Glucagon activates adenylyl cyclase through a DIFFERENT mechanism thereby restoring cAMP synthesis despite the presence of beta-blockers. 11A loading dose of up to 10 mg followed by up to 5 mg/h infusion may be. Beta-blockers (especially selective beta-1 blockers) inhibit the Gs second messenger system normally involved with activating adenylyl cyclase to catalyze the formation of cyclic AMP (cAMP). Glucagon is probably the drug of choice to treat massive beta-blocker overdose. I worry about two things in beta-blocker toxicity: hypoglycemia (which is obviously helped with glucagon) and the heart – namely decreased chronotropy (heart rate), inotropy (contractility), bradyarrhythmias, and hypotension from a combination of the aforementioned. Glucagon is the antidote of choice for beta blocker toxicity because it increases intracellular cAMP and cardiac contractility. But how is an anti-insulin hormone useful in treating this toxicity? In other words, glucagon can improve cardiac contractility and AV conduction by circumventing an existing beta blockade. At high enough concentrations, cAMP activates a non-adrenergic pathway that improves inotropy and chronotropy.

In the ICU, I use a higher dose of glucagon (5-10 mg + drip titrated to effect) to reverse life-threatening hypoglycemia (with an amp or two of D50W) and to treat beta-blocker toxicity. Glucagon activates adenylate cyclase in the myocardium, which increase cAMP production.

Interestingly, glucagon has also been shown to relax smooth muscle in the airway via a nitric oxide/prostaglandin-mediated mechanism. In the OR, I most commonly administer 1 mg IV glucagon to relax gastrointestinal smooth muscle in cases like esophagectomies where esophago-gastric manipulation is critical. Glucagon (GlucaGen) is a secretin-type peptide hormone made in the pancreas responsible for catabolism primarily to produce glucose via glycogenolysis and gluconeogenesis in this sense, it’s an “anti-insulin” used in the treatment of profound hypoglycemia. Because it may bypass the -receptor site, glucagon can be considered as an alternative therapy for profound -blocker intoxications.

Glucagon beta blocker antidote