Some medicines can affect how dexamethasone works. Tell your doctor if you are using any of the following:Aminoglutethimide, aprepitant, carbamazepine, carfilzomib, cholestyramine, cobicistat, cyclosporine, digitalis, digoxin, ephedrine, indinavir, indomethacin, lenalidomide, pancuronium, phenobarbital, phenytoin, pomalidomide, ritonavir, thalidomideBirth control pills (including estrogen)Blood thinner (including warfarin)Diuretic (water pill)Insulin and oral diabetes medicineMedicine to treat an infection (including amphotericin B, azithromycin, clarithromycin, erythromycin, isoniazid, itraconazole, ketoconazole, rifampin)NSAID pain or arthritis medicine (including aspirin, celecoxib, diclofenac, naproxen)Potassium supplement