Eradication of H. pylori with pantoprazole, clarithromycin, and metronidazole in duodenal ulcer patients: a head-to-head comparison between two regimens of different duration

Studies on Isoniazid Derivatives through a Medicinal Chemistry Approach for the Identification of New Inhibitors of Urease and Inflammatory Markers

A library of thiosemicarbazide derivatives of isoniazid 3-27, was synthesized and evaluated for their anti-inflammatory and urease inhibition activities, by using in vitro bioassays. Among these compounds 9, 10, 12, 21, and 26 were identified as new derivatives. Prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs) and infections caused by Helicobacter pylori (ureolytic bacteria), are the two most significant causes of gastric and peptic ulcers. We focused on the identification of the dual inhibitors of inflammation and urease enzyme. Compound 23 was identified as the best dual inhibitor of inflammation (ROS; IC50 = 12.3 µg/mL), and urease enzyme inhibition activity (IC50 = 22.4 µM). Many of these compounds showed comparable activities to the standard anti-inflammatory drug (ibuprofen, IC50 = 11.2 µg/mL) and urease inhibitor (thiourea/acetohydraoxamic acid, IC50 = 21.1/20.3 µM). Compound 12 was found to be the most potent urease inhibitor (IC50 = 12.3 µM) and good inhibitor of inflammation (IC50 = 27.7 µg/mL). Compounds 19, 11, 13, 9, 17, 10, and 16, were also found to be potent inhibitors of urease. Cytotoxicity was also evaluated and all the compounds were found to be non-cytotoxic, except compound 18 and the parent drug isoniazid (IC50 = 29.5 and 28.5 µM, respectively).

In vitro and In vivo Anti-Helicobacter pylori Activities of Centella asiatica Leaf Extract

Helicobacter pylori infection is associated with an increased risk of developing upper gastrointestinal tract diseases. However, treatment failure is a major cause of concern mainly due to possible recurrence of infection, the side effects, and resistance to antibiotics. The aim of this study was to investigate the activities of Centella asiatica leaf extract (CAE) against H. pylori both in vitro and in vivo. The minimum inhibitory concentrations (MICs) against 55 clinically isolated strains of H. pylori were tested using an agar dilution method. The MICs of CAE ranged from 0.125 mg/mL to 8 mg/mL, effectiveness in inhibiting H. pylori growth was 2 mg/mL. The anti-H. pylori effects of CAE in vivo were also examined in H. pylori-infected C57BL/6 mice. CAE was orally administrated once daily for 3 weeks at doses of 50 mg/kg and 250 mg/kg. CAE at the 50 mg/kg dose significantly reduced H. pylori colonization in mice gastric mucosa. Our study provides novel insights into the therapeutic effects of CAE against H. pylori infection, and it suggests that CAE may be useful as an alternative therapy.

Optimum duration of regimens for Helicobacter pylori eradication

BACKGROUND

The optimal duration for Helicobacter pylori (H. pylori) eradication therapy is controversial, with recommendations ranging from 7 to 14 days. Several systematic reviews have attempted to address this issue but have given conflicting results and limited their analysis to proton pump inhibitor (PPI), two antibiotics (PPI triple) therapy. We performed a systematic review and meta-analysis to investigate the optimal duration of multiple H. pylori eradication regimens.

OBJECTIVES

The primary objective was to assess the relative effectiveness of different durations (7, 10 or 14 days) of a variety of regimens for eradicating H. pylori. The primary outcome was H. pylori persistence. The secondary outcome was adverse events.

SEARCH METHODS

The Cochrane Library, MEDLINE, EMBASE, and CINAHL were searched up to December 2011 to identify eligible randomised controlled trials (RCTs). We also searched the proceedings of six conferences from 1995 to 2011, dissertations and theses, and grey literature. There were no language restrictions applied to any search.

SELECTION CRITERIA

Only parallel group RCTs assessing the efficacy of one to two weeks duration of first line H. pylori eradication regimens in adults were eligible. Within each regimen, the same combinations of drugs at the same dose were compared over different durations. Studies with at least two arms comparing 7, 10, or 14 days were eligible. Enrolled participants needed to be diagnosed with at least one positive test for H. pylori on the basis of a rapid urease test (RUT), histology, culture, urea breath test (UBT), or a stool antigen test (HpSA) before treatment. Eligible trials needed to confirm eradication of H. pylori as their primary outcome at least 28 days after completion of eradication treatment. Trials using only serology or a polymerase chain reaction (PCR) to determine H. pylori infection or eradication were excluded.

