Influence of food on the bioavailability of an enteric-coated tablet formulation of omeprazole 20 mg under repeated dose conditions

Effect of Food and Dosing Regimen on Safety and Efficacy of Proton Pump Inhibitors Therapy-A Literature Review

Proton pump inhibitors (PPIs) are the first-choice drugs used to prevent and treat acid-related diseases. However, a lack of satisfactory response to the standard PPI dose ("PPI failure") is often reported, especially in patients with gastroesophageal reflux disease. Poor compliance seems to be one of the main causes of PPI failure; hence, it is crucial to gain knowledge on how to properly administer PPIs. In this review, we aimed to evaluate the effect of food, beverages, and dosing regimen on pharmacokinetics and pharmacodynamics of PPIs and to frame recommendations for healthcare professionals to improve both patient's counseling and compliance to treatment with PPIs. A total of 201 papers were identified following a literature search. After full-text evaluation, 64 studies were included in the review. Co-administration of PPIs with a meal may affect both their bioavailability and effectiveness; however, the influence of food depends on the type of drug and its formulation. Except for pantoprazole, PPIs can be administered in the morning or evening; however, morning intake generally provides better daytime control of gastric acidity. In most cases, the choice of the proper schedule of administration should be based on the patient's symptoms and individual dosing preferences.

The role of the pharmacist in the selection and use of over-the-counter proton-pump inhibitors

Background Heartburn and other symptoms of gastro-oesophageal reflux occur in ~30 % of survey respondents in multiple countries worldwide. Heartburn and acid regurgitation are common complaints in the pharmacy, where patients frequently seek relief through medication and advice. The growing number of proton-pump inhibitors available in the over-the-counter setting provides an efficacious choice to patients experiencing frequent heartburn. Pharmacists can assist patients in their treatment decisions whilst inquiring about alarm symptoms that should prompt a physician referral. Aim of the review Provide pharmacists with a review of current clinical research and expert guidelines on use of over-the-counter proton-pump inhibitors. Methods This narrative review was conducted to identify publications relevant to the following themes: overview of available treatments for frequent episodes of heartburn/acid regurgitation; treatment algorithms providing guidance on when to use over-the-counter proton-pump inhibitors; and the role of the pharmacist in the use of over-the-counter proton-pump inhibitors. Results Frequent symptoms of acid reflux, such as heartburn and acid regurgitation, can interfere substantially with daily life activities. Proton-pump inhibitors are the most efficacious treatment for frequent reflux symptoms and are recommended as an appropriate initial treatment in uncomplicated cases. Proton-pump inhibitors have varying pharmacokinetics and pharmacodynamics across the class; 20 mg esomeprazole has higher bioavailability and exposure than over-the-counter omeprazole, for example. However, differences in clinical efficacy for symptom relief have not been demonstrated. The safety and tolerability of proton-pump inhibitors have been well established in clinical trial and post-marketing settings, and use of a short regimen is associated with a very low likelihood of missing a more serious condition. Pharmacists can assist patients with accurate self-diagnosis by asking short, simple questions to characterize the nature, severity, and frequency of symptoms. Additionally, pharmacists can inquire about alarm symptoms that should prompt referral to a physician. Pharmacists should inform those patients for whom over-the-counter proton-pump inhibitors are appropriate on their proper use. Conclusion Over-the-counter proton-pump inhibitors have a valuable role in the treatment of frequent heartburn. Pharmacists have the opportunity to guide patients through selection of the best treatment option for their symptoms.

Indirect evidence for proton pump inhibitor failure in patients taking them independent of meals

PURPOSE

We investigated the association between conditions of proton pump inhibitor (PPI) treatment failure and food intake in an elderly ambulatory population.

METHODS

Our data originate from a large population-based cohort study. During a home visit done by a trained study physician, patients were asked for each medication to state whether it was taken in relation to a meal (before, concurrently with, and after) or independent of a meal. This information was analyzed for all patients taking a PPI daily and correlated to markers of PPI failure.

RESULTS

Out of 2717 patients participating in a home visit and taking at least one medication, 383 took a PPI daily (14.1%). A PPI intake independent of meals was defined as incorrect and was observed in 64 patients, whereas 319 patients took their PPI in relation to a meal, which was defined as the correct intake. Treatment failure was observed in 10 out of 64 (15.6%) PPI users with incorrect intake and in 18 out of 319 (5.6%) PPI users with correct intake. The risk of treatment failure was threefold higher in patients taking their PPI independent of meals (OR 3.35; 95%CI 1.44-7.76).

CONCLUSION

The higher risk for PPI failure in patients taking PPIs independent of meals suggests that synchronized PPI administration with meals is indeed essential, and better counseling of patients is needed.

