Background: Single daily doses of proton pump inhibitors, omeprazole and la
nsoprazole provide effective acid suppression and equal healing and symptom
relief in patients with GERD. Despite this, controversy exists as to the e
fficacy of available proton pump inhibitors in the control of gastric acidi
Aim: To assess the efficacy of omeprazole 20 mg vs. lansoprazole 30 mg and
omeprazole 40 mg vs. lansoprazole 30 mg in intragastric pH control.
Methods: Study I: 12 Helicobacter pylori-negative volunteers (mean age 33 y
ears) were treated with omeprazole 20 mg and lansoprazole 30 mg in random o
rder before breakfast for 7 days. Study II: 24 subjects (mean age 36 years)
were similarly treated with omeprazole 40 mg and lansoprazole 30 mg for 7
days after a baseline pH study. One week washout was arrowed between studie
s, Subjects had the same meal on each study day. On day seven, a 24-h intra
gastric pH study was performed. The percentage lime for which gastric pH >
4 was analysed (Gastrosoft, Synectics Medical Inc.) and expressed as mean /- s.d.
Results: (1) Omeprazole 20 mg and lansoprazole 30 mg showed no significant
difference in the percentage time for which gastric pH > 4 in the daytime a
nd night-time periods. (2) The percentage time for which pH > 4 with omepra
zole 40 mg was significantly greater than lansoprazole 30 mg in both daytim
e (61 +/- 19% vs. 48 +/- 14%, P < 0.001), and night-time periods (34 +/- 21
% vs. 26 +/- 14%, P < 0.05). (3) A large inter-subject variation existed in
both studies. (4) In 10 subjects who participated in both studies, omepraz
ole 40 mg showed a significantly higher percentage time for which pH > 4 in
the daytime (69 +/- 18% vs. 51 +/- 15%, P = 0.015) than omeprazole 20 mg.
Conclusion: These pH data support the therapeutic equivalency of FDA approv
ed doses of omeprazole and lansoprazole.