DATA COLLECTION AND ANALYSIS

Study eligibility and data extraction were performed by two independent review authors. Data analyses were performed within each type of intervention, for both primary and secondary outcomes. The relative risk (RR) and number needed to treat (NNT)/number needed to harm (NNTH) according to duration of therapy were calculated using the outcomes of H. pylori persistence and adverse events. A random-effects model was used. Subgroup analyses and sensitivity analyses were planned a priori.

MAIN RESULTS

In total, 75 studies met the inclusion criteria. Eight types of regimens were reported with at least two comparative eligible durations. They included: PPI + two antibiotics triple therapy (n = 59), PPI bismuth-based quadruple therapy (n = 6), PPI + three antibiotics quadruple therapy (n = 1), PPI dual therapy (n = 2), histamine H2-receptor antagonist (H₂RA) bismuth quadruple therapy (n = 3), H₂RA bismuth-based triple therapy (n = 2), H₂RA + two antibiotics triple therapy (n = 3), and bismuth + two antibiotics triple therapy (n = 2). Some studies provided data for more than one regimen or more than two durations.For the PPI triple therapy, 59 studies with five regimens were reported: PPI + clarithromycin + amoxicillin (PCA); PPI + clarithromycin + a nitroimidazole (PCN); PPI + amoxicillin + nitroimidazole (PAN); PPI + amoxicillin + a quinolone (PAQ); and PPI + amoxicillin + a nitrofuran (PANi). Regardless of type and dose of antibiotics, increased duration of PPI triple therapy from 7 to 14 days significantly increased the H. pylori eradication rate (45 studies, 72.9% versus 81.9%), the RR for H. pylori persistence was 0.66 (95% CI 0.60 to 0.74), NNT was 11 (95% CI 9 to 14). Significant effects were seen in the subgroup of PCA (34 studies, RR 0.65, 95% CI 0.57 to 0.75; NNT 12, 95% CI 9 to 16); PAN (10 studies, RR 0.67, 95% CI 0.52 to 0.86; NNT = 11, 95% CI 8 to 25); and in PAQ (2 studies, RR 0.37, 95% CI 0.16 to 0.83; NNT 3, 95% CI 2 to 10); but not in PCN triple therapy (4 studies, RR 0.87, 95% CI 0.71 to 1.07). Significantly increased eradication rates were also seen for PPI triple therapy with 10 versus 7 days (24 studies, 79.9% versus 75.7%; RR 0.80, 95% CI 0.72 to 0.89; NNT 21, 95% CI 15 to 38) and 14 versus 10 days (12 studies, 84.4% versus 78.5%; RR 0.72, 95% CI 0.58 to 0.90; NNT 17, 95% CI 11 to 46); especially in the subgroup of PAC for 10 versus 7 days (17 studies, RR 0.80, 95% CI 0.70 to 0.91) and for 14 versus 10 days (10 studies, RR 0.69, 95% CI 0.52 to 0.91). A trend towards increased H. pylori eradication rates was seen with increased duration of PCN for 10 versus 7 days, and of PAN for 10 versus 7 days and 14 versus 10 days, though this was not statistical significant. The proportion of patients with adverse events, defined by authors, was marginally significantly increased only between 7 days and 14 days (15.5% versus 19.4%; RR 1.21, 95% CI 1.06 to 1.37; NNTH 31, 95% CI 18 to 104) but not for other duration comparisons. The proportion of patients discontinuing treatment due to adverse events was not significantly different between treatment durations.Only limited data were reported for different durations of regimens other than PPI triple therapy. No significant difference of the eradication rate was seen for all regimens according to different durations except for H₂RA bismuth quadruple therapy, where a significantly higher eradication rate was seen for 14 days versus 7 days, however only one study reported outcome data.

AUTHORS' CONCLUSIONS

Increasing the duration of PPI-based triple therapy increases H. pylori eradication rates. For PCA, prolonging treatment duration from 7 to 10 or from 10 to 14 days is associated with a significantly higher eradication rate. The optimal duration of therapy for PCA and PAN is at least 14 days. More data are needed to confirm if there is any benefit of increasing the duration of therapy for PCN therapy. Information is limited for regimens other than PPI triple therapy; more studies are needed to draw meaningful conclusions for optimal duration of other H. pylori eradication regimens.

Optimum duration of regimens for Helicobacter pylori eradication

BACKGROUND

The optimal duration for Helicobacter pylori (H. pylori) eradication therapy is controversial, with recommendations ranging from 7 to 14 days. Several systematic reviews have attempted to address this issue but have given conflicting results and limited their analysis to proton pump inhibitor (PPI), two antibiotics (PPI triple) therapy. We performed a systematic review and meta-analysis to investigate the optimal duration of multiple H. pylori eradication regimens.

OBJECTIVES

The primary objective was to assess the relative effectiveness of different durations (7, 10 or 14 days) of a variety of regimens for eradicating H. pylori. The primary outcome was H. pylori persistence. The secondary outcome was adverse events.

