Eradication Therapy for Helicobacter pylori Infection in Patients Receiving Hemodialysis: Review.

Patients receiving hemodialysis (HD) often develop gastrointestinal diseases. Recently, although in general population, clinical guidelines for Helicobacter pylori have strongly recommended its eradication in patients to prevent gastric cancer, optimal eradication regimen and optimal dosage of drugs for patients receiving HD have not been established, due to possible incidence of adverse events. Some antimicrobial agents used in eradication therapy, particularly amoxicillin, can exacerbate renal dysfunction. Given the delayed pharmacokinetics of drugs in patients receiving HD compared with those in healthy individuals, drug regimen and dosage should be considered to minimize adverse effects. Although previous studies have investigated the benefits of eradication therapy for patients receiving HD, because most studies were small in terms of the number of enrolled patients, it is hard to show evidence. The numbers of eradication in HD patients have recently increased, and it is important to provide an optimal regimen. The consideration of eradication in patients undergoing HD with a reduction in the drug dose by 1/2-1/3 may prevent adverse events. Additionally, another important consideration is whether adverse events can be prevented while maintaining a similar eradication rate with reduced drug dosages. Recent meta-analysis findings indicate comparable eradication rates in patients receiving HD and healthy individuals, both with the same dosage regimen and at a reduced dosage regimen, with no significant differences (relative risk [RR] for successful eradication: 0.85 [95% confidence interval (CI): 0.48-1.50]). Unlike with the same dosage regimen (RR for adverse events: 3.15 [95% CI: 1.93-5.13]), the adverse events in the dosage reduction regimen were similar to those in healthy individuals (RR: 1.26 [95% CI: 0.23-6.99]). From a pharmacological perspective, the eradication regimen in patients receiving HD should consider the dosage (1/2-1/3 dosage), dosing number (bid), dosing timing of drugs (after HD), and susceptibility to antimicrobial agents.

Eradication therapy for Helicobacter pylori infection improves nutrition status in Japanese hemodialysis patients: a pilot study.

Plasma ghrelin level is influenced by Helicobacter pylori (H. pylori) status and the severity of gastric mucosal atrophy, and the ghrelin level is associated with nutrition status in hemodialysis patients. Here, we investigated the efficacy of H. pylori eradication therapy in improving nutrition status in relation to the ghrelin level in H. pylori-positive hemodialysis patients. Of H. pylori-positive patients receiving hemodialysis at 8 dialysis center, 21 patients underwent gastroduodenoscopy for evaluation of the severity of gastric atrophy, and nutrition markers and plasma ghrelin levels before and 1 year after H. pylori eradication therapy were evaluated. Serum cholinesterase level was significantly increased after H. pylori eradication compared with the level before eradication (303.2 ± 76.0 vs 287.3 ± 68.1 IU/L, p = 0.029). In particular, cholesterol (before, 196.6 ± 23.2 mg/dl; after, 206.1 ± 25.9 mg/dl, p = 0.042) and cholinesterase levels (before, 296.9 ± 70.8 IU/L; after, 316.4 ± 73.8 IU/L, p = 0.049) increased more strongly in patients with mild-moderate atrophy than those with severe atrophy, irrespective of improvement of plasma acyl-ghrelin and desacyl-ghrelin levels after eradication therapy. In conclusion, H. pylori eradication may improve nutrition status by increasing serum cholinesterase and cholesterol levels in hemodialysis patients, especially those with mild and moderate gastric mucosal atrophy.

Efficacy of Reduced Dosage of Amoxicillin in an Eradication Therapy for Helicobacter pylori Infection in Patients on Hemodialysis: A Randomized Controlled Trial.

