The antifibrinolytic properties of cimetidine.

The mucosal fibrinolytic activity was estimated in 24 patients with duodenal ulcer and in 11 patients with gastric ulcer. The fibrinolytic activity was estimated in biopsy specimens taken during gastroscopy. Specimens were taken in the corpus, in the antrum, and in the duodenal mucosa. In patients with duodenal ulcer the fibrinolytic activity was significantly higher in the corpus and antrum mucosa, whereas no difference was observed in the duodenal mucosa compared with controls. Gastric ulcer patients had, compared with controls, significantly higher activity in the corpus mucosa only. Fourteen patients with duodenal ulcer and five with gastric ulcer were treated with 1 g cimetidine daily for 4 weeks. The mucosal fibrinolytic activity was estimated before and after treatment in the above-mentioned regions. A significant reduction was observed after treatment in patients with duodenal ulcer, both in the corpus and in the duodenal mucosa, whereas no difference was seen in the duodenum. In patients with gastric ulcer a reduction was observed in the corpus mucosa only. The fibrinolytic activity estimated was plasminogen activator, and not other proteases, in all estimations.