From the Guidelines
Glucagon can be used as a temporary treatment for severe bradycardia, particularly in patients with beta-blocker or calcium channel blocker overdose or toxicity, with a recommended dose of 3-10 mg IV with infusion of 3-5 mg/h, as stated in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Key Points
- The dose of glucagon for treating bradycardia is 3-10 mg IV with infusion of 3-5 mg/h, according to the guidelines 1.
- Glucagon works by activating adenylyl cyclase in cardiac cells through a non-beta-adrenergic pathway, increasing intracellular cAMP levels and enhancing cardiac contractility and heart rate.
- Glucagon should be considered a temporizing measure while preparing more definitive treatments like transcutaneous pacing, atropine, or vasopressors.
- Side effects of glucagon include nausea, vomiting, and hyperglycemia.
- The onset of action is typically within 1-3 minutes with a duration of 5-20 minutes, necessitating continuous infusion for sustained effect.
Clinical Considerations
- Glucagon requires adequate glycogen stores to be effective, so it may have limited utility in malnourished patients or those with liver disease.
- The use of glucagon in patients with central nervous system depression requires protection of the airway before administration.
- Concomitant use of dopamine alone or in combination with isoproterenol and milrinone may decrease the effectiveness of glucagon, as suggested by animal studies 1.
From the Research
Role of Glucagon in Treating Bradycardia
- Glucagon has been used as a potential treatment for symptomatic bradycardia, particularly in patients taking maintenance beta-blocker therapy 2.
- A case series reported that glucagon therapy was effective in obviating the need for further treatment in three patients with symptomatic bradycardia and hypotension who were taking beta-blockers 2.
- However, there is limited research on the use of glucagon in treating bradycardia, and further study is warranted to evaluate and define its role in this setting 2.
Comparison with Other Treatments
- Atropine is commonly used as a first-line therapy for symptomatic bradycardia, but it may not be effective in all cases and can even worsen the condition in some patients 3.
- Other treatments for bradycardia include percutaneous pacing, permanent pacemaker placement, and medications such as isoproterenol, dopamine, dobutamine, or epinephrine 4, 5.
- Traditional Chinese medicine (TCM) has also been used to treat bradycardia, with a case report showing that Chinese patent medicine (CPM) can be an effective alternative therapy for sinus bradycardia and cardiac sinus arrests 5.