BACKGROUND: An optimum Helicobacter pylori-eradication regimen for hemodialysis patients is yet to be established because of different pharmacokinetics of amoxicillin involved between hemodialysis patients and healthy subjects. We investigated to establish appropriate doses of amoxicillin for H. pylori infection eradication in hemodialysis patients. METHODS: Of 409 hemodialysis patients screened for H. pylori infection, 37 H. pylori-positive patients were randomized to different 1-week eradication regimens: esomeprazole 20 mg twice a day (b.i.d.) and clarithromycin 200 mg b.i.d., plus amoxicillin at either 750 mg b.i.d. (group A; conventional) or 250 mg b.i.d. (group B; experimental). Sixty-three patients with normal renal function received the conventional regimen (group C). Successful eradication was confirmed by urea breath testing. RESULTS: Eradication rates of group B (reduced amoxicillin-regimen) were 84.2% in intention-to-treat analysis and 88.9% in per-protocol analysis, which were similar with group A (77.8 and 77.8%) and group C (74.6 and 81.0%). However, the incidence of adverse events in group A was significantly higher than that in group C (22.2 vs. 5.1%, p = 0.027). CONCLUSIONS: In H. pylori-positive hemodialysis patients, amoxicillin at 250 mg b.i.d. may be an appropriate scheme for eradication with equivalent effects to the conventional therapy and safety effects for adverse events.

Four-times-daily Dosing of Rabeprazole with Sitafloxacin, High-Dose Amoxicillin, or Both for Metronidazole-Resistant Infection with Helicobacter pylori in Japan.

BACKGROUND: The bacterial resistance of Helicobacter pylori to antimicrobial agents such as clarithromycin and metronidazole has been increasing worldwide, leading to the failure of eradication treatment. Here, we present an eradication regimen consisting of four-times-daily dosing (q.i.d.) of rabeprazole with potent acid inhibition. AIM: To investigate the efficacy of eradication therapy with rabeprazole q.i.d. and amoxicillin or sitafloxacin in Japanese infected with a metronidazole-resistant strain. METHODS: We retrospectively investigated the efficacy of eradication regimens with rabeprazole q.i.d. for 7 days in 111 Japanese pooled patients infected with a metronidazole-resistant strain of H. pylori at Hamamatsu University School of Medicine Hospital or the Shiga University of Medical Science Hospital: 1, with sitafloxacin 100 mg twice daily (b.i.d.) (n = 82); 2, with amoxicillin 500 mg q.i.d. (n = 15); and 3, with amoxicillin q.i.d. and sitafloxacin b.i.d.-combined regimen (n = 14). Eradication status was assessed at 8 weeks via a 13 C-urea breath test. RESULTS: Eradication rate on intention-to-treat analysis was 93.7% (95% confidence interval: 87.4-97.4%, 104/111), irrespective of the high prevalence of strains resistant to clarithromycin (81.1%, 90/111) and levofloxacin (42.3%, 47/111). No significant differences in eradication rates were observed among the different treatment regimens (p = .408), eradication history (p = .096) and different CYP2C19 genotypes (p = .789). On multivariate analysis, no significant risk factor for eradication failure by therapy with potent acid inhibition was seen. CONCLUSION: In Japanese patients infected with metronidazole-resistant strains of H. pylori, eradication rates exceeding 90% can be achieved using appropriate dosing of antibiotic agents with strain susceptibility (amoxicillin q.i.d. and/or sitafloxacin b.i.d.) together with acid inhibition for a full 24 h and rabeprazole 10 mg q.i.d. These findings may be further evidence for dual therapy with rabeprazole q.i.d. and an antibiotic agent (amoxicillin q.i.d. or sitafloxacin b.i.d.) in Japanese patients with metronidazole-resistant strains.

Natural Course of Helicobacter pylori Infection in Japanese Hemodialysis Patients.

INTRODUCTION: Helicobacter pylori (H. pylori) infection is one of the major risk factors for gastrointestinal morbidity in hemodialysis patients. Primary end point is to investigate H. pylori infection rate in hemodialysis patients. As secondary end point, we clarified whether pepsinogen (PG) level was related with H. pylori infection status in hemodialysis patients. METHODS: Serum levels of PG I, II, and anti-H. pylori IgG antibody were assessed in 500 Japanese hemodialysis patients. RESULTS: H. pylori infection rate was 15.0% (75/500; 95% CI 12.0-18.4). The duration of hemodialysis in H. pylori-positives was 4.6 ± 3.8 years, which was significantly shorter than in H. pylori-negatives (7.3 ± 6.9, p = 0.001). PG I levels positively correlated with the PG II level and PG I/II ratio (|R| = 0.661, p < 0.001, and |R| = 0.544, p <0.001, respectively). Using a cutoff value of 7.75, the sensitivity and specificity of PG I/II ratio for predicting H. pylori-negatives were 86.3 and 87.8%, respectively (area under the curve 0.930). CONCLUSIONS: In hemodialysis patients, infection rate with H. pylori was <20%, with lower rates in patients receiving hemodialysis for longer terms. A PG I/II ratio with a cutoff value of 7.75 may be useful for screening for H. pylori status.

