Objective: Unfractioned heparin reportedly improves severe ulcerative colitis and Crohn's disease, but most of the few observations made have been published as abstracts. This prospective study evaluated whether heparin results in improvement of disease activity in patients with highly active, refractory ulcerative colitis or Crohn's disease.

Methods: Thirteen patients with ulcerative colitis and four patients with Crohn's disease received continuous intravenous heparin, aiming at a partial thromboplastin time of about 60 s for 2 wk. The following 6 wk, patients injected 12,500 units of heparin twice daily. All patients received sulphasalzine (1 g t.i.d.). Clinical and laboratory data were assessed weekly during the first month of treatment and every other week thereafter.

Results: A significant decline of clinical activity (p = 0.0059), C-reactive protein (p = 0.0119), and erythrocyte sedimentation rate (p = 0.0096) was observed in the ulcerative colitis patients. In Crohn's disease clinical activity and laboratory values remained unchanged. Seven patients with ulcerative colitis but none of the Crohn's disease patients achieved complete remission after an average of 4 wk. In ulcerative colitis the histology (p = 0.0431) but not the endoscopic score (p = 0.1088) improved significantly. In one patient with ulcerative colitis, massive colonic bleeding was observed on day 11 of the study.

Conclusions: These data are further evidence of a beneficial effect of unfractioned heparin in the therapy of patients with highly active ulcerative colitis. Because of possible serious bleeding, intravenous heparin should be administered in hospitalized patients only.