Antibiotic therapy for treatment in relapse of intestinal Crohn's disease. A prospective randomized study.

We have undertaken a prospective randomized trial of one month's antimicrobial therapy for patients with symptomatic relapse of Crohn's disease. Criteria for entry included two major symptoms: fever, abdominal pain, diarrhea, weight loss, abdominal mass or complications (excluding perianal disease); and two hematologic abnormalities: hemoglobin, ESR, albumin, C reactive protein, iron, or total iron binding capacity. Patients were monitored for the aforementioned clinical and hematologic (hemoglobin, albumin, CRP) parameters over six weeks and for changes in fecal flora. Randomization was to four groups: metronidazole alone (M), cotrimoxazole alone (C), metronidazole and cotrimoxazole (C plus M), or double placebo (P). Seventy-two patients entered the study (18 = M, 16 = C, 21 = C plus M, 17 = P). After two weeks, improvement was reported as follows: M = 67 percent, C = 17 percent, C plus M = 71 percent, P = 35 percent. In the metronidazole group, two patients required surgery and one had troublesome side effects. In the cotrimoxazole group, two had side effects. In the combined group (C plus M), four had troublesome side effects and two of the placebo group (P) required operation. By four weeks, there was no difference in response among the groups: (M = 44 percent, C = 62 percent, C plus M = 57 percent, P = 41 percent). Antimicrobials had no effect on fecal flora or hematologic parameters. These results indicate that antimicrobials have little therapeutic potential for relapse of intestinal Crohn's disease.