis;pancreatitis; interstitial pneumonitis; systemic lupuserythematosus-like syndrome, pellagra, hyperreflexia,difficulty with micturition, hyperglycaemia, andgynaecomastia reported; hearing loss and tinnitus (inchildren with end-stage renal impairment); when usedwith tyramine or histamine rich foods, tachycardia,palpitation, hypotension, flushing, headache, dizziness,and sweating also reportedIndication and doseTuberculosis, used in combination with otherdrugs see notes aboveIsoniazid (Non-proprietary) ATablets, isoniazid 50 mg, net price 56-tab pack =£11.10; 100 mg, 28-tab pack = £11.30. Label: 8, 22Injection, isoniazid 25 mg/mL, net price 2-mL amp =£11.04Extemporaneous formulations available seeExtemporaneous Preparations, p. 6PYRAZINAMIDECautions see Monitoring in notes above; also diabetes;interactions: Appendix 1 (pyrazinamide)Hepatic disorders Children and their carers should be toldhow to recognise signs of liver disorder, and advised todiscontinue treatment and seek immediate medical attentionif symptoms such as persistent nausea, vomiting, malaise orjaundice develop5 Infections