Systematic review: impaired drug absorption related to the co-administration of antisecretory therapy

Appropriateness of Proton Pump Inhibitor (PPI) prescription in patients admitted to hospital: Attitudes of general practitioners and hospital physicians in Italy

INTRODUCTION

Proton pump inhibitor (PPI) prescriptions have raised concern for both huge increase of health expenditure and possible long-term adverse effects.

OBJECTIVE

To evaluate appropriateness of PPI prescription in ambulatory and hospital care.

DESIGN

Observational cohort study.

PATIENTS

Patients admitted to the Internal Medicine Unit of Bologna S. Orsola Hospital between 15/09/2013 and 15/12/2013. Data on clinical condition and drug therapy were collected at three time points: admission (reflecting GP's prescription), hospital stay and discharge.

MAIN MEASURES

Appropriateness of PPI use was evaluated as follows: (1) agreement between PPI use/non-use and appropriate clinical condition; (2) in PPI users, assessment of Medication Appropriateness Index (MAI). Differences in appropriateness among time points were analyzed by chi-square test. Logistic regression model was used to identify possible determinants of PPI appropriateness.

KEY RESULTS

Among 280 patients, 56% received PPI at least once in the three time points. Appropriateness, according to indication of use, was similar between admission and hospital stay (61% vs. 62%; p=0.82) and between hospital stay and discharge (62% vs. 59%; p=0.94). MAI score showed important, although statistically non-significant, change in appropriateness between admission and hospital stay (20% vs. 28%; p=0.16). Age≥65 was always associated with appropriate PPI use (up to OR=4.37; p<0.01), whereas cardiovascular comorbidity and conditions requiring analgesic treatment influenced appropriateness only at admission (OR=3.84; p<0.01 and OR=0.34; p<0.01, respectively).

CONCLUSIONS

Hospital clinicians only rarely reconsidered GP's choice to prescribe PPI. Room for improvement in PPI appropriateness is represented by (1) assessing gastrointestinal risk in each patient under analgesics and anti-inflammatory drugs, and (2) short-term re-evaluation of PPI prescription after discharge.

Drug–Drug Interactions: Regulatory and Theoretical Considerations, and an Industry Perspective

In this review, a number of theoretical bases and regulatory framework are presented for drug–drug interactions (DDIs), with emphasis on those related to absorption and distribution. Also presented is an industry perspective on how to approach these issues in support of drug development. Overall, holistic integration and understanding of the pharmaceutical (e.g., pH-dependent solubility) and pharmacological (e.g., gastrointestinal physiology and therapeutic margin) profiles, as well as pharmacokinetics and underlying absorption and disposition determinants (e.g., clearance, volume of distribution, permeability and protein binding) of drug candidates in various clinical setting should be considered as this can be valuable in ensuring the safe and effective use of new drugs.

Pharmacokinetic considerations for drugs administered in the critically ill

Significant physiological changes are common among critically ill patients. This case-based review describes the consequences of these changes on the selection and dosing of medications.

Proton pump inhibitors therapy vs H2 receptor antagonists therapy for upper gastrointestinal bleeding after endoscopy: A meta-analysis

AIM: To compare the therapeutic effects of proton pump inhibitors vs H₂ receptor antagonists for upper gastrointestinal bleeding in patients after successful endoscopy.

METHODS: We searched the Cochrane library, MEDLINE, EMBASE and PubMed for randomized controlled trials until July 2014 for this study. The risk of bias was evaluated by the Cochrane Collaboration’s tool and all of the studies had acceptable quality. The main outcomes included mortality, re-bleeding, received surgery rate, blood transfusion units and hospital stay time. These outcomes were estimated using odds ratios (OR) and mean difference with 95% confidence interval (CI). RevMan 5.3.3 software and Stata 12.0 software were used for data analyses.

