[Stomach tolerance of acetylsalicylic acid by addition of calcium carbonate. A study of a 2-treatment/3-period cross-over design].

18 male volunteers (age 24 +/- 4 years; Broca index 0.94 +/- 0.08; mean +/- SD) underwent six upper endoscopies (three control and three test investigations) in a single blind two treatments-crossover designed study which evaluated the effect of buffering on aspirin-induced (one single oral dose of 0.5 g aspirin to fasted subjects) gastroduodenal mucosal injury. All subjects had a normal endoscopy prior to applications of 0.5 g plain aspirin (group A; swallowed) or 0.5 g aspirin + 0.3 g calcium carbonate (group B; chewed before swallowing). The sequence groups were A-B-B (n = 9) or B-A-A (n = 9). In advance fo the performed tests a washout period of six days was chosen. Endoscopies were performed two hours after ingestion of the respective tablets. The appearance of corpus, antrum, and duodenum was scored. Biopsies were taken for histological examinations. 15 volunteers experienced no gastrointestinal side effects. Three complained short-lasting gastric burning (two of group A, one of group B). In both treatment groups no significant lesions of the duodenum were found. Buffering significantly (p less than 0.0005) reduced mucosal injuries which occurred mainly as submucosal hemorrhage but without histological alterations of the mucosal architecture after aspirin ingestion. These findings suggest that oral administration of calcium carbonate buffered, chewable aspirin tablets is less harmful to the gastric mucosa than plain aspirin.