Medical therapy. Management of the refractory patient

Effect of food on the pharmacokinetics of omeprazole, pantoprazole and rabeprazole

Background

The pharmacokinetics of proton pump inhibitors (PPIs) may be affected by food intake. We aimed to evaluate the effect of food on the pharmacokinetics of omeprazole, rabeprazole, and pantoprazole.

Setting

The study population comprised 186 healthy volunteers participating in 6 bioequivalence clinical trials.

Method

Subjects were evaluated to determine the effect of a high-fat breakfast on the pharmacokinetics of omeprazole (n = 36), rabeprazole (n = 69), and pantoprazole (n = 81).

Main outcome measure

Drug plasma concentrations were measured using high-performance liquid chromatography coupled to mass spectrometry.

Results

Food affected the pharmacokinetics of omeprazole (increased T_max and decreased AUC and C_max), pantoprazole (increased T_max and decreased AUC), and rabeprazole (increased T_max, C_max and half-life). Food increased variability in T_max for all 3 drugs, delaying absorption around 3 to 4 h and until 20 h in some subjects.

Conclusion

As food delays the absorption of PPIs and increases their variability, it would be better to administer these drugs under fasting conditions.

Trial registration

European Union Drug Regulating Authorities Clinical Trials Database: EudraCT: 2004–003863-59 (registration date 05/MAR/2004), EudraCT 2006–001162-17 (registration date 17-MAR-2006), EudraCT: 2007–002489-37 (registration date 12-JUN-2007), EudraCT: 2007–002490-31 (registration date 12-JUN-2007), EudraCT: 2010–024029-19 (registration date 23-NOV-2010).

Dosing of proton pump inhibitors is suboptimal among otolaryngologists treating reflux-induced upper-respiratory disease

Objective

To evaluate the practice of otolaryngologists treating reflux-induced upper-respiratory disease in a nationwide survey.

STUDY DESIGN

Survey study using an anonymous questionnaire containing clinical vignettes.

SUBJECTS AND METHODS

The survey was mailed to all 6,899 board-certified fellow members in practice in the American Academy of Otolaryngology–Head and Neck Surgery residing in the United States.

RESULTS

One thousand seven hundred twenty questionnaires were returned. Respondents empirically treated reflux-induced upper-respiratory disease with proton pump inhibitors once daily and twice daily 63% and 31%, respectively. Fifteen percent did not instruct their patients on how to take the proton pump inhibitors. Of those who instructed their patients, 22% advised dosing before breakfast, 32% before breakfast and again before dinner, and 46% recommended other timings. When prescribing twice-per-day dosing, 64% responded to give before breakfast and dinner and 28% responded before breakfast and at bedtime.

CONCLUSION

Suboptimal dosing of proton pump inhibitors is prevalent among otolaryngologists treating reflux-induced upper-respiratory disease.

Gastroesophageal Acid Reflux Control 5 Years After Antireflux Surgery, Compared With Long-term Esomeprazole Therapy

BACKGROUND & AIMS

We compared the ability of laparoscopic antireflux surgery (LARS) and esomeprazole to control esophageal acid exposure, over a 5-year period, in patients with chronic gastroesophageal reflux disease (GERD). We also studied whether intraesophageal and intragastric pH parameters off and on therapy were associated with long-term outcomes.

METHODS

We analyzed data from a prospective, randomized, open-label trial comparing the efficacy and safety of LARS vs esomeprazole (20 or 40 mg/d) over 5 years in patients with chronic GERD. Ambulatory intraesophageal and intragastric 24-hour pH monitoring data were compared between groups before LARS or the start of esomeprazole treatment, and 6 months and 5 years afterward. A secondary aim was to evaluate the association between baseline and 6-month pH parameters and esomeprazole dose escalation, reappearance of GERD symptoms, and treatment failure over 5 years in patients receiving LARS or esomeprazole.

RESULTS

In the LARS group (n = 116), the median 24-hour esophageal acid exposure was 8.6% at baseline and 0.7% after 6 months and 5 years (P < .001 vs baseline). In the esomeprazole group (n = 151), the median 24-hour esophageal acid exposure was 8.8% at baseline, 2.1% after 6 months, and 1.9% after 5 years (P < .001, therapy vs baseline, and LARS vs esomeprazole). Gastric acidity was stable in both groups. Patients who required a dose increase to 40 mg/d had more severe supine reflux at baseline, and decreased esophageal acid exposure (P < .02) and gastric acidity after dose escalation. Esophageal and intragastric pH parameters, off and on therapy, did not predict long-term symptom breakthrough.

CONCLUSIONS

In a prospective study of patients with chronic GERD, esophageal acid reflux was reduced greatly by LARS or esomeprazole therapy. However, patients receiving LARS had significantly greater reductions in 24-hour esophageal acid exposure after 6 months and 5 years. Esophageal and gastric pH, off and on therapy, did not predict long-term outcomes of patients. Abnormal supine acid exposure predicted esomeprazole dose escalation. ClinicalTrials.Gov identifier: NCT00251927 (available: http://clinicaltrials.gov/ct2/show/NCT00251927).

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.

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.

Consumer use of over-the-counter proton pump inhibitors in patients with gastroesophageal reflux disease

OBJECTIVES

Optimal administration of proton pump inhibitor (PPI) for the treatment of gastroesophageal reflux disease (GERD) requires consideration of meal timing. Since becoming available over the counter (OTC), no studies have assessed treatment patterns and symptom control in OTC consumers. The objective of this study was to survey dosing patterns and symptom control in OTC and prescription PPI users.