Proton pump inhibitor formulary considerations in the acutely ill. Part 1: Pharmacology, pharmacodynamics, and available formulations

OBJECTIVE

To review important proton pump inhibitor (PPI) pharmacologic, pharmacokinetic, and pharmacodynamic principles in acutely ill patients, compare PPI formulation options for patients unable to swallow a tablet or capsule, and provide clinicians with guidance when making hospital formulary decisions with this class of agents.

DATA SOURCES

MEDLINE (1966-May 2005) and the Cochrane Library databases were searched using the key words proton pump inhibitor, acid suppression, peptic ulcer disease, gastrointestinal bleeding, stress ulcer prophylaxis, and critical illness. Bibliographies of cited references were reviewed, and a manual search of abstracts from recent gastroenterology, critical care, and surgery scientific meetings was completed.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the data sources were evaluated, and all information deemed relevant was included for this review.

DATA SYNTHESIS

PPIs have become a mainstay for acute acid suppression in hospitalized patients over other therapeutic options. Various commercially available PPI products are available for administration, either enterally or parenterally, to patients unable to swallow a tablet or capsule. Newer oral PPI formulations offer numerous advantages over older products. The results of studies comparing the pharmacokinetics and pharmacodynamics of different PPI dosage forms and routes of administration are among the factors to consider when making formulary decisions.

CONCLUSIONS

While the introduction of new PPI products has expanded the therapeutic options for acid suppression in acutely ill patients, a number of unresolved questions remain surrounding the interchangeability of these products, the clinical significance of one PPI formulation over the other, and how oral/enteral PPI therapy should be used as step-down therapy after parenteral PPI therapy.

Overview of pharmacologic agents for acid suppression in critically ill patients

PURPOSE

The physiology of acid secretion, rationale and goals for acid suppression in critically ill patients, and mechanism of action, pharmacokinetics, pharmacodynamics, and safety of histamine H2-receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) are discussed.

SUMMARY

Acid-suppressant therapy may be used in critically ill patients to prevent stress-related mucosal disease or the recurrence of peptic ulcer bleeding. The intragastric pH goal is 3.5-4.5 and 6 or higher, respectively. H2RAs block only one of three pathways in acid secretion and provide less potent acid suppression than PPIs, which block the final common pathway in acid secretion. In addition, tolerance that occurs with H2RAs does not occur with PPIs. All PPIs work in a similar manner, but differences exist in the pharmacokinetic profiles and binding to the proton pump; the clinical relevance of these differences remains debated. The safety profiles of H2RAs and PPIs are similar; however, the H2RA dose, but not the PPI dose, must be adjusted for patients with renal dysfunction. The risk of drug interactions mediated by cytochrome P-450 enzymes is lower with PPIs than with cimetidine, an H2RA. Several new PPI dosage forms have been introduced, facilitating drug administration in the critical care setting.

CONCLUSION

Both H2RAs and PPIs are safe agents to use for providing acid suppression in critically ill patients, but PPIs offer several potential advantages over H2RAs.

What the physician needs to know for correct management of gastro-oesophageal reflux disease and dyspepsia

Upper gastrointestinal symptoms are highly prevalent; usually those consulting have multiple symptoms, confounding management. Here, common clinically relevant management issues are considered based on the best available evidence. Regardless of the presenting symptoms, determine if there are any alarm features; these have a low positive predictive value for malignancy but all patients with them should be referred for prompt upper gastrointestinal endoscopy. Ask about medications; of most importance are the non-steroidal anti-inflammatory drugs (NSAIDs), both non-selective and COX-2 selective. Try to ascertain if the symptom pattern suggests gastro-oesophageal reflux disease (GERD) or not. Dominant heartburn, however, may be of limited value; if the background prevalence of GERD is 25% and the patient complains of dominant heartburn, then the likelihood that such a patient has GERD as identified by 24-h oesophageal pH testing is only just over 50%. If reflux disease is strongly suspected and there are no alarm features, give an empirical trial of a proton pump inhibitor (PPI). Symptoms cannot separate adequately functional from organic dyspepsia. Endoscopy in dyspepsia with no alarm features is more costly than an empirical management approach. H. pylori testing and treatment remains in most settings the preferable initial choice for managing dyspepsia without obvious GERD. However, a PPI trial may offer a similar outcome and may be preferable in low H. pylori prevalence areas; head-to-head management trials in primary care are lacking.

Pharmacologic features of proton pump inhibitors and their potential relevance to clinical practice

In conclusion, PPIs differ slightly in their PK and PD properties and in their propensity to interact with other medications. Inhibition of acid secretion is a function of proton pump inhibition, and PPIs work in a similar fashion to achieve this goal. PK/PD principles can be used to optimize PPI therapy when considering issues related to administration, such as timing of drug delivery relative to the number of active pumps and the drug's AUC.