SEARCH METHODS

The Cochrane Library, MEDLINE, EMBASE, and CINAHL were searched up to December 2011 to identify eligible randomised controlled trials (RCTs). We also searched the proceedings of six conferences from 1995 to 2011, dissertations and theses, and grey literature. There were no language restrictions applied to any search.

SELECTION CRITERIA

Only parallel group RCTs assessing the efficacy of one to two weeks duration of first line H. pylori eradication regimens in adults were eligible. Within each regimen, the same combinations of drugs at the same dose were compared over different durations. Studies with at least two arms comparing 7, 10, or 14 days were eligible. Enrolled participants needed to be diagnosed with at least one positive test for H. pylori on the basis of a rapid urease test (RUT), histology, culture, urea breath test (UBT), or a stool antigen test (HpSA) before treatment. Eligible trials needed to confirm eradication of H. pylori as their primary outcome at least 28 days after completion of eradication treatment. Trials using only serology or a polymerase chain reaction (PCR) to determine H. pylori infection or eradication were excluded.

DATA COLLECTION AND ANALYSIS

Study eligibility and data extraction were performed by two independent review authors. Data analyses were performed within each type of intervention, for both primary and secondary outcomes. The relative risk (RR) and number needed to treat (NNT)/number needed to harm (NNTH) according to duration of therapy were calculated using the outcomes of H. pylori persistence and adverse events. A random-effects model was used. Subgroup analyses and sensitivity analyses were planned a priori.

MAIN RESULTS

In total, 75 studies met the inclusion criteria. Eight types of regimens were reported with at least two comparative eligible durations. They included: PPI + two antibiotics triple therapy (n = 59), PPI bismuth-based quadruple therapy (n = 6), PPI + three antibiotics quadruple therapy (n = 1), PPI dual therapy (n = 2), histamine H2-receptor antagonist (H₂RA) bismuth quadruple therapy (n = 3), H₂RA bismuth-based triple therapy (n = 2), H₂RA + two antibiotics triple therapy (n = 3), and bismuth + two antibiotics triple therapy (n = 2). Some studies provided data for more than one regimen or more than two durations.For the PPI triple therapy, 59 studies with five regimens were reported: PPI + clarithromycin + amoxicillin (PCA); PPI + clarithromycin + a nitroimidazole (PCN); PPI + amoxicillin + nitroimidazole (PAN); PPI + amoxicillin + a quinolone (PAQ); and PPI + amoxicillin + a nitrofuran (PANi). Regardless of type and dose of antibiotics, increased duration of PPI triple therapy from 7 to 14 days significantly increased the H. pylori eradication rate (45 studies, 72.9% versus 81.9%), the RR for H. pylori persistence was 0.66 (95% CI 0.60 to 0.74), NNT was 11 (95% CI 9 to 14). Significant effects were seen in the subgroup of PCA (34 studies, RR 0.65, 95% CI 0.57 to 0.75; NNT 12, 95% CI 9 to 16); PAN (10 studies, RR 0.67, 95% CI 0.52 to 0.86; NNT = 11, 95% CI 8 to 25); and in PAQ (2 studies, RR 0.37, 95% CI 0.16 to 0.83; NNT 3, 95% CI 2 to 10); but not in PCN triple therapy (4 studies, RR 0.87, 95% CI 0.71 to 1.07). Significantly increased eradication rates were also seen for PPI triple therapy with 10 versus 7 days (24 studies, 79.9% versus 75.7%; RR 0.80, 95% CI 0.72 to 0.89; NNT 21, 95% CI 15 to 38) and 14 versus 10 days (12 studies, 84.4% versus 78.5%; RR 0.72, 95% CI 0.58 to 0.90; NNT 17, 95% CI 11 to 46); especially in the subgroup of PAC for 10 versus 7 days (17 studies, RR 0.80, 95% CI 0.70 to 0.91) and for 14 versus 10 days (10 studies, RR 0.69, 95% CI 0.52 to 0.91). A trend towards increased H. pylori eradication rates was seen with increased duration of PCN for 10 versus 7 days, and of PAN for 10 versus 7 days and 14 versus 10 days, though this was not statistical significant. The proportion of patients with adverse events, defined by authors, was marginally significantly increased only between 7 days and 14 days (15.5% versus 19.4%; RR 1.21, 95% CI 1.06 to 1.37; NNTH 31, 95% CI 18 to 104) but not for other duration comparisons. The proportion of patients discontinuing treatment due to adverse events was not significantly different between treatment durations.Only limited data were reported for different durations of regimens other than PPI triple therapy. No significant difference of the eradication rate was seen for all regimens according to different durations except for H₂RA bismuth quadruple therapy, where a significantly higher eradication rate was seen for 14 days versus 7 days, however only one study reported outcome data.

