Insulin Glargine

Insulin Glargine is a long-acting insulin analogue used to help maintain blood glucose levels within an appropriate range in people with diabetes mellitus. It is produced using recombinant DNA technology and is structurally modified from human insulin to provide a prolonged and relatively steady glucose-lowering effect. After subcutaneous injection, the solution forms a depot in the tissue from which insulin is released gradually, helping provide basal insulin coverage for an extended period. Insulin Glargine binds to insulin receptors and promotes glucose uptake by tissues such as skeletal muscle and fat, while reducing glucose production by the liver. It also influences fat and protein metabolism. In type 1 diabetes, it is generally used alongside mealtime insulin because basal insulin alone does not replace the body's full insulin requirement. In type 2 diabetes, it may be used alone or with other glucose-lowering medicines, including mealtime insulin when needed. It is usually administered once daily, although the exact schedule depends on the specific product and clinical circumstances. Treatment requires individual dose adjustment and regular blood glucose monitoring. Recognising and preventing low blood glucose is central to safe use, as insulin requirements can change with meals, physical activity, illness, kidney or liver function, and other medicines.

Insulin Glargine was developed as a long-acting insulin analogue to provide more sustained basal insulin activity than intermediate-acting insulin preparations. Its prolonged action results from changes in its amino acid structure that affect its solubility after subcutaneous injection and allow gradual release into the circulation. The reference product Lantus received European Union marketing authorisation on 9 June 2000 following assessment by the European Medicines Agency. In the United States, insulin glargine products have subsequently received FDA approvals, including Basaglar in 2015 and Semglee in 2020, with an interchangeable biosimilar version approved in 2021. Clinical development included trials comparing insulin glargine with NPH insulin in people with type 1 and type 2 diabetes, assessing blood glucose control and safety. Product indications, age limits, concentrations, and instructions may differ between formulations and countries, so the relevant local prescribing information should be followed.

Insulin Glargine is used to improve glycaemic control in people with type 1 and type 2 diabetes, subject to the approved indication of the specific product. In type 1 diabetes, it provides basal insulin coverage and is used with short-acting or rapid-acting insulin to manage glucose increases associated with meals. In type 2 diabetes, it may be prescribed when lifestyle measures and other glucose-lowering medicines do not provide adequate control, or when insulin therapy is otherwise clinically indicated. It can be used alone as basal insulin or in combination with oral or injectable diabetes medicines, depending on the patient's treatment plan. Insulin Glargine is not intended to treat diabetic ketoacidosis. Age eligibility and other approved uses vary by product, so the applicable prescribing information should be checked.

Insulin Glargine is administered by subcutaneous injection, commonly into the abdomen, thigh, or upper arm, depending on the product instructions. Many formulations are given once daily at a consistent time, but the recommended schedule can vary by formulation. The dose is individualised according to diabetes type, previous insulin use, blood glucose readings, meals, activity, concurrent medicines, and treatment goals. In adults with type 2 diabetes, some product labels recommend an initial dose of 10 units daily or a weight-based starting dose; people with type 1 diabetes generally require a personalised basal-and-mealtime insulin regimen. These are general prescribing principles, not instructions to start or change a dose without medical supervision. Injection sites should be rotated, and insulin glargine should not be mixed or diluted with other insulin or solutions unless the specific product information explicitly permits it. Regular glucose monitoring is required, with dose adjustments made under clinical guidance.

The most important and commonly reported side effect of Insulin Glargine is hypoglycaemia, or low blood glucose. Symptoms may include sweating, trembling, hunger, dizziness, headache, confusion, and a rapid heartbeat. Other possible effects include weight gain, redness, swelling, itching, or discomfort at the injection site. Repeated injections into the same area may cause changes in the fatty tissue under the skin, including thickening or localised indentations, which can affect insulin absorption. Some people may experience swelling due to fluid retention. Side effects vary between individuals and can be influenced by dose, diet, physical activity, other medicines, and kidney or liver function. Patients should be taught how to recognise and manage low blood glucose and should seek medical advice if reactions persist or become troublesome.

Severe hypoglycaemia can cause seizures, loss of consciousness, injury, or other life-threatening complications and requires prompt treatment. Severe allergic reactions, including anaphylaxis, are possible but uncommon. Insulin therapy can also cause low blood potassium levels, which may be serious in susceptible patients. Rapid changes in insulin treatment or inadequate insulin delivery can result in poor glucose control and, particularly in type 1 diabetes, diabetic ketoacidosis. Insulin Glargine must not be used during an episode of hypoglycaemia or by individuals with a known serious hypersensitivity to the relevant product or its ingredients. Accidental substitution of insulin products or concentrations can cause dangerous dosing errors, so the product label and prescribed dose must be checked before each administration. Treatment should not be stopped or altered abruptly without professional guidance, especially in people with type 1 diabetes.

Insulin requirements may decrease in people with kidney or liver impairment and in some older adults, increasing the need for careful glucose monitoring and dose review. Changes in diet, exercise, illness, pregnancy, stress, or body weight can also affect insulin needs. Medicines such as other glucose-lowering agents may increase the risk of hypoglycaemia, while corticosteroids, some diuretics, thyroid hormones, and certain other medicines may raise blood glucose or alter insulin requirements. Beta-blockers can mask some warning signs of hypoglycaemia, and alcohol may increase or prolong the risk of low blood glucose. Patients should inform their healthcare professional about all prescription medicines, non-prescription products, and supplements they use. Injection sites should be rotated, and insulin should be stored according to the specific product instructions, protected from excessive heat and freezing. Insulin Glargine should not be shared between patients, even if the needle is changed.

Before starting or adjusting Insulin Glargine, assess the patient's diabetes type, current glucose profile, previous insulin regimen, risk of hypoglycaemia, kidney and liver function, and ability to administer injections safely. Confirm the exact product, concentration, delivery device, and prescribed dose, because insulin products are not automatically interchangeable unit for unit in every clinical situation. Provide clear counselling on injection technique, site rotation, storage, glucose monitoring, and the recognition and management of hypoglycaemia. Explain that basal insulin is not a substitute for mealtime insulin when the latter is required. Review glucose records after initiation and dose changes, and reassess treatment during acute illness, changes in eating patterns, pregnancy, or introduction of interacting medicines. Pharmacists should reinforce label checking and device-specific instructions, while prescribers should individualise titration and ensure that patients understand when to seek urgent medical assistance.