Insulin Glargine
Insulin glargine is a long-acting basal insulin analogue used in type 1 and selected type 2 diabetes. It provides a relatively flat 24-hour profile that mimics endogenous basal insulin secretion when used at a fixed daily time.
- Chemical formula
- C267H404N72O78S6
- CAS number
- 160337-95-1
- ATC code
- A10AE04
- Molecular weight
- 6063 Da
- Drug class
- Long-acting insulin analogue
- Also known as
- HOE 901, Insulina glargina
What is it?
Insulin glargine is a recombinant human insulin analogue produced in Escherichia coli, in which two arginine residues are added to the B-chain and the A-chain glycine substitutes asparagine. These changes shift the isoelectric point so the molecule is soluble in the slightly acidic injection solution but precipitates in subcutaneous tissue, from which it dissolves slowly. It was approved in 2000 and is supplied at standard concentration (U-100) and as a more concentrated formulation (U-300) under different brand names.
Mechanism of action
Insulin glargine binds the insulin receptor with similar affinity to human insulin, activating intracellular signalling that increases glucose uptake in muscle and adipose tissue, suppresses hepatic glucose production and promotes lipogenesis. The slow precipitation and gradual redissolution at the injection site result in a relatively flat plasma profile lasting approximately 24 hours, which closely mimics the basal phase of endogenous insulin secretion. Prandial glucose control usually requires a separate rapid-acting insulin or non-insulin therapy.
Pharmacokinetics
After subcutaneous injection, insulin glargine reaches a relatively constant glucose-lowering effect within several hours, with no pronounced peak. Duration of action is approximately 22 to 26 hours for the U-100 formulation and may extend further for the U-300 formulation. Like other insulins, it is degraded by tissue insulinases and renal pathways. Hepatic and renal impairment increase the variability of response and require closer dose titration. Drug interactions include other antidiabetics, beta-blockers, corticosteroids and several CNS-active medications.
Indications
Insulin glargine is approved as basal insulin therapy in adults and paediatric patients with type 1 diabetes mellitus and in adults with type 2 diabetes mellitus when oral or non-insulin injectable therapy is insufficient or contraindicated. It is also used in selected pregnancy and gestational diabetes scenarios under specialist supervision. According to the prescribing information, treatment must be initiated and adjusted by a clinician, with attention to total daily insulin requirements and timing.
Safety profile
Hypoglycaemia is the most important adverse effect of any insulin and can be severe in case of missed meals, prolonged exercise, alcohol intake or interaction with other glucose-lowering agents. Other adverse effects include weight gain, injection-site reactions, lipohypertrophy and rare hypersensitivity. Insulin should never be administered intravenously in glargine form because the precipitation depot mechanism does not apply. According to the prescribing information, patients should be educated on dose adjustment, sick-day rules and recognition of hypoglycaemia.
Products containing this ingredient
Frequently asked questions
What is the difference between insulin glargine and NPH insulin? ▾
Insulin glargine is a long-acting analogue with a relatively flat 24-hour profile, while NPH is an intermediate-acting human insulin with a clear peak between four and ten hours after injection. In randomised trials, glargine produces less nocturnal hypoglycaemia for similar HbA1c reduction and is usually given once daily. The choice between the two depends on cost, availability, prescribing context and individual response, and is made by the clinician.
When should insulin glargine be injected? ▾
According to the prescribing information, insulin glargine is given once daily at the same time, often at bedtime or in the morning. Consistency in timing supports steady-state coverage and reduces glucose variability. The pen or vial is injected subcutaneously into the abdomen, thigh or upper arm, with rotation of injection sites to prevent lipohypertrophy. The precise dose, timing and combination with other therapies are determined by the prescriber.
How is insulin glargine different from insulin glargine U-300? ▾
Both contain the same active molecule, but the U-300 formulation is three times more concentrated than U-100, which alters the precipitation depot dynamics. The U-300 product produces a flatter and longer profile and may reduce nocturnal hypoglycaemia in some patients, with slightly higher dose requirements. According to the prescribing information, switching between the two strengths requires careful dose retitration and is supervised by the prescriber.
Does insulin glargine require refrigeration? ▾
Yes. Unopened pens and vials are stored in a refrigerator between 2°C and 8°C. After first use, the pen or vial can usually be kept at room temperature below a defined limit for the period stated in the leaflet, after which it should be discarded. Freezing damages the product. Cold-chain integrity is one reason regulatory agencies caution against purchasing insulin from unverified online sources.
What are the main contraindications for insulin glargine? ▾
Known hypersensitivity to insulin glargine or any excipient is a formal contraindication. Glargine is not used to treat diabetic ketoacidosis, where rapid-acting insulin via continuous infusion is preferred. Caution is required in renal or hepatic impairment, in pregnancy where dose requirements change and in any condition that alters glucose metabolism. According to the prescribing information, the medical history and current medication list must be reviewed by a clinician before initiation.
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.