AUTHORS' CONCLUSIONS

Increasing the duration of PPI-based triple therapy increases H. pylori eradication rates. For PCA, prolonging treatment duration from 7 to 10 or from 10 to 14 days is associated with a significantly higher eradication rate. The optimal duration of therapy for PCA and PAN is at least 14 days. More data are needed to confirm if there is any benefit of increasing the duration of therapy for PCN therapy. Information is limited for regimens other than PPI triple therapy; more studies are needed to draw meaningful conclusions for optimal duration of other H. pylori eradication regimens.

Docosahexaenoic acid inhibits Helicobacter pylori growth in vitro and mice gastric mucosa colonization

H. pylori drug-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. For some bacterial species it has been demonstrated that fatty acids have a growth inhibitory effect. Our main aim was to assess the ability of docosahexaenoic acid (DHA) to inhibit H. pylori growth both in vitro and in a mouse model. The effectiveness of standard therapy (ST) in combination with DHA on H. pylori eradication and recurrence prevention success was also investigated. The effects of DHA on H. pylori growth were analyzed in an in vitro dose-response study and n in vivo model. We analized the ability of H. pylori to colonize mice gastric mucosa following DHA, ST or a combination of both treatments. Our data demonstrate that DHA decreases H. pylori growth in vitro in a dose-dependent manner. Furthermore, DHA inhibits H. pylori gastric colonization in vivo as well as decreases mouse gastric mucosa inflammation. Addition of DHA to ST was also associated with lower H. pylori infection recurrence in the mouse model. In conclusion, DHA is an inhibitor of H. pylori growth and its ability to colonize mouse stomach. DHA treatment is also associated with a lower recurrence of H. pylori infection in combination with ST. These observations pave the way to consider DHA as an adjunct agent in H. pylori eradication treatment.

Pantoprazole: a proton pump inhibitor with oral and intravenous formulations

Proton pump inhibitors (PPI) are a significant part of therapy for most acid-related diseases including gastroesophageal reflux disease, peptic ulcer disease and acute gastrointestinal bleeding. Pantoprazole is one of several available proton pump inhibitor agents and provides dose-dependent control of gastric acid secretion. Pantoprazole has indications in gastroesophageal reflux disease and peptic ulcer disease, along with indications as co-therapy in the eradication of Helicobacter pylori infection and in the control of the acid secretion associated with the Zollinger-Ellison syndrome, as well as in NSAID ulcer prevention. Pantoprazole is available in both oral and intravenous formulations. It is effective across all age groups, although only indicated in adults (and adolescents in Europe). It has been approved for use in over 100 countries and has been used for over 13 years. Pantoprazole has an excellent safety profile and a low potential for drug-drug interactions. While still widely prescribed, pantoprazole and the other branded proton pump inhibitors are under considerable market pressure from the less expensive but similarly effective generic and over-the-counter formulations of omeprazole.

2-week triple therapy for Helicobacter pylori infection is better than 1-week in clinical practice: a large prospective single-center randomized study

BACKGROUND

Proton pump inhibitor (PPI)-based triple therapies are considered the standard regimens for Helicobacter pylori eradication, but the optimal duration of these regimens is still controversial. The aim of this study was to compare the efficacy of 1-week versus 2-week triple therapies in H. pylori-positive patients.

MATERIALS AND METHODS

A total of 486 consecutive H. pylori-positive patients were randomized to receive omeprazole, 20 mg b.i.d., clarithromycin 500 mg b.i.d., and either amoxicillin 1 g b.i.d. or metronidazole 500 mg b.i.d. for 1 or 2 weeks. Upper gastrointestinal endoscopy and histology were performed at entry and 2 months after the end of therapy. H. pylori status was defined according to histology and urea breath test.

RESULTS

At intention-to-treat analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin achieved a significantly higher eradication rate than 1- or 2-week regimens with metronidazole (70% versus 52%, p = .003, versus 56%, p < .01) and the same therapy for 1-week (70% versus 57%, p = .05). At per-protocol analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin showed a significantly higher eradication rate than 1-week of amoxicillin and metronidazole (77% versus 62%; p = .03) but no difference with 1-week same regimen (66%) or 2-week metronidazole and clarithromycin regimen (72%). Compliance and tolerability were good for all regimens.

CONCLUSIONS

Two-week therapies, independently of antibiotic combination, lead to a significant increase of H. pylori eradication rate compared to 1-week therapies, with same compliance and tolerability, even if, taking account of low-eradication rates, one must question whether the triple therapy should still be used.

