Pharmacokinetic drug interaction profiles of proton pump inhibitors

Impact of proton pump inhibitors on pathologic response rates following fluoropyrimidine-based neoadjuvant chemotherapy in pancreatic cancer patients

BACKGROUND

Proton pump inhibitors (PPIs) negatively impact fluoropyrimidine-based chemotherapy efficacy in colorectal cancer. This study assessed PPI impact on major pathologic response (mPR) rates of pancreatic adenocarcinoma (PDAC) patients receiving fluoropyrimidine-based chemotherapy.

METHODS

An institutional retrospective review of resected PDAC patients receiving neoadjuvant fluoropyrimidine-based chemotherapy (98% FOLFIRINOX) from 2011 to 2021 was conducted. Outcomes were stratified by use or nonuse of PPIs within 6 months of neoadjuvant chemotherapy initiation. Primary outcome was mPR defined as complete or near complete response.

RESULTS

Among 540 patients included, the median age was 64 (IQR: 60-70) years, 297 (55%) were male, and 202 (37%) were PPI users. 170 (31%) patients had mPR with similar rates among PPI users and nonusers (29% vs. 33%, p = 0.38). No difference in mPR was seen between PPI users and nonusers receiving chemoradiation (35% vs. 36%, p = 0.89) or ≥8 cycles of NAC (33% vs. 36%, p = 0.55). Median OS for PPI users was 30.9 versus 31.7 months for nonusers (p = 0.62). On multivariable analysis, PPI therapy was not associated with decreased survival.

CONCLUSION

PPI usage did not significantly influence mPR or OS following neoadjuvant fluoropyrimidine-based chemotherapy in resected PDAC patients. Further analysis of all patients, not just those who underwent resection, is required.

An update on oral antiplatelet drug interactions with proton pump inhibitors: what are the risks?

INTRODUCTION

Aspirin and anti-P2Y12 are widely prescribed in cardiovascular patients, often in combination with proton pump inhibitors (PPIs) to limit the risk of upper gastrointestinal bleedings. The potential interaction between PPIs and antiplatelet agents has been widely discussed, but doubts remain as to whether PPIs may reduce the cardiovascular protection provided by aspirin, prasugrel, ticagrelor, and clopidogrel.

AREAS COVERED

Many pharmacokinetic (PK) and pharmacodynamic (PD) studies have confirmed the interaction, especially between PPIs and clopidogrel, but with uncertain consequences on clinical outcomes. Therefore, we aimed to summarize the evidence for the widespread combined use of oral antiplatelet drugs and PPIs, to outline the current evidence supporting or opposing drug-drug interaction, and to discuss the clinical implications of such interactions.

EXPERT OPINION

A large body of evidence describes the PK/PD interaction of antiplatelet drugs with PPIs and its potential role in increasing clinical cardiovascular adverse events, but no solid clinical data have confirmed these effects. In the light of the published studies, there seems to be no restriction on the choice of PPI with aspirin, prasugrel, and/or ticagrelor. The choice of a PPI with no (or minimal) interference with the hepatic cytochrome P450 2C19 is preferred in patients receiving clopidogrel.

Acute upper and lower gastrointestinal bleeding management in older people taking or not taking anticoagulants: a literature review

Acute upper and lower gastrointestinal (GI) bleeding may be a potentially life-threatening event that requires prompt recognition and an early effective management, being responsible for a considerable number of hospital admissions. Methods. We perform a clinical review to summarize the recent international guidelines, helping the physician in clinical practice. Older people are a vulnerable subgroup of patients more prone to developing GI bleeding because of several comorbidities and polypharmacy, especially related to an increased use of antiplatelet and anticoagulant drugs. In addition, older patients may have higher peri-procedural risk that should be evaluated. The recent introduction of reversal strategies may help the management of GI bleeding in this subgroup of patients. In this review, we aimed to (1) summarize the epidemiology and risk factors for upper and lower GI bleeding, (2) describe treatment options with a focus on pharmacodynamics and pharmacokinetics of different proton pump inhibitors, and (3) provide an overview of the clinical management with flowcharts for risk stratification and treatment. In conclusion, GI is common in older patients and an early effective management may be helpful in the reduction of several complications.

Sodium citrate buffer improves pazopanib solubility and absorption in gastric acid-suppressed rat model

Pazopanib exhibits pH-dependent solubility and its absorption depends primarily on the stomach pH. Significant decrease of pazopanib absorption by coadministration with proton pump inhibitors in clinical situation need to be overcome. Thus, the purpose of this study is firstly to investigate the effect of acidic beverages and sodium citrate buffer on the solubility of pazopanib and secondly to examine the effect of sodium citrate buffer on pazopanib absorption in a rat model with esomeprazole-mediated gastric acid suppression. Pazopanib solubility decreased with increasing pH of sodium citrate buffer in vitro. Interestingly, its solubility in some acidic beverages was significantly lower than that in sodium citrate buffer of the same pH. The AUC0-24h of pazopanib administered in tap water to rats treated with esomeprazole (ESP rats) was 66 % lower than that in the control rats treated with saline. However, AUC0-24h was 4.8 times higher in ESP rats that received pazopanib with sodium citrate buffer (pH 2.3) compared to ESP rats that received pazopanib with tap water. Our results indicate that the drug-drug interactions between pazopanib and proton pump inhibitors can be overcome, at least in part, by suspending pazopanib in sodium citrate buffer.

