All corticosteroid drugs, including prednisone, can cause sodium retention, resulting in dose-related fluid retention. Corticosteroids with strong mineralocorticoid effects, such as fludrocortisone and hydrocortisone, produce the greatest amount of fluid retention. However, some corticosteroids that lack significant mineralocorticoid activity (e.g., dexamethasone, triamcinolone, betamethasone) may produce minor fluid retention. Corticosteroid-induced fluid retention can be severe enough to cause hypertension, and patients with preexisting hypertension may develop a worsening of blood pressure control when these drugs are initiated. The principal mechanism of corticosteroid- induced hypertension is the overstimula- tion of the mineralocorticoid receptor, resulting in sodium retention in the kidney. This results in volume expansion and a subsequent increase in blood pressure. Corticosteroid-induced hypertension may respond to diuretic therapy. The smallest effective dose and shortest duration of steroid therapy should be used in order to decrease the development of this adverse effect.
Fludrocortisone causes significant blood pressure increases and, thus, is useful in treating patients with postural hypotension. In a study of 64 elderly patients receiving an average dose of 75 mcg of fludrocortisone for approximately five months, four patients had to withdraw because of druginduced hypertension. The study investigators concluded that fludrocortisone therapy was poorly tolerated in elderly patients, even at low doses.