Dexamethasone is preferred over hydrocortisone for initial management of vasogenic cerebral oedema from a brain tumour. The pharmacological property justifying this choice is:

• A Longer half-life allowing once-daily dosing only
• B Direct cytotoxic effect on tumour cells reducing vasogenic oedema
• C Better penetration through intact blood-brain barrier than all other steroids
• D High glucocorticoid potency with negligible mineralocorticoid activity ✓

Explanation

Reducing tumour-associated vasogenic oedema requires potent glucocorticoid activity, while mineralocorticoid effects cause sodium retention and hypokalaemia that serve no purpose here. Dexamethasone has about 25 times the glucocorticoid potency of hydrocortisone with essentially zero mineralocorticoid activity, whereas hydrocortisone retains significant mineralocorticoid action. The benefit comes from reduction of capillary permeability, not direct tumour toxicity.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.