A comprehensive review on potential drug-drug interactions of proton pump inhibitors with antidiabetic drugs metformin and DPP-4 inhibitors

A drug interaction is a condition in which two or more drugs are taken at the same time. Type 2 diabetes mellitus is a significant contributor to polypharmacy. Proton pump inhibitors (PPIs) are often prescribed in combination with metformin or DPP-4 inhibitors (sitagliptin, saxagliptin, linagliptin, and alogliptin) or a combined dose of metformin and DPP-4 inhibitor to treat gastritis in diabetic patients. This review article mainly focused on evaluating the potential drug-drug interactions (DDIs) between PPIs (i.e. esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole) with metformin and PPIs with DPP-4 inhibitors. The findings demonstrated the existence of pharmacokinetic and pharmacodynamic DDIs between the aforementioned PPIs with metformin and DPP-4 inhibitors, which could impact the biological activities (i.e., hypoglycemia) of these drugs. Moreover, this review suggested that esomeprazole could be the best drug in the PPI group to be prescribed simultaneously with metformin and DPP-4 inhibitors, as most of the antidiabetic drugs of this study did not show any interaction with esomeprazole. The findings of this study also revealed that both antidiabetic drugs and PPIs could have positive interactions as PPIs have the potential to lessen the gastrointestinal side effects of metformin and DPP-4 inhibitors. To achieve the greatest therapeutic impact with the fewest side effects, careful dose control of these drugs is required. So, more extensive research on both human and animal subjects are needed to ascertain the veracity of this hypothesis.

Production of an O-desmethylated product, a major human metabolite, of rabeprazole sulfide by bacterial P450 enzymes

Rabeprazole is a common type of proton pump inhibitor (PPI) used to treat various peptic disorders. Unlike most PPI drugs, rabeprazole is spontaneously reduced to rabeprazole sulfide (thioether) when it is given to patients. As a result, rabeprazole sulfide is considered one of the active metabolites of rabeprazole. Rabeprazole sulfide is mainly metabolized to desmethyl rabeprazole sulfide by CYP2C19 and CYP2D6 in people. However, the pharmacological efficacy and safety of desmethyl rabeprazole sulfide have not yet been investigated. Its usage is challenging due to the high cost associated with the drug. In this study, we found CYP102A1 mutants that can produce desmethyl rabeprazole sulfide as a major metabolite of rabeprazole sulfide. The chemical characteristics of the major product were confirmed using high-performance liquid chromatography, LC-mass spectrometry, and nuclear magnetic resonance spectroscopy. CYP102A1 mutants R47L/F87V/L188Q, R47L/F87V/L188Q/A335V/Q359R, and R47L/F87V/L188Q/I254V/D351E showed kcat values of 39, 93, and 88 min-1, respectively, for O-desmethylation of rabeprazole sulfide. Furthermore, the highest concentration of desmethyl rabeprazole sulfide product from 2 mM rabeprazole sulfide at optimal conditions was obtained in bacterial whole-cell biotransformation with the R47L/F87V/L188Q mutant, reaching 0.63 mM at 4-h incubation. In conclusion, we present a platform that facilitates the efficient and sustainable production of the desmethylated product from rabeprazole sulfide for use in the biopharmaceutical industry.

Combined contributions of cytochrome P450s (CYPs) and non-enzymatic metabolism in the in vitro biotransformation of anaprazole, a novel proton pump inhibitor

Anaprazole, a new proton pump inhibitor (PPI), is designed for the treatment of acid-related diseases, such as gastric ulcers and gastroesophageal reflux. This study explored the in vitro metabolic transformation of anaprazole. The metabolic stabilities of anaprazole in human plasma and human liver microsomes (HLM) were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Then, the contribution (%) of non-enzymatic and cytochrome P450s (CYPs) enzyme-mediated anaprazole metabolism was assessed. To obtain the metabolic pathways of anaprazole, the metabolites generated in HLM, thermal deactivated HLM, and cDNA-expressed recombinant CYPs incubation systems were identified by ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Results showed that anaprazole was very stable in human plasma and unstable in HLM. The contribution (%) of non-enzymatic vs. CYPs enzyme-mediated metabolism was 49% vs. 51%. CYP3A4 was the major enzyme (48.3%), followed by CYP2C9 (17.7%) and CYP2C8 (12.3%), in responsible for the metabolism of anaprazole. Specific chemical inhibitors targeting CYP enzymes notably blocked the metabolic transformation of anaprazole. Six metabolites of anaprazole were identified in the non-enzymatic system, whereas 17 metabolites were generated in HLM. The biotransformation reactions mainly included sulfoxide reduction to thioether, sulfoxide oxidation to sulfone, deoxidation, dehydrogenation, O-dealkylation or O-demethylation of thioether, O-demethylation and dehydrogenation of thioether, O-dealkylation and dehydrogenation of thioether, thioether O-dealkylation and dehydrogenation of thioether, and O-dealkylation of sulfone. Both enzymatic and non-enzymatic metabolisms contribute to the clearance of anaprazole in human. Anaprazole is less likely to develop drug-drug interactions in clinical use compared to other PPIs.

