BNF for Children 2011-2012

30 Emergency treatment of poisoning BNFC 2011–2012Emergency treatment of poisoningbut sotalol may induce ventricular tachyarrhythmias(sometimes of the torsade de pointes type). The effectsof massive overdosage can vary from one beta-blockerto another; propranolol overdosage in particular maycause coma and convulsions.Acute massive overdosage must be managed in hospitaland expert advice should be obtained. Maintenance of aclear airway and adequate ventilation is mandatory. Anintravenous injection of atropine is required to treatbradycardia (40 micrograms/kg, max. 3 mg). Cardiogenicshock unresponsive to atropine is probably besttreated with an intravenous injection of glucagon (50–150 micrograms/kg, max. 10 mg) [unlicensed indicationand dose] in glucose 5% (with precautions to protect theairway in case of vomiting) followed by an intravenousinfusion of 50 micrograms/kg/hour. If glucagon is notavailable, intravenous isoprenaline (available from ‘special-order’manufacturers or specialist importing companies,see p. 809) is an alternative. A cardiac pacemakercan be used to increase the heart rate.Calcium-channel blockersFeatures of calcium-channel blocker poisoning includenausea, vomiting, dizziness, agitation, confusion, andcoma in severe poisoning. Metabolic acidosis andhyperglycaemia may occur. Verapamil and diltiazemhave a profound cardiac depressant effect causing hypotensionand arrhythmias, including complete heartblock and asystole. The dihydropyridine calcium-channelblockers cause severe hypotension secondary toprofound peripheral vasodilatation.Activated charcoal should be considered if the childpresents within 1 hour of overdosage with a calciumchannelblocker; repeated doses of activated charcoalare considered if a modified-release preparation isinvolved (although activated charcoal may be effectivebeyond 1 hour with modified-release preparations). Inchildren with significant features of poisoning, calciumchloride or calcium gluconate (section 9.5.1.1) is givenby injection; atropine is given to correct symptomaticbradycardia. In severe cases, an insulin and glucoseinfusion may be required in the management of hypotensionand myocardial failure. For the management ofhypotension, the choice of inotropic sympathomimeticdepends on whether hypotension is secondary to vasodilatationor to myocardial depression—advice shouldbe sought from the National Poisons Information Service.Hypnotics and anxiolyticsBenzodiazepines Benzodiazepines taken alone causedrowsiness, ataxia, dysarthria, nystagmus, and occasionallyrespiratory depression, and coma. Theypotentiate the effects of other central nervous systemdepressants taken concomitantly. Activated charcoalcan be given within 1 hour of ingesting a significantquantity of benzodiazepine, provided the child is awakeand the airway is protected. Use of the benzodiazepineantagonist flumazenil [unlicensed indication] can behazardous, particularly in mixed overdoses involvingtricyclic antidepressants or in benzodiazepine-dependentpatients. Flumazenil may prevent the need forventilation, particularly in children with severe respiratorydisorders; it should be used on expert advice andnot as a diagnostic test in children with a reduced levelof consciousness.Iron saltsIron poisoning in childhood is usually accidental. Thesymptoms are nausea, vomiting, abdominal pain, diarrhoea,haematemesis, and rectal bleeding. Hypotensionand hepatocellular necrosis can occur later. Coma,shock and metabolic acidosis indicate severe poisoning.Advice should be sought from the National PoisonsInformation Service if a significant quantity of iron hasbeen ingested within the previous hour.Mortality is reduced by intensive and specific therapywith desferrioxamine, which chelates iron. The serumironconcentration is measured as an emergency andintravenous desferrioxamine given to chelate absorbediron in excess of the expected iron binding capacity. Insevere toxicity intravenous desferrioxamine should begiven immediately without waiting for the result of theserum-iron measurement.DESFERRIOXAMINE MESILATE(Deferoxamine Mesilate)Cautions section 9.1.3Renal impairment section 9.1.3Pregnancy section 9.1.3Breast-feeding section 9.1.3Side-effects section 9.1.3Licensed use licensed for use in children (age rangenot specified by manufacturer)Indication and doseIron poisoning. By continuous intravenous infusionNeonate up to 15 mg/kg/hour, reduced after 4–6hours; max. 80 mg/kg in 24 hours (in severe cases,higher doses on advice from the National PoisonsInformation Service)Child 1 month–18 years up to 15 mg/kg/hour,reduced after 4–6 hours; max. 80 mg/kg in 24hours (in severe cases, higher doses on advicefrom the National Poisons Information Service)Chronic iron overload section 9.1.3PreparationsSection 9.1.3LithiumLithium intoxication can occur as a complication oflong-term therapy and is caused by reduced excretionof the drug because of a variety of factors includingdehydration, deterioration of renal function, infections,and co-administration of diuretics or NSAIDs (or otherdrugs that interact). Acute deliberate overdoses mayalso occur with delayed onset of symptoms (12 hours ormore) due to slow entry of lithium into the tissues andcontinuing absorption from modified-release formulations.The early clinical features are non-specific and mayinclude apathy and restlessness which could be confusedwith mental changes due to the child’s depressive