From the Guidelines
Glucagon can be used as an antidote for beta blocker overdose, given as 3-10 mg IV bolus, followed by an infusion of 3-5 mg/hour, to help counteract cardiovascular depression by activating adenylyl cyclase through a pathway independent of beta-receptors. In beta blocker toxicity, glucagon can help increase cardiac contractility and heart rate by bypassing the blocked beta receptors. However, glucagon should be considered as just one component of comprehensive management, which may also include:
- IV fluids
- Vasopressors
- Calcium
- High-dose insulin therapy
- In severe cases, lipid emulsion therapy or extracorporeal support The effectiveness of glucagon can be limited in severe overdoses, and its effects may be transient. Additionally, glucagon can cause side effects including nausea, vomiting, and hyperglycemia. Treatment should be initiated promptly and managed in a hospital setting, ideally with consultation from a poison control center or toxicologist 1. Some key points to consider when using glucagon for beta blocker overdose include:
- The recommended dose of glucagon is a bolus of 3 to 10 mg, administered slowly over 3 to 5 minutes, followed by an infusion of 3 to 5 mg/h 1
- The infusion rate is titrated to achieve an adequate hemodynamic response (appropriate mean arterial pressure and evidence of good perfusion) 1
- Glucagon commonly causes vomiting, and in patients with central nervous system depression, the airway must be protected before glucagon administration 1
From the FDA Drug Label
• Beta-blockers: Patients taking beta-blockers may have a transient increase in pulse and blood pressure. Table 1: Clinically Significant Drug Interactions with Glucagon for Injection Beta-Blockers Clinical Impact: Patients taking beta-blockers may have a transient increase in pulse and blood pressure when given Glucagon for Injection. Intervention: The increase in blood pressure and heart rate may require therapy in patients with coronary artery disease
Glucagon is not an antidote for beta blockers. It may even cause a transient increase in pulse and blood pressure in patients taking beta-blockers, which may require therapy in patients with coronary artery disease 2 2 2.
From the Research
Glucagon as an Antidote for Beta Blocker Overdose
- Glucagon has been studied as a potential antidote for beta blocker overdose, with some evidence suggesting its effectiveness in reversing the cardiovascular depression associated with beta-blockade 3, 4.
- The mechanism of action of glucagon in this context is thought to bypass the beta-adrenergic receptor site, allowing it to increase heart rate and myocardial contractility even in the presence of beta-receptor blocking drugs 3.
- Studies have reported the use of glucagon in cases of severe beta-blocker overdose, with doses ranging from 50 micrograms/kg iv loading dose to 1-15 mg/h continuous infusion 3, 4.
- While glucagon may be effective in improving haemodynamics, its use is not without potential side effects, including nausea, vomiting, hypokalemia, and hyperglycemia 3.
Comparison with Other Treatments
- Other treatments for beta-blocker overdose, such as catecholamines, vasopressors, and high-dose insulin euglycaemic therapy, have also been studied and may be effective in improving haemodynamics and reducing mortality 5, 6.
- The choice of treatment may depend on the specific circumstances of the overdose and the patient's response to initial therapy.
- Glucagon may be considered as an alternative therapy for profound beta-blocker intoxications, particularly in cases where other treatments are not effective or available 3, 4.