THE COMPARATIVE EFFECTS OF LANSOPRAZOLE, OMEPRAZOLE, AND RANITIDINE IN SUPPRESSING GASTRIC-ACID SECRETION

The effects on 24-hour intragastric pH levels of once-daily doses of l ansoprazole 15 mg and lansoprazole 30 mg were compared with the effect s of omeprazole 20 mg QD and ranitidine 150 mg QID in a phase I, rando mized, double-masked, four-way crossover study conducted in 29 healthy male volunteers. Subjects received each treatment regimen for 5 conse cutive days with at least a 2-week washout between treatment periods. Ambulatory 24-hour intragastric pH values were monitored in each subje ct at baseline (2 days before crossover period 1) and again before dos ing on day 5 of each of the four crossover treatment periods. Gastric pH values increased during all four regimens, with significantly highe r mean 24-hour pH values noted in subjects receiving lansoprazole 30 m g QD (4.53 +/- 0.16) compared with those receiving lansoprazole 15 mg QD (3.97 +/- 0.16), omeprazole 20 mg QD (4.02 +/- 0.16), or ranitidine 150 mg QID (3.59 +/- 0.16). Lansoprazole 30 mg produced significantly greater mean percentages of time that the gastric pH was above 3.0 an d 4.0 (75% and 63%, respectively) compared with the other treatment re gimens. The mean percentages of time during which gastric pH was above 3.0 and 4.0, respectively, for the other treatments were lansoprazole 15 mg, 64% and 48%; omeprazole 20 mg, 63% and 51%; and ranitidine 150 mg, 52% and 38%. All treatment regimens were well tolerated, with no clinically significant differences between the regimens. Multiple-dose lansoprazole 30 mg QD produced a significantly increased intragastric pH level and significantly longer durations of increased intragastric pH level compared with lansoprazole 15 mg QD, omeprazole 20 mg QD, an d ranitidine 150 mg QID.