beclomethasone

Beclomethasone dipropionate is a synthetic glucocorticoid that acts on intracellular glucocorticoid receptors, translocating to the nucleus to alter gene transcription—upregulating anti-inflammatory proteins (e.g., lipocortin-1/annexin A1, which inhibits phospholipase A2) and downregulating pro-inflammatory mediators (cytokines like IL-4, IL-5, IL-13, TNF-alpha, and enzymes like COX-2). This decreases airway mucosal edema, mucus production, and inflammatory cell infiltration (eosinophils, mast cells, T lymphocytes), leading to reduced bronchial hyperresponsiveness. It has minimal systemic absorption when inhaled correctly due to high first-pass hepatic metabolism, making it safer than systemic corticosteroids for long-term use. Clinically, it is a mainstay of persistent asthma management per GINA/NAEPP step-therapy guidelines, used daily to prevent exacerbations, in contrast to short-acting beta-agonists which are used for acute symptom relief. It is not effective for acute bronchospasm and has a delayed onset of action (days to weeks). Intranasal formulations treat allergic rhinitis by reducing nasal mucosal inflammation. Adverse effects: local effects include oral thrush (candidiasis) and dysphonia due to laryngeal myopathy—both minimized by rinsing mouth after use and using a spacer device. Systemic absorption at high doses can cause adrenal suppression, growth retardation in children (usually minimal effect on final adult height), osteoporosis, and skin thinning/easy bruising. Unlike systemic steroids, it does not typically cause hyperglycemia, weight gain, or significant HPA axis suppression at standard doses. Drug class comparison: other ICS agents include fluticasone, budesonide, mometasone, and ciclesonide—all share a similar mechanism but differ in potency, lipophilicity, and systemic bioavailability. Clinical pearls for boards: distinguish ICS (controller, anti-inflammatory) from SABA (reliever, bronchodilator); ICS + LABA combination therapy (e.g., fluticasone-salmeterol) is used in moderate-severe persistent asthma; oral candidiasis risk emphasizes counseling patients to rinse mouth post-inhalation.