Background: Over-the-counter status has recently been approved for low-dose H2-antagonists in several countries. Insufficient information is currently available on the effect of food in low-dose H2-antagonist therapy.
Aim: Compare the antisecretory efficacy of low-dose ranitidine and famotidine in fasting and non-fasting volunteers.
Methods: Twenty volunteers were randomized into a double-blind, placebo-controlled, multiple-step crossover study comparing the antisecretory efficacy of 75 mg ranitidine, 10 mg famotidine and placebo over 12 h using intragastric pH-metry. Two standard meals were given after 4 h and 8 h of medication. Fifteen volunteers also participated in a second study comparing the antisecretory effect of both drugs, both with and without meals.
Results: In non-fasting subjects, the percentage of time with pH > 4 was similarly elevated for both drugs compared with placebo over the first 8 h: ranitidine 39.3%, famotidine 29.5%, placebo 9.5% (P < 0. 001); but not for the last 4 h after the second meal (P > 0.05). Comparing the first 4-h period with the second, the percentage of pH > 4 was significantly reduced for both drugs in the second period in the subjects given food at the end of the initial 4-h period (ranitidine 56.9% vs. 26.6%, P = 0.005; famotidine 46.6% vs. 13.3%, P < 0.001). It remained more or less constant, however, for the second 4-h period in fasting subjects (ranitidine 41% vs. 28.1%, P = 0.46; famotidine 52.7% vs. 52.2%, P = 0.12).
Conclusion: In non-fasting volunteers both low-dose H2-antagonists had comparable antisecretory effects and were superior to placebo over the first 8 h of therapy. Both drugs achieved a slightly higher antisecretory effect without food intake compared to with food intake.