Protective effect of cimetidine on aspirin-induced gastric mucosal damage.

Aspirin alters the gastric mucosal barrier as measured by ionic flux and potential difference. The effect of cimetidine on aspirin-induced alterations in gastric mucosa was studied in five normal male volunteers. Aspirin effects were studied with and without previous treatment with cimetidine. Mean (+/- SEM) basal potential difference was -48 +/- 1 mV. After 600 mg of aspirin in 1 dl of isotonic saline, potential difference decreased in 10 min to -39 +/- 1 mV (P less than 0.001) and returned to baseline within 60 min. Control biopsies showed 2% damaged mucosal cells compared with 20% damaged at the time of maximal drop in potential difference (P less than 0.001) after aspirin. Recovery to 9% damage occurred by 60 min. In subjects pretreated with 300 mg cimetidine, potential difference rose during 1 h to -62 +/- 1 mV (P less than 0.001). After aspirin potential difference fell to -48 +/- 1 mV compared with -39 +/- 1 mV with aspirin alone (P less than 0.01) and returned to -62 +/- 1 mV at 60 min. The cimetidine-treated group showed 4% mucosal damage at the peak potential difference fall after aspirin, significantly less (P less than 0.02) than in the untreated subjects.