Influence of low-dose proton pump inhibitors administered concomitantly or separately on the anti-platelet function of clopidogrel.

Proton pump inhibitors (PPIs) at low doses can effectively prevent gastrointestinal bleeding due to aspirin and are widely used in Japan for gastroprotection in patients taking anti-platelet agents. We examined the influence of different PPIs at low doses administered concomitantly or separately on anti-platelet functions of clopidogrel. In 41 healthy Japanese volunteers with different CYP2C19 genotypes who took clopidogrel 75 mg in the morning alone, or with omeprazole 10 mg, esomeprazole 10 mg, lansoprazole 15 mg, or rabeprazole 10 mg, either concomitantly in the morning or separately in the evening, we measured the inhibition of platelet aggregation (IPA, %) using VerifyNow P2Y12 assay at 4 h after the last clopidogrel dose on Day 7 of each regimen. IPA by clopidogrel with rabeprazole administered at lunchtime, approximately 4 h after clopidogrel, was also measured. Mean IPAs in those concomitantly receiving omeprazole, esomeprazole, lansoprazole or rabeprazole (47.2 ± 21.1%, 43.2 ± 20.2%, 46.4 ± 18.8%, and 47.3 ± 19.2%, respectively) were significantly decreased compared with those receiving clopidogrel alone (56.0%) (all ps < 0.001). This decrease was observed when PPIs were administered separately in the evening. However, IPA by clopidogrel with rabeprazole administered at lunchtime was 51.6%, which was markedly similar to that of clopidogrel alone (p = 0.114). All tested PPIs reduce the efficacy of clopidogrel when administered concomitantly. Our preliminary data suggest that administration of rabeprazole 4 h following clopidogrel may minimize potential drug-drug interactions.

Severity of Gastric Mucosal Atrophy Is the Major Determinant of Plasma Ghrelin Level in Hemodialysis Patients.

BACKGROUND: Ghrelin, an orexigenic hormone, has multiple favorable functions including protein anabolism enhancement, anti-inflammatory actions, and cardiovascular protection. A low plasma ghrelin level is associated with increased mortality in patients treated with hemodialysis (HD). However, it is unclear whether the plasma ghrelin level in HD patients correlates with the severity of gastric mucosal atrophy and Helicobacter pylori status. METHODS: Seventy-eight maintenance HD patients and 51 non-dialysis patients with chronic kidney disease were evaluated for severity of gastric mucosal atrophy by gastroduodenoscopy and for H. pylori status using an anti-H. pylori-antibody and rapid urease test. Plasma acyl and des-acyl ghrelin levels were measured and their associations with relevant clinical parameters were investigated. RESULTS: Des-acyl ghrelin level in HD patients was significantly higher than that in patients with kidney function preserved. Although acyl and des-acyl ghrelin levels were similar between current H. pylori positive and negative HD patients, both levels decreased significantly with the progress of endoscopic gastric mucosal atrophy in HD patients. Serum pepsinogen (PG) I level and PG I/II ratio decreased significantly according to the severity of atrophy in HD patients and positively significantly correlated with both ghrelin levels. Multiple regression analysis showed significant positive correlations between acyl ghrelin and PG I levels (ß = 0.738, p < 0.001) and significant negative correlations between ghrelin and age, albumin, and creatinine levels. CONCLUSIONS: Gastric atrophy is the major determinant of ghrelin level in HD patients. Management practices, such as H. pylori eradication, before advanced atrophy may be required to prevent the decrease of ghrelin levels and improve the prognosis of HD patients.

Improvement of gastroesophageal reflux disease in Japanese patients with spinal kyphotic deformity who underwent surgical spinal correction.

