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Isoproterenol
Aka: Isoproterenol
- Pathophysiology
- Synthetic Sympathomimetic amine
- Pure Beta Adrenergic Agonist
- Potent Chronotropic effects
- Increases Heart Rate
- Potentiates AV conduction
- Potent Inotropic effects
- Increases cardiac contractility
- Markedly increases Cardiac Output
- Causes Peripheral vasodilatation
- Decreases Diastolic pressure
- Causes Bronchodilation
- Markedly increases myocardial oxygen demand
- May provoke Myocardial Ischemia
- May decrease coronary perfusion
- Pharmacokinetics
- Very short half-life (<1.5 minutes)
- Indications
- Other inotropic agents preferred over Isoproterenol
- Dobutamine
- Amrinone
- Hemodynamically significant Bradycardia (pulse present)
- Specific Uses
- Heart Block
- Bradycardia in denervated transplanted heart
- Unresponsive to other measures
- Atropine
- Epinephrine
- Transcutaneous pacing or transvenous pacing
- Dopamine
- Contraindication
- Ischemic Heart Disease
- Pediatric Infusion (Same as Epinephrine preparation)
- Preparation
- Draw up "x" mg of Isoproterenol
- Where "x" = 0.6 x Weight in Kilograms
- Add enough D5W or NS for 100 ml total
- At this dilution:
- Infusion rate of 1 ml/h provides 0.1 ug/kg/min
- Start Dose: 10 ml/hour (10 ug/kg/min)
- Titrate to clinical response, adjusting every 5 min
- Adult Infusion
- Preparation
- Dissolve 1 mg Isoproterenol in 250 ml D5W
- Final Concentration: 4 ug/ml
- Start Dose: 2 ug/min
- Titrate: 2-10 ug/min to clinical response
- Heart Rate over 60 beats per minute
- Precautions
- Decreases Diastolic Blood Pressure
- No alpha adrenergic effect
- Increases Heart Rate (less diastolic filling time)
- May precipitate Myocardial Ischemia
- Increases myocardial oxygen demand
- Decreases coronary perfusion
- Induces Arrhythmias
- Ventricular Tachycardia
- Ventricular Fibrillation
- Exacerbates tachyarrhythmias due to Digitalis Toxicity
- Precipitates Hypokalemia