BNF for Children 2011-2012

BNFC 2011–2012 9.1.3 Drugs used in hypoplastic, haemolytic, renal anaemias 451tions include skin ulceration, renal failure, and increasedsusceptibility to infection. Pneumococcal vaccine (section14.4), haemophilus influenzae type b vaccine (section14.4), an annual influenza vaccine (section 14.4),and prophylactic penicillin (Table 2, section 5.1) reducethe risk of infection. Hepatitis B vaccine (section 14.4)should be considered if the child is not immune.In most forms of sickle-cell disease, varying degrees ofhaemolytic anaemia are present accompanied byincreased erythropoiesis; this may increase folaterequirements and folate supplementation may be necessary(section 9.1.2).Hydroxycarbamide can reduce the frequency of crisesand the need for blood transfusions. Hydroxycarbamideshould be considered, in consultation with a specialistcentre, for children who have recurrent episodes ofacute pain (more than 3 admissions in the previous 12months, or who are very symptomatic in the community)or who have had 2 or more episodes of acute sicklechest syndrome in the last 2 years (or 1 episode requiringventilatory support). Beneficial effects of hydroxycarbamidemay not become evident for several months.Myelosuppression, and skin reactions are the mostcommon side-effects.HYDROXYCARBAMIDE(Hydroxyurea)Cautions see section 8.1 and notes above; also monitorrenal and hepatic function before and duringtreatment; monitor full blood count before treatment,then every 2 weeks for the first 2 months and thenevery 2 months thereafter (or every 2 weeks if onmax. dose); leg ulcers (review treatment if cutaneousvasculitic ulcerations develop); interactions: Appendix1 (hydroxycarbamide)Hepatic impairment manufacturer advises caution inmild to moderate impairment; avoid in severeimpairmentRenal impairment reduce initial dose by 50% if estimatedglomerular filtration rate less than 60 mL/minute/1.73 m 2 ; avoid if estimated glomerular filtrationrate less than 30 mL/minute/1.73 m 2Pregnancy avoid (teratogenic in animal studies);manufacturer advises effective contraception beforeand during treatment; see also section 8.1Breast-feeding discontinue breast-feedingSide-effects see section 8.1 and notes above; alsoheadache; less commonly dizziness, and rash; rarelyreduced sperm count and activity; fever, amenorrhoea,bleeding, and hypomagnesaemia also reportedIndication and doseSickle-cell disease (see notes above). By mouthChild 2–18 years initially 10–15 mg/kg oncedaily, increased every 12 weeks in steps of 5 mg/kg daily according to response; usual dose 15–30 mg/kg daily (max. 35 mg/kg daily)Iron overloadSevere tissue iron overload can occur in aplastic andother refractory anaemias, mainly as the result ofrepeated blood transfusions. It is a particular problemin refractory anaemias with hyperplastic bone marrow,especially thalassaemia major, where excessive ironabsorption from the gut and inappropriate iron therapycan add to the tissue siderosis.Iron overload associated with haemochromatosis canbe treated with repeated venesection. Venesection mayalso be used for patients who have received multipletransfusions and whose bone marrow has recovered.Where venesection is contra-indicated, and in thalassaemia,the long-term administration of the iron chelatingcompound desferrioxamine mesilate is useful.Subcutaneous infusions of desferrioxamine are givenover 8–12 hours, 3–7 times a week; the dose shouldreflect the degree of iron overload. The initial doseshould not exceed 30 mg/kg. For established overloadthe dose is usually between 20 and 50 mg/kg daily.Desferrioxamine (up to 2 g per unit of blood) may alsobe given at the time of blood transfusion, provided thatthe desferrioxamine is not added to the blood and is notgiven through the same line as the blood (but the twomay be given through the same cannula).Iron excretion induced by desferrioxamine is enhancedby ascorbic acid (vitamin C, section 9.6.3) 100–200 mgdaily by mouth; it should be given separately from foodsince it also enhances iron absorption. Ascorbic acidshould not be given to children with cardiac dysfunction;in children with normal cardiac function ascorbicacid should be introduced 1 month after starting desferrioxamine.Desferrioxamine infusion can be used to treat aluminiumoverload in dialysis patients; theoretically 100 mgof desferrioxamine binds with 4.1 mg of aluminium.Deferasirox, an oral iron chelator, is licensed for thetreatment of chronic iron overload in children over 6years with thalassaemia major who receive frequentblood transfusions (more than 7 mL/kg/month ofpacked blood cells). It is also licensed for chronic ironoverload when desferrioxamine is contra-indicated orinadequate in children with thalassaemia major whoreceive infrequent blood transfusions (less than 7 mL/kg/month of packed red blood cells), in children withother anaemias, and in children aged 2 to 5 years.The Scottish Medicines Consortium (p. 3) has advised(January 2007) that deferasirox is accepted forrestricted use within NHS Scotland for the treatmentof chronic iron overload associated with the treatmentof rare acquired or inherited anaemias requiring recurrentblood transfusions. It is not recommended forpatients with myelodysplastic syndromes.Deferiprone, an oral iron chelator, is licensed for thetreatment of iron overload in children over 6 years ofage with thalassaemia major in whom desferrioxamineis contra-indicated or is inadequate. Blood dyscrasias,particularly agranulocytosis, have been reported withdeferiprone.9 Nutrition and bloodSiklos c (Nordic) TATablets, scored, f/c, hydroxycarbamide 1 g, net price30-tab pack = £500.00Extemporaneous formulations available seeExtemporaneous Preparations, p. 6DEFERASIROXCautions eye and ear examinations required beforetreatment and annually during treatment; monitorbody-weight, height and sexual developmentannually; monitor serum-ferritin concentration