Active Crohn’s Disease
The goal of treatment for active Crohn’s disease is to achieve remission; however, in many patients, reduction of symptoms so that the patient may carry out normal activities or reduction of the steroid dose required for control is a significant accomplishment.
In the majority of patients, active Crohn’s disease is treated with sulfasalazine, mesalamine derivatives, or steroids, although azathioprine, mercaptopurine, or metronidazole is frequently used.
Sulfasalazine is more effective when Crohn’s disease involves the colon.
Mesalamine derivatives (such as Pentasa or Asacol) that release mesalamine in the small bowel may be more effective than sulfasalazine for ileal involvement.
Steroids are frequently used for the treatment of active Crohn’s disease, particularly with more severe presentations. Steroids are preferred for treatment of severe Crohn’s disease, mainly because these agents can be given parenterally and response to therapy may occur sooner than with other agents. Once remission is achieved, however, it may prove difficult to reduce steroid dosage without reintroduction of active disease.
Metronidazole (given orally up to 20 mg/kg/day) may be useful in some patients with Crohn’s disease, particularly in patients with colonic involvement or those with perineal disease.
The immunosuppressive agents (azathioprine and mercaptopurine) are generally limited to use in patients not achieving adequate response to standard medical therapy, or to reduce steroid doses when toxic doses are required. The usual dose of azathioprine is 2 to 2.5 mg/kg/day and 1 to 1.5 mg/kg/day for mercaptopurine. Up to 6 months may be required to observe a response.
A genetic polymorphism causes deficiency of the enzyme thiopurine S-methyltransferase in some people, reduces mercaptopurine metabolism and increases the risk of bone marrow suppression.
Cyclosporine is not recommended for Cronn’s disease except for patients with symptomatic and severe perianal or cutaneous fistulas. The dose of cyclosporine is important in determining efficacy. An oral dose of 5 mg/kg/day was not effective, whereas 7.9 mg/kg/day was effective. However, toxic effects limit application of the higher dosage.
Methotrexate, given as a weekly injection of 5 to 25 mg has demonstrated efficacy for induction of remission in Crohn’s disease as well as for maintenance therapy.
Infliximab, 5 mg/kg single infusion, is effective for refractory or fistulizing Crohn’s disease when given everyday for 8 weeks.
Maintenance of Remission
Prevention of recurrence of disease is clearly more difficult with Crohn’s disease than with ulcerative colitis. Sulfasalazine and oral mesalamine derivatives are effective in preventing acute recurrences in quiescent Crohn’s disease.
Steroids also have no place in the prevention of recurrence of Crohn’s disease; these agents do not appear to alter the long-term course of the disease.
Although the published data are not consistent, there is evidence to suggest that azathioprine and mercaptopurine are effective in maintaining remission in Crohn’s disease.