RESULTS: Ten randomized controlled trials involving 1283 patients were included in this review; 678 subjects were in the proton pump inhibitors (PPI) group and the remaining 605 subjects were in the H₂ receptor antagonists (H₂RA) group. The meta-analysis results revealed that after successful endoscopic therapy, compared with H₂RA, PPI therapy had statistically significantly decreased the recurrent bleeding rate (OR = 0.36; 95%CI: 0.25-0.51) and receiving surgery rate (OR = 0.29; 95%CI: 0.09-0.96). There were no statistically significant differences in mortality (OR = 0.46; 95%CI: 0.17-1.23). However, significant heterogeneity was present in both the numbers of patients requiring blood transfusion after treatment [weighted mean difference (WMD), -0.70 unit; 95%CI: -1.64 - 0.25] and the time that patients remained hospitalized [WMD, -0.77 d; 95%CI: -1.87 - 0.34]. The Begg’s test (P = 0.283) and Egger’s test (P = 0.339) demonstrated that there was no publication bias in our meta-analysis.

CONCLUSION: In patients with upper gastrointestinal bleeding after successful endoscopic therapy, compared with H₂RA, PPI may be a more effective therapy.

Appropriate prescribing and important drug interactions in older adults

Polypharmacy, specifically the overuse and misuse of medications, is associated with adverse health events, increased disability, hospitalizations, and mortality. Mechanisms through which polypharmacy may increase adverse health outcomes include decreased adherence, increased drug side effects, higher use of potentially inappropriate medications, and more frequent drug-drug interactions. This article reviews clinical problems associated with polypharmacy and presents a framework to optimize prescribing for older adults.

Pharmacokinetic evaluation of esomeprazole for the treatment of gastroesophageal reflux disease

INTRODUCTION

Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related diseases such as gastroesophageal reflux disease (GERD). They are recommended by the American College of Gastroenterology for healing erosive esophagitis (EO) and as long-term treatment in patients with healed EO. The available PPIs differ somewhat in their pharmacokinetics and clinical properties, but whether these differences are of clinical relevance is a matter of debate. Some safety concerns have been raised with the use of PPIs, mostly an increased incidence of infectious diseases such as community-acquired pneumonia or Clostridium difficile diarrhea.

AREAS COVERED

This article explores the results of clinical studies on the pharmacokinetics and pharmacodynamics of esomeprazole , as well as on its clinical efficacy to manage patients with GERD.

EXPERT OPINION

GERD is a public health concern as its worldwide incidence and associated complications are increasing alongside the exponentially increasing problem of obesity. PPIs are the first pharmacological option because of their efficacy and overall positive risk-to-benefit ratio. Improved efficacy with the use of stereospecific isomers of PPIs, such as esomeprazole, has not yet been convincingly demonstrated. Nevertheless, because of individual experience with former treatment, some patients may report better symptom control when treated with a specific PPI rather than with others.

Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms?

Recent research has established that many children and adult diagnosed with autism experience gastrointestinal symptoms. Furthermore, research has demonstrated that gastrointestinal symptoms can impact drug availability and absorption. In this paper we explore the presence of gastrointestinal symptoms in autism and put forth a call for a formal evaluation of the potential relationship between gastrointestinal symptoms and psychotropic medication effectiveness in individuals with autism.

Proton pump inhibitor therapy and potential long-term harm

PURPOSE OF REVIEW

This review summarizes the recent literature on the potential side-effects of proton pump inhibitors (PPIs) and known interactions with the metabolism/absorption of other drugs.

RECENT FINDINGS

Data confirm that PPIs are a very well tolerated drug class. Their high safety, efficacy and wide distribution lead to overuse, inappropriate dosage or excessive duration of treatment. Despite the absorption of micronutrients or other plausible effects on the development of bacterial infections linked to PPI-induced hypochlorhydria, it is difficult to demonstrate an association between PPI and specific symptoms. A possible negative effect of PPIs on bone integrity appears weak, but hypomagnesemia is likely a PPI drug class effect. A higher risk of Clostridium difficile infection and other infectious diseases such as small intestinal bacterial overgrowth and spontaneous bacterial peritonitis remain controversial in PPI users. However, the careful use of PPIs in cirrhotic or otherwise fragile patients is mandatory. Short-term or long-term PPI use may trigger microscopic colitis, and the management of this condition may include PPI withdrawal. The effect of PPIs on stimulating exocrine or endocrine gastric cell proliferation is poorly understood. A diagnostic delay or masking of diseases such as gastrinoma is difficult to evaluate.

