BNF for Children 2011-2012

20 Prescribing in palliative care BNFC 2011–2012Prescribing in palliative carewhich can provide good control of symptoms with littlediscomfort or inconvenience to the patient.Syringe driver rate settingsStaff using syringe drivers should be adequatelytrained and different rate settings should be clearlyidentified and differentiated; incorrect use ofsyringe drivers is a common cause of medicationerrors.Indications for the parenteral route are:. inability to take medicines by mouth owing tonausea and vomiting, dysphagia, severe weakness,or coma;. malignant bowel obstruction for which surgery isinappropriate (avoiding the need for an intravenousinfusion or for insertion of a nasogastric tube);. refusal by the child to take regular medication bymouth.Bowel colic and excessive respiratory secretionsHyoscine hydrobromide (p. 198) effectively reducesrespiratory secretions and is sedative (but occasionallycauses paradoxical agitation); it is given in a subcutaneousor intravenous infusion dose of 40–60 micrograms/kg/24hours. Glycopyrronium (p. 636) mayalso be used.Hyoscine butylbromide (p. 40) is effective in bowelcolic, is less sedative than hyoscine hydrobromide, butis not always adequate for the control of respiratorysecretions; it is given by subcutaneous infusion (important:hyoscine butylbromide must not be confused withhyoscine hydrobromide, above).should not be mixed) does not apply to the use ofsyringe drivers in palliative care. Provided that there isevidence of compatibility, selected injections can bemixed in syringe drivers. Not all types of medicationcan be used in a subcutaneous infusion. In particular,chlorpromazine, prochlorperazine, and diazepam arecontra-indicated as they cause skin reactions at theinjection site; to a lesser extent cyclizine and levomepromazinealso sometimes cause local irritation.In theory injections dissolved in water for injections aremore likely to be associated with pain (possibly owing totheir hypotonicity). The use of physiological saline (sodiumchloride 0.9%) however increases the likelihood ofprecipitation when more than one drug is used; moreoversubcutaneous infusion rates are so slow (0.1–0.3 mL/hour) that pain is not usually a problem whenwater is used as a diluent.Diamorphine can be given by subcutaneous infusion ina strength of up to 250 mg/mL; up to a strength of40 mg/mL either water for injections or physiologicalsaline (sodium chloride 0.9%) is a suitable diluent—above that strength only water for injections is used (toavoid precipitation).The following can be mixed with diamorphine:Cyclizine 1Hyoscine hydrobromideDexamethasone 2LevomepromazineHaloperidol 3 Metoclopramide 4Hyoscine butylbromide MidazolamSubcutaneous infusion solution should be monitoredregularly both to check for precipitation (and discoloration)and to ensure that the infusion is running at thecorrect rate.Convulsions If a child has previously been receivingan antiepileptic drug or has a primary or secondarycerebral tumour or is at risk of convulsion (e.g. owing touraemia) antiepileptic medication should not bestopped. Midazolam (p. 234) is the benzodiazepine antiepilepticof choice for continuous subcutaneous infusion.Nausea and vomiting Levomepromazine (p. 175)causes sedation in about 50% of patients. Haloperidol(p. 174) has little sedative effect.Cyclizine (p. 193) is particularly likely to precipitate ifmixed with diamorphine or other drugs (see underMixing and Compatibility); it is given by subcutaneousinfusion.Pain control Diamorphine (p. 205) is the preferredopioid since its high solubility permits a large dose to begiven in a small volume (see under Mixing and Compatibility).The table on p. 21 shows approximate equivalentdoses of morphine and diamorphine.Restlessness and confusion Haloperidol has littlesedative effect. Levomepromazine (p. 175) has a sedativeeffect. Midazolam is a sedative and an antiepilepticthat may be suitable for a very restless patient.Mixing and compatibility The general principle thatinjections should be given into separate sites (andProblems encountered with syringe drivers Thefollowing are problems that may be encountered withsyringe drivers and the action that should be taken:. if the subcutaneous infusion runs too quickly checkthe rate setting and the calculation;. if the subcutaneous infusion runs too slowly checkthe start button, the battery, the syringe driver, thecannula, and make sure that the injection site is notinflamed;. if there is an injection site reaction make sure thatthe site does not need to be changed—firmness orswelling at the site of injection is not in itself anindication for change, but pain or obvious inflammationis.1. Cyclizine may precipitate at concentrations above 10 mg/mL or in the presence of sodium chloride 0.9% or as theconcentration of diamorphine relative to cyclizine increases;mixtures of diamorphine and cyclizine are alsolikely to precipitate after 24 hours.2. Special care is needed to avoid precipitation of dexamethasonewhen preparing it.3. Mixtures of haloperidol and diamorphine are likely toprecipitate after 24 hours if haloperidol concentration isabove 2 mg/mL.4. Under some conditions, infusions containing metoclopramidebecome discoloured; such solutions should bediscarded.