From the Guidelines
The starting dose for isoproterenol (isoprenaline) infusion should be 1–20 mcg/min, based on heart rate response, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Key Considerations
- Isoproterenol is a non-selective beta-adrenergic agonist that increases heart rate and cardiac output by stimulating beta-1 and beta-2 receptors.
- The infusion should be administered using an infusion pump for precise control, and the patient should be closely monitored for potential development of ischemic chest pain 1.
- Dose adjustments should be made gradually, based on the patient's heart rate response, to minimize the risk of adverse effects such as tachycardia, arrhythmias, and hypotension.
Administration Details
- The isoproterenol infusion can be prepared as a solution in 5% dextrose or normal saline, with a concentration that allows for easy titration.
- The patient's heart rate, blood pressure, ECG, and symptoms should be closely monitored during administration, with adjustments made as needed to achieve the desired clinical effect while minimizing adverse effects.
Clinical Context
- Isoproterenol is primarily used in emergency situations for bradycardia, heart block, or cardiogenic shock when other treatments have failed, and its use should be guided by the patient's individual clinical needs and response to treatment 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Initiate Isoproterenol Hydrochloride Injection at the lowest recommended dose and increase gradually based on patient response (2.2) Recommended initial dosage: Shock: 0.5 mcg to 5 mcg per minute as an intravenous infusion (2.2) Bronchospasm: 10 mcg to 20 mcg intravenous injection (2.2)
The starting dose for isoproterenol (isoprenaline) infusion is 0.5 mcg to 5 mcg per minute as an intravenous infusion for shock, and 10 mcg to 20 mcg as an intravenous injection for bronchospasm 2, 3, 4.
From the Research
Starting Dose for Isoproterenol Infusion
The starting dose for isoproterenol infusion varies depending on the specific medical context and patient population.
- In a study comparing the hemodynamic effects of prenalterol and isoprenaline in patients with complete heart block, isoprenaline was given as a continuous infusion at two increasing doses, starting with 1.7 micrograms/min 5.
- A study on the metabolic and cardiovascular effects of infusions of low doses of isoprenaline in man used infusion rates of 5 and 15 ng min-1 kg-1 body weight 6.
- In a study exploring the utility of isoproterenol in unmasking latent escape rhythm in pacemaker-dependent patients, isoproterenol was infused at 1 microg/min for 2 minutes, followed by 2 microg/min for 2 minutes 7.
- Another study used an initial dosage of 3.8 gamma/minute, which was progressively increased until the heart rate was equal to or greater than 130/minute 8.
- A study on the hemodynamic effect of isoprenaline and dobutamine immediately after correction of tetralogy of Fallot used increasing doses of isoprenaline, starting with 0.05 micrograms/kg/min 9.