Effect on Intragastric pH of a PPI with a Prolonged Plasma Half-Life: Comparison between Tenatoprazole and Esomeprazole on the Duration of Acid Suppression in Healthy Male Volunteers

OBJECTIVE: To compare the inhibitory effect of a novel proton pump inhibitor (PPI), tenatoprazole 40 mg once daily, with esomeprazole 40 mg once daily on intragastric acidity. METHODS: A randomized, investigator-blind, two-way, crossover study was conducted in 30 healthy Helicobacter pylori negative male volunteers. Tenatoprazole 40 mg or esomeprazole 40 mg was administered once daily for 7 consecutive days with a 4-wk washout period between treatments. Ambulatory 24-h intragastric pH was recorded at baseline, after 7 days' treatment, and 3 and 5 days after treatment was stopped. RESULTS: At presumed steady-state (day 7), median 24-h pH values were 5.02 and 4.79 for tenatoprazole and esomeprazole, respectively. There was a significant difference between tenatoprazole and esomeprazole during the nocturnal period when mean pH was 4.64 +/- 0.67 versus 3.61 +/- 0.90, respectively (p < 0.0001), as well as a significantly higher mean percentage of time with pH >4 on tenatoprazole (72.5 +/- 14.9 vs 62.2 +/- 13.6, p < 0.0001). The effect of tenatoprazole was still present 5 days after treatment withdrawal especially during the night-time. The mean area under the plasma concentration-time curve and elimination half-time was significantly higher in the tenatoprazole group as compared with the esomeprazole group. CONCLUSION: Tenatoprazole 40 mg daily provides a prolonged duration of acid suppression and a shorter nocturnal acid breakthrough in healthy volunteers, even after stopping the drug. Thus, tenatoprazole may provide greater clinical efficacy for patients in whom a once daily PPI is ineffective. Further studies are indicated.