Insulin therapy in diabetes mellitus

Concept of basal-bolus therapy

To fully compensate for type 1 diabetes mellitus, a basal-bolus regimen is used, which artificially recreates the function of the pancreas. This approach includes two independent treatment components:

• Simulation of basal (background) secretion. This component is necessary to cover the body's basic hormone needs between meals and at night. Long-acting analogs (prolonged-release drugs) are used for this purpose. Their pharmacokinetics are such that the duration of effect exceeds 12 hours. These drugs are administered 1–2 times a day, which allows for a smooth hormone concentration "plateau" in the blood without sharp spikes.
• Simulation of prandial secretion. This component is responsible for the assimilation of carbohydrates that enter the body during meals. In this case, ultra-short-acting analogs are used. They are absorbed very rapidly, and their total duration of action ranges from 3 to 5 hours. Injections are given immediately before breakfast, lunch, and dinner. This provides peak hormone surges for each food load, protecting the patient from postprandial hyperglycemia.

Insulin pump application

In modern endocrinology, an alternative to classical multiple daily injections using pen injectors is the insulin pump. The key pharmacological feature of pump therapy is that the device is loaded with only one type of drug—ultra-short-acting analogs.

Physiological hormone production when using a pump is simulated through two different operational modes of the device:

1. Basal mode. The device operates continuously throughout all 24 hours, delivering the hormone in micro-doses. This completely replaces the need to give separate injections of a prolonged-release drug to maintain the background level.
2. Bolus mode. This function is activated by the patient themselves before each meal. The device delivers an additional (bolus) dose of ultra-short-acting insulin, which is necessary to compensate for the upcoming carbohydrate load and prevent a glucose spike.

Injection technique rules

Insulin preparations must be administered strictly subcutaneously (s.c.). Specialized medical equipment is used to perform the injections: insulin syringes or modern pen injectors, which are necessarily equipped with thin disposable needles.

To ensure proper drug absorption, injections are performed in strictly defined anatomical areas:

• anterior abdominal wall;
• anterolateral surface of the thighs;
• upper outer quadrant of the buttocks;
• outer surface of the arm.

Glycemic control and dosage calculation

The success of therapy directly depends on the regularity of monitoring. To keep glucose metrics as close as possible to the values of a healthy person, it is required to measure blood sugar levels at least 4 times a day. Mandatory self-monitoring points include measurements before meals, before bedtime, and before any physical activity. Monitoring is also necessary at the slightest deterioration in well-being.

In pediatric practice, the selection of baseline dosages is the prerogative of the pediatric endocrinologist, who takes into account the individual characteristics of the organism. Nevertheless, before each injection, the patient (or their parents) must independently adapt the dose. This adjustment relies on three main factors:

1. Current glycemia: baseline blood glucose level at the time of calculation.
2. Dietary carbohydrates: planned food volume, as carbohydrates raise sugar levels.
3. Physical activity: presence and intensity of upcoming exertion, as exercise lowers glucose levels and, consequently, reduces the body's need for exogenous insulin.

Class and exam questions

What else to study on this topic

• Pharmacokinetic features of long-acting insulin analogs
• Action profiles of ultra-short-acting insulin analogs
• Algorithms for setting up the basal mode of an insulin pump
• The impact of dietary carbohydrates on postprandial glycemia
• Mechanisms of changes in insulin requirements during physical exertion
• Prevention and management of hypoglycemic episodes

Other topics in the section «Chapter 11. Endocrine Diseases in Children»

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.