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.

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. Interestingly, glucagon has also been shown to relax smooth muscle in the airway via a nitric oxide/prostaglandin-mediated mechanism.

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. But how is an anti-insulin hormone useful in treating this toxicity?

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. 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 activates adenylyl cyclase through a DIFFERENT mechanism thereby restoring cAMP synthesis despite the presence of beta-blockers.

Drop me a comment below with questions! 🙂



My posts do NOT constitute medical advice nor do they reflect the views of the institutions and organizations I'm affiliated with. Please read this site's Disclaimer and Terms of Use for more information.

Related Articles


  1. Love your posts!! I find the triple uses of Glucagon to be so interesting. As a Type 1DM, I knew about this drug (long before nursing school). Then as a former ED nurse, we used to use this for foreign bodies in the esophagus (usually meat)–often did the trick. Finally, as a flight nurse, this was a protocol for beta blocker OD.
    Fascinating how one drug can be so diverse. I never understood how it works to treat all three; so thanks for explaining it well. I often challenge my nursing students about this drug.

Leave a Reply

Your email address will not be published. Required fields are marked *

Check Also