BNF for Children 2011-2012

184 4.3.1 Tricyclic antidepressant drugs BNFC 2011–20124 Central nervous systemTricyclic antidepressant drugs should be avoided for thetreatment of depression in children.St John’s wort (Hypericum perforatum) is a popularherbal remedy on sale to the public for treating milddepression in adults. It should not be used for thetreatment of depression in children because St John’swort can induce drug metabolising enzymes and anumber of important interactions with conventionaldrugs, including conventional antidepressants, havebeen identified (see Appendix 1, St John’s wort).Furthermore, the amount of active ingredient variesbetween different preparations of St John’s wort andswitching from one to another can change the degree ofenzyme induction. If a child stops taking St John’s wort,the concentration of interacting drugs may increase,leading to toxicity.Hyponatraemia and antidepressant therapyHyponatraemia (possibly due to inappropriate secretionof antidiuretic hormone) has been associatedwith all types of antidepressants; however, it hasbeen reported more frequently with SSRIs thanwith other antidepressant drugs. Hyponatraemiashould be considered in all children who developdrowsiness, confusion, or convulsions while takingan antidepressant drug.Suicidal behaviour and antidepressant therapyThe use of antidepressant drugs has been linkedwith suicidal thoughts and behaviour. Where necessary,children should be monitored for suicidal behaviour,self-harm, and hostility, particularly at thebeginning of treatment or if the dose is changed.Management Children should be reviewed every 1–2weeks at the start of antidepressant treatment. Treatmentshould be continued for at least 4 weeks beforeconsidering whether to switch antidepressant due tolack of efficacy. In cases of partial response, continuefor a further 2–4 weeks. Following remission, antidepressanttreatment should be continued at the samedose for at least 6 months. Children with a history ofrecurrent depression should continue treatment for atleast 2 years.Withdrawal Withdrawal effects may occur within 5days of stopping treatment with antidepressant drugs;they are usually mild and self-limiting, but in some casesmay be severe. The risk of withdrawal symptoms isincreased if the antidepressant is stopped suddenlyafter regular administration for 8 weeks or more. Thedose should preferably be reduced gradually over about4 weeks, or longer if withdrawal symptoms emerge (6months in children who have been on long-term maintenancetreatment). See also section 4.3.1, and section4.3.3.Anxiety Management of acute anxiety in children withdrug treatment is contentious (section 4.1.2). Forchronic anxiety (of longer than 4 weeks’ duration), itmay be appropriate to use an antidepressant drugbefore a benzodiazepine.4.3.1 Tricyclic antidepressantdrugsStudies have shown that tricyclic antidepressants arenot effective for treating depression in children.For reference to the role of some tricyclic antidepressantdrugs in some forms of neuralgia, see section 4.7.3,and in nocturnal enuresis in children, see section 7.4.2.Dosage It is important to use doses that are sufficientlyhigh for effective treatment but not so high as to causetoxic effects. Low doses should be used for initial treatment.In most children the long half-life of tricyclic antidepressantdrugs allows once-daily administration, usually atnight; the use of modified-release preparations is thereforeunnecessary.Cautions Tricyclic antidepressant drugs should beused with caution in children with cardiovascular disease(see also Contra-indications, below); because of therisk of arrhythmias, children with concomitant conditionssuch as hyperthyroidism and phaeochromocytomashould be treated with care. Care is also needed inchildren with epilepsy and diabetes.Tricyclic antidepressant drugs have antimuscarinicactivity, and therefore caution is needed in childrenwith chronic constipation, urinary retention, or thosewith a susceptibility to angle-closure glaucoma. Tricyclicantidepressant drugs should be used with cautionin children with a significant risk of suicide, or a historyof psychosis or bipolar disorder, because antidepressanttherapy may aggravate these conditions; treatmentshould be stopped if the child enters a manic phase.Skilled tasks Drowsiness may affect the performanceof skilled tasks (e.g. driving); effects of alcoholenhanced.Contra-indications Tricyclic antidepressants are contra-indicatedin arrhythmias (particularly heart block),and in the manic phase of bipolar disorder. Avoid treatmentwith tricyclic antidepressant drugs in acute porphyria(section 9.8.2).Hepatic impairment The sedative effects of tricyclicantidepressant drugs are increased in children withhepatic impairment. They should be avoided in severeliver disease.Breast-feeding The amount of tricyclic antidepressantssecreted into breast milk is too small to be harmful(but see Doxepin, p. 185).Side-effects Arrhythmias and heart block occasionallyfollow the use of tricyclic antidepressants, particularlyamitriptyline, and may be a factor in the suddendeath of children with cardiac disease; other cardiovascularside-effects include postural hypotension, tachycardia,and ECG changes.Central nervous system side-effects are common, andinclude anxiety, dizziness, agitation, confusion, sleepdisturbances, irritability, and paraesthesia; drowsiness