[The effect of proton pump inhibitor on intragastric acidity and it relation to S-mephenytoin hydroxylase genetic polymorphism].
OBJECTIVE
To study the effect of proton pump inhibitor rabeprazole (Rab) and omeprazole (Ome) on intragastric acidity and it relationship to S-mephenytoin hydroxylase (CYP2C19) genetic polymorphism.


METHODS
Thirty duodenal ulcer patients were randomly divided into two groups. They were treated by the following strategies: Rab 10mg or Ome 20mg twice daily orally for two days. Intragastric pH over 24 hours was recorded from morning of the second day. Blood CYP2C19 genotyping of each patient was detected by PCR-restriction enzyme analysis.


RESULTS
In Rab group, the mean intragastric pH values of the PM, hetEM and homEM were 6.3 +/- 0.1, 6.1 +/- 0.2, 6.0 +/- 0.1, no significant difference was observed among the three different genotype groups. In Ome group, they were 6.3 +/- 0.1, 5.9 +/- 0.2, 5.6 +/- 0.3. The differences were significant (P < 0.05). After treated with Rab for 24 hours, the mean and median 24 h intragastric pH values were significant higher than that of Ome (6.1 +/- 0.2, 6.1 +/- 0.3 vs 5.8 +/- 0.4, 5.7 +/- 0.4, P < 0.05). The reason was that big difference existed in homEM type between Rab (6.0 +/- 0.1) than Ome (5.6 +/- 0.3) group. NAB occurred in 3 patients of each group. The sustaining time of NAB in Rab group was shorter than that of Ome group [(2.6 +/- 0.2) h vs (3.4 +/- 0.6) h].


CONCLUSIONS
The effect of Rab on control of intragastric pH was less affected by an individual's CYP2C19 status. Both Rab and Ome could not overcome NAB, but Rab could shorten the sustaining time of nocturnal acid breakthrough.
Wang
Hong
H
Department of Gastroenterology, First Municipal People's Hospital of Guangzhou, 510180 China. wong.hong@163.com
Nie
Yu-qiang
YQ
Dai
Shou-jun
SJ
She
Qing-zhu
QZ
Li
Yu-yuan
YY
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000293:Adolescent; D000328:Adult; D000368:Aged; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D001562:Benzimidazoles / Q000494:pharmacology*; D065731:Cytochrome P-450 CYP2C19; D004381:Duodenal Ulcer / Q000188:drug therapy / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005745:Gastric Acidity Determination; D006801:Humans; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000235:genetics*; D009853:Omeprazole / Q000494:pharmacology*; D011110:Polymorphism, Genetic; D054328:Proton Pump Inhibitors; D064750:Rabeprazole
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D064750:Rabeprazole; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D009853:Omeprazole