Insulin Glargine
Overview
Insulin Glargine is a long-acting recombinant human insulin analogue designed to provide continuous basal insulin activity over approximately 24 hours following subcutaneous administration. It differs structurally from native human insulin by specific amino acid modifications that cause the solution to precipitate in subcutaneous tissue after injection, forming microdeposits that slowly release insulin into the bloodstream. This mechanism results in a relatively flat and peakless insulin profile, helping to maintain stable fasting and between-meal blood glucose levels. Insulin Glargine is typically administered once daily at a consistent time, offering convenience and predictable glucose control. It is widely used in both type 1 and type 2 diabetes as part of basal-bolus regimens or in combination with oral antidiabetic agents. Its long duration of action supports reduced glycemic variability and improved overall metabolic stability when used with appropriate monitoring and dose titration.
Background and Date of Approval
Insulin Glargine was developed in the 1990s as the first long-acting basal insulin analogue to address limitations of intermediate-acting insulins. The United States Food and Drug Administration approved Insulin Glargine in the year 2000 for the treatment of diabetes mellitus. The European Medicines Agency granted approval in the same year, marking its global introduction into clinical practice. These approvals were supported by pivotal clinical trials demonstrating sustained 24-hour insulin activity, improved fasting glucose control, and a reduced risk of nocturnal hypoglycemia compared with older basal insulin formulations. Over time, additional follow-on and biosimilar versions have been approved in multiple regions, reinforcing the role of Insulin Glargine as a foundational therapy in diabetes management.
Uses
Insulin Glargine is indicated for improving glycemic control in adults and children with type 1 diabetes mellitus and in adults with type 2 diabetes mellitus who require basal insulin therapy. It is intended to meet baseline insulin needs and is not suitable for the treatment of diabetic ketoacidosis, where short-acting insulin is required. In clinical practice, Insulin Glargine is commonly used alongside rapid-acting insulin analogues for mealtime coverage in type 1 diabetes and in combination with oral or injectable non-insulin antidiabetic agents in type 2 diabetes when adequate glycemic control cannot be achieved with other therapies alone.
Administration
Insulin Glargine is administered by subcutaneous injection into the abdomen, thigh, or upper arm once daily at approximately the same time each day. Injection sites should be rotated to reduce the risk of lipodystrophy and local skin reactions. It should not be mixed with other insulin products in the same syringe. Dosing is individualized based on prior insulin use, fasting blood glucose levels, body weight, and overall metabolic needs. In insulin-naive patients, treatment is typically initiated at a conservative dose and titrated gradually based on fasting glucose monitoring to achieve target glycemic levels while minimizing hypoglycemia risk.
Side Effects
The most common side effect associated with Insulin Glargine is hypoglycemia, which may present with symptoms such as sweating, tremor, hunger, dizziness, palpitations, or confusion. Injection site reactions including redness, swelling, itching, or discomfort may occur. Weight gain can be observed during ongoing insulin therapy, particularly as glycemic control improves. These effects vary among individuals and are generally manageable with appropriate dose adjustments, education, and regular monitoring.
Warnings
Serious adverse events include severe hypoglycemia, which can result in seizures, loss of consciousness, coma, or death if not promptly recognized and treated. Insulin therapy may also cause hypokalemia due to insulin-driven potassium shifts into cells, potentially leading to cardiac rhythm disturbances. Rare but serious systemic allergic reactions, including anaphylaxis, have been reported. Insulin Glargine should not be administered during episodes of hypoglycemia. Caution is advised in patients with renal or hepatic impairment, as reduced insulin clearance may increase the duration and severity of hypoglycemia.
Precautions
Prior to initiating Insulin Glargine therapy, baseline evaluation of glycemic control and review of concomitant medications are recommended. Certain drugs such as beta-blockers, alcohol, corticosteroids, and other glucose-lowering agents can alter insulin requirements or mask the warning symptoms of hypoglycemia. Insulin needs may change during illness, surgery, pregnancy, stress, or significant changes in diet or physical activity. Patients should be counselled on correct injection technique, consistent timing of administration, and early recognition and management of hypoglycemia.
Expert Tips
Optimal use of Insulin Glargine requires individualized dose titration guided by fasting blood glucose values and overall glycemic patterns. Emphasize the importance of consistent daily dosing time to maintain stable basal insulin levels. Educate patients on injection site rotation and the need for regular glucose monitoring. Advise patients to keep a fast-acting carbohydrate readily available to manage hypoglycemia. Collaboration with diabetes educators and regular follow-up can enhance adherence, safety, and long-term glycemic outcomes.
## FAQ
What is Insulin Glargine?
Insulin Glargine is a long-acting basal insulin analogue used to maintain stable baseline blood glucose levels in diabetes mellitus.
How is Insulin Glargine administered?
It is administered by subcutaneous injection once daily at the same time each day.
What conditions is Insulin Glargine used for?
It is used in type 1 diabetes mellitus and in type 2 diabetes mellitus when basal insulin therapy is required.
What are common side effects?
Common side effects include hypoglycemia, injection site reactions, and weight gain.
What serious risks should be monitored?
Serious risks include severe hypoglycemia, hypokalemia, and rare systemic allergic reactions.
How long is treatment continued?
Treatment is generally long term and adjusted continuously based on glycemic control and patient response.
What monitoring is required during treatment?
Monitoring includes frequent blood glucose testing, periodic clinical review, and assessment for hypoglycemia and other adverse effects.
## References
FDA approval of Insulin Glargine, 2000
EMA approval of Insulin Glargine, 2000
Pivotal clinical trials demonstrating prolonged basal insulin action and reduced nocturnal hypoglycemia