Rifabutin- and furazolidone-based Helicobacter pylori eradication therapies after failure of standard first- and second-line eradication attempts in dyspepsia patients

BACKGROUND

Optimal management approach is not well defined for subjects who fail initial first- and second-line Helicobacter pylori eradication attempts and are dealt on a case-by-case basis by the specialists.

AIM

To evaluate the efficacy and safety of standard and 'rescue' eradication therapies at primary and secondary care levels.

METHODS

H. pylori infected dyspepsia patients referred to our C13 urea breath testing laboratory between January 1999 to February 2002 were included. Eradication failure at secondary care level was treated using strategies including antibiotic sensitivity testing and the use of rifabutin- and furazolidone-based therapies.

RESULTS

3280 patients received standard first-line eradication therapy, which was successful in 2530 (77%) patients. Second-line therapy (bismuth-based 'quadruple') or triple therapy (altering constituent antibiotics) was successful in 56% of 270 treated patients. Subsequent eradication attempts using rifabutin-based (n = 34) and furazolidone-based (n = 10) regimens were successful in 38% and 60% patients respectively. H. pylori eradication rates were significantly different for guidelines compliant (94.8%) and non-compliant (82%) groups (P = 0.0001). H. pylori eradication rates for non-ulcer dyspepsia (40%) and peptic ulcer disease (36%) were not significantly different.

CONCLUSIONS

Available H. pylori eradication therapies remain very effective and compliance to guidelines achieves high success rates. Furazolidone-based 'rescue' regimen achieved high eradication rates after failure of the standard first-line, second-line and rifabutin-based therapies.

Effect of Helicobacter pylori eradication on high-density lipoprotein cholesterol

We examined the effect of Helicobacter pylori (H. pylori) eradication on lipids and apolipoproteins in 87 patients with duodenal ulcers. A significant increase was observed in high-density lipoprotein (HDL) cholesterol (+24.7%, p <0.001), apolipoprotein AI (+9.0%, p <0.001), and apolipoprotein AII (+11.7%, p <0.001) after eradication. Minor increases occurred in total cholesterol, triglycerides, and apolipoprotein B, whereas low-density lipoprotein cholesterol remained unchanged. Our results suggest that chronic H. pylori infection reduces plasma levels of HDL cholesterol and that eradication improves the lipoprotein pattern.

Pantoprazole based therapies in Helicobacter pylori eradication: a systematic review and meta-analysis

AIM

To perform a systematic review on the efficacy of pantoprazole based therapies in Helicobacter pylori eradication, and to conduct a meta-analysis comparing the efficacy of pantoprazole and other proton pump inhibitors (PPIs) when co-prescribed with antibiotics.

METHODS

Studies evaluating pantoprazole combined with antibiotics were considered. Only randomized clinical trials comparing pantoprazole and other PPIs when co-prescribed with antibiotics, and differing only in the PPI (pantoprazole vs other), were eligible for inclusion in the meta-analysis. Bibliographical searches in several electronic databases, and manual search of abstracts from congresses, were conducted. The percentage (weighted mean) of patients with eradication success was calculated. Meta-analysis was performed combining the odds ratios (ORs) of the individual studies in a global OR.

RESULTS

The mean eradication rate with pantoprazole plus clarithromycin for 14 days was 60%. Cure rates with 7 day pantoprazole based triple regimens were higher: pantoprazole, amoxicillin and clarithromycin (78%); pantoprazole, clarithromycin and nitroimidazole (84%); and pantoprazole, amoxicillin and nitroimidazole (74%). Twelve studies comparing pantoprazole and other PPIs were selected for the meta-analysis, including 534 and 603 patients, respectively. The mean eradication rate for H. pylori using pantoprazole plus antibiotics was 83%, and 81% when other PPIs were used (OR = 1; 95% confidence interval (CI) from 0.61 to 1.64). When sub-analysis was performed, including only studies comparing pantoprazole with omeprazole, or pantoprazole with lansoprazole, differences were also statistically non-significant. The meta-analysis of the six studies prescribing equivalent doses of all PPIs demonstrated similar results with pantoprazole and with other PPIs (OR = 1.07; 95% CI from 0.71 to 1.62), the results being statistically homogeneous.

CONCLUSIONS

Pantoprazole achieves similar cure rates to those of omeprazole and lansoprazole when co-prescribed with antibiotics for the eradication of H. pylori infection.

Eradication of Helicobacter pylori by 7-day triple-therapy regimens combining pantoprazole with clarithromycin, metronidazole, or amoxicillin in patients with peptic ulcer disease: results of two double-blind, randomized studies

AIM

To compare the short-term (7-day) safety and efficacy of two triple-therapy regimens using pantoprazole with those of two dual-therapy regimens (one with pantoprazole and one without), for Helicobacter pylori eradication in patients with peptic ulcer disease.

