Which of the following correctly explains why inhaled corticosteroids (ICS) like fluticasone are preferred over systemic steroids for long-term asthma control?

• A ICS are structurally different from systemic steroids and do not bind glucocorticoid receptors systemically
• B ICS are rapidly degraded to inactive metabolites in lung tissue before entering the circulation
• C ICS have high first-pass hepatic extraction (>99% for fluticasone), minimising systemic bioavailability from swallowed drug, while delivering high local concentrations to airways ✓
• D ICS selectively bind non-classical membrane glucocorticoid receptors present only in bronchial epithelium

Explanation

Fluticasone and other modern ICS are designed for high local potency combined with extensive first-pass hepatic extraction (fluticasone: ~99%, budesonide: ~90%) of any drug that is swallowed or absorbed from the oropharynx. This dramatically limits systemic bioavailability, reducing HPA axis suppression, osteoporosis risk, and growth retardation compared to oral corticosteroids, while achieving therapeutic bronchial concentrations.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.