The effects on fasting gastric pH of eight medical regimens were evaluated during a 10-h period in 8
duodenal ulcer patients. Our goal was to find a regimen that would produce sustained, fasting
achlorhydria (pH greater than 7.0) in every patient. The effects of commonly prescribed bolus doses of
cimetidine,
antacid, or their combination were studied first. Mean gastric pH with
cimetidine (300 mg/6 h intravenously),
antacid (30 ml/h intragastrically), and their combination was 3.5, 4.6, and 6.8, respectively. Although mean pH with the combination was significantly higher than with either
drug alone (p less than 0.05), sustained
achlorhydria was not achieved. Next we tested constant-infusion regimens of
cimetidine (50 mg/h intravenously),
antacid (0.5 ml/min intragastrically), and their combination. Whereas infusions of
cimetidine or
antacid alone produced mean pH levels of 4.3 and 5.2, respectively, not significantly different from their bolus counterparts, the combination regimen resulted in a mean pH of 7.4. However, sustained
achlorhydria was still not produced in each patient. Only when the dose of
cimetidine infusion was doubled to 100 mg/h and administered with a constant infusion of
antacid was sustained
achlorhydria achieved in each patient.