BNF for Children 2011-2012

182 4.2.3 Antimanic drugs BNFC 2011–20124 Central nervous systemLithium is used to treat acute episodes of mania inchildren who have responded to lithium before andwhose symptoms are not severe.The decision to give prophylactic lithium usuallyrequires specialist advice, and must be based on carefulconsideration of the likelihood of recurrence in theindividual child, and the benefit of treatment weighedagainst the risks. The full prophylactic effect of lithiummay not occur for six to twelve months after the initiationof therapy. An atypical antipsychotic or valproate(given alone or as adjunctive therapy with lithium) arealternative prophylactic treatments in patients whoexperience frequent relapses or continuing functionalimpairment. Long-term use of lithium has been associatedwith thyroid disorders and mild cognitive andmemory impairment. Long-term treatment shouldtherefore be undertaken only with careful assessmentof risk and benefit, and with monitoring of thyroidfunction at baseline and every 6 months (more often ifthere is evidence of deterioration). Renal functionshould be monitored at baseline and every 6 monthsthereafter (more often if there is evidence of deteriorationor the patient has other risk factors, such as startingACE inhibitors, NSAIDs, or diuretics). The need forcontinued therapy should be assessed regularly andchildren should be maintained on lithium after 3 to 5years only if benefit persists.Serum concentrations Lithium salts have a narrowtherapeutic/toxic ratio and should not be prescribedunless facilities for monitoring serum-lithium concentrationsare available. Samples should be taken 12 hoursafter the dose to achieve a serum-lithium concentrationof 0.4–1 mmol/litre. A target serum-lithium concentrationof 0.8–1 mmol/litre is recommended for acuteepisodes of mania, and for patients who have previouslyrelapsed or have sub-syndromal symptoms. It is importantto determine the optimum range for each individualchild. Serum-lithium monitoring should be performedweekly after initiation and after each dose change untilconcentrations are stable, then every 3 months thereafter.Additional serum-lithium measurements should bemade if a child develops significant intercurrent diseaseor if there is a significant change in a child’s sodium orfluid intake.Overdosage, usually with serum-lithium concentrationof over 1.5 mmol/litre, may be fatal and toxic effectsinclude tremor, ataxia, dysarthria, nystagmus, renalimpairment, and convulsions. If these potentially hazardoussigns occur, treatment should be stopped, serumlithiumconcentrations redetermined, and steps taken toreverse lithium toxicity. In mild cases withdrawal oflithium and administration of sodium and fluid willreverse the toxicity. A serum-lithium concentration inexcess of 2 mmol/litre requires urgent treatment asdescribed under Emergency Treatment of Poisoning,p. 30.Interactions Lithium toxicity is made worse by sodiumdepletion, therefore concurrent use of diuretics(particularly thiazides) is hazardous and should beavoided. For other interactions with lithium, seeAppendix 1 (lithium).Withdrawal While there is no clear evidence of withdrawalor rebound psychosis, abrupt discontinuation oflithium increases the risk of relapse. If lithium is to bediscontinued, the dose should be reduced gradually overa period of at least 4 weeks (preferably over a period ofup to 3 months). Children and carers should be warnedof the risk of relapse if lithium is discontinued abruptly.If lithium is stopped or has to be discontinued abruptly,consider changing therapy to an atypical antipsychoticor valproate.Lithium treatment packsA lithium treatment pack may be given to patientson initiation of treatment with lithium. The packconsists of a patient information booklet, lithiumalert card, and a record book for tracking serumlithiumconcentration.Packs may be purchased from 3MTel: 0845 610 1112nhsforms@spsl.uk.comLITHIUM CARBONATECautions measure serum-lithium concentration regularly(every 3 months on stabilised regimens), measurerenal function and thyroid function every 6months on stabilised regimens and advise childrenand carers to seek attention if symptoms of hypothyroidismdevelop (females are at greater risk) e.g.lethargy, feeling cold; maintain adequate sodium andfluid intake; test renal function before initiating and ifevidence of toxicity, avoid in cardiac disease, andconditions with sodium imbalance such as Addison’sdisease; reduce dose or discontinue in diarrhoea,vomiting, and intercurrent infection (especially ifsweating profusely); psoriasis (risk of exacerbation);diuretic treatment, myasthenia gravis; surgery (section15.1); if possible avoid abrupt withdrawal (seenotes above); interactions: Appendix 1 (lithium)Counselling Children should maintain adequate fluid intakeand avoid dietary changes which reduce or increase sodiumintake; lithium treatment packs are available (see above)Renal impairment avoid if possible or reduce doseand closely monitor serum-lithium concentrationPregnancy avoid if possible in first trimester (risk ofteratogenicity, including cardiac abnormalities); doserequirements increased in second and third trimesters(but on delivery, return abruptly to normal); closemonitoring of serum-lithium concentration advised(risk of toxicity in neonate)Breast-feeding present in milk and risk of toxicity ininfant—avoidSide-effects gastro-intestinal disturbances, fine tremor,renal impairment (particularly impaired urinaryconcentration and polyuria), polydipsia, leucocytosis;also weight gain and oedema (may respond to dosereduction); hyperparathyroidism and hypercalcaemiareported; signs of intoxication are blurred vision,increasing gastro-intestinal disturbances (anorexia,vomiting, diarrhoea), muscle weakness, increasedCNS disturbances (mild drowsiness and sluggishnessincreasing to giddiness with ataxia, coarse tremor,lack of coordination, dysarthria), and require withdrawalof treatment; with severe overdosage (serumlithiumconcentration above 2 mmol/litre) hyperreflexiaand hyperextension of limbs, convulsions, toxicpsychoses, syncope, renal failure, circulatory failure,coma, and occasionally, death; goitre, raised antidiuretichormone concentration, hypothyroidism,hypokalaemia, ECG changes, and kidney changesmay also occur; see also Emergency Treatment ofPoisoning, p. 30