The inadvertent consequences of drug recalls: A case study of a recall of pantoprazole generics from the markets

Introduction

Drug recalls may impact treatment plans or access to suitable therapies. Thus, they inadvertently affect treatment outcomes.

Objective

We aimed to examine the impact of recalls on patients' safety using pantoprazole-containing products recall as a case study in terms of the occurrence of potential drug-drug interactions (pDDIs).

Methods

This retrospective study used de-identified electronic health records of adult patients who had a prescription for oral proton pump inhibitors (PPIs) including pantoprazole, esomeprazole, lansoprazole, or omeprazole from April 2020 through September 2021 from a large tertiary care hospital. The study outcome definition was the prevalence of pDDIs in PPIs users before and after the recall date (March 2021). Changes in the prevalence of pDDIs were modeled using interrupted time-series. The rate ratio of pDDIs in the 12 months before and 6 months after the recall was modeled using negative binomial regression.

Results

A total of 1,826 pDDIs were identified, and the median monthly prevalence of pDDI before the recall was 102.5 which increased to 115.5 after the recall. A change in the level of pDDIs occurred immediately after the recall date, followed by a gradual decrease over time. The rate of pDDIs was 69% higher after the recall compared to the baseline (rate ratio 1.69; 95% confidence interval, 0.75-1.91).

Discussion

Recall of pantoprazole-containing products was associated with a higher rate of pDDIs. However, the prevalence of pDDIs gradually decreased over time. We highlight the importance of planning of recall process and coordinating all potential stakeholders to avoid potential harms.Word count: 1450.

A Pharmacogenetics-Based Approach to Managing Gastroesophageal Reflux Disease: Current Perspectives and Future Steps

Proton pump inhibitors (PPIs) are commonly used medications to treat acid-related conditions, including gastro-esophageal reflux disease (GERD). Gastroenterology guidelines mention the importance of CYP2C19 in PPI metabolism and the influence of CYP2C19 genetic variations on variable responses to PPIs, but do not currently recommend the genotyping of CYP2C19 prior to prescribing PPIs. There are strong data to support the influence of CYP2C19 genetic variations on the pharmacokinetics of PPIs and clinical outcomes. Existing pharmacogenetic guideline recommendations for dose increases focus on H. pylori and erosive esophagitis indications, but PPIs are also the main therapy for treating GERD. Recent data suggest GERD patients being treated with a PPI may also benefit from genotype-guided dosing. We summarize the literature supporting this contention and highlight future directions for improved management of patients with GERD through precision medicine approaches.

Evaluation of CYP2C19-Mediated Pharmacokinetic Drug Interaction of Tegoprazan, Compared with Vonoprazan or Esomeprazole

BACKGROUND AND OBJECTIVE

CYP2C19-mediated drug interactions of acid-reducing agents are clinically important given the high possibility of concomitant administration with CYP2C19 substrates. This study aimed to evaluate the effect of tegoprazan on the pharmacokinetics (PK) of a CYP2C19 substrate, proguanil, compared with vonoprazan or esomeprazole.

METHODS

A two-part, randomized, open-label, two-sequence, three-period crossover study was conducted in 16 healthy CYP2C19 extensive metabolizers (eight subjects per part). In each period, a single oral dose of atovaquone/proguanil 250/100 mg was administered alone or co-administered with tegoprazan 50 mg, esomeprazole 40 mg (Part 1 only) or vonoprazan 20 mg (Part 2 only). The plasma and urine concentrations of proguanil and its metabolite, cycloguanil, were measured up to 48 h post-dose. PK parameters were calculated using a non-compartmental method and compared between administered alone and co-administered with tegoprazan, vonoprazan or esomeprazole.

RESULTS

Co-administration of tegoprazan did not significantly affect the systemic exposure of proguanil and cycloguanil. In contrast, co-administration of vonoprazan or esomeprazole increased proguanil systemic exposure and decreased cycloguanil systemic exposure, and the magnitude of the corresponding change was greater with esomeprazole co-administration than vonoprazan co-administration.

