Pharmacology · patient case question
What is the mechanism of action of DEXAMETHASONE?
Patient case: Mechanisms of action — candesartan, dexamethasone, rivaroxaban
Scenario: Mechanism-of-action questions on three medications from the patient's list.
Show answer and explanation
Correct answer: C. Agonist at glucocorticoid receptors
- A. Dexamethasone has minimal MINERALOCORTICOID activity — this is precisely why it is preferred when sodium and water retention must be avoided.
- B. It is an agonist, not an antagonist. (Mifepristone is an example of a glucocorticoid receptor antagonist.)
- C. Correct. Dexamethasone is a synthetic corticosteroid that acts as an AGONIST at intracellular GLUCOCORTICOID receptors. The receptor-ligand complex translocates to the nucleus and alters gene transcription — suppressing phospholipase A2 (blocking both the cyclooxygenase and lipoxygenase pathways), reducing cytokine production and inhibiting leukocyte migration.
- D. Spironolactone is the mineralocorticoid receptor antagonist.
Note: DENTAL RELEVANCE: dexamethasone is used to reduce post-operative oedema after third molar surgery. In patients on long-term steroids, consider ADRENAL SUPPRESSION and the potential need for supplementation before major procedures, and remember the increased risk of infection and delayed healing.