METHODS

H. pylori infection was identified by rapid urease (CLOtest), and confirmed by histology and culture. Patients were enrolled into one of two randomized, double-blind, multicenter, parallel-group studies. In study A, patients received oral pantoprazole 40 mg, clarithromycin 500 mg, and metronidazole 500 mg (PCM); pantoprazole, clarithromycin and amoxicillin 1000 mg (PCA); or pantoprazole and clarithromycin (PC). In study B, patients received PCM, PCA, PC, or clarithromycin and metronidazole without pantoprazole (CM). Treatments were given twice daily for 7 days. H. pylori status after therapy was assessed by histology and culture at 4 weeks after completing the course of study treatment. Modified intent-to-treat (MITT; each study: n = 424, n = 512) and per-protocol (PP; each study: n = 371, n = 454) populations were analyzed. The MITT population comprised all patients whose positive H. pylori status was confirmed by culture and histology; the PP population comprised patients who also complied with > or = 85% of study medication doses.

RESULTS

A total of 1016 patients were enrolled. Cure rates among patients with clarithromycin-susceptible H. pylori strains were 82 and 86% for PCM, and 72 and 71% for PCA, in studies A and B, respectively. Cure rates among patients with metronidazole-susceptible H. pylori strains were 82 and 87% for PCM, and 71 and 69% for PCA, in studies A and B, respectively. The combined eradication rates observed with the PCM regimen were superior to those of all other regimens tested. Side-effects were infrequent and mild.

CONCLUSIONS

PCM had the highest overall eradication rate in these two studies examining 7-day treatment regimens. All regimens were safe and well tolerated.

Analysis of the rdxA gene in high-level metronidazole-resistant clinical isolates confirms a limited use of rdxA mutations as a marker for prediction of metronidazole resistance in Helicobacter pylori

Metronidazole (Mtz) resistance in the gastric pathogen Helicobacter pylori is closely associated with inactivation of the nitroreductase gene rdxA. In order to identify respective mutations for diagnostic purposes we analyzed the rdxA gene in a collection of high-level Mtz-resistant clinical H. pylori isolates. Size alterations in the rdxA gene region were found in only two out of 45 and one out of 40 isolates showing lower-level (minimal inhibitory concentrations (MICs) 32-192 microg ml(-1)) and high-level (MIC>/=256 microg ml(-1)) Mtz resistance, respectively. Point mutations that interrupt the rdxA reading frame were detected in two out of eight high-level resistant isolates (MICs>/=256 microg ml(-1)). Most remarkably, the rdxA gene sequence was found to be identical in four out of five high-level Mtz-resistant and -susceptible paired H. pylori isolates from the same patients each. Taken together, these results demonstrate that although some isolates carry classical resistance-associated rdxA mutations, as described earlier, the use of rdxA mutations as a marker for prediction of Mtz resistance is limited.

Pantoprazole: an update of its pharmacological properties and therapeutic use in the management of acid-related disorders

Pantoprazole (Protonix) is an irreversible proton pump inhibitor (PPI) that reduces gastric acid secretion. In combination with two antimicrobial agents (most commonly metronidazole, clarithromycin or amoxicillin) for 6-14 days, pantoprazole 40 mg twice daily produced Helicobacter pylori eradication rates of 71-93.8% (intent-to-treat [ITT] or modified ITT analysis) in patients without known antibacterial resistance. Pantoprazole-containing triple therapy was at least as effective as omeprazole- and similar in efficacy to lansoprazole-containing triple therapy in large trials. In the treatment of moderate to severe gastro-oesophageal reflux disease (GORD), oral pantoprazole 40 mg/day was as effective as other PPIs (omeprazole, omeprazole multiple unit pellet system, lansoprazole and esomeprazole) and significantly more effective than histamine H(2)-antagonists. Pantoprazole 20 mg/day provided effective mucosal healing in patients with GORD and mild oesophagitis. Intravenous pantoprazole 40 mg/day can be used in patients who are unable to take oral medication. Oral pantoprazole 20-40 mg/day for up to 24 months prevented relapse in most patients with healed GORD. According to preliminary data, oral pantoprazole 20 or 40 mg/day was effective at healing and preventing non-steroidal anti-inflammatory drug (NSAID)-related ulcers, and intravenous pantoprazole was at least as effective as intravenous ranitidine in preventing ulcer rebleeding after endoscopic haemostasis. Oral or intravenous pantoprazole up to 240 mg/day maintained target acid output levels in most patients with hypersecretory conditions, including Zollinger-Ellison syndrome. Oral and intravenous pantoprazole appear to be well tolerated in patients with acid-related disorders in short- and long-term trials. Tolerability with oral pantoprazole was similar to that with other PPIs or histamine H(2)-antagonists in short-term trials. Formal drug interaction studies have not revealed any clinically significant interactions between pantoprazole and other agents. In conclusion, pantoprazole is an effective agent in the management of acid-related disorders. As a component of triple therapy for H. pylori eradication and as monotherapy for the healing of oesophagitis and maintenance of GORD, pantoprazole has shown similar efficacy to other PPIs and greater efficacy than histamine H(2)-antagonists. Limited data suggest that it is also effective in Zollinger-Ellison syndrome and in preventing ulcer rebleeding. Pantoprazole is well tolerated with minimal potential for drug interactions. The availability of pantoprazole as both oral and intravenous formulations provides flexibility when the oral route of administration is not appropriate. Thus, pantoprazole is a valuable alternative to other PPIs in the treatment of acid-related disorders.

