Shanti has been diagnosed to have brain tumor. You would prefer to give her betamethasone /dexamethasone over hydrocoisone as steroids to decrease her cerebral edema because:

* Triamcinolone, Betamethasone, Dexamethasone and Paramethasone are selective glucocoicoids (have zero mineralocoicoid action). * These are preferred for cerebral edema because they lack salt and water retaining potential (mineralocoicoid action).