The use of proton pump inhibitors in children: a comprehensive review

Proton pump inhibitors (PPIs) belong to a group of chemically related compounds whose primary function is the inhibition of acid production in the final common metabolic pathway of gastric parietal cells. PPIs are highly selective and effective in their action and have few short- or long-term adverse effects. These pharmacologic features have made the development of PPIs the most significant advancement in the management of acid peptic related disorders in the last two decades. There are numerous published adult studies that describe the pharmacology, efficacy and safety of these anti-secretory agents; however, in the pediatric population, there are very few comparable studies, particularly multicenter studies with significant patient enrollment. In preparing this article, our aim was to perform a comprehensive review of the literature on the clinical pharmacology and use of PPIs in the pediatric population, and to briefly review some recent articles. Relevant literature was identified by performing MEDLINE/Pubmed searches from January 1990 to December 2001. Combinations of the following search terms were use to analyze these databases: proton pump inhibitor, children, pediatrics, gastroesophageal reflux disease (GERD), esophagitis, intestinal metaplasia, Helicobacter pylori, omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, and safety. Abstracts from the 14th annual conference of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) 2001, and the Disease and Digestive Week 2001, were also included in the review. All pediatric studies reviewed were limited to either omeprazole or lansoprazole. The dosage range used for the management of GERD and related disorders with lansoprazole was 0.73-1.66 mg/kg/day (maximum 30 mg/day). The dosage range for GERD management using omeprazole was 0.3-3.5 mg/kg (maximum 80 mg/day). The dosage range for omeprazole used for H. pylori was 0.5-1.5 mg/kg/day, with a maximum dosage of 40 mg/day, and lansoprazole-containing regimens for H. pylori eradication used dosages ranging from 0.6-1.2 mg/kg/day, with a maximum dosage of 30 mg/day. Few severe adverse events were reported with the use of either drug. Eradication rates for H. pylori were 56-87% for lansoprazole-based triple therapy, and 75-94% for omeprazole-based eradication regimens. To date, there are no published controlled trials of sufficient power comparing the efficacy of the five commercially available PPIs in children, for a variety of acid peptic diseases. Studies suggest that PPIs are highly effective for the management of GERD and related disorders, and are a critically needed component of triple therapy to eradicate H. pylori. PPIs have a very good tolerability profile in adults and children, but long-term tolerability studies are needed, particularly in the pediatric population. Multicenter studies are critically needed to evaluate the second-generation PPIs, to compare PPI efficacy to each other, and to assess the importance of developmental and genetic pharmacology of these drugs in children with acid-peptic disease.

Acid inhibitory potency of twice a day omeprazole is not affected by eradication of Helicobacter pylori in healthy volunteers

BACKGROUND AND AIMS

The acid inhibitory effect of proton pump inhibitors is reported to be greater in the presence than in the absence of an H. pylori infection. This study was undertaken to test the hypothesis that the acid inhibitory effect of omeprazole given twice a day is greater in H. pylori infected healthy volunteers than in the same individuals following eradication because of differences in the pharmacodynamics of omeprazole, greater duodenogastric reflux, the effects of ammonia produced by the H. pylori, or lower gastric juice concentrations of selected cytokines, which may inhibit gastric acid secretion.

MATERIALS AND METHODS

We undertook 24-hour pH-metry in 12 H. pylori-positive healthy volunteers: (1) when on no omeprazole; (2) when on omeprazole 20 mg bid for 8 days; (3) 2 months after eradication of H. pylori and when on no omeprazole; and (4) after eradication of H. pylori and when on omeprazole 20 mg twice a day.

RESULTS

In subjects given omeprazole, eradication of H. pylori reduced pH and percentage pH >or= 3, as well as increasing the area under the H+ concentration-time curve. These differences were not due to alterations in (1) gastric juice concentrations of IL-1alpha, IL-8, IL-13, epidermal growth factor, or bile acids; (2) serum gastrin concentrations; or (3) the pharmacokinetics of omeprazole. There was no change in the difference in the H+ concentration-time curve 'without omeprazole' minus 'with omeprazole', when comparing 'after' versus 'before' eradication of H. pylori.

CONCLUSIONS

Eradication of H. pylori was not associated with an alteration in the acid inhibitory potency when comparing the difference in gastric acidity 'with' versus 'without' omeprazole. When the results were expressed by simply taking into account the acid measurements while on omeprazole before versus after eradication of H. pylori, the acid inhibition with omeprazole was greater in the presence than in the absence of a H. pylori infection. The clinical significance of the small difference is not clear.