[Radiotelemetric study of the effects of antacids and cimetidine on intragastric pH (author's transl)].

Radiotelemetric measurement of intragastric pH constitutes a simple method for assessing the activity of surface antacids and antisecretory agents in man. The time during which the intragastric pH is maintained at 3.5 or above is the bet criterion of therapeutic effectiveness. One hundred and fifty-two measurements were performed to evaluate the effects of six antacids administered in the usual doses and of cimetidine, milk (250 ml) and a standard continental breakfast. The results showed that the effects of antacids were extremely brief (less than 30 minutes). The delay in onset of cimetidine activity (more than 45 minutes) and the time it maintained intragastric pH above 3.5 were determined. These in vivo results correlated positively with in vitro measurements. The authors suggest that the dosage of surface antacids should be expressed in anti-acid mEq, knowing that 50 mEq produce as therapeutic effect lasting approximately 30 minutes. The data provided by radiotelemetry could be used to adjust the anti-acid treatment to the diet and the time of the day. The method also seems to be applicable to the study of new antacids and antisecretory drugs.