BACKGROUND AND AIM: Spinal kyphotic deformity occasionally results in gastroesophageal reflux disease (GERD). The effects of acid reflux on the esophagus in kyphotic patients are unclear, however, and it is unknown whether acid reflux, endoscopic GERD, and reflux-related symptoms improve following surgical spinal correction in these patients. Herein, we investigated the characteristics of GERD in kyphotic patients and the improvement in GERD following surgical correction. METHODS: In 48 patients with severe kyphotic deformity scheduled for surgical spinal correction, we conducted esophagogastroduodenoscopy, 24-h pH monitoring and three questionnaire surveys, including the frequency scale for the symptoms of GERD (FSSG). We repeated these measurements after surgical correction and compared pre- and post-surgery values. RESULTS: Of 48 patients, 70.8% [95% CI: 55.9-83.0%, 34/48] had endoscopically evaluated esophageal mucosal injury. Regarding pH before surgery, 64.9% (CI: 47.5-79.8%, 24/37) had abnormal acid reflux (intraesophageal pH < 4 more than 5% of the time). FSSG score was significantly associated with the severity of GERD, and the positive rate was 52.6% (CI: 35.8-69.0%, 20/38). Following surgical correction, esophageal mucosal injury improved endoscopically in 90% of patients, and median total FSSG score significantly decreased from 8 (0-30) to 5 (0-19) (P = 0.005). Regarding pH after surgery, prevalence of abnormal acid reflux decreased from 66.7% (95% CI: 41.0-86.7%) to 33.3% (95% CI: 13.3-59.0%) (P = 0.045). CONCLUSION: Surgical spinal correction in kyphosis patients improves not only kyphotic deformity-related disorders but also esophageal mucosal injury, abnormal acid reflux, and reflux-related symptoms.

Factors associated with healing of artificial ulcer after endoscopic submucosal dissection with reference to Helicobacter pylori infection, CYP2C19 genotype, and tumor location: Multicenter randomized trial.

BACKGROUND AND AIM: Healing speed of peptic ulcer is affected by a number of factors, including Helicobacter pylori (H. pylori) infection and intragastric pH. Acid inhibition exerted by proton pump inhibitors differs by CYP2C19 genotype. Herein, we investigated whether healing speed of artificial ulcers formed after endoscopic submucosal dissection (ESD) was influenced by H. pylori infection, CYP2C19 genotype, or other factors. METHODS: A total of 96 H. pylori-positive patients with gastric tumors scheduled for ESD were randomly assigned to receive eradication therapy for H. pylori before ESD (pre-ESD eradication) (n = 44) or after (post-ESD eradication) (n = 52). Patients received eradication therapy consisting of lansoprazole 30 mg, amoxicillin 750 mg, and clarithromycin 200 mg twice daily for 1 week. After ESD, lansoprazole 30 mg was given once daily for 8 weeks. Ulcer size was endoscopically measured on the next day and at 4 and 8 weeks after ESD. RESULTS: Mean reduction rate of artificial ulcer area in the pre-ESD eradication group was 94.7% ± 5.5% at 4 weeks, which was similar to that in the post-ESD eradication group (94.7% ± 6.7%, P = 0.987), irrespective of CYP2C19 genotype. In multivariate analyses, location of gastric tumor (middle and upper, odds ratio: 4.05, 95% CI: 1.620-10.230, P = 0.003) was a factor for 97% reduction of artificial ulcer area at 4 weeks post-ESD, but CYP2C19 genotype and H. pylori infection were not. CONCLUSION: Healing speed of ESD-induced artificial ulcer was affected by tumor location, but not by time of H. pylori eradication, resected size, or CYP2C19 genotype.

Influence of prostate stem cell antigen gene polymorphisms on susceptibility to Helicobacter pylori-associated diseases: a case-control study.