CONCLUSION

Tegoprazan, unlike vonoprazan and esomeprazole, exhibited negligible CYP2C19-mediated PK interaction. It suggests that as an alternative to other acid-reducing agents, tegoprazan can be used concomitantly with CYP2C19 substrates in clinical settings.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04568772 (Registered on September 29, 2020).

The concomitant use of proton pump inhibitors and BRAF/MEK inhibitors in metastatic melanoma

BACKGROUND

Proton-pump inhibitors (PPIs) are commonly used by patients with cancer, although they could reduce the absorption of oral anticancer targeted therapies. The US Food and Drug Administration states that the effect of PPIs on the efficacy of dabrafenib use by patients with metastatic melanoma is unknown. As a precautionary measure, the European Society for Medical Oncology recommends avoiding PPIs for patients receiving dabrafenib.

OBJECTIVES

To determine the effect of the concomitant use of PPIs and BRAF/MEK inhibitors in patients with metastatic melanoma.

METHODS

Patients with advanced melanoma receiving BRAF/MEK inhibitors as first-line treatments between 2015 and 2017 in France were selected using the French National Health Insurance database. We compared time-to-treatment discontinuation (TTD) and overall survival (OS) according to concomitant PPI exposure. We balanced the baseline characteristics of patients exposed and nonexposed to PPIs using an overlap weighting method based on a propensity score.

RESULTS

The metastatic melanoma cohort comprised 1028 patients receiving BRAF/MEK inhibitors, including 361 (35.1%) patients using PPIs. PPI users had more comorbidities and a more severe metastatic disease. After having equally distributed metastatic sites and comorbidities across patients exposed and nonexposed to PPIs, concomitant PPI use was not associated with shorter TTD [weighted hazard ratio (wHR) 1.03, 95% confidence interval (CI) 0.86-1.24] or OS (wHR 1.11, 95% CI 0.88-1.39). Consistent results were observed when restricting the population to patients receiving dabrafenib, or when narrowing exposure to PPIs with stronger inhibition of cytochromes.

CONCLUSIONS

In a population-based cohort of patients with advanced melanoma, the concomitant use of PPIs and BRAF/MEK inhibitors was not associated with worse outcome.

Potential factors of Helicobacter pylori resistance to clarithromycin

OBJECTIVES

A comparative dissolution kinetics test (CDKT) and bioequivalence studies of generic proton pump inhibitors (PPIs) do not model pharmacological acid suppression (PAS) and pathological duodenogastric reflux (PDGR). This study aimed to model them in CDKT to assess drugs stability and potential pantoprazole-clarithromycin interactions.

METHODS

In CDKT, PDGR (dissolution medium pH 7.00 ± 0.05, preexposure at pH 1.20 ± 0.05) and PAS (pH 4.00 ± 0.05) were modelled for original pantoprazole (OP) and its generics (GP1-4). In CDKT with high-performance liquid chromatography, dissolution gastric medium in adequate (pH 4.00 ± 0.05) and inadequate (pH 1.20 ± 0.05) PAS were modelled for original clarithromycin (OC) and its generics (GC1-4).

RESULTS

After exposure in pH 7.00 ± 0.05, pantoprazole was released from GP1 within 10 min in the amount of 68.8%. In рН 4.00 ± 0.05, 83.0% and 81.5% of pantoprazole were released from GP1 and GP4. When OP, GP2 and GP3 were placed in pH 7.00 ± 0.05, pantoprazole was released in amount: 99.4%, 88.0% and 98.2%. Clarithromycin releasing from OC, GC1, GC2, GC3, GC4 in pH 4.00 ± 0.05 was 93.5%, 91.6%, 92.9%, 79.4% and 83.0%. In pH 1.20 ± 0.05: 9.7%, 6.7%, 8.5%, 33.3%, 28.8%.

CONCLUSIONS

Destruction of enteric coats of some local pantoprazole generics in CDKT-models might be a potential factor for inadequate therapy.

Inappropriate proton pump inhibitor lansoprazole prescription in older adults hospitalized in long-term care unit

Purpose

We evaluated the use of the PPI treatment by physicians in older adults hospitalized in a long-term care unit.

Methods

We included 40 patients aged 65 years or older with a lansoprazole prescription hospitalized in long-term care unit from January 2018 to January 2022. Patient characteristics, gastroduodenal history, dose of lansoprazole, indication, days of prescription, and number of medications were collected from electronic patient records.

Results

The mean age of patients was 84.2 ± 9.3. Patients were taking between 5 and 24 (mean = 12.7, SD = 4.4) medications overall with 15 patients taking low dose of aspirin (75 mg daily) and 8 patients taking an antiplatelet. Most patients (82.5%) received once-daily lansoprazole treatment, 55% of whom took a dose of 15 mg. Five patients were treated with the maximum dose of lansoprazole 30 mg twice daily. Only seven patients had an appropriate indication. The minimum of treatment time was 3 days and the maximum was 1198 days; moreover, 24 patients (60%) were still in treatment.

