URINARY EXCRETION OF PREDNISOLONE AFTER INTRARECTAL THERAPY IN ULCERATIVE COLITIS

Drug therapy of inflammatory bowel disease

Although the etiology of inflammatory bowel disease is unknown and specific therapy is unavailable, enough information on existing empiric agents is available to allow rational therapy. These agents include sulfasalazine, steroids, immunosuppressive drugs, metronidazole and cholestyramine. Sulfasalazine is a two-part molecule that depends on bacterial cleavage in the colon to deliver locally acting 5-aminosalicylate, whose mechanism of action may relate to inhibition of prostaglandin synthesis. The other half of the molecule, sulfapyridine, is responsible for most of the side effects of the drug. While the efficacy of sulfasalazine in the treatment and prevention of attacks of ulcerative colitis is well established, its use in Crohn's disease appears to be limited to patients with active colitis and ileo-colitis. Sulfasalazine is of major benefit in preventing relapses in patients with ulcerative colitis in remission. New formulations of 5-aminosalicylate may allow delivery of the apparently active moiety to the small bowel and colon without concomitant sulfapyridine toxicity. Corticosteroids are highly effective in acute attacks of ulcerative colitis and Crohn's ileitis and ileo-colitis; the mechanism of antiinflammatory action remains speculative. However, maintenance therapy with steroids is ineffective in preventing relapses or recurrent attacks of either ulcerative colitis or Crohn's disease. Steroid enemas allow topical administration to patients with distal colitis and proctitis with few systemic side effects. In children with growth failure associated with active Crohn's disease, amelioration by steroid therapy may actually restore normal growth. Immunosuppressive agents such as azathioprine and 6-mercaptopurine are of little value in active Crohn's disease when administered alone; however, in combination with other agents they may help diminish steroid dose, close fistulae and prevent relapse. Their mode of action likely depends on long-term cytostatic effects on immune effector cells. Concern for leukopenia and the development of late malignancy has limited their use to patients not responding to other therapies. Metronidazole, an antimicrobial agent that is effective against anaerobes, has recently been shown useful in Crohn's disease involving the colon and perianal area. Its mechanism of action is uncertain, but may be related to its antibacterial actions on anaerobes. Cholestyramine can be successfully used to control bile salt-induced diarrhea in Crohn's patients with terminal ileal resections. Effective drug therapy of inflammatory bowel disease is only part of a total program of management including reassurance, frequent explanation, well-timed use of surgery, and an understanding physician.

Rectally administered prednisolone--evidence for a predominantly local action

Plasma prednisolone levels have been compared in healthy volunteers and in patients suffering from idiopathic proctocolitis after the administration of standard retention enemata containing either prednisolone-21-phosphate or prednisolone metasulphobenzoate sodium. The levels were significantly lower after the latter, irrespective of the presence or degree of activity of the disease. Prednisolone metasulphobenzoate appeared to be as effective as the 21-phosphate ester for the treatment of proctocolitis in the few patients where the two drugs were compared. It seems possible that the beneficial effect of the form of therapy is exerted predominantly locally, rather than by systemic action.

Plasma prednisolone levels and adrenocortical responsiveness after administration of prednisolone-21-phosphate as a retention enema

Plasma prednisolone levels have been measured by radioimmunoassay after oral and rectal administration to healthy volunteers and to patients with idiopathic proctocolitis. The amount of prednisolone absorbed from a 20 mg retention enema given to patients with proctocolitis was about 44% of that absorbed from the same dose orally administered. Adrenocortical response to synthetic ACTH in patients receiving prolonged rectal therapy was either normal, or only slightly impaired, and this may be related to the pattern of steroid absorption rather than to the total amount absorbed.

Plasma prednisolone levels after administration of prednisolone-21-phosphate as a retention enema in colitis

A competitive protein-binding assay was used to measure plasma prednisolone levels after administration of prednisolone-21-phosphate retention enemas to seven patients with colitis. Prednisolone appeared in the plasma of all patients after the enema, and concentrations rose to a peak within three hours. In five of the patients plasma prednisolone levels were also measured after the same dose of prednisolone by mouth. Although in individual patients the plasma levels achieved by enema were often quite different from those achieved by mouth, overall the levels achieved by each mode of administration were of a similar order. These findings suggest that 20 mg prednisolone given by retention enema may well exert a systemic effect.

Betamethasone 17-valerate and prednisolone 21-phosphate retention enemata in proctocolitis. A multicentre trial

The efficacy of betamethasone 17-valerate (5 mg) and prednisolone 21-phosphate (20 mg) retention enemata in the outpatient treatment of distal proctocolitis was compared in a formal clinical trial. The two treatments were equally effective in inducing remissions of the disease, but the betamethasone valerate enema produced less adrenal suppression.