Control of intragastric pH with omeprazole 20 mg, omeprazole 40 mg and lansoprazole 30 mg.
BACKGROUND
Single daily doses of proton pump inhibitors, omeprazole and lansoprazole provide effective acid suppression and equal healing and symptom relief in patients with GERD. Despite this, controversy exists as to the efficacy of available proton pump inhibitors in the control of gastric acidity.


OBJECTIVE
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 years) were treated with omeprazole 20 mg and lansoprazole 30 mg in random order 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 allowed between studies. Subjects had the same meal on each study day. On day seven, a 24-h intragastric pH study was performed. The percentage time 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 and night-time periods. (2) The percentage time for which pH > 4 with omeprazole 40 mg was significantly greater than lansoprazole 30 mg in both daytime (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, omeprazole 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.


CONCLUSIONS
These pH data support the therapeutic equivalency of FDA approved doses of omeprazole and lansoprazole.
Katz
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Oesophageal Laboratory, Department of Medicine, Graduate Hospital, Philadelphia, PA 19146, USA. pkatz19512@aol.com
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Castell
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D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D002940:Circadian Rhythm; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D054328:Proton Pump Inhibitors; D013810:Therapeutic Equivalency
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D009853:Omeprazole