Conclusion

Few PPI prescriptions had an indication in the patient’s electronic record. Prescriptions were ongoing with no date of discontinuation or re-evaluation.

Pollen Typhae-Based Magnetic-Powered Microrobots toward Acute Gastric Bleeding Treatment

Traditional Chinese herbal medicine (TCHM) is the naturally available pharmaceutical with millennia of evolution from ancient China, capable of a superior therapeutic index and minimized unwanted effects on the human body. This work presents a therapeutic microrobotic platform based on pollen typhae (PT), a typical type of TCHM, fabricated by coating porous PT microspheres with Fe3O4 nanoparticles (PT robots) via electrostatic adsorption. The PT robots exhibit effective and controllable motion in various biological media upon external magnetic control and, meanwhile, preserve the inherent hemostasis property of PT. The blood clotting capacity of PT robots is attributed to their stimulation of the endogenous blood coagulation pathway and platelets with increased counts, which could be further improved by their effective magnetic propulsion. The remote magnetic control also allows the manipulation of PT robots in mice stomach, inducing enhanced binding and prolonged retention of PT robots in stomach mucosa. Moreover, PT robots upon magnetic control show an enhanced hemostatic effect in treating the mice bearing acute gastric bleeding compared with other passive groups. This work offers a facile and feasible route to integrate TCHM with manmade micromachines possessing the innate curative features of TCHM. Such a design expanded the versatility of microrobots and can be generalized to vast types of TCHM for broader biomedical applications.

The Safety of Long-Term Proton Pump Inhibitor Use on Cardiovascular Health: A Meta-Analysis

Introduction: Proton pump inhibitors (PPIs) are one of the most prescribed classes of drugs worldwide as a first-line treatment of acid-related disorders. Although adverse effects are rare and rapidly reversible after a short exposure, concerns have been recently raised about a greater toxicity on cardiovascular health after a longer exposure, especially when combined with clopidogrel. We aimed to evaluate the safety of long-term PPI use on cardiovascular health in patients with known atheromatous cardiovascular disease. Methods: A literature search was conducted in the PubMed, Embase, and Cochrane Library databases and grey literature in April 2022. Articles published between 2014 and 2022 were considered relevant if they were designed as randomized controlled trials (RCTs) that included post hoc analyses or prospective observational studies and if they investigated clinical cardiovascular outcomes associated with PPI use for 6 months or more in patients suffering from cardiovascular disease requiring antiplatelet agent therapy and/or coronary angioplasty. Statistical analyses were performed using RevMan 5.4 software (Computer program, the Cochrane Collaboration, 2020, London, UK). The risk of bias was assessed using the Cochrane risk-of-bias tool for the RCTs and the Newcastle−Ottawa scale for the observational studies. Results: A total of 10 full-text articles involving 53,302 patients were included. Substantial heterogeneity was found among the 10 included studies. The primary analysis showed no significant differences between the PPI group and the control group for the risks of major adverse cardiovascular events (MACEs), all-cause death (ACD), or target vessel revascularization (TVR) using a random-effects model (OR 1.15, 95% CI 0.98−1.35, p = 0.08, I2 = 73%; OR 1.24, 95% CI 0.94−1.65, p = 0.13, I2 = 63%; and OR 1.19, 95% CI 0.76−1.87, p = 0.45, I2 = 61%, respectively). The primary analysis yielded similar results for the risks of myocardial infarction (MI), stroke, and cardiovascular death (CVD) using a fixed-effects model (OR 0.98, 95% CI 0.88−1.09, p = 0.66, I2 = 0%; OR 1.02, 95% CI 0.90−1.17, p = 0.73, I2 = 0%; and OR 1.04, 95% CI 0.94−1.16, p = 0.44, I2 = 35%, respectively). Likewise, a subgroup analysis based on eight randomized controlled trials failed to identify any association between PPI use and the risks of MACEs, MI, stroke, TVR, ACD, or CVD using a fixed-effects model (overall pooled OR 1.01, 95% CI 0.96−1.06; p = 0.66; I2 = 0%). The pulled data from the two included observational studies (OS) demonstrated a significantly increased risk of MACEs in the PPI group (OR 1.42, 95% CI [1.29−1.57], p <0.001; I2 = 0%). In another subgroup analysis, no evidence of an increased risk of adverse cardiovascular events in the co-therapy PPI/clopidogrel versus clopidogrel alone groups was found with the exception of the risk of ACD (OR 1.50, 95% CI 1.23−1.82, p = 0.001, I2 = 0%). Nevertheless, after performing a sensitivity analysis reaching heterogeneity I2 = 0%, the co-prescription of PPIs and clopidogrel was at increased risk of MACEs (p < 0.001), CVD (p = 0.008), and TVR (p < 0.001) but remained statistically non-significant for the risk of MI (p = 0.11). Conclusions: The overall results of this meta-analysis showed that long-term PPI use was not associated with an increased risk of adverse cardiovascular events. However, inconsistent results were found for combined PPI/clopidogrel therapy. These results should be considered with caution in light of the significant heterogeneity, the limited number of included studies, and the lack of adjustment for potential confounders.

