BNF for Children 2011-2012

172 4.2.1 Antipsychotic drugs BNFC 2011–20124 Central nervous system2. Bear in mind risk factors, including obesity.3. Consider potential for drug interactions—see interactions:Appendix 1 (antipsychotics).4. Carry out ECG to exclude untoward abnormalitiessuch as prolonged QT interval; repeat ECG periodicallyand reduce dose if prolonged QT interval orother adverse abnormality develops.5. Increase dose slowly and not more often than onceweekly.6. Carry out regular pulse, blood pressure, and temperaturechecks; ensure that patient maintains adequatefluid intake.7. Consider high-dose therapy to be for limited periodand review regularly; abandon if no improvementafter 3 months (return to standard dosage).Important When prescribing an antipsychotic for administrationon an emergency basis, the intramuscular dose should belower than the corresponding oral dose (owing to absence offirst-pass effect), particularly if the child is very active(increased blood flow to muscle considerably increases therate of absorption). The prescription should specify the dose foreach route and should not imply that the same dose can begiven by mouth or by intramuscular injection. The dose ofantipsychotic for emergency use should be reviewed at leastdaily.4.2.1 Antipsychotic drugsThere is little information on the efficacy and safety ofantipsychotic drugs in children and adolescents andmuch of the information available has been extrapolatedfrom adult data; in particular, little is known about thelong-term effects of antipsychotic drugs on the developingnervous system. Antipsychotic drugs should beinitiated and managed under the close supervision of anappropriate specialist.Antipsychotic drugs are also known as ‘neuroleptics’and (misleadingly) as ‘major tranquillisers’. Antipsychoticdrugs generally tranquillise without impairingconsciousness and without causing paradoxical excitementbut they should not be regarded merely as tranquillisers.For conditions such as schizophrenia thetranquillising effect is of secondary importance.In the short term they are used to calm disturbedchildren whatever the underlying psychopathology,which may be schizophrenia, brain damage, mania,toxic delirium, or agitated depression. Antipsychoticdrugs are used to alleviate severe anxiety but this tooshould be a short-term measure.Schizophrenia Antipsychotic drugs relieve psychoticsymptoms such as thought disorder, hallucinations, anddelusions, and prevent relapse. Although they are usuallyless effective in apathetic withdrawn children, theysometimes appear to have an activating influence. Childrenwith acute schizophrenia generally respond betterthan those with chronic symptoms. Children shouldreceive antipsychotic drugs for 4–6 weeks before thedrug is deemed ineffective.Long-term treatment of a child with a definite diagnosisof schizophrenia may be necessary even after the firstepisode of illness in order to prevent the manifest illnessfrom becoming chronic. Withdrawal of drug treatmentrequires careful surveillance because children whoappear well on medication may suffer a disastrousrelapse if treatment is withdrawn inappropriately. Inaddition the need for continuation of treatment maynot become immediately evident because relapse isoften delayed for several weeks after cessation of treatment.Antipsychotic drugs are considered to act by interferingwith dopaminergic transmission in the brain by blockingdopamine D 2 receptors, which may give rise to theextrapyramidal effects described below, and also tohyperprolactinaemia. Antipsychotic drugs may alsoaffect cholinergic, alpha-adrenergic, histaminergic, andserotonergic receptors.Choice of drug is influenced by the potential for sideeffectsand is often guided by individual circumstancese.g. the psychological effects of potential weight gain.The drugs most commonly used in children are haloperidol,risperidone, and olanzapine.Cautions Assess child for movement disorders beforestarting treatment. Monitor neurological parameters,bowel habit, pulse, and blood pressure. Regular clinicalmonitoring of endocrine function should be consideredwhen children are taking an antipsychotic known toincrease prolactin levels; this includes measuring weightand height, assessing sexual maturation, and monitoringmenstrual function. Children with schizophrenia shouldhave physical health monitoring (including cardiovasculardisease risk assessment) at least once per year.Antipsychotic drugs should be used with caution inchildren with cardiovascular disease; an ECG may berequired (see individual drug monographs), particularlyif physical examination identifies cardiovascular riskfactors, if there is a personal history of cardiovasculardisease, or if the child is being admitted as an inpatient.Antipsychotic drugs should also be used with caution inchildren with epilepsy (and conditions predisposing toepilepsy), depression, myasthenia gravis (avoid chlorpromazine,pericyazine and prochlorperazine in theseconditions) or a susceptibility to angle-closure glaucoma.Caution is also required in severe respiratorydisease and in children with a history of jaundice orwho have blood dyscrasias (perform blood counts ifunexplained infection or fever develops). As photosensitisationmay occur with higher dosages, childrenshould avoid direct sunlight. Interactions: Appendix 1(antipsychotics).Contra-indications Antipsychotic drugs may be contra-indicatedin comatose states, CNS depression, andphaeochromocytoma.Skilled tasks Drowsiness may affect performance ofskilled tasks (e.g. driving or operating machinery), especiallyat start of treatment; effects of alcohol areenhanced.Withdrawal There is a high risk of relapse if medicationis stopped after 1–2 years. Withdrawal of antipsychoticdrugs after long-term therapy should always begradual and closely monitored to avoid the risk of acutewithdrawal syndromes or rapid relapse. Children shouldbe monitored regularly for signs and symptoms ofrelapse for 2 years after withdrawal of antipsychoticmedication.Hepatic impairment All antipsychotics can precipitatecoma if used in hepatic impairment; phenothiazinesare hepatotoxic.