Pharmacology · single question
What is the mechanism of action of dexamethasone?
Show answer and explanation
Correct answer: B. Glucocorticoid receptor agonist
- A. Incorrect. Glucocorticoids inhibit rather than activate inflammatory phospholipase signalling.
- B. Correct. Dexamethasone is a synthetic glucocorticoid that binds the intracellular glucocorticoid receptor. The complex translocates to the nucleus and alters gene transcription, inducing lipocortin (which inhibits phospholipase A2) and suppressing inflammatory cytokines.
- C. Incorrect. COX inhibition is the mechanism of NSAIDs, acting further downstream in the arachidonic acid pathway.
- D. Incorrect. Mineralocorticoid receptor antagonism describes spironolactone. Dexamethasone in fact has negligible mineralocorticoid activity.