Rebuilding trust in proton pump inhibitor therapy

Introduction of proton pump inhibitor (PPI) therapy into clinical practice has revolutionized treatment approach to acid-related diseases. With its clinical success came a widespread use of PPI therapy. Subsequently, several studies found that PPIs were oftentimes overprescribed in primary care and emergency setting, likely attributed to seemingly low side-effect profile and physicians having low threshold to initiate therapy. However, now there is a growing concern over PPI side-effect profile among both patients and providers. We would like to bring more awareness to the currently available guidelines on PPI use, discuss clinical indications for PPIs and the evidence behind the reported side-effects. We hope that increased awareness of proper PPI use will make the initiation or continuation of therapy a well informed and an evidence-based decision between patient and physician. We also hope that discussing evidence behind the reported side-effect profile will help clarify the growing concerns over PPI therapy.

Evaluation of the pharmacokinetics of trazpiroben (TAK-906) in the presence and absence of the proton pump inhibitor esomeprazole

Trazpiroben, a dopamine D2 /D3 receptor antagonist under development to treat gastroparesis, displays decreasing solubility with increasing pH. This single-sequence, open-label, two-period, crossover study evaluated the effect of esomeprazole, a proton pump inhibitor that raises gastric pH, on the single-dose pharmacokinetics, safety, and tolerability of trazpiroben in healthy adults (NCT03849690). In total, 12 participants were enrolled and entered period 1 (days 1-3), receiving a single oral dose of trazpiroben 25 mg on day 1. After a 4-day washout, participants then entered period 2 (days 8-13) and received esomeprazole 40 mg once daily on days 8-12, with a single oral dose of trazpiroben 25 mg co-administered 1 h post esomeprazole dosing on day 11. Geometric mean area under the curve from time 0 extrapolated to infinity (AUC∞ ) and maximum plasma concentration (Cmax ) values were generally similar when trazpiroben was administered alone versus alongside esomeprazole (AUC∞ , 44.03 vs. 38.85 ng h/ml; Cmax , 19.76 vs. 17.24 ng/ml). Additionally, the associated geometric mean ratio (GMR; co-administration: administration alone) 90% confidence intervals (CIs) suggested no clinically meaningful difference between treatment groups (AUC∞ , GMR 0.88, 90% CI 0.78-1.00; Cmax , 0.87, 90% CI 0.70-1.09). Mean apparent first-order terminal elimination half-life values were similar between treatments, illustrating co-administration with esomeprazole had minimal effect on trazpiroben elimination. Trazpiroben was well-tolerated in healthy adults following administration alone and alongside esomeprazole, with no clinically relevant adverse events reported. The lack of evidence of any clinically meaningful drug-drug interaction supports the co-administration of esomeprazole with trazpiroben.

Simultaneous Determination of Loratadine and Its Metabolite Desloratadine in Beagle Plasma by LC-MS/MS and Application for Pharmacokinetics Study of Loratadine Tablets and Omeprazole‑Induced Drug-Drug Interaction

Background

Loratadine (LTD) is a Biopharmaceutical Classification System II basic drug with pH-sensitive aqueous solubility and dissolution is a speed-limiting step of its absorption. The drug dissolution and the gastrointestinal tract pH conditions are likely to influence the in vivo pharmacokinetic behavior of LTD tablets.

Materials and Method

A rapid, sensitive, and reliable bioanalytical method for simultaneous quantitation of LTD and its active metabolite desloratadine (DL) in beagle plasma was developed and validated based on liquid chromatography tandem mass spectrometry (LC-MS/MS). Sample preparation in low plasma consumption was accomplished by liquid–liquid extraction. The chromatographic separation was achieved on a Phenomenex Kinetex C8 column using acetonitrile and 5 mM ammonium formate as the mobile phase. A comparative pharmacokinetics study of three LTD tablets with different dissolution rates was conducted in male beagles in fasting state and an omeprazole-induced drug–drug interaction (DDI) study was subsequently performed under pretreatment of omeprazole.

Results and Conclusion

The method showed a good linear correlation over the concentration ranges of 0.008–24 ng/mL for LTD and 0.8–800 ng/mL for DL, and was successfully applied to analyze the two compounds in beagle plasma. Pharmacokinetic results showed in the fasting state the three LTD tablets were equivalent in beagles in terms of effective components. DL of the three tablets were equivalent, indicating metabolite was less susceptible to pharmaceutic preparation factors for LTD tablets in beagles. Moreover, significant changes in LTD and DL pharmacokinetics parameters were observed under the effect of omeprazole-induced pH increase in gastrointestinal tract, suggesting that DDI effects are of concern for the curative effect of LTD when combined with omeprazole. The findings will contribute to the future pharmaceutical preparations research as well as the clinical application of LTD.