METHODS

Patients at five clinics were surveyed regarding diagnosis of GERD, use of OTC or prescription PPIs, information on time of day dosing, demographics, and Gastroesophageal Reflux Disease Symptom Assessment Scale (GSAS; 2001, Johnson & Johnson).

RESULTS

Of the 1,959 patients surveyed, 610 (31%) used PPIs for GERD. Of these, 190 (31%) and 223 (37%) received prescriptions from gastroenterologists (GIs) and primary care physicians (PCPs), respectively; 197 (32%) purchased OTC PPIs. Of the patients prescribed PPIs by GIs, 71% were optimal users, whereas 47% of patients receiving prescriptions from PCPs and 39% of consumers used PPIs optimally (P<0.001 compared with GIs). GSAS symptom, frequency, and severity scores were significantly better in patients prescribed PPIs by GIs (all P<0.001, GI compared with PCP and consumer). GSAS symptom, frequency, and severity scores were also significantly better in patients using PPIs optimally (P<0.001 for all parameters) compared with those taking PPIs suboptimally or excessively.

CONCLUSIONS

Patients receiving prescription PPI from a GI are more likely to be optimal users with better symptom control. Conversely, consumers are more likely to be suboptimal users with inadequate symptom control.

Rabeprazole 10 mg q.d.s. decreases 24-h intragastric acidity significantly more than rabeprazole 20 mg b.d. or 40 mg o.m., overcoming CYP2C19 genotype

BACKGROUND

Standard dosing (i.e. once daily) of proton pump inhibitors (PPIs) cannot inhibit acid secretion for a full 24 h. Better therapeutic regimens using PPIs are required to sustain potent acid inhibition for the full 24 h in all patients with acid-related diseases.

AIM

To evaluate acid inhibitory effects by different dosing times of a PPI at the same daily dosage, in a study involving 70 rounds of pH monitoring.

METHODS

Using pH monitoring, we evaluated the efficacy of different divided treatment regimens with the same total daily dose of rabeprazole (40 mg o.m., 15 rounds; 20 mg b.d., 20 rounds; 10 mg q.d.s., 35 rounds) on day 7 or 8 of PPI dosing.

RESULTS

In the study of divided treatment, the median pH (when administered once, twice or four times to achieve a daily dose of 40 mg) was 4.8 (3.6-6.4), 5.7 (4.1-7.4), 6.6 (4.9-8.4), respectively. When comparing the median pHs at the same CYP2C19 genotype among different dosing times of rabeprazole, the median pH attained with 10 mg q.d.s. was significantly higher than that in 40 mg o.m. or 20 mg b.d. Increase in the frequency of dosing effectively increased pH [median percent time of pH > 4.0 with q.d.s. therapy: 95.5% (63.2-100.0%)], irrespective to CYP2C19 genotype.

CONCLUSION

Four times daily dosing with rabeprazole 10 mg achieved potent acid inhibition, including during the night-time, suggesting its potential usefulness as a regimen for patients who are refractory to standard once daily PPI treatment.

Endoscopy in gastro-oesophageal reflux disease

Although gastro-oesophageal reflux disease is basically a clinical diagnosis, oesophago-gastroduodenoscopy is essential to assess the type and severity of tissue damage. The main role for endoscopy is to detect metaplastic or premalignant changes complicating gastro-oesophageal reflux, and allow for surveillance. Routine biopsies are potentially useful to increase the diagnostic precision in case of minimal mucosal abnormalities. Management algorithms should include endoscopy to be performed early in the course of disease in most patients, even in the absence of alarm symptoms. Routine use of the Los Angeles classification of oesophagitis and the Prague classification for metaplasia is necessary for a precise description and biopsy sampling. Magnification chromoendoscopy is particularly useful in the hands of experienced endoscopists, whereas novel technologies including confocal laser endomicroscopy may become an important method in specialised centres to optimise the surveillance of premalignant mucosa.

Effect of CYP2C19 genotypes on the pharmacokinetic/pharmacodynamic relationship of rabeprazole after a single oral dose in healthy Chinese volunteers

AIMS

To explore the pharmacokinetic/pharmacodynamic relationship of rabeprazole and the role of CYP2C19 genotypes after a single oral dose in healthy Chinese volunteers by a population approach.

METHODS

Plasma concentration time profile data and intragastric pH values of 19 genotyped healthy male adults after a single oral dose of rabeprazole in an open label randomized fashion were used for this population analysis. Simulation technology was performed to examine the rabeprazole response in subjects with different CYP2C19 genotypes to further investigate the effect of acid inhibition.

RESULTS

The pharmacokinetics of rabeprazole was characterized by a two-compartment model with first order absorption and with an absorption lag-time. The results show that clearance of rabeprazole was affected by CYP2C19 genotypes (average clearances of homEM, hetEM, and PM were 13.9, 11.5, and 8.74 L·h(-1) respectively). An effect compartment with a sigmoidal Emax model was considered more rational for analyzing the relationship between rabeprazole concentrations and intragastric pH values. Simulated results suggest that rabeprazole 20 mg once daily for PMs is sufficient, but might be administered more frequently for other genotypes in treating gastro-esophageal reflux disease.

CONCLUSION

The CYP2C19 genotype played a considerable role in the pharmacokinetic characteristics of rabeprazole, and this might need to be taken into account for clinical use.

The GABA(B) receptor agonist AZD9343 inhibits transient lower oesophageal sphincter relaxations and acid reflux in healthy volunteers: a phase I study

BACKGROUND

Transient lower oesophageal sphincter relaxations (TLESRs) represent an interesting target for the treatment of gastro-oesophageal reflux. Baclofen reduces TLESRs and reflux episodes, but is not optimal for clinical application because of its central side effects. Therefore, new agents are required.

