Pulmonology · USMLE Step 1 and Step 2

Inhaled Corticosteroids song

Inhaled Corticosteroids - Mechanism & Side Effects, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Inhaled Corticosteroids

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Key points in this song10

Inhaled corticosteroids (ICS) are the first-line long-term controller therapy for persistent asthma at all severity levels in both adults and children.
ICS work by binding intracellular glucocorticoid receptors, suppressing NF-κB transcription, reducing synthesis of pro-inflammatory cytokines (IL-4, IL-5, IL-13), and decreasing airway eosinophilic inflammation.
The most common local side effects are oropharyngeal candidiasis and dysphonia; both are prevented by rinsing the mouth after each use and using a spacer device.
Systemic side effects from high-dose or long-term ICS use include HPA axis suppression, reduced bone mineral density, skin thinning, and growth suppression in children — distinguishing them from oral corticosteroids in magnitude, not mechanism.
Fluticasone has high first-pass metabolism and low oral bioavailability (<1%), making it one of the least systemically absorbed ICS agents; budesonide has intermediate systemic absorption.
Budesonide is the preferred ICS during pregnancy due to the most robust safety data (FDA Category B).
ICS do not provide bronchodilation and are ineffective as rescue therapy; short-acting beta-2 agonists (SABAs) like albuterol remain the mainstay for acute symptom relief.
Step-up therapy in the NAEPP guidelines adds a long-acting beta-2 agonist (LABA) to ICS before increasing ICS dose; LABAs must never be used as monotherapy in asthma due to increased asthma-related mortality risk.
ICS reduce airway hyperresponsiveness, decrease exacerbation frequency, and lower the risk of asthma-related hospitalization and death, but do not alter the natural progression or cure the underlying disease.
Unlike systemic corticosteroids, ICS do not cause hyperglycemia, hypertension, or significant immunosuppression at standard therapeutic doses — a key USMLE distinction in choosing long-term asthma management.