BACKGROUND: Patients with duodenal ulcer have a reduced risk of developing gastric cancer compared to those without. Recently, the prostate stem cell antigen (PSCA) rs2294008 C>T polymorphism was found to be associated with different pathogenesis of duodenal ulcer and gastric cancer developments. However, whether PSCA rs2294008 C>T polymorphism is associated with severity of gastric mucosal atrophy is unclear. We examined the influence of the PSCA rs2294008 C>T polymorphism on susceptibility to H. pylori-related diseases and the relationships between PSCA polymorphism and gastric mucosal atrophy. METHODS: PSCA rs2294008 C>T polymorphism was assessed in H. pylori-positive Japanese patients (n = 488) with noncardia gastric cancer (n = 193), gastric ulcer (n = 84), duodenal ulcer (n = 61), and atrophic gastritis (n = 150), as well as in H. pylori-negatives (n = 266). RESULTS: Frequency of PSCA rs2294008 C/C genotype in duodenal ulcer was 36.1%, which was significantly higher than those with gastric cancer (12.4%), gastric ulcer (19.0%), gastritis (10.7%), and H. pylori-negatives (19.5%) (p < .001). Compared with duodenal ulcer, having the T allele significantly increased the risk of gastric cancer (OR: 3.97, 95% CI: 2.02-7.80; p < .001), gastric ulcer (2.40, 1.13-5.10; p = .023), and gastritis (4.72, 2.26-9.86; p < .001). Mean pepsinogen (PG) I/PG II ratio in T allele carriers (2.17 ± 0.75) was significantly lower than that in C/C genotype (3.39 ± 1.27, p < .001). CONCLUSIONS: The PSCA rs2294008 C>T polymorphism is associated with differing susceptibilities to H. pylori-associated diseases. The PSCA rs2294008 C>T polymorphism may be acting through induction of gastric mucosal atrophy, finally leading to development of gastric ulcer and gastric cancer in PSCA rs2294008 T allele carriers, but not duodenal ulcer.

One-day front-loading with four doses of rabeprazole followed by a standard twice-daily regimen provides sufficient acid inhibition in extensive metabolizers of CYP2C19.

BACKGROUND: Four times daily dosing (qid) with a proton pump inhibitor can cause rapid increase in intragastric pH. We investigated the efficacy of the front-loading with rabeprazole 10 mg qid on a subsequent regimen with rabeprazole 10 mg twice daily (bid) for 7 days in extensive metabolizers (EMs) of CYP2C19. METHODS: Five EMs received three different 1-week regimens in a crossover manner as follows: (1) rabeprazole 10 mg bid for 7 days; (2) a front-loading regimen of rabeprazole (rabeprazole 10 mg qid on day 0 and bid on days 1 to 7); and (3) rabeprazole 10 mg qid for 7 days. Five intermediate metabolizers (IMs) and four poor metabolizers (PMs) received rabeprazole 10 mg bid regimen only. Twenty-four-hour intragastric pH-monitorings were performed on days 1, 4, and 7. Area under the intragastric pH-time curves (AUCs) from days 1 to 7 was calculated using 24-h median intragastric pHs on days 1, 4, and 7. RESULTS: Twenty-four-hour intragastric pHs in the front-loading group on days 1, 4, and 7 were 5.1, 4.9, and 5.1, respectively. The median AUC with front-loading in EMs (34.4, pH·day) was significantly higher than that in EMs with rabeprazole 10 mg bid (30.74, p = 0.043). No statistically significant differences in median AUCs were noted among front-loading in EMs, rabeprazole 10 mg qid in EMs (37.2), rabeprazole 10 mg bid in IMs (37.3), and PMs (39.4). CONCLUSIONS: The one-day front-loading regimen of rabeprazole 10 mg qid provided sufficient acid inhibition for 7 days, even in CYP2C19 EMs.

Potent Gastric Acid Inhibition Over 24 Hours by 4-Times Daily Dosing of Esomeprazole 20 mg.

BACKGROUND: When administered at a standard dose, proton pump inhibitors (PPIs) do not always provide sufficient acid inhibition for all subjects, particularly in extensive metabolizers (EMs) of CYP2C19. Whether esomeprazole at a dose of 20 mg four times daily dosing (q.i.d.) can attain sufficient acid inhibition throughout 24 h in EMs remains unclear. We therefore investigated the efficacy of esomeprazole q.i.d. for acid inhibition. METHODS: In a randomized cross-over design, 30 Helicobacter pylori-negative healthy young Japanese volunteers received esomeprazole at a dose of 20 mg two times a day (b.i.d.) or q.i.d. for 7 days. A pH monitoring was conducted before the trial as a control and on day 7 of both regimens. RESULTS: Median pH values in the q.i.d. regimen were significantly higher than those with the b.i.d. regimen in EMs (b.i.d.: 5.3, q.i.d.: 6.6, p = 0.022), intermediate metabolizer (IM) (b.i.d.: 5.5, q.i.d.: 6.8, p = 0.005) and poor metabolizer (PM) (b.i.d.: 6.2, q.i.d.: 7.0, p = 0.047), respectively. Median pH with the b.i.d. regimen differed significantly by CYP2C19 genotypes (p = 0.004), but not the q.i.d. regimen (p = 0.384). CONCLUSION: Esomeprazole q.i.d. achieved potent acid inhibition in all Helicobacter pylori-negative subjects, irrespective of CYP2C19 genotype, which might be one of the rescue regimens for patients' refractory to PPI treatment.

Efficacy of tailored Helicobacter pylori eradication treatment based on clarithromycin susceptibility and maintenance of acid secretion.

BACKGROUND: Insufficient acid inhibition during Helicobacter pylori eradication treatment and bacterial resistance to antibiotics often causes eradication failure. Four times daily dosing (q.i.d.) of a proton-pump inhibitor (PPI) achieves potent acid inhibition, suggesting its potential usefulness as a regimen for eradicating H. pylori infection. Therefore, a tailored eradication regimen based on antibiotic susceptibility and maintenance of acid inhibition should have a high success rate. We investigated the efficacy of such treatment based on clarithromycin (CAM) susceptibility. METHODS: Using 153 H. pylori-positive Japanese patients, we investigated the efficacy of tailored eradication strategy: (1) Patients infected with CAM-sensitive H. pylori were treated with a PPI (rabeprazole 10 mg q.i.d.), amoxicillin 500 mg q.i.d., and CAM 200 mg b.i.d. (n = 89), and (2) patients infected with CAM-resistant were given the same doses of rabeprazole and amoxicillin and metronidazole 250 mg b.i.d. (n = 64) for 1 week. RESULTS: In the tailored regimen group, the overall eradication rate was 96.7% (95% CI: 92.5-98.9%, 148/153) in the intention-to-treat (ITT) analysis and 97.4% (93.4-99.3%, 148/152) in the PP analysis. The eradication rates for the CAM- and metronidazole-based treatments were similar (95.5% and 98.4%, respectively, p = .400). The tailored treatment achieved a high eradication rate in CYP2C19 rapid metabolizers who were a resistance genotype for PPI treatment (94.3% (86.0-98.4%, 66/70)). DISCUSSION: A tailored H. pylori eradication regimen based on CAM susceptibility and maintaining acid secretion (rabeprazole 10 mg q.i.d.) is useful because it can achieve an eradication rate exceeding 95%, irrespective of eradication history, thus overcoming differences among CYP2C19 genotypes.

Sitafloxacin-based third-line rescue regimens for Helicobacter pylori infection in Japan.

BACKGROUNDS: Quinolone-based regimens have been used as the rescue for eradication of Helicobacter pylori. Sitafloxacin is known to have low minimum inhibitory concentration for H. pylori. Here, we compared two sitafloxacin-based eradication regimens as rescue for the eradication of H. pylori. METHODS: We attempted to eradicate H. pylori in 180 Japanese patients who had never failed in eradication of H. pylori with the triple proton pump inhibitor/amoxicillin/clarithromycin therapy (1st line) and the triple proton pump inhibitor/amoxicillin/metronidazole therapy (2nd line). They were assigned to either the triple therapy with rabeprazole 10 mg b.i.d./q.i.d., amoxicillin 500 mg q.i.d, and sitafloxacin 100 mg b.i.d. (RAS) for 1 or 2 weeks or the triple therapy with rabeprazole 10 mg b.i.d./q.i.d., metronidazole 250 mg b.i.d., and sitafloxacin 100 mg b.i.d. (RMS) for 1 or 2 weeks. Eradication was assessed via the (13) C-urea breath test and rapid urease test. RESULTS: Intention-to-treat and per-protocol analyses of eradication rates were 84.1% (37/44) and 86.4% (37/43) with RAS for 1 week, 88.9% (40/45) and 90.9% (40/44) for RAS for 2 weeks, 90.9% (40/44) and 90.9% (40/44) for 1 week-RMS and 87.2% (41/47) and 91.1% (41/45) with RMS for 2 weeks. We noted no statistical significant differences in eradication rates among four regimens. CONCLUSION: All of the above-described rescue regimens proved relatively equally useful in the eradication of H. pylori. Of them, RAS for 2 weeks and RMS for 1 or 2 weeks could attain the rescue eradication rates higher than 90% by per-protocol analysis.

Comparison of acid inhibition with standard dosages of proton pump inhibitors in relation to CYP2C19 genotype in Japanese.

INTRODUCTION: The aim of therapeutic regimens using proton pump inhibitors (PPIs) in patients with acid-related diseases is to potently inhibit acid secretion for the full 24 h. However, optimum treatment is still unclear because the pharmacodynamics of PPIs differ among CYP2C19 genotypes and most of the previous studies have had loss of sample power. METHODS: Using pH monitoring, we compared acid inhibition at standard dosage of omeprazole (20 mg, 50 times), lansoprazole (30 mg, 68 times), and rabeprazole (10 mg, 65 times) in Helicobacter pylori-negative healthy young Japanese volunteers. RESULTS: Median pH with rabeprazole was 5.4 (3.3-7.5), which was significantly greater than with either omeprazole [4.4 (2.1-7.3)] or lansoprazole [4.8 (3.5-6.4)] (both P < 0.05). Median 24-h pH differed among the different CYP2C19 genotypes in all three PPIs. In CYP2C19 extensive metabolizers (EMs), the genotype that is refractory to PPI treatment, median pH with omeprazole, lansoprazole, and rabeprazole was 3.8 (2.1-4.4), 4.5 (3.5-5.3) and 4.8 (3.3-7.5), respectively. DISCUSSION: Treatment with the selected PPIs at their standard dosages had difficulty maintaining acid inhibition for a full 24 h, especially in CYP2C19 EM. However, rabeprazole has the merit of less influence of CYP2C19 genotype compared with the other PPIs.

Intra-gastric pH following single oral administrations of rabeprazole and esomeprazole: double-blind cross-over comparison.

Comparisons between the acid inhibitory effects of rabeprazole and esomeprazole after single oral administration with standard doses have not been previously presented. We examined intra-gastric pH after oral administrations of these two proton pump inhibitors using 24-h pH monitoring. Fifty-four normal volunteers not infected by Helicobacter pylori were investigated. Using a cross-over design, we administered 10 mg of rabeprazole or 20 mg of esomeprazole in 27 at 30 min after supper and in the remaining 27 subjects at 15 min before supper, and performed 24-h pH monitoring. Intra-gastric pH data were nearly identical when the proton pump inhibitors were taken after meals. Even if the data were compared in different CYP2C19 genotypes, rabeprazole and esomeprazole did not show the difference. In poor metabolizer, both of the drugs showed stronger acid inhibition. When taken before meals, intra-gastric pH after esomeprazole administration was slightly but not significantly higher than that observed after rabeprazole administration not only in daytime but also in nighttime period. In conclusion, rabeprazole and esomeprazole were similarly effective when administered after a meal.

Association of gastric mucosal injury severity with platelet function and gastric pH during low-dose aspirin treatment.

INTRODUCTION: The antiplatelet effects of low-dose aspirin (LDA) vary between individuals. Here, we investigated the relationship between the incidence of LDA-induced mucosal injury, antiplatelet effects of LDA, and intragastric pH. METHODS: We evaluated gastric injury severity and platelet function using the VerifyNow® System before and after administration of 100 mg aspirin for 7 days to 18 young healthy subjects (study 1). We investigated whether injury was correlated with platelet function and gastric juice pH in 45 patients with cardiovascular disease administered LDA daily (study 2). RESULTS: In study 1, platelet aggregation was attenuated by LDA to different degrees. Although 55.6% of subjects (10/18) developed gastric injury of modified Lanza score (MLS) ≥ 3, no significant difference in platelet function was detected between the mild (n = 8, MLS: 0-2) and severe injury groups (n = 10, MLS: 3-5). In study 2, the severity of LDA-induced injury was associated with gastric juice pH, but not with antiplatelet effects of LDA. DISCUSSION: In contrast to gastric juice pH, the antiplatelet effect had no correlation with the severity of gastric mucosal injury. Monitoring gastric acidity, rather than platelet function, may be useful for predicting the risk of gastric injury during LDA treatment.

Antiplatelet drugs are a risk factor for esophageal mucosal injury.

BACKGROUND: In esophagus whether antiplatelet drugs, such as low-dose aspirin (LDA) and clopidogrel, induce mucosal injury by pH changes or by acid reflux is unclear. We designed to clarify which mechanism was responsible. METHODS: In study 1, 80 patients taking LDA and 80 age- and sex-matched subjects who underwent endoscopy for dyspeptic symptoms or for a health check-up were evaluated the endoscopic incidence of esophageal mucosal injury and severity. In study 2, 35 healthy subjects were treated with LDA 100 mg (regimen A), and then 20 randomly selected subjects were dosed clopidogrel 75 mg (regimen C), LDA/clopidogrel (regimen AC), or LDA/clopidogrel/rabeprazole 10 mg for 7 days. Subjects underwent endoscopy and 24-hour pH measurements on day 7. RESULTS: In study 1, the prevalence of esophageal injury in LDA patients was 40.0%, significantly higher than in non-LDA subjects (25.0%, p = 0.042). In study 2, significant increases in incidence of injury were observed with regimens A (45.8%) and AC (50.0%), but not with C (20.0%), on day 7. Among subjects in whom pH was >5.0 and <4.0 for less than 40% of time, none developed esophageal injury. CONCLUSIONS: LDA caused esophageal injury in half of patients and volunteers. Acid-inhibitory drugs effectively prevented the development of LDA-induced, not clopidogrel, esophageal injury.

[Present status and future prospects of third line rescue regimens for H. pylori infection].

Recent reports have suggested that the candidates of the third rescue regimens for H. pylori infection in Japan are fluoroquinolone-based regimens and the dual therapy with high doses of proton pump inhibitor and amoxicillin. Of fluoroquinolones, sitafloxacin has the strong anti-H. pylori effect as AMPC has and is effective for strains resistant to levofloxacin. Sitafloxacin-based regimens have been reported to yield relatively sufficient eradication rates as the third line therapy. The dual therapy with high doses of proton pump inhibitor and amoxicillin has also been reported to attain the sufficient rescue rates. To achieve the high rescue eradication rates, the eradication regimens must be designed based on well-understanding of reasons for eradication failure, such as the resistance patterns of the bacteria, and the pharmacological characteristics of agents used for H. pylori eradication therapy.

Ability of rabeprazole to prevent gastric mucosal damage from clopidogrel and low doses of aspirin depends on CYP2C19 genotype.

BACKGROUND & AIMS: Low doses of aspirin can injure the gastric mucosa. It is not clear whether other drugs such as the antiplatelet agent clopidogrel also cause gastric mucosal injury or exacerbate aspirin-induced injury, or whether proton pump inhibitors prevent damage. METHODS: Twenty Japanese subjects with different CYP2C19 genotypes were randomly assigned to groups that were given a low dose of aspirin (100 mg; A), clopidogrel (75 mg; C), low dose of aspirin and clopidogrel (AC), or low dose of aspirin in combination with clopidogrel and rabeprazole (10 mg; ACR) once daily for 7 days. Subjects underwent gastroduodenoscopy and platelet tests on days 3 and 7; gastric mucosal damage was assessed by using the modified Lanza score (MLS). We performed 24-hour intragastric pH monitoring on day 7 of each regimen. We also analyzed the effects of the AC regimen on 30 patients with different CYP2C19 genotypes. RESULTS: Subjects in groups A, C, and AC had significantly higher levels of gastric mucosal damage on days 3 and 7, compared with baseline. The median MLS for the AC group was similar to that of the A group. Helicobacter pylori-negative subjects in the ACR group with different CYP2C19 genotypes had significant differences in MLS, intragastric pH, and platelet function. Gastric mucosal injury was inhibited equally among H pylori-positive subjects in the ACR group. Rabeprazole did not appear to affect platelet function or intragastric pH in subjects given clopidogrel. CONCLUSIONS: Clopidogrel and low doses of aspirin cause a similar degree of gastric mucosal damage. Rabeprazole prevented this damage without reducing the antiplatelet function of clopidogrel. However, its prophylactic effect varies with CYP2C19 genotype in H pylori-negative subjects.