SUMMARY

Short-term standard dose PPI treatment is low risk. Long-term PPI use may complicate health conditions by various mechanisms linked to PPIs and/or to hypochlorhydria.

Mechanistic understanding of the effect of PPIs and acidic carbonated beverages on the oral absorption of itraconazole based on absorption modeling with appropriate in vitro data

Proton pump inhibitors (PPIs) are potent gastric acid suppressing agents and are among the most widely sold drugs in the world. However, even though these antisecretory agents are regarded as safe, they can alter the pharmacokinetics of coadministered drugs. Due to the suppression of gastric acid secretion, they can significantly alter the intragastric pH conditions and are thus likely to affect the bioavailability of coadministered drugs requiring an acidic gastric environment for dissolution and subsequent absorption. Among these drugs can be found itraconazole, a poorly soluble triazole-type antifungal compound. Based on observations reported in the literature, gastric pH alterations due to the coadministration of PPIs or acidic beverages can significantly decrease (PPI) or increase (e.g., Coca-Cola) the bioavailability of this compound. In the present work we estimated the fraction of itraconazole that can be absorbed (fabs) from Sporanox capsules or an itraconazole-HBenBCD complex formulation after oral administration with and without coadministration of a PPI or an acidic (carbonated) beverage. For this purpose, the sensitivity of the two formulations toward the impact of various gastric variations (pH, volume, and emptying rate) as they can result from such administration conditions was studied using solubility and dissolution experiments and a physiologically based absorption model. Simulating coadministration of the two formulations with a PPI resulted in a significant (∼ 10-fold) decrease in itraconazole fabs, indicating the pH to be essential for in vivo dissolution and subsequent absorption. The fabs of itraconazole after coadministration of an acidic beverage (Coca-Cola) was far lower than the fabs obtained for itraconazole alone and did not support the observations reported in the literature. These results clearly indicate that in contrast to PPIs, which seem to affect itraconazole bioavailability mainly via intragastric pH changes, coadministered Coca-Cola is likely to alter a range of gastrointestinal parameters relevant to in vivo dissolution rather than solely affecting the intragastric pH.

Drug absorption, distribution, metabolism and excretion considerations in critically ill adults

INTRODUCTION

All critically ill patients require medication to treat organ dysfunction. However, the pharmacokinetics of drugs used to treat these patients is complex due to frequent alterations in drug absorption, distribution, metabolism, and excretion (ADME).

AREAS COVERED

This review examines pharmacokinetic aspects of drug administration for adult intensive care unit (ICU) patients. Specifically, the authors examine the ADME changes that occur and which should be considered by clinicians when delivering drug therapy to critically ill patients.

EXPERT OPINION

Dosage pharmacokinetics determined from single-dose or limited-duration administration studies in healthy volunteers may not apply to critically ill patients. Organ dysfunction among these patients may be due to pre-existing disease or the effects of a systemic or locoregional inflammatory response precipitated by their illness. Alterations in pharmacokinetics observed among the critically ill include altered bioavailability after enteral administration, increased volume of distribution and blood-brain barrier permeability and changes in P-glycoprotein and cytochrome P450 enzyme function. However, the effect of these changes on clinically important outcomes remains uncertain and poorly studied. Future investigations should examine not only pharmacokinetic changes among the critically ill, but also whether recognition of these changes and alterations in drug therapy directed as a consequence of their observation alters patient outcomes.

