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esmolol

esmolol

see also beta blockers

Summary:

  • Beta1 blocker with T1/2=10min due to rapid hydrolysis of an ester linkage by RBC esterases thus useful as antiarrhythmic & in critically ill pt.
  • Peak IV effect 6-10min, rapid attenuation over 20min. after stop inf.
  • May have striking hypotensive effects in normal subjects!!
  • Little if any intrinsic activity, no memb-stab. activity;
  • 250mg/ml to dilute or as 10mg/ml, infusion concentrations > 10mg/ml irritate vein and should be given via CVC
  • incompatible with bicarbonate but compatible with dopamine, morphine, nitroprusside, nitroglycerin, lignocaine

drug interactions:

  • calcium channel blockers ⇒ AV block, myocardial depression, risk of cardiac arrest
  • vasocontrictor inotropes (dopamine, adrenaline) ⇒ danger of blocking contractility when systemic vascular resistance is high
  • catecholamine depleting agents ⇒ marked hypotension, bradycardia
  • digoxin ⇒ digoxin levels 10-20% higher
  • morphine ⇒ esmolol levels 46% higher
  • suxamethonium ⇒ longer duration of action of suxamethonium to 5-8min.

Mx of SVT or AF with rapid ventricular rate:

  • see SVT, AF
  • 0.5mg/kg IV esmolol diluted over 1 minute, then 50ug/kg/min infusion (eg. 5g in 500ml 5%D ⇒ 10mg/ml) for 4 min
  • if heart rate controlled maintain infusion at rate that controls heart rate
  • if heart rate not controlled, give increase in titrated steps with each step consisting of:
    • further load dose 0.5mg/kg over 1min
    • increase infusion rate by 50ug/kg/min (to max. rate of 200ug/kg/min) for 4-10min
  • once rate stabilised can change to longer acting agent:
    • propranolol 10-30mg 6-8h o, or digoxin 0.125-0.5mg 6h o/iv
    • halve esmolol infusion rate 30min after 1st dose of longer acting agent
    • if satisfactory rate control maintained for 1st hour after 2nd dose of longer acting agent, cease esmolol.
  • (max. 300µg/kg/min?) Can use for up to 48hrs;
esmolol.txt · Last modified: 2009/02/24 21:06 (external edit)