AIM

To study the effect of AZD9343, a new selective GABA(B) receptor agonist, in healthy volunteers.

METHODS

A total of 27 subjects participated in a placebo-controlled, randomized, two-centre phase I study. Subjects underwent oesophageal manometry and pH-metry for 3 h postprandially. Before meal ingestion, a single oral dose of placebo, 60 and 320 mg AZD9343 or 40 mg baclofen was given on four separate days.

RESULTS

Somnolence was reported after 320 mg AZD9343 and baclofen. Reversible short-lasting paraesthesia was reported after AZD9343. AZD9343 320 mg and baclofen significantly reduced the number of TLESRs with 32% and 40% respectively. Acid reflux was significantly decreased by AZD9343 and baclofen. Like baclofen, AZD9343 increased LES pressure before meal intake. AZD9343 320 mg and baclofen significantly reduced the swallowing rate.

CONCLUSIONS

Like baclofen, AZD9343 dose-dependently decreases the number of TLESRs and acid reflux episodes, increases LES pressure and reduces swallowing, extending the concept that GABA(B) agonists are potent reflux inhibitors. However, discovery of analogues with an improved side effect profile is warranted.

Does the presence of a hiatal hernia affect the efficacy of the reflux inhibitor baclofen during add-on therapy?

OBJECTIVES

Reflux inhibitors, like the gamma-aminobutyric acid type B (GABA(B)) receptor agonist, baclofen, block transient lower esophageal sphincter relaxations (TLESRs) and are proposed as an add-on therapy in patients with proton pump inhibitor (PPI)-resistant gastroesophageal reflux. However, as other mechanisms of reflux become more important in the presence of a hiatal hernia (HH), the efficacy of reflux inhibitors to reduce acid and non-acid exposure may be hampered. Therefore, we compared the effect of baclofen in patients with no HH (-HH) and those with a large HH during PPI treatment.

METHODS

A total of 27 gastroesophageal reflux disease (GERD) patients on PPI were included; 16 had -HH and 11 had a large (> or =3 cm) HH (+HH). During PPI treatment, the effect of baclofen (3 x 20 mg) on acid and non-acid reflux was evaluated in a randomized, double-blind, placebo-controlled cross-over study. Reflux was measured during 24 h using combined esophageal impedance and pH-metry.

RESULTS

The majority of reflux events consisted of both gaseous and liquid reflux with a significant increase in non-acid, mixed reflux episodes in +HH patients compared with those in -HH patients. Acid exposure time was in the normal range in both patient groups during both placebo and baclofen. In this study, baclofen significantly reduced the total number of reflux episodes with 36% in -HH patients and 43% in +HH patients, but did not change the number of acid reflux episodes or total acid exposure time.

CONCLUSIONS

This study shows that baclofen is also effective in patients with GERD with +HH, further underscoring the potential of reflux inhibitors as treatment of GERD.

A comparative study of intragastric acidity during post-breakfast and pre-dinner administration of low-dose proton pump inhibitors: a randomized three-way crossover study

BACKGROUND

The absorption and bioavailability of proton pump inhibitors is influenced by food intake. Proton pump inhibitors bind to the parietal cell active proton pump, which is maximally stimulated after dinner: usually the largest meal of the day. However, it has not been fully clarified whether the efficacy of proton pump inhibitors differs between post-breakfast and pre-dinner dosing.

AIM

To perform a pH-monitoring study to clarify this issue for two low-dose proton pump inhibitors.

SUBJECTS AND METHODS

The subjects were 20 healthy male volunteers (seven Helicobacter pylori-positive and 13 H. pylori-negative), who were divided into two groups of 10 and administered 15 mg lansoprazole or 10 mg rabeprazole, respectively. All subjects underwent ambulatory intragastric 24-h pH- monitoring under three conditions allocated randomly: (i) without medication, (ii) seventh day of post-breakfast administration and (iii) eighth day of pre-dinner administration of each drug.

RESULTS

There was no significant difference in the percentage time during which pH > or =4.0 in the 24-h period between post-breakfast and pre-dinner administration of both drugs (56.6% vs. 55.8%; P = 0.557), although intragastric acidity during administration of both drugs was significantly lower than that without medication.

CONCLUSIONS

The timing of drug administration does not significantly influence the efficacy of low-dose proton pump inhibitors.

Acid-suppressive effects of rabeprazole: comparing 10mg and 20mg twice daily in Japanese Helicobacter pylori-negative and -positive CYP2C19 extensive metabolisers

BACKGROUND

Rabeprazole 10mg b.i.d. is often administered as therapy for eradication of Helicobacter pylori (H. pylori) and is also proposed as therapy for refractory gastro-oesophageal reflux disease. However, there has not been a comprehensive assessment of its acid-suppressive effects.

AIMS

To compare the acid-suppressive effects of rabeprazole 10mg b.i.d. with 20mg b.i.d. considering H. pylori status.

SUBJECTS

Thirteen H. pylori-negative and eleven H. pylori-positive Japanese CYP2C19 extensive metabolisers (<35 years).

METHODS

Intragastric pH was measured for 24h three times in a randomised manner; on day 7 of the repeated administration of rabeprazole 10mg b.i.d. or 20mg b.i.d., or a placebo.