Pharmacokinetics and pharmacodynamics of the antiplatelet combination aspirin (acetylsalicylic acid) plus extended-release dipyridamole are not altered by coadministration with the potent CYP2C19 inhibitor omeprazole

BACKGROUND

The fixed-dose combination of aspirin (acetylsalicylic acid) 25 mg plus extended-release dipyridamole 200 mg (ASA+ER-DP) is used for long-term secondary stroke prevention in patients who have experienced non-cardioembolic stroke or transient ischemic attack. Although the theoretical risk is low that the antiplatelet activity of ASA+ER-DP will be affected by concomitant use of a proton pump inhibitor (PPI), no formal drug-drug interaction studies have been conducted.

OBJECTIVE

This study aimed to determine whether the PPI omeprazole influences the pharmacokinetic (PK) and pharmacodynamic (PD) behavior of ASA+ER-DP.

STUDY DESIGN AND SETTING

This was a randomized, open-label, multiple-dose, crossover, drug-drug interaction study carried out in a clinical trial unit.

PARTICIPANTS

Sixty healthy male and female volunteers aged 18-50 years were included in the study.

INTERVENTION

Participants were randomized to one of two treatment sequences (ABCD or CDAB), each comprising four 7-day treatments with a washout of ≥14 days between the second and third treatments. Treatment A=ASA+ER-DP 25 mg/200 mg (Aggrenox®) twice daily (BID) alone; B=ASA+ER-DP 25 mg/200 mg BID+omeprazole (Prilosec®) 80 mg once daily (QD) following ASA+ER-DP alone for 7 days; C=omeprazole 80 mg QD alone; D=omeprazole 80 mg QD+ASA+ER-DP 25 mg/200 mg BID following omeprazole alone for 7 days.

MAIN OUTCOME MEASURES

The main outcome measures were systemic PK exposure to ER-DP and ASA inhibition of arachidonic acid-induced platelet aggregation.

RESULTS

Systemic exposure to ER-DP was similar with and without omeprazole, based on steady-state area under the concentration-time curve (AUC) from 0 to 12 h (AUC0-12,ss, ng·h/mL) and maximum plasma concentration (Cmax,ss, ng/mL). For the treatment comparison D versus A, the percent mean ratios were 96.38 (90% confidence interval [CI] 90.96-102.13) for AUC0-12,ss and 92.03 (86.95-97.40) for Cmax,ss. The ER-DP concentration versus time profiles were nearly superimposable. There was no effect on the PDs of the ASA component: the extent of ASA inhibition of arachidonic acid-induced platelet aggregation was almost identical with and without omeprazole, with a percent mean ratio for treatment D versus A = 99.02 (90 % CI 98.32-99.72) at 4 h after last dose. All treatments were well tolerated.

CONCLUSION

The PK and PD behavior of ASA + ER-DP was not altered by concurrent administration of omeprazole.

Considerations for the use of proton-pump inhibitors in older adults

OBJECTIVE

To investigate current concerns regarding the use of proton-pump inhibitors (PPIs) in older adults.

DATA SOURCES

A literature search was conducted in MEDLINE (1948 to April week 3 2011) to identify relevant publications. Key words searched included proton-pump inhibitor, safety, adverse events, elderly, and older adults. Additional data sources were obtained through a bibliographic review of selected articles.

DATA SELECTION

Relevant studies conducted in older adults published in English that examined risks associated with the use of PPIs were included in this review.

DATA SYNTHESIS

The older adult population in the United States is growing at an astounding rate. With the increase in age, there are many factors that make the elderly susceptible to acid-related gastrointestinal disorders that require treatment with PPIs. However, PPI use in the elderly has been shown to lead to a number of health concerns. Recent data have shown that PPI use is associated with an increased risk of fractures, Clostridium difficile infection, community-acquired pneumonia, vitamin and mineral deficiencies, and drug interactions. These concerns will be further investigated and weighed against the benefits of PPI use in this population.

CONCLUSIONS

Patient-specific characteristics must be taken into consideration when recommending and/or prescribing PPIs to older adults.

