Luminal bicarbonate outflow in chronic antral erosions is suppressed by pirenzepine.

The effects of pirenzepine and ranitidine on luminal HCO3- outflow occurring in subjects with chronic antral erosions have been investigated in a double-blind study. Thirty outpatients with chronic erosions of the gastric antrum were randomly treated for 4 weeks with either pirenzepine 50 mg b.i.d. or ranitidine 150 mg b.i.d. Endoscopic appearance and intragastric bicarbonate content were assessed before and after treatment. At endoscopic follow-up pirenzepine was found to be significantly more effective than ranitidine in promoting disappearance of antral erosions. In the ranitidine group the abnormally high intraluminal HCO3 content was reduced only in healed subjects, while no changes were observed in patients with persisting erosions. In contrast pirenzepine induced normalization of intragastric bicarbonate both in healed and in unhealed patients. The results suggest that pirenzepine suppresses luminal HCO3 leakage by functionally strengthening mucosal defences even before anatomical repair is obtained.