Influence of Piperine and Omeprazole on The Regional Absorption of Daclatasvir from Rabbit Intestine

The study assessed the site dependent intestinal absorption of daclatasvir and investigated the effects of piperine and omeprazole on such absorption utilizing in situ rabbit intestinal perfusion technique. The intestinal absorption of daclatasvir was assessed in four segments: duodenum, jejunum, ileum, and colon. The effect of co-perfusion with omeprazole was monitored through the tested anatomical sites. The effect of piperine, a P-glycoprotein (P-gp) inhibitor on daclatasvir absorption from jejunum and ileum was tested. The results showed that daclatasvir was incompletely absorbed from the rabbit small and large intestine. The absorptive clearance per unit length (PeA/L) was site dependent and was ranked as colon > duodenum > jejunum > ileum. This rank is the opposite of the rank of P-gp intestinal content suggesting possible influence for P-gp. Co-perfusion with omeprazole increased PeA/L and this was evidenced also with reduced the L95% of daclatasvir from both small and large intestinal segments. Significant enhancement in daclatasvir absorption through jejunum and ileum was shown in presence of piperine. Daclatasvir showed site dependent intestinal absorption in a manner suggesting its affection by P-gp efflux. This effect was inhibited by piperine. Co-administration of daclatasvir with omeprazole can enhance intestinal absorption a phenomenon which requires extension to human pharmacokinetic investigation. This article is protected by copyright. All rights reserved.

Clinical study of drug-drug interaction between omeprazole and pyrotinib after meal

AIMS

We aimed to investigate the effect of omeprazole on the pharmacokinetics (PK) of pyrotinib and determine the safety of this combination in healthy Chinese volunteers.

METHODS

Eighteen healthy volunteers were enrolled in this single-dose and self-controlled study. Pyrotinib (400 mg per oral) was administered 30 minutes after the standard meal. Omeprazole was administered from day 6 (D6) to D10 (40 mg, per oral). On D10, the subjects took omeprazole under fasting conditions, followed by pyrotinib 30 minutes after the standard meal. Blood samples for PK analyses in each phase were collected for analysing the drug concentration. Safety was assessed via clinical laboratory tests and physical examinations.

RESULTS

Compared with a single dose of pyrotinib, pyrotinib coadministered with omeprazole showed no significant difference in exposure, elimination, half-life and apparent clearance rate. The mixed-effects model revealed that the least-squares geometric mean ratios of area under the concentration-time curve (AUC)_0-t , AUC_0-∞ and maximum plasma concentration (C_max, 90% confidence intervals) of pyrotinib alone and pyrotinib coadministered with omeprazole were 0.94 (0.82, 1.08), 0.94 (0.83, 1.08) and 0.91 (0.806, 1.038), respectively, indicating the absence of significant differences in AUC_0-t , AUC_0-∞ and C_max . During the treatment period, 6 subjects (33.3%) reported 8 adverse events during pyrotinib monotherapy and omeprazole administration, respectively; 10 subjects (55.6%) reported 34 adverse events in the combined administration phase.

CONCLUSION

Omeprazole, a proton-pump inhibitor, did not significantly impact the PK properties of pyrotinib, and a good safety profile was observed on coadministration.

Pattern of systemic antibiotic use and potential drug interactions: Evaluations through a point prevalence study in Ankara University Hospitals

Background/aim

Most of the hospitalized patients are on a number of drugs for comorbidities and/or to prevent nosocomial infections. This necessitates a careful consideration of drug interactions not only to avoid possible toxicities but also to reach the highest efficiency with drug treatment. We aimed to investigate drug interactions related to systemic antibiotic use and compare three different databases to check for drug interactions while characterizing the main differences between medical and surgical departments.

Materials and methods

This point prevalence study covered data on 927 orders for patients hospitalized between June 3 and 10, 2018 in Ankara University Hospitals. Systemic antibiotic use and related drug interactions were documented using UptoDate, Drugs, and Medscape and comparisons between the departments of medical and surgical sciences were made.

Results

The number of orders, or the number of drugs or antibiotics per order were not different between the medical and surgical sciences departments. A total of 1335 antibiotic-related drug interactions of all levels were reported by one, two, or all three databases. UptoDate reported all common and major interactions. Pantoprazole was the most commonly prescribed drug and appeared in 63% of all orders. Among 75 different molecules, ceftriaxone and meropenem were the two most prescribed antibiotics by the surgical and medical departments, respectively.

Conclusion

A dramatic variance existed amongst antibiotics prescribed by different departments. This indicated the requirement for a centralized role of an infectious diseases specialist. Especially for the hospitalized patient, prophylactic coverage with at least one antibiotic brought about a number of drug interactions. A precise evaluation of orders in terms of drug interactions by a clinical pharmacist (currently none on duty) will reduce possible drug-related hazards.