Recent use of proton pump inhibitor-based triple therapies for the eradication of H pylori: a broad data review

INTRODUCTION

For the eradication of Helicobacter pylori a 1-week triple therapy combining proton pump inhibitors with two antibiotics has been recommended as a gold standard therapy. However, a recent broad data review on the efficacy of the different regimens is missing. Therefore, the aim of this study was to systematically review the recent literature.

METHODS

We undertook a broad data review of the efficacy of nine different 7-day triple therapies consisting of a proton pump inhibitor (lansoprazole, pantoprazole, omeprazole) in its standard dosage and two antibiotics. Relevant original papers on H. pylori eradication in adults, published in English or German between 1995 and 2000, were identified from MEDLINE searches. Studies were reviewed and selected according to predefined criteria.

RESULTS

Our predefined criteria were fulfilled by 79 full paper articles including 112 study arms with 8383 patients on intention-to-treat, or 6787 patients on per-protocol basis, respectively. The mean eradication rates unweighted or weighted by the number of patients in the study arm vary from 71.9% to 83.8% for intention-to-treat analysis and from 78.5% to 91.2% for per-protocol analysis.

CONCLUSIONS

All nine PPI based triple therapy regimens are very effective in H. pylori eradication. The current literature review underlines that the use of either lansoprazole, omeprazole, or pantoprazole combined with two antibiotics yield similar high eradication rates.

The impact of Helicobacter pylori resistance on the efficacy of a short course pantoprazole based triple therapy

BACKGROUND: Many of the currently used Helicobacter pylori eradication regimens fail to cure the infection due to either antimicrobial resistance or poor patient compliance. Those patients will remain at risk of developing potentially severe complications of peptic ulcer disease. AIM: We studied the impact of the antimicrobial resistance on the efficacy of a short course pantoprazole based triple therapy in a single-center pilot study. METHODS: Forty previously untreated adult patients (age range 20 to 75 years, 14 males) infected with Helicobacter pylori and with inactive or healing duodenal ulcer disease were assigned in this open cohort study to 1 week twice daily treatment with pantoprazole 40 mg, plus clarithromycin 250 mg and metronidazole 400 mg. Helicobacter pylori was assessed at entry and 50 ± 3 days after the end of treatment by rapid urease test, culture and histology of gastric biopsies. The criteria for eradication was a negative result in the tests. Susceptibility of Helicobacter pylori to clarithromycin and metronidazole was determined before treatment with the disk diffusion test. RESULTS: One week treatment and follow up were complete in all patients. Eradication of Helicobacter pylori was achieved in 35/40 patients (87.5%) and was higher in patients with nitroimidazole-susceptible strains [susceptible: 20/20 (100%), resistant: 10/15 (67%)]. There were six (15%) mild adverse events reports. CONCLUSIONS: A short course of pantoprazole-based triple therapy is well tolerated and effective in eradicating Helicobacter pylori. The baseline metronidazole resistance may be a significant limiting factor in treatment success.

Eradication of Helicobacter pylori: current perspectives

Helicobacter pylori appears to be a necessary cofactor for the majority of non-drug-associated duodenal and gastric ulcers. H. pylori infection is a chronic and transmissible infectious disease whose eradication has proved difficult. The last decade has seen > 1000 clinical trials using different eradication regimens. Many of these trials had severe limitations, some of which will be discussed here. The current review also focuses on the regimens that were used in the past, the present regimens and possibilities for the future. Also highlighted are some other aspects of H. pylori management, such as eradication failures and drug resistance.

