Drug Interaction Report

MONITOR: The overuse or abuse of laxatives can cause significant loss of electrolytes and potentiate the risk of hypokalemia associated with corticosteroid therapy. Corticosteroids promote the retention of sodium and water and the excretion of potassium. Although these effects are primarily associated with mineralocorticoids like fludrocortisone, they may also occur with higher dosages of glucocorticoids or adrenocorticotropic agents, particularly if given systemically for longer than brief periods.

MANAGEMENT: In general, laxatives should only be used on a short-term, intermittent basis in recommended dosages. During concomitant therapy with corticosteroids, particularly if fludrocortisone or large doses of a glucocorticoid or adrenocorticotropic agent is given, patients should be counseled to recognize potential signs and symptoms of hypokalemia such as fatigue, myalgia, and muscle weakness. If maintenance of bowel regularity is required, patients should be advised to exercise and increase fiber in the diet and/or consider the use of bulk-forming laxatives.

Antacids and agents with acid-neutralizing effects may impair the oral absorption of dexamethasone, prednisolone, prednisone, and other orally administered corticosteroids, although data from published studies are somewhat conflicting. The mechanism of interaction and clinical significance are unknown. No particular intervention is necessary during concomitant therapy with these agents, but clinicians should be aware of the potential for interaction.

ADJUST DOSING INTERVAL: Administration with food may increase the absorption of calcium. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption.

MANAGEMENT: Calcium may be administered with food to increase absorption. Consider withholding calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid.