Evidence that the degree and duration of acid suppression are related to Helicobacter pylori eradication by triple therapy.
OBJECTIVE
Eradication rates of Helicobacter pylori by a proton pump inhibitor-based triple therapy depend on CYP2C19 genotype status. We investigated whether gastric acid inhibition during an eradication therapy would influence the eradication rates attained by the triple therapy.


METHODS
Thirty-two patients with H. pylori infection underwent the first-line triple therapy with lansoprazole 30 mg, amoxicillin 750 mg, and clarithromycin 400 mg b.i.d. for 1 week. In all 32 patients, the 24-hour intragastric pH monitoring was performed on day 6 during the treatment period.


RESULTS
The intention-to-treat-based eradication rate by the first-line therapy was 75.0% (24/32, 95%CI: 56.60-88.54%). In patients with successful eradication, the median 24-hour pH was 6.4 (range; 5.0-7.6), which was significantly higher than that in patients without eradication [5.2 (2.2-6.2), p = .0131]. The median percentage time of pH < 4.0 during 24-hour postdose in patients with eradication [0.5% (0.0-31.6%)] was significantly shorter than that in patients without eradication [26.7% (6.0-72.2%), p = .0017]. These parameters for acid inhibition significantly differed among the different CYP2C19 genotype groups. When the percentage time of pH < 4.0 and 24-hour pH were attained < 10% and > 6.0, respectively, during the eradication treatment, the majority of patients could eradicate H. pylori infection, irrespective of the bacterial susceptibility to clarithromycin.


CONCLUSIONS
The sustained intragastric pH > 4.0 for a longer postdose time appears to be required for a successful eradication of H. pylori with lansoprazole and acid-labile antibiotics.
Sugimoto
Mitsushige
M
First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan. mitsu@hama-med.ac.jp
Furuta
Takahisa
T
Shirai
Naohito
N
Kodaira
Chise
C
Nishino
Masafumi
M
Ikuma
Mutsuhiro
M
Ishizaki
Takashi
T
Hishida
Akira
A
D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D005744:Gastric Acid / Q000737:chemistry; D005838:Genotype; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000900:Anti-Bacterial Agents; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D000658:Amoxicillin; D003577:Cytochrome P-450 Enzyme System; D017291:Clarithromycin