[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Insulins](https://durgical.com/en/pharmacology/classes/insulins/) › Insulin glargine [Pharmacology](https://durgical.com/en/pharmacology/) · [Insulins](https://durgical.com/en/pharmacology/classes/insulins/) # Insulin glargine A long-acting insulin analogue: it forms tiny deposits under the skin and gives a steady, almost peakless basal level for about a day. Updated 2026-11-01 - Class: [Insulins](https://durgical.com/en/pharmacology/classes/insulins/) - Receptor: Insulin receptor - ATC code: A10AE04 - WHO Model List of Essential Medicines ## ⚠ High-alert medication An error with this medicine can cause serious harm: double checks and protocols are used. ◎**Insulin receptor**Insulin glargine ⓘ The figure shows human insulin bound to site 1 of an insulin receptor fragment. Glargine (and its active metabolites) binds the same site; its changes affect absorption, not this contact. **Target in 3D:** Insulin receptor. PDB structure 4OGA (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4OGA) · Drag to rotate · pinch to zoom ## Mechanism of action Glargine differs from human insulin by a glycine at position A21 and two extra arginines at the end of the B chain. It is formulated as a clear acidic solution; at the neutral pH of the subcutaneous tissue it precipitates into micro-deposits that release insulin slowly and evenly. The released insulin activates the insulin receptor like human insulin, lowering glucose output by the liver and increasing uptake by muscle and fat. - Clear acidic solution precipitates at the neutral pH under the skin - Micro-deposits release insulin slowly, with no marked peak - Activates the insulin receptor like human insulin - Provides a steady basal level for about a day ## Pharmacokinetics **Absorption** Subcutaneous; slow, prolonged absorption with a relatively constant level over 24 hours and no pronounced peak, unlike NPH. **Metabolism** Partly cleaved at the end of the B chain in the subcutaneous depot into two active metabolites with insulin-like activity. **Onset and duration** Long acting: starts slowly and lasts about a day, so it is usually given once daily at the same time. ## Indications - Basal insulin in type 1 diabetes, with mealtime insulin [Type 1 diabetes mellitus →](https://durgical.com/en/conditions/type-1-diabetes-mellitus/) - Basal insulin in type 2 diabetes, alone or with oral drugs [Type 2 diabetes mellitus →](https://durgical.com/en/conditions/type-2-diabetes-mellitus/) ## Adverse effects ### Common - Hypoglycemia (less nocturnal hypoglycemia than with NPH) - Weight gain - Injection-site reactions, lipodystrophy and localized cutaneous amyloidosis - Low potassium ### Serious (rare, important) - Severe hypoglycemia - Severe allergic reactions (rare) ## Contraindications - During an episode of hypoglycemia - Hypersensitivity to insulin glargine or an excipient ## Key interactions **Beta-blockers, clonidine** Can blunt the warning signs of hypoglycemia. **Other glucose-lowering drugs** Raise the risk of hypoglycemia. **Corticosteroids, diuretics, atypical antipsychotics, niacin** Reduce the glucose-lowering effect. **Thiazolidinediones (pioglitazone)** Fluid retention and possible heart failure. ## What is monitored - Fasting blood glucose (guides basal adjustments) - HbA1c - Injection sites ## Administration and safety - Subcutaneous only: not given intravenously or in an insulin pump. - Never diluted or mixed with any other insulin or solution in the same syringe. - It is a clear solution like rapid insulins: the label is checked to avoid confusing basal and mealtime insulin. - Pens, needles and syringes are never shared between patients. ## Nursing care - Before: fasting glucose and the time of the last basal dose. - Give it at about the same time each day, even if the patient is not eating, unless the protocol says otherwise. - Watch for hypoglycemia and rotate injection sites. - Teach that glargine is not a correction insulin for a high reading. ## Pregnancy and breastfeeding Limited data have not shown a clear risk; it may be continued in pregnancy when it controls glucose well, with frequent monitoring. ## Memory aid «Glargine goes to sleep under the skin»: the acidic solution crystallizes at body pH and wakes up slowly all day. Acidic means never mixed with another insulin. ## Test yourself Think of the answer, then tap the question to see it. ## Why can glargine not be mixed with rapid-acting insulin in one syringe? It is formulated at an acidic pH; mixing raises the pH, causes early precipitation and changes the action of both insulins. ## What makes glargine almost peakless? It precipitates into micro-deposits at the neutral pH of the subcutaneous tissue and dissolves slowly, giving a steady release. ## A patient on glargine has repeated low readings at night. Which part of the regimen is checked first? The basal dose: fasting and night readings mainly reflect basal insulin. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/insulin-glargine/) ## Related drugs - [Isophane (NPH) insulin](https://durgical.com/en/pharmacology/isophane-insulin/) - [Insulin degludec](https://durgical.com/en/pharmacology/insulin-degludec/) - [Insulin detemir](https://durgical.com/en/pharmacology/insulin-detemir/) - [Regular human insulin](https://durgical.com/en/pharmacology/regular-human-insulin/) ## Related conditions - [Type 1 diabetes mellitus](https://durgical.com/en/conditions/type-1-diabetes-mellitus/) - [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/) [← Back to the class: Insulins](https://durgical.com/en/pharmacology/classes/insulins/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Insulin Glargine (rDNA origin) Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a600027.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - INSULIN GLARGINE- insulin glargine-yfgn injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=3ac85ebb-5594-59c8-77fd-df254329d151) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 51 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=A10AE04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **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/insulin-glargine/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/insulin-glargine/