Roflumilast is a selective PDE4 inhibitor used in severe COPD with frequent exacerbations. Its anti-inflammatory mechanism relevant to COPD pathophysiology is:

• A Selective PDE4B and PDE4D inhibition in neutrophils and macrophages raises cAMP, suppressing neutrophilic inflammation (TNF-α, IL-8, LTB4 release) that drives COPD exacerbations ✓
• B Inhibition of PDE4 in bronchial smooth muscle causes bronchodilation by raising intracellular cAMP, similar to theophylline but with greater smooth muscle selectivity
• C Roflumilast activates the glucocorticoid receptor via cAMP-dependent phosphorylation, enhancing steroid anti-inflammatory effects
• D Roflumilast inhibits TGF-β signalling in airway fibroblasts, preventing small airway remodelling

Explanation

COPD is characterized by neutrophil-predominant inflammation in the small airways and parenchyma, driven by IL-8, TNF-α, LTB4, and reactive oxygen species from activated neutrophils and macrophages. Roflumilast selectively inhibits the PDE4 isoform (the dominant phosphodiesterase in leukocytes), raising intracellular cAMP and activating PKA, which phosphorylates and inactivates pro-inflammatory transcription factors. PDE4B is critical in neutrophil/macrophage function; PDE4D inhibition mediates nausea (the major side effect, limiting tolerability). Roflumilast has minimal bronchodilator effect — it is an add-on anti-inflammatory agent for severe COPD (FEV1 <50%, chronic bronchitis phenotype, ≥2 exacerbations/year), not a bronchodilator.

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

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Written and medically reviewed by the StethoPrep medical team.