What is the duration of action of insulin glargine (Lantus)?

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From the Guidelines

Insulin glargine typically lasts for 24 hours in the body, providing a steady, long-acting insulin effect throughout the day. This long duration of action makes it suitable for once-daily dosing, usually administered at the same time each day to maintain consistent blood glucose control. According to the study published in the American Family Physician in 2006 1, the duration of action of insulin glargine is 24 hours, with no peak action time, reducing the risk of hypoglycemia. Another study published in the same journal in 2006 1 also supports this, stating that glargine slowly releases insulin over 24 hours, causing more physiologic basal insulin levels.

Some key points to consider when using insulin glargine include:

  • It works by forming microprecipitates in the subcutaneous tissue after injection, which slowly dissolve and release insulin into the bloodstream at a relatively constant rate.
  • This creates a "peakless" profile, meaning there is less risk of hypoglycemia compared to intermediate-acting insulins.
  • Some patients may experience slightly shorter or longer durations of effect based on individual factors such as dose, injection site, physical activity, and metabolism.
  • For optimal blood glucose management, insulin glargine should be used as part of a comprehensive diabetes treatment plan that may include mealtime insulin for those with type 1 diabetes or certain cases of type 2 diabetes.
  • It's essential to monitor blood glucose levels regularly when using insulin glargine to ensure appropriate coverage throughout the full 24-hour period, as supported by the study 1 that compared glargine insulin with insulin isophane suspension in patients with type 1 diabetes.

From the FDA Drug Label

The median time between subcutaneous injection and the end of pharmacological effect was 14.5 hours (range: 9. 5 to 19.3 hours) for NPH insulin, and 24 hours (range: 10. 8 to >24 hours) (24 hours was the end of the observation period) for Insulin Glargine. The duration of action after abdominal, deltoid, or thigh subcutaneous administration of Insulin Glargine was similar The time course of action of insulins, including Insulin Glargine, may vary between patients and within the same patient.

The effect of insulin glargine lasts for at least 24 hours, with a range of 10.8 to more than 24 hours. The duration of action may vary between patients and within the same patient 2.

  • Key points:
    • Median time to end of pharmacological effect: 24 hours
    • Range of duration of action: 10.8 to more than 24 hours
    • Duration of action may vary between patients and within the same patient

From the Research

Insulin Glargine Duration of Action

  • The duration of action of insulin glargine is approximately 24 hours, providing a fairly constant, basal insulin supply without peaks in plasma insulin levels 3, 4, 5, 6, 7.
  • Insulin glargine precipitates after subcutaneous injection, slowing absorption and resulting in a flat pharmacokinetic profile with a duration of action of at least 24 hours 4, 5.
  • The activity profile of insulin glargine lacks a pronounced peak, more closely resembling that of endogenous basal insulin, and appears more likely to be associated with a reduced incidence of hypoglycemia, particularly nocturnal hypoglycemia 5, 6.

Clinical Efficacy and Tolerability

  • Insulin glargine has similar tolerability and produces similar glycemic control to once- or twice-daily human NPH insulin, with a similar glucose-lowering effect on a molar basis 3, 6.
  • A decreased incidence of hypoglycemia, particularly at night, has been reported with insulin glargine compared with human NPH insulin 3, 4, 5, 6, 7.
  • Insulin glargine appears to be comparable to human NPH insulin in terms of toxicity, adverse effects, immunogenicity, and potential for drug interactions 6.

Administration and Dosage

  • Insulin glargine is administered once daily at bedtime, providing basal insulin coverage for 24 hours 4, 5, 6.
  • Patients previously receiving twice-daily isophane insulin (NPH) should receive an insulin glargine dosage 20% less than the total daily dose of NPH insulin 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Insulin glargine: a new long-acting insulin product.

American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists, 2002

Research

Insulin glargine: a new basal insulin.

The Annals of pharmacotherapy, 2002

Research

Insulin glargine.

Clinical therapeutics, 2001

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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