RESULTS

In median intragastric pH value and percent time of pH>3.0, >4.0, >5.0, >6.0, and >7.0 for 24h, no significant differences were observed between the two doses in either H. pylori-negative or H. pylori-positive subjects. At either dose, these parameters were significantly higher in H. pylori-positive subjects than in H. pylori-negative subjects. Nocturnal acid breakthrough occurred in seven and two of the thirteen H. pylori-negative subjects and one and two of the eleven H. pylori-positive subjects at each dose, respectively.

CONCLUSIONS

The effects of rabeprazole 10mg b.i.d. were equal to those of 20mg b.i.d. in H. pylori-positive subjects; whereas in H. pylori-negative subjects, 20mg b.i.d. was superior for prevention of nocturnal acid breakthrough.

Sub-optimal proton pump inhibitor dosing is prevalent in patients with poorly controlled gastro-oesophageal reflux disease

BACKGROUND

Proton pump inhibitors are the most potent drug treatment for gastro-oesophageal reflux disease. Pre-meal dosing maximizes efficacy while sub-optimal dose timing may limit efficacy.

AIM

To determine the prevalence of sub-optimal proton pump inhibitor dosing in a community-based gastro-oesophageal reflux disease population.

MATERIALS AND METHODS

One hundred patients on proton pump inhibitors referred for persistent gastro-oesophageal reflux disease symptoms were questioned about their proton pump inhibitor dosing habits and classified as optimal or sub-optimal dosers. Optimal dosers took proton pump inhibitors with or up to 60 min before meals. Sub-optimal dosers took proton pump inhibitors >60 min before meals, after meals, as needed, or at bedtime.

RESULTS

Forty-six percent dosed optimally. Fifty-four percent dosed sub-optimally with 21 of 54 (39%) dosing >60 min before meals, 16 (30%) after meals, 15 (28%) at bedtime and two (4%) as needed. Only 6% of the subjects on once-daily proton pump inhibitor regimens and 33% of subjects taking proton pump inhibitors two- to three times daily dosed in a manner that maximized acid suppression (15-30 min before a meal).

CONCLUSIONS

In this study, 54% of patients dosed proton pump inhibitors sub-optimally and only 12% dosed in a manner that maximized acid suppression. As sub-optimal proton pump inhibitor dose timing can limit efficacy, patients with refractory symptoms should be asked about dose timing to avoid inappropriate and costly dose escalations.

Review article: putting immediate-release proton-pump inhibitors into clinical practice--improving nocturnal acid control and avoiding the possible complications of excessive acid exposure

Nocturnal gastro-oesphageal reflux is an under-appreciated clinical challenge. This condition may cause symptoms such as nocturnal heartburn, or it may be asymptomatic. In addition, patients may experience sleep disturbances that can potentially lead to complications such as erosive oesophagitis and Barrett's oesophagus, and may be a risk factor for development of oesophageal adenocarcinoma. Delayed-release proton-pump inhibitors (PPIs) have traditionally been effective in treating both daytime and night-time reflux symptoms, but are limited in control of nocturnal acidity by their pharmacodynamic characteristics. This narrative review addresses the prevalence, impact and pharmacologic approaches used to control nocturnal acidity. Methods to optimize nocturnal acid control include careful attention to dosing schedule, using higher doses of PPIs, adding an histamine H2-receptor antagonist at bedtime to once or twice daily delayed-release PPI, or using immediate-release omeprazole (Zegerid powder for oral suspension; Santarus, Inc., San Diego, CA, USA). This new formulation appears to provide sustained control of intragastric pH at steady state, and when dosed at bedtime, and may be effective in improving control of nocturnal pH and treating night-time GERD.

Histamine-2 receptor antagonists at night improve gastroesophageal reflux disease symptoms for patients on proton pump inhibitor therapy

While night-time symptoms of gastroesophageal reflux disease (GERD) are common, considerable controversy exists regarding the use of histamine-2 receptor antagonists (H2Ras) for night-time reflux control. Some studies have suggested possible tolerance to H2RA while others have suggested that long-term efficacy of gastric acid control can be maintained with night-time H2RA use. The aim of this study was to identify if GERD patients have sustained symptom improvement with long-term use of night-time H2RA. Records of 56 consecutive GERD patients on twice daily proton pump inhibitor (PPI) and night-time H2RA therapy were reviewed. During a phone interview patients were asked a 5-item questionnaire, which included overall assessment of symptoms, night-time symptoms, sleep disturbance, duration and frequency of therapy. Of the 56 patients, 39 (31 women, mean age 56) completed the questionnaire (15 were not reached and 2 did not recall enough information). All respondents had taken night-time H2RA for at least 1 month (28/39 patients with > 6 months duration) with 33/39 patients taking H2RAs every night. The addition of H2RA led to an improvement in overall symptoms in 28/39 (72%) patients, improvement in night-time reflux symptoms in 25/34 (74%) patients and improvement of GERD-associated sleep disturbance in 18/27 (67%) patients. Five (13%) patients had stopped the H2RA on their own, stating that its efficacy waned after 1 month. Our results suggest that the majority of patients report persistent improvement in GERD symptoms from night-time H2RA use and that possible clinically important tolerance to H2RAs occurs in a small number of patients. Further prospective, placebo-controlled studies may help confirm that there is a role for night-time H2RAs in GERD symptom control.

[Gastroesophageal reflux disease refractory to esomeprazole]

Resistance to proton pump inhibitors (PPI) in gastroesophageal reflux disease (GERD), which has been described in patients treated with omeprazole, could explain some exceptional cases of treatment failure and the need for surgery. The objective test of resistance to PPI is obtained with 24-hour intragastric pH-metry performed during treatment. A gastric pH of less than 4 for more than 50% of recording time indicates resistance. We present a patient with non-erosive GERD and treatment failure to omeprazole and proven resistance to esomeprazole which, to our knowledge, has only been reported in patients with Barrett's esophagus.

