Question

Which of the following phrases correctly describes insulin glargine? (A) it is injected at mealtimes (B) proline and lysine are transposed in the B chain (C) aspartate is substituted for proline in the B chain (D) it is slowly absorbed over 24 hours (E) it is administered by inhalation

Short answer

Option (D) is correct: insulin glargine is slowly absorbed over 24 hours.

Step-by-step solution

Identify the Key Features of Insulin Glargine

First, we need to understand what insulin glargine is. It is a long-acting insulin analog designed to provide a slow and steady release of insulin over an extended period, typically around 24 hours, with minimal peaks.

Evaluate Each Option

Go through each option to determine if it accurately describes insulin glargine: - (A) Insulin glargine is not injected at mealtimes; short-acting insulins are used for that purpose. - (B) Transposition of proline and lysine in the B chain describes insulin lispro, not glargine. - (C) Aspartate substitution for proline in the B chain refers to insulin aspart, not glargine. - (D) Being slowly absorbed over 24 hours is characteristic of insulin glargine. - (E) Insulin glargine is not administered by inhalation; it is injected subcutaneously.

Choose the Correct Option

Based on the evaluation, option (D) correctly describes insulin glargine, as it is slowly absorbed over 24 hours, making it suitable for maintaining basal insulin levels.

Key concepts

Long-acting Insulin

Long-acting insulin, like insulin glargine, is a critical component in diabetes management. Its main feature is its ability to maintain blood sugar levels steadily for an extended period. Unlike short-acting insulins, which act quickly to cover glucose spikes during meals, long-acting insulin is designed for basal or background insulin control. This means it provides a slow release of insulin into the bloodstream, which is particularly useful for covering insulin needs between meals and overnight.

Insulin glargine achieves this by forming microprecipitates in the subcutaneous tissue, from which insulin is slowly and gradually released. This ensures a continuous, low-level insulin supply that mimics the natural baseline insulin secretion of the pancreas.

The primary advantage of long-acting insulins is their ability to maintain more stable blood glucose levels throughout the day and night, reducing the risk of highs and lows. This steadiness helps improve overall glucose control and can significantly enhance quality of life for individuals with diabetes.

Insulin Analog

Insulin analogs are modified versions of human insulin. Scientists have altered certain amino acids in the insulin molecule to improve its absorption, distribution, metabolism, and elimination characteristics. These modifications allow insulin analogs to either act faster or last longer than regular human insulin formulations.

Insulin glargine is one such modified insulin, designed as a long-acting analog. By substituting glycine for asparagine at position 21 in the A chain and adding two arginines to the C-terminus of the B chain, glargine's structure is altered to affect its solubility and absorption rate. This modification significantly extends its duration of action.

The aim of these analogs is to mimic the body's natural patterns of insulin secretion more closely, offering benefits such as fewer injections and a more predictable action profile. As a result, they help improve compliance and glucose control for people with diabetes.

Pharmacokinetics

Pharmacokinetics is the study of how drugs move through the body, including processes like absorption, distribution, metabolism, and excretion. For insulin glargine, understanding its pharmacokinetics is crucial to maximizing its therapeutic benefits for diabetes management.

After subcutaneous injection, insulin glargine precipitates in the tissue, forming a depot from which it is slowly absorbed into the bloodstream. This absorption process is gradual and provides a steady level of insulin, minimizing peaks that could lead to hypoglycemia. The slow absorption of glargine also means that it does not require the frequent dosing that rapid-acting insulins do.

The extended activity of insulin glargine, lasting up to 24 hours, supports simplification of the dosing regimen for patients. By ensuring prolonged effectiveness with once or twice daily dosing, insulin glargine helps maintain consistent management of blood sugar levels.

Diabetes Mellitus Management

Effective diabetes mellitus management includes a combination of medication, lifestyle changes, and regular monitoring of blood glucose levels. Insulin glargine plays a significant role in this management, especially for individuals with Type 1 diabetes and some with Type 2 diabetes who require insulin therapy.

The goal of using insulin glargine in diabetes management is to keep blood sugar levels as close to normal as possible, minimizing the risks of both hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar). Its once-daily dosing, in many cases, allows for a more straightforward routine without the need for multiple daily injections, enhancing adherence to the treatment plan.

In addition to medication, diabetes management plans often include dietary modifications, exercise, regular blood sugar testing, and education. This holistic approach, with medications like insulin glargine, helps prevent diabetes-related complications and improves overall quality of life.