Budesonide: Locally Acting Glucocorticoid: Effects, Indications and Notes

Budesonide is a synthetic glucocorticoid developed primarily for local application. Compared with systemic corticosteroids, budesonide undergoes an extensive first-pass effect in the liver: after absorption, a large proportion of the compound is rapidly metabolised, which reduces the systemic burden of local administration compared with other glucocorticoids. This property makes budesonide a favourable compound for conditions requiring a local anti-inflammatory effect without pronounced systemic adverse effects.

Budesonide is used in various areas of medicine, including pulmonology, ear, nose and throat medicine, and gastroenterology. The specific formulation is tailored to the respective indication and determines where and how the compound is released at its site of action.

Mechanism of Action

Like all glucocorticoids, budesonide exerts its effect via the intracellular glucocorticoid receptor. After binding to this receptor, the complex enters the cell nucleus and influences the transcription of specific genes. The synthesis of pro-inflammatory mediators such as histamine, prostaglandins and leukotrienes is inhibited. Simultaneously, anti-inflammatory proteins are expressed in greater quantities.

The locally anti-inflammatory effect is particularly pronounced with budesonide. The lipophilic structure of the molecule enables good penetration into mucosal tissue, supporting local efficacy. At the cellular level, budesonide inhibits the migration of inflammatory cells such as mast cells, eosinophils and other immune cells into the affected tissue.

The effect of budesonide does not set in immediately with regular use but builds up over days to weeks. Consistent continuous use is therefore important in chronic conditions, even when no acute symptoms are present.

Indications

Bronchial Asthma

In pulmonology, budesonide is an established compound for inhaled maintenance therapy in bronchial asthma. Regular inhalation provides sustained suppression of the chronic airway inflammation. This can contribute to reducing the frequency and severity of asthma attacks. Budesonide is available as a single-ingredient product and in combination with long-acting bronchodilators (beta-2 agonists). The combination is used in patients whose asthma cannot be adequately controlled with a corticosteroid alone.

Chronic Obstructive Pulmonary Disease

In chronic obstructive pulmonary disease (COPD), budesonide is also used by inhalation in certain situations, usually in combination with long-acting bronchodilators. Guidelines provide for corticosteroids in COPD for defined patient groups, particularly those with frequent exacerbations.

Allergic and Chronic Rhinitis

As a nasal spray, budesonide is approved for the treatment of allergic rhinitis (hay fever) and non-allergic chronic rhinitis. Local application directly to the nasal mucosa enables effective reduction of inflammation and mucosal swelling without notable systemic effects. Typical symptoms such as sneezing, nasal pruritus, rhinorrhoea and nasal congestion can be substantially relieved by regular use.

Crohn's Disease

In gastroenterology, budesonide is used orally in special controlled-release formulations for active Crohn's disease. The formulation is designed to release the compound preferentially in the terminal ileum and ascending colon, where it acts locally on the inflamed intestinal mucosa. The pronounced first-pass effect in the liver reduces systemic availability after absorption, thereby lowering the risk of systemic corticosteroid adverse effects.

Microscopic Colitis

Budesonide is one of the few approved treatment options for microscopic colitis, a condition characterised by chronic watery diarrhoea without endoscopically visible changes. Both collagenous and lymphocytic colitis respond to budesonide.

Ulcerative Colitis

Budesonide is also used as an enema (rectal foam or retention enema) in ulcerative colitis of the distal colon to treat inflammation in the rectum and sigmoid colon.

Use in Children

In paediatrics, budesonide is used for croup-type respiratory conditions, where it can be administered by inhalation or nebuliser. Dosage is adapted to the child's body weight and age.

Formulations

Budesonide is available in the following formulations:

• Inhalation powders and pressurised metered-dose inhalers for use in asthma and COPD
• Nebuliser solutions for inhalation therapy, including in children
• Nasal sprays for the treatment of rhinitis
• Controlled-release capsules for inflammatory bowel disease
• Rectal foam preparations and enema solutions for use in ulcerative colitis

Notes on Administration

For inhaled budesonide, correct inhalation technique is critical for efficacy. After inhalation, the oral cavity should be rinsed with water to reduce the risk of oral candidiasis (Candida infection in the mouth). This is because residual compound can deposit in the oral cavity and weaken the local immune defence.

Budesonide nasal sprays should be used regularly and consistently for optimal effect. The effect generally does not fully develop until after several days to weeks of regular use, which is why short-term use is often insufficient for chronic conditions.

Adverse Effects

With local administration, the side-effect profile of budesonide is more favourable than that of systemically administered corticosteroids. Nevertheless, undesirable effects may occur:

• Inhaled: hoarseness, cough, oral candidiasis (Candida fungal infection of the mouth), local airway irritation
• Nasal spray: mucosal irritation, epistaxis, dryness in the nose
• Oral (for bowel conditions): at higher doses or with prolonged use, systemic corticosteroid-typical effects may occur, though less pronounced than with classical corticosteroids
• With all formulations and prolonged use: possible impairment of endogenous cortisol production

Drug Interactions

Certain compounds metabolised via the liver enzyme CYP3A4 can influence budesonide levels in the body. These include some antifungal agents such as itraconazole or ketoconazole, and certain antiviral compounds. These compounds inhibit CYP3A4 and thereby slow the metabolism of budesonide, which can lead to its accumulation. A dose adjustment of budesonide may be required in such situations. Medical advice is important before taking other medications concurrently.

Frequently Asked Questions

Why is budesonide better tolerated than prednisolone in bowel conditions?

The difference lies in the first-pass effect. After absorption from the intestine, budesonide is very rapidly metabolised in the liver to inactive metabolites. As a result, only a small proportion of the absorbed compound enters the systemic circulation. Prednisolone, in contrast, is barely metabolised in the liver and acts systemically. For the local treatment of intestinal inflammation, budesonide is therefore more favourable because it produces fewer systemic corticosteroid effects.

Can budesonide nasal spray be used long-term?

Budesonide nasal sprays have been developed for long-term use and, based on current evidence, have a good safety profile when used as directed. With long-term use over many years, however, regular medical check-ups are advisable to detect any local changes in the nasal mucosa at an early stage. Children should be monitored regularly for height development, as inhaled and nasal corticosteroids may influence growth velocity in some children.

Does budesonide inhalation protect against asthma attacks?

Budesonide belongs to the controller medications in asthma, i.e. the compounds used daily for disease control. It does not provide acute protection against an attack but reduces airway hypersensitivity through sustained anti-inflammatory action. For the treatment of acute asthma attacks, short-acting bronchodilators (relievers) are used. Both groups of compounds complement each other and should not be confused.