Using absorption simulation and gastric pH modulated dog model for formulation development to overcome achlorhydria effect

Impaired absorption of weakly basic drugs in patients with reduced gastric acidity can lead to loss of efficacy of the therapeutic agent. Hence, a robust formulation which can provide adequate exposure in achlorhydric patients is imperative to achieve the desired efficacy. In this report, formulation development of a weakly basic Merck compound A is described. Compound A shows lower solubility at higher pH and thus is prone to reduced exposure under conditions of achlorhydria, as the compound's solubility increases only in environments of less than pH 2. Several formulations with or without an acidifier were developed and characterized by in vitro dissolution and in gastric pH modified dog model to assess their bioperformance in high gastric pH conditions. To predict the bioperformance of these formulations in humans, a dissolution based absorption model was developed and validated against the observed PPI-interaction data in the clinic and the gastric pH-adjusted dog data. An additional absorption model was developed to allow for incorporation of the dog PK data to provide translation of preclinical to clinical exposure. Based on the in vitro dissolution, in silico absorption modeling and preclinical in vivo data, a citric acid-based formulation (F2) was selected for a human pharmacokinetic study. This study showed that exposures from F2 were not meaningfully different in the presence of proton pump inhibitor (PPI) as compared to non-PPI, thus confirming that the F2 formulation was successful in overcoming the achlorhydria effect. These efforts also highlighted that the complementary use of in vitro/in silico/in vivo (IVISIV) tools may be a helpful strategy in the development of formulations to overcome the achlorhydria effect and achieve adequate exposure in patients with high gastric pH.

Serum level of pepsinogen significantly associated with gastric distress induced by amino-bisphosphonates

To elucidate whether serum levels of pepsinogens are associated with the occurrence of gastrointestinal adverse events induced by amino-bisphosphonates (amino-BP), the serum levels of pepsinogen were measured in amino-BP users. Our results indicate that measurement of pepsinogen I is useful in predicting gastric distress induced by amino-BP in osteoporosis.

INTRODUCTION

To elucidate whether serum levels of pepsinogens are associated with the occurrence of gastrointestinal adverse events induced by amino-BP, the serum levels of pepsinogen I and II were measured in amino-BP users.

METHODS

When the patients complained of gastric distress symptoms during the first 6 months after amino-BP use resulting in discontinuation of the drug, endoscopical examinations were performed to assess whether gastric lesions were present. A total of 223 amino-BP users were enrolled in the study, of which 47 patients refused to take the drug due to gastric distress symptoms. The remaining 176 patients did not complain of any gastric distress.

RESULTS

Among 47 patients, eight patients showed obvious gastric lesions such as gastric or duodenal ulcers and acute gastric mucosal lesions in the endoscopical examination. The remaining 39 patients did not show any gastric lesions. The possible confounding factors, such as a Helicobactor pylori infection or concurrent use of ulcerogenic agents, did cause not affect gastric distress in amino-BP users. The serum pepsinogen I level was significantly associated with severity of the gastric lesion 46.8 ± 27.7, 60.8 ± 32.4, and 103.4 ± 49.2 ng/ml for patients without any gastric distress, with gastric distress accompanied no gastric lesions, and with gastric distress accompanied gastric lesions, respectively.

CONCLUSIONS

ROC analysis revealed that the cutoff value of pepsinogen I for expectation of gastric regions was 76.8 ng/ml. The results clearly indicate that measurement of pepsinogen I may be useful in predicting gastric distress induced by amino-BP in osteoporosis.

The relationship among proton pump inhibitors, bone disease and fracture

INTRODUCTION

There is growing concern about a possible association between the use of proton pump inhibitors (PPIs) and the development of fragility fractures, most notably hip and vertebral fractures. As PPIs are widely used in clinical practice, this association is of paramount clinical importance.

AREAS COVERED

The authors review the published papers analyzing the relationship between PPI use and the occurrence of fragility fractures. The authors also explore the data supporting possible mechanisms through which PPIs may increase the risk of fracture, including the effects of PPIs on calcium homeostasis, bone mineral density and direct effects of PPIs on bone metabolism.

