From the Guidelines
Isoproterenol should be used with caution in patients with bradycardia, particularly those with coronary artery disease, due to its potential to increase myocardial oxygen demand, and its use is generally limited to specific situations such as temporary management of symptomatic bradycardia or treating torsades de pointes, as evidenced 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 can increase heart rate and contractility, but it may also increase myocardial oxygen demand, which can be detrimental in patients with coronary artery disease.
- The typical adult dosage of isoproterenol ranges from 2-10 mcg/min as an intravenous infusion, titrated to the desired heart rate response, as noted in the 2018 ACC/AHA/HRS guideline 1.
- Isoproterenol has largely been replaced by more selective agents in many clinical scenarios, but it remains valuable in specific situations, such as temporary management of symptomatic bradycardia while awaiting pacemaker placement or treating torsades de pointes.
Important Side Effects
- Tachycardia
- Arrhythmias
- Hypotension
- Tremors
Clinical Context
- Isoproterenol is predominantly used in the electrophysiology laboratory (1-20 mcg/min intravenously) and has only a second-line role in treatment of bradycardia in the setting of resuscitation, as stated in the 2018 ACC/AHA/HRS guideline 1.
- Two RCTs of isoproterenol as adjunctive therapy in the setting of cardiac arrest did not show improved return of spontaneous circulation or survival to hospital discharge, highlighting the need for caution when using this medication in critical care settings 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Isopreteronol Overview
- Isopreteronol, also known as isoproterenol, is a medication used to treat various conditions, including asymptomatic sinus bradycardia, asthma, and atrioventricular nodal reentrant tachycardia.
- The effects of isoproterenol on the heart and lungs have been studied in several research papers 2, 3, 4, 5, 6.
Cardiac Effects
- Isoproterenol has been used to evaluate chronotropic reserve in patients with asymptomatic sinus bradycardia, and the results show that it can differentiate those with inadequate chronotropic reserves, possibly requiring preventive pacemaker implantations 2.
- The medication has also been used to induce atrioventricular nodal reentrant tachycardia in patients undergoing slow pathway ablation, and it has been found to be more effective than atropine in inducing the arrhythmia 5.
- Isoproterenol-induced cardiac hypertrophy has been studied, and the results suggest that it is not associated with increases in left ventricular angiotensin II, and that the circulatory or cardiac renin-angiotensin system may not play a role in the cardiac trophic responses to beta-receptor stimulation 6.
Respiratory Effects
- Isoproterenol has been used as a bronchodilator in patients with asthma, and it has been found to be effective in improving lung function, although it may have a shorter duration of action compared to other medications such as ipratropium bromide and albuterol 3, 4.
- The medication has been compared to other bronchodilators, and the results show that it may have similar efficacy, but with more significant cardiovascular side effects 4.
Comparison with Other Medications
- Isoproterenol has been compared to atropine in several studies, and the results show that it may have different effects on the heart and lungs, with isoproterenol being more effective in inducing atrioventricular nodal reentrant tachycardia and improving lung function in patients with asthma 2, 5.
- The medication has also been compared to other bronchodilators, such as ipratropium bromide and albuterol, and the results show that it may have similar efficacy, but with more significant cardiovascular side effects 3, 4.