BNF for Children 2011-2012

BNFC 2011–2012 2.5.4 Alpha-adrenoceptor blocking drugs 99they have largely fallen from use in adults and are rarelyused in children.2.5.4 Alpha-adrenoceptorblocking drugsDoxazosin and prazosin have post-synaptic alphablockingand vasodilator properties and rarely causetachycardia. They can, however, reduce blood pressurerapidly after the first dose and should be introduced withcaution.Alpha-blockers can be used with other antihypertensivedrugs in the treatment of resistant hypertension.DOXAZOSINCautions care with initial dose (postural hypotension);pulmonary oedema due to aortic or mitral stenosis;cataract surgery (risk of intra-operative floppy irissyndrome); heart failure; interactions: Appendix 1(alpha-blockers)Driving May affect performance of skilled tasks e.g. drivingContra-indications history of postural hypotensionHepatic impairment use with caution; manufactureradvises avoid in severe impairment—no informationavailablePregnancy no evidence of teratogenicity; manufacturersadvise use only when potential benefit outweighsriskBreast-feeding accumulates in milk in animal studies—manufactureradvises avoidSide-effects gastro-intestinal disturbances; oedema,hypotension, postural hypotension, palpitation,tachycardia; dyspnoea, rhinitis, coughing; asthenia,fatigue, vertigo, dizziness, headache, paraesthesia,sleep disturbance, anxiety, depression; influenza-likesymptoms; back pain, myalgia; less commonly weightchanges; angina, myocardial infarction; hypoaesthesia,syncope, tremor, agitation, micturition disturbances,impotence, epistaxis, arthralgia, gout, tinnitus,hypersensitivity reactions (including pruritus,purpura, rash); very rarely cholestasis, hepatitis,jaundice, bradycardia, arrhythmias, bronchospasm,hot flushes, gynaecomastia, priapism, abnormal ejaculation,leucopenia, thrombocytopenia, blurredvision, and alopeciaLicensed use not licensed for use in childrenIndication and doseHypertension (see notes above). By mouthChild 6–12 years 500 micrograms once daily,increased at 1-week intervals to 2–4 mg dailyChild 12–18 years 1 mg daily, increased after 1–2weeks to 2 mg once daily, and thereafter to 4 mgonce daily if necessary; usual max. 4 mg daily(rarely up to 16 mg daily may be required)Dysfunctional voiding section 7.4.1Doxazosin (Non-proprietary) ATablets, doxazosin (as mesilate) 1 mg, net price 28-tab pack = 93p; 2 mg, 28-tab pack = 99p; 4 mg, 28-tabpack = £1.39. Counselling, initial dose, drivingBrands include Doxadura cCardura c (Pfizer) ATablets, doxazosin (as mesilate) 1 mg, net price 28-tabpack = £10.56; 2 mg, 28-tab pack = £14.08. Counselling,initial dose, drivingExtemporaneous formulations available seeExtemporaneous Preparations, p. 6Modified-releaseNote Children stabilised on immediate-release doxazosin canbe transferred to the equivalent dose of modified-release doxazosinDoxazosin (Non-proprietary) ATablets, m/r, doxazosin (as mesilate) 4 mg, net price28-tab pack = £6.33. Label: 25, counselling, initialdose, drivingBrands include Doxadura c XL, Raporsin c XL, Slocinx c XLCardura c XL (Pfizer) ATablets, m/r, doxazosin (as mesilate) 4 mg, net price28-tab pack = £5.70; 8 mg, 28-tab pack = £9.98.Label: 25, counselling, initial dose, drivingPRAZOSINCautions first dose may cause collapse due to hypotension(therefore should be taken on retiring to bed);cataract surgery (risk of intra-operative floppy irissyndrome); interactions: Appendix 1 (alpha-blockers)Driving May affect performance of skilled tasks e.g. drivingContra-indications not recommended for congestiveheart failure due to mechanical obstruction (e.g. aorticstenosis)Hepatic impairment start with low doses and adjustaccording to responseRenal impairment start with low doses in moderateto severe impairment; increase with cautionPregnancy no evidence of teratogenicity; manufactureradvises use only when potential benefit outweighsriskBreast-feeding present in milk; manufacturer advisesuse with cautionSide-effects gastro-intestinal disturbances; posturalhypotension, oedema, palpitation; dyspnoea, nasalcongestion; drowsiness, headache, depression, nervousness,vertigo; urinary frequency; weakness;blurred vision; less commonly tachycardia, insomnia,paraesthesia, sweating, impotence, arthralgia, eyedisorders, tinnitus, epistaxis, allergic reactionsincluding rash, pruritus, and urticaria; rarely pancreatitis,flushing, vasculitis, bradycardia, hallucinations,worsening of narcolepsy, gynaecomastia,priapism, urinary incontinence, and alopeciaLicensed use not licensed for use in children under12 yearsIndication and doseHypertension (see notes above). By mouthChild 1 month–12 years 10–15 micrograms/kg2–4 times daily (initial dose at bedtime) increasedgradually to max. 500 micrograms/kg daily individed doses (not exceeding 20 mg daily)Child 12–18 years 500 micrograms 2–3 timesdaily (initial dose at bedtime), increased after 3–7days to 1 mg 2–3 times daily for a further 3–7 days;further increased gradually if necessary to max.20 mg daily in divided doses2 Cardiovascular system