Clinical relevance of esophageal and gastric pH measurements in patients with gastro-esophageal reflux disease (GERD)

BACKGROUND

Gastro-esophageal reflux disease (GERD) is a highly prevalent disease caused by the exposure of the esophagus to refluxed gastric contents. Proton pump inhibitors (PPIs) are the mainstay of current treatment. At present, the assessment of the efficacy of different PPIs in the treatment of GERD employs two measures: esophageal and gastric pH monitoring. Esophageal pH monitoring is the most accurate method of detecting reflux episodes and, therefore, its role as a diagnostic modality is well accepted. Gastric pH monitoring, on the other hand, is an accurate measure of gastric acid pH, but its relevance to patients with GERD is questionable, since recordings correlate poorly with esophageal acid exposure.

OBJECTIVE

This paper reviews (based on a Medline literature search, 1980-2004) the clinical relevance of esophageal and gastric pH measurements in both the management of GERD and in the evaluation of the efficacy of PPI therapy.

FINDINGS AND CONCLUSIONS

Evidence presented suggests that the assessment of esophageal pH yields data of greater relevance to patients with GERD than does data from gastric pH. This largely arises from the fact that esophageal pH monitoring assesses the pH of the refluxate and the frequency of reflux episodes at the mucosal site affected by the disease. The use of esophageal pH monitoring is recommended in patients who fail to present with endoscopic evidence of esophagitis, those with extra-esophageal symptoms, those who have failed traditional anti-reflux therapies, and those who are potential candidates for anti-reflux surgery. In recent years, the technique has benefited from the development of a wireless pH probe, and there is also an increasing body of evidence supporting its use in combination with other emerging technologies, such as Bilitec monitoring and multichannel intraluminal impedance. Such an approach is anticipated to aid both the diagnosis of GERD and the characterization of gastro-esophageal reflux (GER) in these patients.

Therapeutic choices in reflux disease: defining the criteria for selecting a proton pump inhibitor

Gastroesophageal reflux disease (GERD) is among the most common disorders of the gastrointestinal tract, with symptoms affecting a substantial proportion of the US population on a daily basis. Heartburn and related symptoms arise from a number of pathophysiologic mechanisms, including dilated intercellular spaces, increased duration of acid reflux, greater proximal extent of reflux, and esophageal sensitivity. Chronic reflux may result in serious complications, such as esophageal erosions or ulceration, stricture, and Barrett esophagus. The goals of GERD therapy are to relieve patients' symptoms and prevent complications. Proton pump inhibitors (PPIs) represent the most effective treatment option for GERD, relieving symptoms, healing erosions, and maintaining a healed mucosa. Differences in the pharmacokinetics and pharmacodynamics among the PPIs may result in differences in intragastric pH holding time as well as the onset of symptom relief. Lansoprazole and esomeprazole produce similar degrees and onset of symptom relief, with both providing greater symptom relief as compared with omeprazole. Although manufactured as capsules containing enteric-coated granules, lansoprazole, omeprazole, and esomeprazole maintain their high level of pharmacologic efficacy when the capsule contents are emptied into soft foods or various liquids. Lansoprazole and pantoprazole also are manufactured as intravenous formulations, and lansoprazole is available as strawberry-flavored granules for oral suspension and as an orally disintegrating tablet. These alternative routes of administration are particularly beneficial in the management of acid-related disorders in infants, children, the elderly, and patients of all ages who have difficulty swallowing or are unable to swallow intact capsules or tablets and those in the critical care setting.

Effect of splitting the dose of esomeprazole on gastric acidity and nocturnal acid breakthrough

BACKGROUND

Twice-daily dosing is increasingly used to improve gastric acid control, although not all proton-pump inhibitors are more effective when doses are split. Standard dose esomeprazole provides better gastric acid control than other standard dose proton-pump inhibitors.

AIMS

To compare the effect of standard dose esomeprazole (1 x 40 mg) with 20 mg b.d. on gastric acidity.

METHODS

Thirteen healthy subjects participated in this crossover study, receiving esomeprazole 2 x 20 mg and 1 x 40 mg for 7 days in random order with a washout period of at least 7 days. Gastric 24-h pH was measured on days 1, 2 and 6.

RESULTS

Median gastric 24-h pH was higher during 2 x 20 mg esomeprazole on day 2 (P < 0.01), no differences were detected on day 6. Night-time gastric acid suppression was significantly improved by 2 x 20 mg esomeprazole on all study days (P < 0.05). Nocturnal acid breakthrough was observed on all study days in subjects receiving 1 x 40 mg, but in only 85% (first night), 64% (second night), and 45% of subjects (sixth night) with 2 x 20 mg (P < 0.05).

CONCLUSION

Splitting the esomeprazole dose improves initial acid suppression, this effect starts at the first night. Maximal benefit is achieved on day 2, while the effect on night-time acid control is detectable during the entire first week of treatment.

Medical management of patients with esophageal or supraesophageal gastroesophageal reflux disease

With the common use of proton pump inhibitors (PPIs), the medical treatment of gastroesophageal reflux disease (GERD) and its complications is now successful in relieving symptoms, healing esophagitis, and preventing complications. Physiologic factors that may contribute to a poor response to these drugs include the considerable variation in the bioavailability of PPIs, the need to take PPIs with meals, the influence of Helicobacter pylori-associated gastritis, and genetic variation in enzyme capacity, resulting in rapid and slow metabolizers of PPIs. Subsets of reflux patients, such as the elderly, pregnant women, and those with supraesophageal symptoms or Barrett esophagus, may have special treatment requirements. Medical treatment of GERD with PPIs has been demonstrated to equal the success of antireflux surgery in short- and long-term follow-up with reasonably few side effects. Furthermore, a good response to PPI therapy predicts a successful outcome with antireflux surgery.

