[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Drugs that raise blood glucose](https://durgical.com/en/pharmacology/classes/drugs-that-raise-blood-glucose/) › Glucagon [Pharmacology](https://durgical.com/en/pharmacology/) · [Drugs that raise blood glucose](https://durgical.com/en/pharmacology/classes/drugs-that-raise-blood-glucose/) # Glucagon The emergency treatment for severe hypoglycemia when the person cannot eat: it releases the glucose stored in the liver. Updated 2026-11-01 - Class: [Drugs that raise blood glucose](https://durgical.com/en/pharmacology/classes/drugs-that-raise-blood-glucose/) - Receptor: Glucagon receptor (GCGR) - ATC code: H04AA01 - WHO Model List of Essential Medicines ◎**Glucagon receptor (GCGR)**Glucagon ⓘ The figure shows human glucagon bound to the human glucagon receptor coupled to its Gs protein. The nanobody used to stabilize the complex is not part of the receptor. **Target in 3D:** Glucagon receptor (GCGR). PDB structure 6LMK (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6LMK) · Drag to rotate · pinch to zoom ## Mechanism of action Glucagon binds its Gs-coupled receptor on liver cells. Adenylyl cyclase makes cAMP, protein kinase A is activated and phosphorylates the enzymes of glycogen metabolism: glycogen phosphorylase is switched on and glycogen synthase off, so glucose is released within minutes. Gluconeogenesis also increases. In the gut, glucagon relaxes smooth muscle, which is used during radiology. - Binds the glucagon receptor on liver cells (Gs, cAMP) - Protein kinase A switches glycogen breakdown on - The liver releases glucose and makes new glucose - Blood glucose rises within minutes if glycogen is stored ## Pharmacokinetics **Absorption** Given by injection (subcutaneous, intramuscular or intravenous); nasal powder forms also exist. **Metabolism** Broken down quickly in the liver, kidney and plasma. **Onset and duration** Glucose rises within minutes; the effect is short, so food follows once the person can swallow. ## Indications - Severe hypoglycemia in people with diabetes, when they cannot take sugar by mouth - Diagnostic aid in radiology, to briefly relax the stomach and bowel ## Adverse effects ### Common - Nausea and vomiting - Headache - Fast heart rate, transient rise in blood pressure - Injection-site reactions ### Serious (rare, important) - Severe high blood pressure in pheochromocytoma - Rebound hypoglycemia in insulinoma - Allergic reactions - Necrolytic migratory erythema with continuous infusion ## Contraindications - Pheochromocytoma - Insulinoma - Hypersensitivity to glucagon - Glucagonoma, when used as a diagnostic aid ## Key interactions **Beta-blockers** Transient rise in pulse and blood pressure. **Indomethacin** Glucagon may fail to raise glucose or may even cause hypoglycemia. **Warfarin** Its anticoagulant effect may increase. **Anticholinergic drugs** Not combined for gut relaxation during radiology: more gut side effects. ## What is monitored - Blood glucose after the dose and until the person eats - Level of consciousness and airway - Pulse and blood pressure ## Administration and safety - Kits with powder are mixed with the supplied diluent just before use and given at once. - Family members and caregivers of people on insulin are taught to use it. - After the injection the person is turned onto their side, because vomiting is common. - If there is IV access, intravenous glucose is the first choice in hospital. ## Nursing care - Check glucose before and repeatedly after the dose. - Protect the airway and place in recovery position. - Give oral carbohydrate once the person can swallow, to refill glycogen and prevent relapse. - Look for the cause (insulin or sulfonylurea excess, missed meal, alcohol). ## Pregnancy and breastfeeding Decades of use in pregnancy have not shown a clear risk; severe hypoglycemia itself is the bigger danger. ## Memory aid Glucagon is the key to the liver's sugar pantry: it only works if the pantry is stocked. Starved, adrenal-insufficient or chronically hypoglycemic patients have an empty pantry: give glucose. ## Test yourself Think of the answer, then tap the question to see it. ## Why may glucagon fail in a patient with adrenal insufficiency or after prolonged starvation? It works by releasing liver glycogen; these patients have little glycogen, so intravenous glucose is needed. ## Why is glucagon contraindicated in pheochromocytoma? It can make the tumor release catecholamines and cause a sudden, severe rise in blood pressure. ## What should happen once a patient wakes up after glucagon? They are given carbohydrate by mouth as soon as they can swallow, because the effect is short and glycogen must be refilled. ## Which enzyme does protein kinase A switch on in the liver after glucagon? Glycogen phosphorylase (through phosphorylase kinase), while glycogen synthase is switched off. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/glucagon/) [← Back to the class: Drugs that raise blood glucose](https://durgical.com/en/pharmacology/classes/drugs-that-raise-blood-glucose/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Glucagon Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682480.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - GLUCAGON kit](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8cc40354-b5ac-45b6-a211-93b44444f2a3) (DailyMed (U.S. National Library of Medicine), 2026); [Cryo-EM structure of the human glucagon receptor in complex with Gs](https://www.rcsb.org/structure/6LMK) (RCSB Protein Data Bank, 2020); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/glucagon/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/glucagon/