From the Guidelines
Isoprenaline should be administered at a dosage of 20-60 mcg IV bolus followed by doses of 10-20 mcg, or infusion of 1-20 mcg/min based on heart rate response for the acute medical management of bradycardia attributable to sinus node dysfunction (SND) or atrioventricular block. This recommendation is based on the 2019 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Key Considerations
- Isoprenaline is a non-selective beta-adrenergic receptor agonist that increases heart rate and contractility while causing bronchodilation and peripheral vasodilation.
- The medication should be used with caution in patients with ischemic heart disease, as it increases myocardial oxygen demand.
- Common side effects include tachycardia, palpitations, headache, tremor, and hypotension due to peripheral vasodilation.
- Isoprenaline requires careful monitoring of heart rate, blood pressure, and ECG during administration.
Clinical Context
- Isoprenaline is valuable in specific situations such as temporary management of symptomatic bradycardia while awaiting pacemaker placement or treating torsades de pointes by increasing heart rate.
- The medication has largely been replaced by more selective agents in many clinical scenarios but remains an important option in certain emergency situations.
- The dosage and administration of isoprenaline should be tailored to the individual patient's response and clinical context, as outlined in the 2019 ACC/AHA/HRS guideline 1.
Administration and Monitoring
- Isoprenaline should be administered under close monitoring, with careful attention to heart rate, blood pressure, and ECG changes.
- The medication can be titrated to achieve the desired heart rate response, with doses adjusted as needed to minimize side effects and optimize efficacy.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Isoprenaline Overview
- Isoprenaline is a beta-adrenergic drug used to increase heart rate and facilitate the induction of supraventricular and ventricular tachycardias during electrophysiological studies 2.
- It is also used as a bronchodilator in patients with asthma, with effects comparable to other beta-adrenergic stimulants such as salbutamol and orciprenaline 3, 4.
Cardiovascular Effects
- Isoprenaline infusion can cause a paradoxical bradycardia in some patients, which is a rare phenomenon 2.
- The drug has been shown to increase heart rate, cardiac output, and metabolic rate, with effects that are more pronounced than those of salbutamol 3.
- Isoprenaline has been used to treat unstable third-degree atrioventricular block, with a higher success rate and better tolerability compared to dopamine 5.
Respiratory Effects
- Isoprenaline has bronchodilator effects, which are comparable to those of salbutamol and orciprenaline 3, 4, 6.
- The drug has been shown to increase FEV(1) and improve ventilatory function in patients with asthma, although its effects may be shorter-lived compared to salbutamol 4, 6.