The prophylactic use of a proton pump inhibitor before food and alcohol

BACKGROUND

Patients report that the prophylactic consumption of a proton pump inhibitor minimizes gastrointestinal symptoms expected to be provoked by late-night food and alcohol consumption. The efficacy of this practice has not been studied formally.

AIM

To perform a randomized, double-blind, placebo-controlled trial of a single dose of lansoprazole (30 mg) taken prior to a large meal and alcohol consumption.

METHODS

Study subjects were recruited randomly from local primary care and hospital physicians. Each participant (n = 56; 37 male, 19 female; mean age, 38 years) completed questionnaires before and after the meal. Approximately 90 min prior to the provocative meal, participants were witnessed taking either placebo or 30 mg lansoprazole. Bar tokens were dispensed to permit the accurate quantification of alcohol consumption (mean, 15 units).

RESULTS

Forty per cent of subjects reported significant reflux symptoms. For the entire group, there was no significant difference between lansoprazole and placebo. Post-prandial reflux was more frequent in those consuming > 15 units of alcohol (13/26, 50%) compared with those consuming < 15 units (7/30, 24%; P < 0.05). In the group who consumed > 15 units of alcohol, lansoprazole was associated with a lower rate of heartburn (5/15, 33%) compared with placebo (8/11, 73%; P < 0.05).

CONCLUSION

A single dose of a proton pump inhibitor prior to indulgence was only associated with reduced heartburn in those consuming > 15 units of alcohol.

Review article: gastric acidity--comparison of esomeprazole with other proton pump inhibitors

Gastric acid suppression is the most effective medical therapy to control acidic gastro-oesophageal reflux: individuals in whom therapy fails usually have inadequate acid suppression. Twenty-four-hour intragastric pH-metry measures the percentage of time that gastric pH is above 4 or 3, the critical thresholds for tissue damage and symptom generation in the distal oesophagus. Effective medical therapy must control gastric acidity throughout the daytime, including the postprandial period. It is therefore useful to report the percentage of patients in whom gastric acidity is controlled above pH 4 for at least 16 out of 24 h. Esomeprazole was compared with standard-dose proton pump inhibitors in healthy volunteers and patients with gastro-oesophageal reflux disease. Esomeprazole, 40 mg daily, was significantly more effective at controlling gastric acidity above pH 4 for more than 16 h than lansoprazole, 30 mg daily (38% of individuals vs. 5%, respectively). Esomeprazole, 40 mg daily, also suppressed gastric acidity more effectively and in more individuals than pantoprazole, 40 mg daily, and rabeprazole, 20 mg daily. Esomeprazole, 20 mg daily, was significantly more effective at controlling gastric acidity than lansoprazole, 15 mg daily. The improved acid control with esomeprazole compared with other proton pump inhibitors is likely to result in superior healing rates and improved symptom relief, with fewer therapy-resistant patients.

Persistent gastroesophageal reflux disease symptoms on standard proton-pump inhibitor therapy

Eight patients with refractory GERD symptoms were controlled over a mean of 15.4 years only by the addition of a benzodiazepine to once-daily or twice-daily PPI therapy. In selected patients with refractory GERD, as defined by continued reflux symptoms despite twice-daily PPIs, the addition of a benzodiazepine to the PPI regimen may provide additional control of GERD symptoms.

The pharmacology and clinical relevance of proton pump inhibitors

Gastroesophageal reflux disease is a complex, multifaceted disorder affecting a large proportion of the US population. Its management is based on the principle of optimal antisecretory therapy, mainly with proton pump inhibitors (PPIs). The optimal treatment outcome is complete symptom relief, which can be achieved with optimal use of PPIs. PPI treatment requires an understanding of the pharmacology of these agents as well as their clinical efficacy, strengths, and weaknesses. This paper reviews the pharmacology of PPIs, the principles of optimal dosing, nocturnal gastric acid breakthrough and its clinical importance, and a treatment approach to gastroesophageal reflux disease using these agents.

Managing gastroesophageal reflux disease

A common condition, gastroesophageal reflux disease (GERD) involves the reflux of gastric contents into the esophagus. GERD may contribute to asthma, noncardiac chest pain, and other problems. This article presents trends in GERD management, including pathophysiology, diagnosis, and treatment. The authors also explore lifestyle modifications, pharmacologic therapy, and gastroenterology referral.

Combination drug therapy for gastroesophageal reflux disease

OBJECTIVE

To evaluate the role of combination therapy with proton-pump inhibitors (PPIs) and histamine(2) receptor antagonists in gastroesophageal reflux disease (GERD).

DATA SOURCES

Clinical literature identified through MEDLINE (January 1966-August 2001). Key search terms included gastroesophageal reflux, benzimidazoles; omeprazole; lansoprazole; pantoprazole; rabeprazole; receptor antagonists, histamine(2); therapy, combination drug; therapy, combined modality; and combinations, drug.

DATA SYNTHESIS

Approximately 80-90% of patients show healing of reflux esophagitis after 8 weeks of once-daily PPI therapy. Patients taking PPI therapy twice daily still have nocturnal acid breakthrough (periods of gastric pH <4 lasting for > or =60 min during the night) as much as 70% of the time. The clinical application of this finding has not been shown. One trial has shown that omeprazole in the morning plus ranitidine at bedtime is not as effective as omeprazole twice daily given before the morning and evening meals at controlling nocturnal acid breakthrough. Further, 1 small trial in healthy subjects without GERD showed that the addition of a 1-time dose of ranitidine at bedtime to a twice-daily regimen of omeprazole may decrease the occurrence of nocturnal acid breakthrough. However, the clinical significance of this finding is not clear.

