What type of insulin is Basaglar (insulin glargine) and what are its recommended dosing and administration for diabetes?

Basaglar: Long-Acting Basal Insulin for Diabetes Management

Basaglar (insulin glargine) is a long-acting basal insulin analog administered once daily at the same time each day to provide 24-hour background insulin coverage without a pronounced peak, making it ideal for controlling fasting glucose and between-meal hyperglycemia in both type 1 and type 2 diabetes. 1, 2

Insulin Classification and Pharmacokinetics

Basaglar belongs to the long-acting basal insulin class, specifically as a biosimilar to Lantus (insulin glargine 100 units/mL). 2 The key pharmacokinetic properties that distinguish it from other insulin types include:

• Onset of action: Approximately 1 hour after subcutaneous injection 1
• Peak action: No pronounced peak—provides a relatively constant concentration profile over 24 hours 1
• Duration of action: Approximately 24 hours, allowing once-daily dosing 1
• Mechanism: Slowly releases insulin over 24 hours, causing more physiologic basal insulin levels 1

This peakless profile fundamentally differentiates Basaglar from intermediate-acting insulins like NPH (which peaks at 6-8 hours) and from rapid-acting insulins like lispro or aspart (which peak at 1-2 hours). 1

Recommended Dosing and Administration

Initial Dosing for Type 2 Diabetes

For insulin-naïve adults with type 2 diabetes, start Basaglar at 10 units once daily OR 0.1-0.2 units/kg body weight once daily, administered at the same time each day. 3, 2, 4 The American Diabetes Association explicitly supports this starting range across multiple guidelines. 3

• Continue metformin (unless contraindicated) and possibly one additional non-insulin agent when initiating Basaglar 3, 2
• For patients with severe hyperglycemia (HbA1c ≥9% or blood glucose ≥300-350 mg/dL), consider higher starting doses of 0.3-0.4 units/kg/day 3

Initial Dosing for Type 1 Diabetes

For adults with type 1 diabetes, the recommended starting dose is approximately one-third of the total daily insulin requirements (roughly 0.2-0.25 units/kg/day as basal insulin), with short-acting premeal insulin providing the remainder. 4 Total daily insulin requirements typically range from 0.4-1.0 units/kg/day, with 0.5 units/kg/day being typical for metabolically stable patients. 1, 3

Titration Protocol

Increase Basaglar by 2 units every 3 days if fasting glucose is 140-179 mg/dL, or by 4 units every 3 days if fasting glucose is ≥180 mg/dL, until fasting blood glucose reaches the target of 80-130 mg/dL. 3 This systematic titration approach is endorsed by the American Diabetes Association and should be implemented with daily fasting glucose monitoring. 3

• If hypoglycemia occurs without clear cause, reduce the dose by 10-20% immediately 3
• Equip patients with self-titration algorithms based on self-monitoring of blood glucose to improve glycemic control 3

Administration Guidelines

• Administer subcutaneously once daily at any time of day, but at the same time every day 1, 2, 4
• Inject into the abdominal area, thigh, or deltoid, rotating injection sites within the same region 4
• Do NOT administer intravenously or via an insulin pump 4
• Do NOT dilute or mix Basaglar with any other insulin or solution due to its acidic pH formulation 3, 2, 4

Critical Threshold: When to Add Prandial Insulin

When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day without achieving glycemic targets, add prandial insulin rather than continuing to escalate basal insulin alone. 3 This threshold prevents "overbasalization," which leads to increased hypoglycemia risk without improved control. 3

Clinical signals of overbasalization include:

• Basal dose >0.5 units/kg/day 3
• Bedtime-to-morning glucose differential ≥50 mg/dL 3
• Hypoglycemia episodes 3
• High glucose variability 3

When these signs appear, start prandial insulin with 4 units of rapid-acting insulin before the largest meal (or 10% of the basal dose) rather than further increasing Basaglar. 3

Combination Therapy Considerations

Continue metformin at maximum tolerated dose (up to 2,000-2,550 mg daily) when using Basaglar, as this combination reduces total insulin requirements by 20-30% and provides superior glycemic control compared to insulin alone. 3 The American Diabetes Association explicitly recommends maintaining metformin unless contraindicated. 3

When basal insulin approaches 0.5-1.0 units/kg/day without achieving HbA1c goals, consider adding a GLP-1 receptor agonist instead of prandial insulin, as this combination offers comparable glucose-lowering with less hypoglycemia and weight gain. 3

Safety Advantages Over NPH Insulin

Basaglar demonstrates a lower risk of symptomatic and nocturnal hypoglycemia compared to NPH insulin, the primary safety advantage of this long-acting analog. 1, 5, 6, 7, 8 The absence of a peak action time reduces hypoglycemia risk and allows for more stable blood glucose levels between meals and overnight. 1

Common Pitfalls to Avoid

• Never delay insulin initiation in patients not achieving glycemic goals with oral medications, as this prolongs hyperglycemia exposure and increases complication risk 3
• Never discontinue metformin when starting Basaglar unless contraindicated, as this leads to higher insulin requirements and more weight gain 3
• Never continue escalating Basaglar beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this causes overbasalization with increased hypoglycemia and suboptimal control 3
• Never use Basaglar as monotherapy in type 1 diabetes, as it can precipitate diabetic ketoacidosis—short-acting insulin at mealtimes is obligatory 1, 3, 4

Biosimilar Considerations

Basaglar is a biosimilar to Lantus (insulin glargine 100 units/mL) and follows identical dosing, titration, and administration guidelines. 2 Both products are administered once daily at the same time each day, with starting doses of 10 units or 0.1-0.2 units/kg/day for insulin-naïve type 2 diabetes patients. 2 The American Diabetes Association notes that Basaglar typically has a lower cost compared to the reference product Lantus, though specific pricing varies by region and insurance coverage. 2