BNF for Children 2011-2012

98 2.5.2 Centrally acting antihypertensive drugs BNFC 2011–20122 Cardiovascular systemRevatio c (Pfizer) TATablets, f/c, sildenafil (as citrate), 20 mg, net price 90-tab pack = £373.50Extemporaneous formulations available seeExtemporaneous Preparations, p. 6TOLAZOLINECautions mitral stenosis; cardiotoxic accumulationmay occur with continuous infusion, particularly inrenal impairment—monitor blood pressure regularlyfor sustained systemic hypotension; interactions:Appendix 1 (alpha-blockers)Contra-indications peptic ulcer diseaseRenal impairment accumulates in renal impairment;risk of cardiotoxicity; lower doses may be necessarySide-effects nausea, vomiting, diarrhoea, epigastricpain; flushing, tachycardia, cardiac arrhythmias;headache, shivering, sweating; oliguria, metabolicalkalosis, haematuria, blood dyscrasias (includingthrombocytopenia); blotchy skin; at high doses severehypotension, marked hypertension, renal failure, andhaemorrhage reportedLicensed use not licensed for use in childrenIndication and doseCorrection of pulmonary vasospasm in neonates. By intravenous injection and continuous intravenousinfusion (maintenance)Neonate initially 1 mg/kg by intravenous injectionover 2–5 minutes, followed if necessary by continuousintravenous infusion of 200 micrograms/kg/hour with careful blood pressure monitoring;doses above 300 micrograms/kg/hour associatedwith cardiotoxicity and renal failure. By endotracheal administrationNeonate 200 micrograms/kgAdministration for continuous intravenous infusion,dilute with Glucose 5% or Sodium Chloride 0.9%.Prepare a fresh solution every 24 hours.For endotracheal administration, dilute with 0.5–1 mL of Sodium Chloride 0.9%Tolazoline (Non-proprietary)Injection, tolazoline 25 mg/mLAvailable from ‘special-order’ manufacturers or specialistimporting companies, see p. 8092.5.2 Centrally actingantihypertensive drugsMethyldopa, a centrally acting antihypertensive, is oflittle value in the management of refractory sustainedhypertension in infants and children. On prolonged useit is associated with fluid retention (which may bealleviated by concomitant use of diuretics).Methyldopa is effective for the management of hypertensionin pregnancy (see BNF section 2.5.2).Clonidine is also a centrally acting antihypertensive buthas the disadvantage that sudden withdrawal may causea hypertensive crisis. Clonidine is also used underspecialist supervision for pain management, sedation,and opioid withdrawal, attention deficit hyperactivitydisorder, and Tourette syndrome.CLONIDINE HYDROCHLORIDE UCautions must be withdrawn gradually to avoidhypertensive crisis; mild to moderate bradyarrhythmia;constipation; polyneuropathy; Raynaud’ssyndrome or other occlusive peripheral vascular disease;history of depression; interactions: Appendix 1(clonidine)Skilled tasks Drowsiness may affect performance of skilledtasks (e.g. driving); effects of alcohol may be enhancedContra-indications severe bradyarrhythmia secondaryto second- or third-degree AV block or sick sinussyndromeRenal impairment use with cautionPregnancy may lower fetal heart rate, but risk shouldbe balanced against risk of uncontrolled maternalhypertension; avoid intravenous injectionBreast-feeding avoid—present in milkSide-effects constipation, nausea, dry mouth, vomiting,postural hypotension, dizziness, sleep disturbances,headache, malaise, drowsiness, depression,sexual dysfunction; less commonly bradycardia, Raynaud’ssyndrome, delusion, hallucination, paraesthesia,pruritus, rash, urticaria; rarely colonic pseudoobstruction,AV block, gynaecomastia, decreasedlacrimation, nasal dryness, alopecia; also reportedhepatitis, fluid retention, bradyarrhythmia, confusion,impaired visual accommodationLicensed use not licensed for use in childrenIndication and doseSevere hypertension. By mouthChild 2–18 years initially 0.5–1 microgram/kg 3times daily, increased gradually if necessary; max.25 micrograms/kg daily in divided doses (notexceeding 1.2 mg daily). By slow intravenous injectionChild 2–18 years 2–6 micrograms/kg (max.300 micrograms) as a single doseAdministration for intravenous injection, give over10–15 minutes; compatible with Sodium Chloride0.9% or Glucose 5%.For administration by mouth, tablets may be crushedand dissolved in waterCatapres c (Boehringer Ingelheim) AUTablets, scored, clonidine hydrochloride 100 micrograms,net price 100-tab pack = £5.32; 300 micrograms,100-tab pack = £12.39. Label: 3, 8Injection, clonidine hydrochloride 150 micrograms/mL, net price 1-mL amp = 28pExtemporaneous formulations available seeExtemporaneous Preparations, p. 62.5.3 Adrenergic neuroneblocking drugsAdrenergic neurone blocking drugs prevent the releaseof noradrenaline from postganglionic adrenergic neurones.These drugs do not control supine blood pressureand may cause postural hypotension. For this reason