What is the antidote for beta-blocker overdose, as described in the material?

What is the antidote for beta-blocker overdose, as described in the material?

• A. Epinephrine
• B. Calcium gluconate
• C. Glucagon IV
• D. Atropine

Answer: (C)

When a beta-blocker overdoes its effects, the heart’s beta receptors are blocked, so typical sympathetic signals can’t raise heart rate or contractility. Glucagon provides a different route to boost the heart: it binds to glucagon receptors on heart muscle and conduction tissue, activating adenylate cyclase to raise intracellular cAMP, which increases heart rate and contractility independently of beta receptors. That bypasses the blockade and rapidly improves cardiac performance, making glucagon IV the best antidote in this scenario. In practice, a high-dose IV glucagon bolus is given, often followed by an infusion, with attention to potential side effects such as nausea, vomiting, and hyperglycemia. Epinephrine can be less effective when beta receptors are blocked, calcium gluconate helps with calcium-related support but doesn’t reverse the blocker, and atropine may help with slow heart rate but doesn’t address the underlying mechanism.

When a beta-blocker overdoes its effects, the heart’s beta receptors are blocked, so typical sympathetic signals can’t raise heart rate or contractility. Glucagon provides a different route to boost the heart: it binds to glucagon receptors on heart muscle and conduction tissue, activating adenylate cyclase to raise intracellular cAMP, which increases heart rate and contractility independently of beta receptors. That bypasses the blockade and rapidly improves cardiac performance, making glucagon IV the best antidote in this scenario. In practice, a high-dose IV glucagon bolus is given, often followed by an infusion, with attention to potential side effects such as nausea, vomiting, and hyperglycemia. Epinephrine can be less effective when beta receptors are blocked, calcium gluconate helps with calcium-related support but doesn’t reverse the blocker, and atropine may help with slow heart rate but doesn’t address the underlying mechanism.