CONCLUSIONS

No studies in patients with GERD demonstrate that the addition of histamine(2) receptor antagonists to twice-daily PPI therapy provides any further benefit above that derived from PPIs alone. The parameter used to measure the efficacy of combination regimens for GERD thus far--nocturnal acid breakthrough--has not been proven to correlate with improvement of GERD symptoms in any controlled or prospective clinical trials. Further investigation is needed to determine optimal therapy in patients refractory to standard doses of PPIs.

Analysis on the causes for refractory GERD

To analyze the causes of failure in conventional treatment to refractory gastroesophageal reflux diseases (GERD) patients, 16 refractory GERD patients (group R) and 16 cases of GERD primarily diagnosed (group P) were studied. Endoscopy, pathologic examination and 14C urea breath test were conducted in every patient. 24 h ambulatory pH and bilirubin monitoring were performed with Digitrapper MK III and Synetics Bilitec 2000. It was found that esophagitis in group R was more severe than in group P. The rate of Helicobacter pylori infection in group R was significantly lower than in group P. Fraction time pH below 4.00 was not longer while the bile reflux represented by fraction time abs above 0.14 was greater for patients in the group R as compared with those in the group P. The mixed refluxes and pure bile refluxes between the two groups had significant difference. The reflux episodes in the group R mainly occurred during nights. These results indicated that severe esophagitis, especially Barrett's esophagus with complications makes it difficult to control GERD. Severe duodenogastroesophageal refluxes (DGER) are often accompanied by refractory GERD. Mixed refluxes aggravate the esophageal injuries. Pure bile refluxes and nocturnal refluxes may cause failure of administration of proton pump inhibitors (PPI) in the morning. Helicobacter pylori infection and acid refluxes may not be the direct cause of refractoriness. Individual refractory GERD patient without abnormal results on pH or bile reflux recently should be diagnosed again.

Bedtime H2 blockers improve nocturnal gastric acid control in GERD patients on proton pump inhibitors

AIM

Proton pump inhibitors taken twice daily before meals (proton pump inhibitor b.d. AC) effectively controls daytime gastric pH; however, nocturnal gastric acid breakthrough (NAB) occurs in more than 75% of patients. Adding an H2-blocker at bedtime decreases NAB in normal subjects. The efficacy of this regimen has not been evaluated in GERD patients. The aim of this study was to assess the effects of proton pump inhibitor b.d., both with and without bedtime H2-blocker on intragastric pH and the occurrence of NAB in GERD patients.

METHODS

Prolonged ambulatory pH studies in GERD patients were reviewed. Group A: 60 patients (mean age 53 years, male 30) taking either omeprazole 20 mg or lansoprazole 30 mg b.d. Group B: 45 patients (mean age 49 years, male 23) on proton pump inhibitor b.d. (omeprazole 20 mg or lansoprazole 30 mg) plus an H2-blocker at bedtime (ranitidine 300 mg, famotidine 40 mg or nizatidine 300 mg). Eleven patients were evaluated during treatment with both regimens (group C). The percentage time of nocturnal and daytime intragastric pH > 4 and per cent of patients with gastric NAB were analysed. In the patients with NAB, its duration and associated oesophageal acid exposure also were analysed.

RESULTS

Median percentage time intragastric pH > 4 overnight was 51% in group A, compared to 96% in group B (P < 0.0001). Median percentage daytime pH > 4 was 73% in group A and 79.8% in group B (P=0.14). Median percentage time intragastric pH >p 4 overnight increased from 54.6% without H2RA to 96.5% after adding bedtime H2RA (P=0.0013) in group C patients. NAB occurred in 82% patients in group A and 40% in group B (P < 0.0001). The mean duration of oesophageal acid exposure during NAB was significantly shorter in group B (18 +/- 6 min) than in group A (42 +/- 9 min, P=0.04).

SUMMARY

Adding a bedtime H2-blocker to the treatment enhanced nocturnal gastric pH control and decreased NAB compared to the proton pump inhibitor b.d. regimen. A bedtime H2-blocker also decreased oesophageal acid exposure during NAB.

CONCLUSION

Adding a bedtime H2-blocker to a proton pump inhibitor b.d. regimen should be considered in patients who require continued nocturnal gastric acid control whilst taking proton pump inhibitor b.d.

Lessons learned from intragastric pH monitoring

Management of gastroesophageal reflux disease (GERD) is based on the concept that gastric contents, principally acid and pepsin, are responsible for esophageal injury and symptoms of reflux disease. Pharmacologic management in the year 2001 revolves around the basic principle that control of intragastric pH correlates with esophageal healing and, subsequently, symptom relief. Although the majority of patients respond to a single daily dose of a proton pump inhibitor, many patients with reflux disease are "refractory" even to twice daily doses of these drugs. Potential reasons for this less than optimal response can be found when carefully examining the intragastric pH responses of healthy subjects and patients with GERD to these agents when taken at various times of the day, in proximity to meals, and in higher doses. In the past several years, we have explored many of these issues in attempting to understand the mechanisms behind incomplete response to proton pump inhibitors, using combined intragastric and intraesophageal pH monitoring. The "lessons learned" from these and supportive studies are the subject of this review.

