A study by Houben and colleagues looked at the effects of three different treatment regimens known to inhibit acid secretion.

A total of 11 healthy individuals were included in a randomized, multiple, cross-over, double-blind study and intragastric 24-hour pH monitoring was done for all the subjects. Each participant received four dose regimens, for 2 weeks each, including 300 mg ranitidine b.d., a PPI in a dose of 20 mg., 40 mg PPI., and placebo.

Findings from the study -

• There was a significantly greater reduction in gastric acidity during the daytime and during the entire 24-hour period with all three treatment regimens, compared to placebo.
• A significant difference in acid inhibition was noted between ranitidine and 40 mg PPI, but not between ranitidine and 20 mg PPI.
• The reduction in gastric acidity with all three treatments was significantly greater than placebo during night-time as well, with no difference between the two PPI doses and ranitidine.
• There was no statistical difference between the treatment regimens with regard to time of pH > 3.
• The pH remained above 4 for a significantly longer time after ranitidine and the two doses of PPI, in comparison with placebo.

The investigators concluded that 300 mg ranitidine b.d., and 20 mg or 40 mg of PPI therapy are superior to placebo for inhibition of gastric acid.

Source: Houben GMP, Hooi J, Hameeteman W, Stockbrügger RW. Twenty-four-hour intragastric acidity: 300 mg ranitidine b.d., 20 mg omeprazole o.m., 40 mg omeprazole o.m. vs. placebo. Aliment Pharmacol Ther. 1995 Dec;9(6):649-54.