Amiodarone

SCOPE: the UK SPC in this bundle is the INTRAVENOUS product only; the only full oral posology is the US Pacerone tablet label, plus the eMC's IV-to-oral changeover sentence. IV, verbatim (eMC §4.2): 'The standard recommended dose is 5mg/kg bodyweight given by intravenous infusion over a period of 20 minutes to 2 hours. This should be administered as a dilute solution in 250 ml 5% dextrose. This may be followed by repeat infusion up to 1200 mg (approximately 15 mg/kg bodyweight) in up to 500 ml 5% dextrose per 24 hours, the rate of infusion being adjusted on the basis of clinical response... Maintenance dose: 10 - 20 mg per kg bw in physiological glucose solution every 24 hours (on average 600 to 800 mg/ 24 hours up to a maximum of 1200 mg/ 24 hours accordingly 4-5 ampoules, maximum 8 ampoules) for a few days.' EMERGENCY INJECTION (eMC §4.2): 'In extreme clinical emergency, amiodarone may, at the discretion of the clinician, be given as a slow injection of 150-300 mg (or 2.5 - 5 mg/kg) in 10-20 ml 5% glucose over a minimum of 3 minutes. This should not be repeated for at least 15 minutes.' §4.4 adds 'The proposed dose of 5 mg per kg, given as a direct injection, must not be exceeded' - that is a weight-based ceiling, so it is recorded here rather than in maxDose, which carries only the absolute 1200 mg/24 hour infusion ceiling. ADMINISTRATION: central venous route except for cardiopulmonary resuscitation in cardiac arrest related to ventricular fibrillation resistant to defibrillation, where the peripheral route could be used; do not use concentrations below 300 mg per 500 ml; do not exceed 3 mg/ml, to prevent phlebitis; do not add other medicinal products to the infusion fluid or mix in the same syringe or line; bolus injection is discouraged because of hypotension and cardiovascular collapse. CHANGEOVER TO ORAL (eMC §4.2): 'As soon as an adequate response has been obtained (if possible, commence oral maintenance dose on the first day of the infusion), oral therapy should be initiated concomitantly at the usual loading dose (i.e. 200 mg three times a day). Amiodarone should then be phased out gradually.' NOTE THE DISCREPANCY: the US oral label loads at 800 to 1600 mg/day, well above the UK SPC's 200 mg three times a day (600 mg/day) - use the UK SPC of the specific oral tablet prescribed. US ORAL, verbatim: 'Initiate treatment with a loading dose of 800 to 1600 mg/day until initial therapeutic response occurs (usually 1 to 3 weeks). Once adequate arrhythmia control is achieved, or if side effects become prominent, reduce Pacerone tablets dose to 600 to 800 mg/day for one month and then to the maintenance dose, usually 400 mg/day'; divided doses with meals are suggested for total daily doses of 1000 mg or higher, or when gastrointestinal intolerance occurs. INTERACTION DOSE CAP (eMC §4.2, §4.4): 'In patients taking amiodarone concomitantly with simvastatin, the dose of simvastatin should not exceed 20 mg/day' - a simvastatin ceiling, not an amiodarone one. PREREQUISITE (eMC §4.2): 'Amiodarone should only be used when facilities exist for cardiac monitoring, defibrillation, and cardiac pacing'; §4.4 adds that it 'may only be prescribed by competent specialists' and is 'only to be used when other antiarrhythmics have shown insufficient effect'. PAEDIATRIC: paedDose is null - 'The safety and efficacy of amiodarone in children has not been established' and 'Due to the presence of benzyl alcohol, amiodarone intravenous administration is contraindicated in neonates, infants and children up to 3 years old' (eMC §4.2 and §4.3); the US label states safety and effectiveness in paediatric patients have not been established. The 5 mg/kg paediatric figure currently shown on the site page is NOT supported by anything in this bundle. Verify any under-18 use against a children's formulary. The eMC elderly paragraph, §4.4 and §4.8 are truncated at the source-fetch limit.