EXPERT OPINION

Overall, though multiple observational studies have demonstrated an association between PPIs and fragility fractures, the lack of a proven mechanism through which PPIs increase the risk of fracture suggests that this association may not be causal. At this time, the authors do not recommend discontinuing PPIs in patients with a history of fracture or those at increased risk of fracture. However, clinicians should still endeavor to avoid using PPIs in situations where benefits are minimal or clinical indications are lacking.

A comprehensive study demonstrating that p-glycoprotein function is directly affected by changes in pH: implications for intestinal pH and effects on drug absorption

The purpose of this study was to investigate whether changes in the pH of the gastrointestinal tract can directly affect P-glycoprotein (P-gp) function. The effect of changes in extracellular pH on P-gp functionality was examined by testing colchicine (a nonionizable P-gp substrate) in bidirectional Caco-2 and MDR1-Madine Darby canine kidney (MDCK) cell permeability assays, in which the pH of the apical and basolateral chambers was varied. Reduction of the pH from 7.4 to 5.0 and 4.5 markedly increased the apical-to-basolateral flux of colchicine and reduced the basolateral-to-apical flux. The efflux ratio for colchicine was reduced to 1.2 at pH 4.5, compared with values greater than 20 that were measured in the pH range of 5.5-7.4. A similar result was obtained when MDR1-MDCK cells were used in the bidirectional permeability studies. Other nonionizable P-gp substrates (digoxin, dexamethasone, paclitaxel, and etoposide) responded to acidic pH (4.5) in a manner similar to colchicine. Reduced P-gp ATPase activity is a reason for the diminished P-gp function observed at pH 4.5.

Association of long-term proton pump inhibitor therapy with bone fractures and effects on absorption of calcium, vitamin B12, iron, and magnesium

Proton pump inhibitors (PPI) are one of the most widely used classes of drugs. PPIs have a very favorable safety profile, and it is unusual for a patient to stop them because of side effects. However, with increasing numbers of patients chronically taking PPIs for gastroesophageal reflux disease and other common, persistent conditions, the long-term potential adverse effects are receiving increasing attention. An insufficiently studied area receiving much attention is the long-term effect of chronic acid suppression on the absorption of vitamins and nutrients. This increased attention results from the reported potential adverse effect of chronic PPI treatment leading to an increased occurrence of bone fractures. Interest in this area has led to examination of the effects of PPIs on calcium absorption/metabolism and numerous cohort, case-control, and prospective studies of their ability to affect bone density and cause bone fractures. In this article, these studies are systematically examined, as are studies of the effects of chronic PPI use on absorption of VB(12), iron, and magnesium. Studies in each area have led to differing conclusions, but when examined systematically, consistent results of several studies support the conclusion that long-term adverse effects on these processes can have important clinical implications.

Short and long-term PPI treatment for GERD. Do we need more-potent anti-secretory drugs?

Because the reflux of the acidic gastric content into the esophagus plays a major role in the pathogenesis of symptoms of GERD and lesions of erosive esophagitis, acid suppression with a proton pump inhibitor (PPI) is currently the mainstay of anti-reflux therapy. There is a strong correlation between the degree of acid suppression provided by a given drug and its efficacy. The superiority of PPIs over other drugs (antacids, prokinetics and H(2)-receptor antagonists) has now been established beyond doubt, both for short- and long-term treatment. However, there are still some unmet therapeutic needs in GERD; hence, patients with non-erosive reflux disease (NERD) are less responsive to PPIs than those with erosive esophagitis. Moreover, the efficacy of PPIs in patients with atypical symptoms is frequently limited to the relief of associated heartburn or regurgitation. With respect to safety, although most studies on short- and long-term PPI use have provided reassuring data, recent reports have drawn attention to potential side effects or drug-drug interference. Better healing rates in the most severe forms of esophagitis, or a faster onset of symptom relief, may require optimization of acid suppressive therapy with regard to the daily course of acid secretion, especially during the night. Different pharmacological approaches can be considered, with the ultimate goals of achieving faster, stronger and more-sustained acid inhibition. How a better pharmacological profile may translate into clinical benefit should now be tested in appropriate, controlled studies.