Review article: treatment of Helicobacter pylori infection and factors influencing eradication

Currently available Helicobacter pylori eradication therapies are considered very effective and safe. The most recent eradication guidelines proposed in the Maastricht 2-2000 Consensus Report recommend the use of proton pump inhibitors (standard b.d.) along with clarithromycin (500 mg b.d.) and amoxycillin (1000 mg b.d.) or metronidazole (500 mg b.d.) for a minimum of 7 days. The combination of amoxycillin and clarithromycin is preferred because it may favour best results with a second-line proton pump inhibitor quadruple therapy. The recommended second-line therapy includes a combination of a proton pump inhibitor (standard b.d.) with bismuth salt (subsalicylate/subcitrate 120 mg q.d.s.), metronidazole (500 mg t.d.s.), and tetracycline (500 mg q.d.s.) for a minimum of 7 days. Extended proton pump inhibitor-based triple therapy can be used if bismuth is not available. Specialists should manage subsequent failures. Based on direct and indirect evidence from well-designed studies and clinical experience, eradication is recommended in gastric and duodenal ulcers, MALToma, atrophic gastritis, postgastric cancer resection, and in first-degree relatives of gastric cancer patients. The most common reason for treatment failure is poor compliance with eradication guidelines. Antibiotic resistance may be a significant factor in certain geographical areas. Proton pump inhibitors are an integral part of the eradication regimens as proved by meta-analyses of clinical trials. Novel agents used in secondary failure are few and depend on the use of new antibiotics. The role of H. pylori-specific antibiotics, probiotics, and vaccines is not established as yet. Widespread acceptance of the eradication guidelines should be regarded as the single most important factor in eradication success.

Pantoprazole: a new proton pump inhibitor

OBJECTIVE

This paper reviews the pharmacology, clinical efficacy, and tolerability of pantoprazole in comparison with those of other available proton pump inhibitors (PPIs).

METHODS

Relevant English-language research and review articles were identified by database searches of MEDLINE, International Pharmaceutical Abstracts, and UnCover, and by examining the reference lists of the articles so identified. In selecting data for inclusion, the author gave preference to full-length articles published in peer-reviewed journals.

RESULTS

Like other PPIs, pantoprazole exerts its pharmacodynamic actions by binding to the proton pump (H+,K+ -adenosine triphosphatase) in the parietal cells, but, compared with other PPIs, its binding may be more specific for the proton pump. Pantoprazole is well absorbed when administered as an enteric-coated, delayed-release tablet, with an oral bioavailability of approximately 77%. It is hepatically metabolized via cytochrome P2C19 to hydroxypantoprazole, an inactive metabolite that subsequently undergoes sulfate conjugation. The elimination half-life ranges from 0.9 to 1.9 hours and is independent of dose. Pantoprazole has similar efficacy to other PPIs in the healing of gastric and duodenal ulcers, as well as erosive esophagitis, and as part of triple-drug regimens for the eradication of Helicobacter pylori from the gastric mucosa. It is well tolerated, with the most common adverse effects being headache, diarrhea, flatulence, and abdominal pain. In clinical studies, it has been shown to have no interactions with various other agents, including carbamazepine, cisapride, cyclosporine, digoxin, phenytoin, theophylline, and warfarin.

CONCLUSIONS

Pantoprazole appears to be as effective as other PPIs. Its low potential for drug interactions may give it an advantage in patients taking other drugs.

Eradication of Helicobacter pylori with pantoprazole and two antibiotics: a comparison of two short-term regimens

BACKGROUND

High rates of Helicobacter pylori eradication can be achieved by combining proton pump inhibitors with two antibiotics. However, in the search for an optimal therapy a direct comparison of different regimens is necessary.

METHODS

For this open study, 331 patients with duodenal ulcer were screened and randomly allocated to either pantoprazole 40 mg b.d., clarithromycin 500 mg b.d., and metronidazole 500 mg b.d. (PCM) or pantoprazole 40 mg b.d., amoxycillin 1000 mg b.d., and clarithromycin 500 mg b.d. (PAC) for 7 days. Both combinations were followed by a 7-day therapy with pantoprazole 40 mg o.d. alone. Eradication of H. pylori was assessed by use of a 13C-urea breath test 4 weeks after the intake of the last medication.

RESULTS

Eradication rates were 90% in intention-to-treat patients from the PCM (132 out of 147; 95% CI: 84-94%) and the PAC group (135 out of 150; 95% CI: 84-94%). H. pylori was eradicated in 112 out of 117 per protocol patients of the PCM group (96%; 95% CI: 90-99%) and in 119 out of 126 patients of the PAC group (94%; 95% CI: 89-98%). Rapid relief from ulcer pain and a decrease in the mean intensity of other gastrointestinal symptoms was observed. Sixty-nine patients reported adverse events, none of which were related to the intake of pantoprazole. Four serious adverse events, none related to the trial medication, were observed.

CONCLUSIONS

Both pantoprazole-based short-term triple therapies are highly effective and well-tolerated treatment regimens in the eradication of H. pylori.