Gastrointestinal excretion is accomplished using sodium polystyrene sulfonate (Kayexalate), which binds potassium in the colon in exchange for sodium; it can be given orally or as a retention enema. The enema form is faster; the oral route can take four to six hours because it requires the resin to get to the colon before it takes effect. Sodium polystyrene sulfonate often is given with sorbitol to decrease constipation. However, sorbitol can have intestinal complications, with reports of bowel necrosis and perforation in immunocompromised patients. 33 Using furosemide (Lasix) with polystyrene reduces the risk of volume overload because of the sodium that is exchanged for potassium by the resin ( Table 5 2 , 3 ) . 33
During conventional pharmacologic dose corticosteroid therapy, ACTH production is inhibited with subsequent suppression of cortisol production by the adrenal cortex. Recovery time for normal HPA activity is variable depending upon the dose and duration of treatment. During this time the patient is vulnerable to any stressful situation. Although it has been shown that there is considerably less adrenal suppression following a single morning dose of prednisolone (10 mg) as opposed to a quarter of that dose administered every six hours, there is evidence that some suppressive effect on adrenal activity may be carried over into the following day when pharmacologic doses are used. Further, it has been shown that a single dose of certain corticosteroids will produce adrenal cortical suppression for two or more days. Other corticoids, including methylprednisolone, hydrocortisone, prednisone, and prednisolone, are considered to be short acting (producing adrenal cortical suppression for 1¼ to 1½ days following a single dose) and thus are recommended for alternate day therapy.