Glucocorticosteroids: Prednisolone

General Overview and Effects

Glucocorticoids (GCs, GCS) are a crucial group of hormones. Under physiological conditions, they are synthesized in the zona fasciculata and zona reticularis of the adrenal cortex. Their primary physiological role is to regulate carbohydrate and protein metabolism.

Pharmacology utilizes both natural hormones and their numerous synthetic analogs. It is essential to clearly distinguish them from mineralocorticoids. The latter are produced in the zona glomerulosa of the adrenal glands and are primarily responsible for mineral metabolism regulation. Glucocorticosteroids, on the other hand, are valued by clinicians for their unique pharmacodynamic properties. They exhibit pronounced anti-inflammatory, immunosuppressive, antiallergic, and antishock effects. This broad spectrum of effects determines their widespread clinical application across a wide variety of pathologies.

Systemic and Inhaled Therapy

Drugs in this group are traditionally divided into systemic and inhaled forms. Approaches to their prescription, onset of action, and safety profile differ radically.

Systemic GCS (including Prednisolone, Dexamethasone, Methylprednisolone) are used primarily as treatments for severe, life-threatening conditions. When administered parenterally, the therapeutic effect develops very rapidly. However, long-term use of systemic forms requires strict discipline: they must be tapered off exclusively in a gradual manner. Abrupt discontinuation inevitably leads to severe withdrawal syndrome.

Inhaled GCS (Beclometasone, Budesonide) have a completely different therapeutic niche. Their main clinical indication is maintenance therapy for bronchial asthma. They are essential for long-term disease control. Unlike systemic agents, their effect develops slowly. Maximum pharmacological action is achieved only after a week of regular administration. Typically, such drugs are prescribed twice daily.

Here lies a crucial limitation that is often overlooked: inhaled steroids have virtually no efficacy and are not used as emergency rescue medication. They cannot be used to relieve acute bronchospasm. A major advantage of the inhaled route of administration is that systemic effects on the body are almost entirely absent.

Drug Interactions and Carbohydrate Metabolism

Because glucocorticoids actively interfere with carbohydrate metabolism, they exhibit a pronounced counter-regulatory (anti-insulin) effect. This means that when co-administered with insulin, they attenuate its hypoglycemic effect, creating a significant risk of hyperglycemia. A similar attenuation of insulin action is also seen with thiazide diuretics, thyroid hormones, and the anticoagulant heparin.

On the other hand, there are a number of drugs that conversely enhance the hypoglycemic effect of insulin, which can lead to dangerous hypoglycemia. Such drugs include sulfonamides, anabolic steroids, and monoamine oxidase (MAO) inhibitors. Particular clinical caution should be exercised when combining them with beta-blockers. Not only do they enhance the effect of insulin, but they also insidiously mask the clinical symptoms of developing hypoglycemia, preventing the patient from noticing a critical deterioration in their condition in time.

Prevention of Adverse Reactions

The potent systemic action of glucocorticoids is inevitably associated with a high risk of adverse effects. To minimize harm to the patient, the attending physician must follow a series of strict recommendations.

First, the minimum effective dose of the drug sufficient to control the disease should always be used. Second, systemic administration must strictly follow the natural circadian rhythm of hormone production—the drug is prescribed predominantly in the morning hours. Third, as already emphasized, therapy must be tapered smoothly and gradually.

In addition, patients require concomitant supportive therapy and careful medical monitoring:

• To prevent steroid-induced osteoporosis, calcium and vitamin D supplements are mandatory.
• If the patient has a history of peptic ulcer disease, reliable gastroprotection is necessary.
• The physician must regularly monitor blood glucose levels, blood pressure, and electrolyte balance.
• When using inhaled forms, there is a specific rule: after each inhalation, the patient must thoroughly rinse their mouth with water. This simple yet effective measure reliably prevents oral candidiasis.

Class and exam questions

What else to study on this topic

• Prescription writing rules for prednisolone and dexamethasone.
• Pathogenesis of glucocorticoid withdrawal syndrome.
• Mechanisms of the counter-insulin action of steroid hormones.
• Pharmacodynamic features of mineralocorticoids and their effect on mineral metabolism.

Other topics in the "Additional Topics" section

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