BNF for Children 2011-2012

112 2.7.2 Vasoconstrictor sympathomimetics BNFC 2011–20122 Cardiovascular systemChild 1 month–18 years initially 5 micrograms/kg/minute adjusted according to response (max.20 micrograms/kg/minute)Administration for continuous intravenous infusion,dilute to a max. concentration of 3.2 mg/mL withGlucose 5% or Sodium Chloride 0.9%. Infuse higherconcentrations through central venous catheter usinga syringe pump to avoid extravasation and fluidoverload. Incompatible with bicarbonate and otheralkaline solutions.Neonatal intensive care, dilute 30 mg/kg body-weightto a final volume of 50 mL with infusion fluid; anintravenous infusion rate of 0.3 mL/hour provides adose of 3 micrograms/kg/minuteDopamine (Non-proprietary) AConcentrate for intravenous infusion, dopaminehydrochloride 40 mg/mL, net price 5-mL amp = 90p;160 mg/mL, 5-mL amp = £3.40. To be diluted beforeuseIntravenous infusion, dopamine hydrochloride1.6 mg/mL in glucose 5% intravenous infusion, netprice 250-mL container (400 mg) = £11.69. Availablefrom ‘special-order’ manufacturers or specialistimporting companies, p. 8092.7.2 VasoconstrictorsympathomimeticsVasoconstrictor sympathomimetics raise blood pressuretransiently by acting on alpha-adrenergic receptorsto constrict peripheral vessels. They are sometimesused as an emergency method of elevating blood pressurewhere other measures have failed (see also section2.7.1).The danger of vasoconstrictors is that although theyraise blood pressure they also reduce perfusion of vitalorgans such as the kidney.Ephedrine is used to reverse hypotension caused byspinal and epidural anaesthesia.Metaraminol is used as a vasopressor during cardiopulmonarybypass.Phenylephrine causes peripheral vasoconstriction andincreases arterial pressure.Ephedrine, metaraminol and phenylephrine are rarelyneeded in children and should be used under specialistsupervision.Noradrenaline (norepinephrine) is reserved for childrenwith low systemic vascular resistance that is unresponsiveto fluid resuscitation following septic shock, spinalshock, and anaphylaxis.Adrenaline (epinephrine) is mainly used for its inotropicaction. Low doses (acting on beta receptors) causesystemic and pulmonary vasodilation, with someincrease in heart rate and stroke volume and also anincrease in contractility; high doses act predominantlyon alpha receptors causing intense systemic vasoconstriction.EPHEDRINE HYDROCHLORIDECautions hyperthyroidism, diabetes mellitus, hypertension,susceptibility to angle-closure glaucoma,interactions: Appendix 1 (sympathomimetics)Renal impairment use with cautionPregnancy increased fetal heart rate reported withparenteral ephedrineBreast-feeding irritability and disturbed sleepreportedSide-effects nausea, vomiting, anorexia; tachycardia(sometimes bradycardia), arrhythmias, anginal pain,vasoconstriction with hypertension, vasodilation withhypotension, dizziness and flushing; dyspnoea; headache,anxiety, restlessness, confusion, psychoses,insomnia, tremor; difficulty in micturition, urineretention; sweating, hypersalivation; changes inblood-glucose concentration; very rarely angle-closureglaucomaIndication and doseReversal of hypotension from epidural andspinal anaesthesia. By slow intravenous injection of a solutioncontaining ephedrine hydrochloride 3 mg/mLChild 1–12 years 500–750 micrograms/kg or 17–25 mg/m 2 every 3–4 minutes according toresponse; max. 30 mg during episodeChild 12–18 years 3–7.5 mg (max. 9 mg)repeated every 3–4 minutes according to response,max. 30 mg during episodeNasal congestion section 12.2.2Administration for slow intravenous injection, givevia central venous catheterEphedrine Hydrochloride (Non-proprietary) AInjection, ephedrine hydrochloride 3 mg/mL, netprice 10-mL amp = £3.25; 30 mg/mL, net price 1-mLamp = 41pMETARAMINOLCautions see under Noradrenaline; longer duration ofaction than noradrenaline (norepinephrine), seebelow; cirrhosis; interactions: Appendix 1(sympathomimetics)Hypertensive response Metaraminol has a longer durationof action than noradrenaline, and an excessive vasopressorresponse may cause a prolonged rise in blood pressureContra-indications see under NoradrenalinePregnancy may reduce placental prefusion—manufactureradvises use only if potential benefit outweighsriskBreast-feeding manufacturer advises caution—noinformation availableSide-effects see under Noradrenaline; tachycardia;fatal ventricular arrhythmia reported in Laennec’scirrhosisLicensed use not licensed for use in childrenIndication and doseAcute hypotension. By intravenous infusionChild 12–18 years 15–100 mg adjusted accordingto responseEmergency treatment of acute hypotension. By intravenous administrationChild 12–18 years initially by intravenous injection0.5–5 mg, then by intravenous infusion 15–100 mg adjusted according to response