BNF for Children 2011-2012

78 2.2.2 Loop diuretics BNFC 2011–20122 Cardiovascular systemCHLORTALIDONE(Chlorthalidone)Cautions see notes aboveContra-indications see notes aboveHepatic impairment see notes aboveRenal impairment see notes abovePregnancy see notes aboveBreast-feeding see notes aboveSide-effects see notes above; also rarely jaundiceIndication and doseHypertension. By mouthChild 5–12 years 0.5–1 mg/kg in the morningevery 48 hours; max. 1.7 mg/kg every 48 hoursChild 12–18 years 25 mg daily in the morning,increased to 50 mg daily if necessary (but see notesabove)Stable heart failure. By mouthChild 5–12 years 0.5–1 mg/kg in the morningevery 48 hours; max. 1.7 mg/kg every 48 hoursChild 12–18 years 25–50 mg daily in the morning,increased if necessary to 100–200 mg daily(reduce to lowest effective dose for maintenance)Ascites, oedema in nephrotic syndrome. By mouthChild 5–12 years 0.5–1 mg/kg in the morningevery 48 hours; max. 1.7 mg/kg every 48 hoursChild 12–18 years up to 50 mg dailyHygroton c (Alliance) ATablets, yellow, scored, chlortalidone 50 mg, net price28-tab pack = £1.64METOLAZONECautions see notes above; also acute porphyria (section9.8.2)Contra-indications see notes aboveHepatic impairment see notes aboveRenal impairment see notes abovePregnancy see notes aboveBreast-feeding see notes aboveSide-effects see notes above; also chills, chest painLicensed use not licensed for use in childrenIndication and doseOedema resistant to loop diuretics in heartfailure, renal disease, and hepatic disease;pulmonary oedema; adjunct to loop diuretics toinduce diuresis. By mouthChild 1 month–12 years 100–200 micrograms/kg once or twice dailyChild 12–18 years 5–10 mg once daily in themorning, increased to 5–10 mg twice daily inresistant oedemaAdministration tablets may be crushed and mixedwith water immediately before useMetenix 5 c (Sanofi-Aventis) ATablets, blue, metolazone 5 mg, net price 100-tabpack = £18.20Extemporaneous formulations available seeExtemporaneous Preparations, p. 62.2.2 Loop diureticsLoop diuretics inhibit reabsorption of sodium, potassium,and chloride from the ascending limb of the loopof Henlé in the renal tubule and are powerful diuretics.Furosemide and bumetanide are similar in activity;they produce dose-related diuresis. Furosemide isused extensively in children. It can be used for pulmonaryoedema (e.g. in respiratory distress syndrome andbronchopulmonary dysplasia), congestive heart failure,and in renal disease.Cautions Hypovolaemia and hypotension should becorrected before initiation of treatment with loop diuretics;electrolytes should be monitored during treatment(see also Potassium Loss, section 2.2). Loop diureticsshould be used with caution in comatose and precomatosestates associated with liver cirrhosis. Loop diureticscan exacerbate diabetes (but hyperglycaemia less likelythan with thiazides) and gout; they can also cause acuteurinary retention in children with obstruction of urinaryoutflow, therefore adequate urinary output should beestablished before initiating treatment.Contra-indications Loop diuretics should be avoidedin severe hypokalaemia, severe hyponatraemia, anuria,and in renal failure due to nephrotoxic or hepatotoxicdrugs.Hepatic impairment Hypokalaemia induced by loopdiuretics may precipitate hepatic encephalopathy andcoma—potassium-sparing diuretics can be used to preventthis.Renal impairment High doses of loop diuretics mayoccasionally be needed; high doses or rapid intravenousadministration can cause tinnitus and deafness; highdoses of bumetanide can also cause musculoskeletalpain.Pregnancy Furosemide and bumetanide should not beused to treat gestational hypertension because of thematernal hypovolaemia associated with this condition.Side-effects Side-effects of loop diuretics include mildgastro-intestinal disturbances, pancreatitis, hepaticencephalopathy, postural hypotension, temporaryincrease in serum-cholesterol and triglyceride concentration,hyperglycaemia (less common than with thiazides),acute urinary retention, electrolyte disturbances(including hyponatraemia, hypokalaemia (see section2.2), increased calcium excretion (nephrocalcinosisand nephrolithiasis reported with long-term use of furosemidein preterm infants), hypochloraemia, and hypomagnesaemia),metabolic alkalosis, blood disorders(including bone marrow depression, thrombocytopenia,and leucopenia), hyperuricaemia, visual disturbances,tinnitus and deafness (usually with high doses and rapidintravenous administration, and in renal impairment),rash, and photosensitivity.