Insulin Glargine: Uses, Mechanism, and Side Effects

Managing blood glucose day to day often means relying on a long-acting insulin to provide steady background coverage. Insulin glargine is one of the most widely used options in this category, with an extensive record of clinical study and real-world use.

Key takeaways

• Insulin glargine is a long-acting human insulin analog marketed as BASAGLAR KwikPen.
• It is approved to improve glycemic control in adults and children with type 1 diabetes and in adults with type 2 diabetes.
• It is not recommended for treating diabetic ketoacidosis.
• More than 750 clinical trials have been registered studying insulin glargine.
• FAERS reports most often involve blood glucose changes, off label or scheduling issues, and gastrointestinal symptoms like nausea.

What Insulin Glargine Is

Insulin glargine belongs to the insulin analog drug class. Like natural insulin, it works by helping the body regulate glucose metabolism. It lowers blood glucose by promoting glucose uptake into skeletal muscle and fat tissue while reducing glucose production by the liver. It also slows the breakdown of fat and protein and supports protein synthesis, mirroring the broader physiological roles of insulin in the body.

What Insulin Glargine Is Approved For

BASAGLAR, a brand of insulin glargine, is indicated to improve glycemic control in adults and pediatric patients with type 1 diabetes mellitus and in adults with type 2 diabetes mellitus. The label specifically notes that it is not recommended for treating diabetic ketoacidosis. This product's label does not carry a boxed warning.

What the Evidence Shows

Insulin glargine has been studied in more than 750 registered clinical trials. One completed phase 3 trial compared multiple daily injections of insulin glargine plus insulin glulisine against premix insulin treatment in people with type 1 or type 2 diabetes. Another completed phase 3 study compared a new formulation of insulin glargine with Lantus in Japanese patients with type 1 diabetes.

Reported Side Effects

Reports submitted to the FDA Adverse Event Reporting System reflect submitted reports, not confirmed incidence or direct causation. The most frequently reported issues involve blood glucose fluctuations, including blood glucose increased (39,480 reports) and blood glucose decreased (10,601). Other commonly reported categories include off label use (14,191), drug ineffective (10,744), and administration or storage related issues such as inappropriate scheduling (10,358) and product storage error (9,268). Nausea (10,061) and visual impairment (8,956) were also frequently reported.