Histamine receptor antagonists, proton pump inhibitors and their combination in the treatment of gastro-oesophageal reflux disease

The medical treatment of gastro-oesophageal reflux disease is accomplished with the appropriate use of anti-secretory therapy, principally H(2)-receptor antagonists and proton pump inhibitors. In fact, there is a direct correlation between the length of time, in terms of the number of hours per day that the intragastric pH is above 4, and the healing of the oesophagitis. Nowadays, H(2)-receptor antagonists are of limited use as primary treatment, being inferior to proton pump inhibitors in both healing and symptom relief. Although the majority of patients can be effectively managed with carefully titrated doses of proton pump inhibitors, a small number will continue to show difficulty in the management of their disease, principally because of inadequate nocturnal acid control. These patients may benefit from a combination of proton pump inhibitors twice daily with an H(2)-receptor antagonist at bedtime. This article reviews the use of H(2)-antagonists, proton pump inhibitors and their combination in the management of the patient with gastro-oesophageal reflux disease.

Practical approaches to dysphagia caused by Esophageal motor disorders

Dysphagia is a common symptom with which patients present. This review focuses primarily on the esophageal motor disorders that result in dysphagia. Following a brief description of the normal swallowing mechanisms and the messengers involved, more specific motor abnormalities are discussed. The importance of achalasia, as the only pathophysiologically defined esophageal motor disorder, is discussed in some detail, including recent developments in pathogenesis and treatment options. Other esophageal spastic disorders are described, with relevant manometric tracings included. In recent years, the importance of gastroesophageal reflux as a primary cause of esophageal dysmotility has been recognized, and this is also discussed. In addition, the motility disturbances that develop after surgical fundoplication are reviewed.

Proton pump inhibitors: better acid suppression when taken before a meal than without a meal

BACKGROUND

Proton pump inhibitors including omeprazole and lansoprazole inhibit gastric acid secretion by selectively and non-competitively inactivating the H+, K+ ATPase molecules of the parietal cell, but possibly only those that are actively secreting acid. This might imply that stimulation of acid secretion by a meal is necessary for optimal inhibition of gastric secretion.

AIM

To quantify and compare the effect on daytime gastric acidity of omeprazole 20 mg or lansoprazole 30 mg daily taken 15 min before breakfast, with that of the same drug taken without a meal.

METHODS

Twenty-one healthy volunteers were randomized to receive either omeprazole or lansoprazole. They were given the drug for two separate periods of 7 days in randomized order and at least 7 days apart. During one period the study medication was taken before breakfast; during the other it was taken at the same hour, but with no meal until 12:00 hours. Lunch was standardized. On day 7, intragastric pH-metry was performed, starting at 08:00 hours. Tracings were analysed for the 8-h period from 08:00 hours until 16:00 hours with regard to percentage time for which gastric pH was below 4.0 and 3.0, and median gastric pH. Tracings were also analysed after removing the 1 h breakfast period, to exclude the buffering effect of the meal.

RESULTS

When taking the drug with breakfast, the median percentage time for which gastric pH < 4.0 was 17.2 (interquartile range 4.6-45.5), compared with 42.0 (interquartile range 31.4-48.8) when taken without food (P=0.01). Fifteen subjects had better control of gastric acidity when the medication was taken with breakfast. A pH threshold of 3 and median pH showed similar differences. When the breakfast period was removed, the differences were no longer statistically significant.

CONCLUSIONS

When therapy with omeprazole or lansoprazole is indicated, medication should be taken before a meal for optimal control of daytime gastric acidity.

Gastric acidity and acid breakthrough with twice-daily omeprazole or lansoprazole

BACKGROUND

In patients with severe gastro-oesophageal reflux disease (GERD), proton pump inhibitors are being used increasingly in twice-daily regimens to improve control of gastric acidity. Few data exist to compare the ability of the most-often used proton pump inhibitors, omeprazole and lansoprazole, to control gastric acid at twice-daily dosage regimens. Nocturnal acid breakthrough, defined as gastric pH < 4.0 continuously for > 60 min, may compromise treatment goals in patients with GERD.

AIM

To compare the effects of omeprazole 20 mg b.d. or lansoprazole 30 mg b.d. on gastric acidity and the relative ability of each dosage regimen to prevent acid breakthrough.

METHODS

In a crossover pharmacodynamic study, 20 healthy volunteers (10 male, 10 female, mean age 38 years) were given omeprazole 20 mg b.d. or lansoprazole 30 mg b.d. for 7 days each, in a randomized manner. Each dosage regimen was separated by a minimum 7-day period where no medication was administered. On day 7 of each regimen, 24-h intragastric pH-metry was performed. The percentage of time for which gastric pH was below 4.0 and 3.0, the occurrence of daytime and nocturnal acid breakthrough, and the duration of action of each regimen were compared. Non-parametric statistics for paired data were used.

RESULTS

The percentage time for which gastric pH was below 4.0 was significantly lower with omeprazole 20 mg b.d. (median 14.8%) than with lansoprazole 30 mg b. d. (median 24.2; P=0.0372). Fourteen subjects showed more effective acid control when taking omeprazole; these were significantly more often H. pylori-negative patients compared with those for whom acid control was better on lansoprazole (P < 0.001). Nocturnal acid breakthrough occurred in seven patients (35%) on omeprazole and in 10 (50%) on lansoprazole (N.S.).

CONCLUSION

In healthy volunteers, twice-daily dosing of omeprazole 20 mg b.d. appears to be significantly more effective than lansoprazole 30 mg b.d. in controlling gastric acidity. The clinical importance of such a difference remains to be defined in GERD patients.