Effect of esomeprazole and rabeprazole on intragastric pH in healthy Chinese: An open, randomized crossover trial

Background and Aim: Esomeprazole is the S‐isomer of omeprazole, with a stronger acid suppressive effect than omeprazole. This open, randomized crossover study was designed to evaluate the effect of esomeprazole and another proton‐pump inhibitor, rabeprazole, on intragastric pH in healthy Chinese. Methods: Thirty‐six healthy volunteers (26 men and 10 women, aged between 20 and 31 years) were enrolled. Subjects were given either esomeprazole 40 mg (n = 18) or rabeprazole 10 mg (n = 18) orally once daily for 5 days during the first dosing period, then the other medicine at the set dosage for the second dosing period. The two periods were separated by a 14‐day washout phase. The doses were chosen according to the State Food and Drug Administration of China for the treatment of acid‐related diseases. Intragastric pH was continuously monitored for 24 h on days 1 and 5 of each dosing period. CYP2C19 genotypes were analyzed to identify the extensive metabolizers (EM) and poor metabolizers (PM). Results: The percentage of time with intragastric pH >4 was significantly higher (P 4 for at least 16 h on day 1 (63.9% vs 33.3%) and on day 5 (88.9% vs 61.1%) was higher after administration of esomeprazole than after rabeprazole (both P 4 and the median 24‐h intragastric pH than those who were EM. Both drugs were well tolerated. Conclusions: Esomeprazole 40 mg orally once daily is more effective and faster in increasing intragastric pH than rabeprazole 10 mg orally once daily, and thus offers a potential for improved efficacy in acid‐related diseases.