What type of insulin is glargine?

Insulin Glargine Classification

Insulin glargine is a long-acting basal insulin analog designed to provide 24-hour peakless insulin coverage with once-daily subcutaneous administration. 1, 2

Pharmacological Classification and Structure

• Insulin glargine is a recombinant human insulin analog produced through DNA technology using Escherichia coli (K12), with two key structural modifications: asparagine at position A21 is replaced by glycine, and two arginine molecules are added to the C-terminus of the B-chain 2
• These structural changes create a molecule that is soluble at acidic pH (approximately 4.0) but precipitates at the neutral pH of subcutaneous tissue, forming microprecipitates that slowly release insulin over 24 hours 2, 3

Pharmacokinetic Profile

• Insulin glargine has an onset of action of approximately 1 hour, no pronounced peak, and a duration of action of up to 24 hours, distinguishing it from intermediate-acting insulins like NPH 4
• The peakless profile provides relatively constant insulin concentration over 24 hours, mimicking physiologic basal insulin secretion 4, 3
• This pharmacokinetic profile allows once-daily dosing at any consistent time of day 4

Clinical Role as Basal Insulin

• The primary function of insulin glargine is to restrain hepatic glucose production and control hyperglycemia overnight and between meals 1, 4
• In type 1 diabetes, insulin glargine must be combined with rapid-acting insulin analogs to cover prandial (mealtime) insulin needs 4
• In type 2 diabetes, insulin glargine is typically added when oral medications fail to achieve glycemic targets, often used in combination with metformin 5

Comparison with Other Insulin Types

• Long-acting basal analogs (U-100 glargine or detemir) reduce the risk of symptomatic and nocturnal hypoglycemia compared with NPH insulin 1
• Longer-acting formulations (U-300 glargine or degludec) may convey lower hypoglycemia risk compared with U-100 glargine when used in combination with oral agents 1
• Unlike NPH insulin which has a 6-8 hour peak, insulin glargine provides peakless coverage, resulting in more stable glycemic control and fewer nocturnal hypoglycemic episodes 4, 3

Available Formulations

• U-100 glargine (Lantus): Standard concentration providing 24-hour coverage 5
• U-300 glargine (Toujeo): Concentrated formulation with longer duration of action and lower rates of clinically significant hypoglycemia (<54 mg/dL) compared to U-100 glargine 5