Personalized Therapy for Mycophenolate: Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology

ABSTRACT

When mycophenolic acid (MPA) was originally marketed for immunosuppressive therapy, fixed doses were recommended by the manufacturer. Awareness of the potential for a more personalized dosing has led to development of methods to estimate MPA area under the curve based on the measurement of drug concentrations in only a few samples. This approach is feasible in the clinical routine and has proven successful in terms of correlation with outcome. However, the search for superior correlates has continued, and numerous studies in search of biomarkers that could better predict the perfect dosage for the individual patient have been published. As it was considered timely for an updated and comprehensive presentation of consensus on the status for personalized treatment with MPA, this report was prepared following an initiative from members of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT). Topics included are the criteria for analytics, methods to estimate exposure including pharmacometrics, the potential influence of pharmacogenetics, development of biomarkers, and the practical aspects of implementation of target concentration intervention. For selected topics with sufficient evidence, such as the application of limited sampling strategies for MPA area under the curve, graded recommendations on target ranges are presented. To provide a comprehensive review, this report also includes updates on the status of potential biomarkers including those which may be promising but with a low level of evidence. In view of the fact that there are very few new immunosuppressive drugs under development for the transplant field, it is likely that MPA will continue to be prescribed on a large scale in the upcoming years. Discontinuation of therapy due to adverse effects is relatively common, increasing the risk for late rejections, which may contribute to graft loss. Therefore, the continued search for innovative methods to better personalize MPA dosage is warranted.

Impact of gastrointestinal tract variability on oral drug absorption and pharmacokinetics: An UNGAP review

The absorption of oral drugs is frequently plagued by significant variability with potentially serious therapeutic consequences. The source of variability can be traced back to interindividual variability in physiology, differences in special populations (age- and disease-dependent), drug and formulation properties, or food-drug interactions. Clinical evidence for the impact of some of these factors on drug pharmacokinetic variability is mounting: e.g. gastric pH and emptying time, small intestinal fluid properties, differences in pediatrics and the elderly, and surgical changes in gastrointestinal anatomy. However, the link of colonic factors variability (transit time, fluid composition, microbiome), sex differences (male vs. female) and gut-related diseases (chronic constipation, anorexia and cachexia) to drug absorption variability has not been firmly established yet. At the same time, a way to decrease oral drug pharmacokinetic variability is provided by the pharmaceutical industry: clinical evidence suggests that formulation approaches employed during drug development can decrease the variability in oral exposure. This review outlines the main drivers of oral drug exposure variability and potential approaches to overcome them, while highlighting existing knowledge gaps and guiding future studies in this area.

Clinical treatment for hepatitis C reverses CYP2C19 inhibition

AIMS

Infection by the hepatitis C virus (HCV) generates inflammatory response selectively modulating cytochrome P450 protein (CYP) activities. This study assessed the effect of chronic hepatitis C on CYP2C19 activity in patients with HCV.

METHODS

Patients with HCV infection (n = 23) at different fibrosis stages were allocated into groups 1 (F0/F1 and F2, mild to moderate fibrosis) and 2 (F3 and F4, advanced fibrosis stages). Phase 1 was conducted before the treatment with direct-acting antivirals (DAAs) and phase 2 after the sustained virological response. Participants were administered 2 mg of a single oral dose of omeprazole (OME) as probe drug in both phases. Metabolic ratios (MRs) (plasma samples collected at 4 h after OME administration) were calculated by dividing plasma concentrations of 5-hydroxyomeprazole by OME.

RESULTS

The MRs for group 1 were 0.45 (0.34-0.60, 90% confidence interval) and 0.69 (0.50-0.96) for phases 1 and 2, respectively, while the MRs for group 2 were 0.25 (0.21-0.31) and 0.41 (0.30-0.56) for phases 1 and 2, respectively. MRs were different (P < .05) between phases 1 and 2 for both groups, as well as between groups 1 and 2 in phase 1, but not in phase 2 (P > .05).

CONCLUSIONS

Both groups presented different MRs before and after treatment with DAAs, evidencing that CYP2C19 inhibition during inflammation was at least partially reversed after DAA treatment. Groups 1 and 2 were also found to be different in phase 1 but not phase 2, showing that CYP2C19 metabolic activity does not differ between groups after DAA treatment.

Proton Pump Inhibitors and Oncologic Treatment Efficacy: A Practical Review of the Literature for Oncologists

Proton pump inhibitors (PPIs) are the most commonly used anti-acid drugs worldwide, including among cancer patients. However, drug-drug interactions between PPIs and other agents may lead to decreased drug absorption with possible reduced therapeutic benefit, or even increased toxicity. Unfortunately, only scarce data exist regarding the safety of concomitant PPI use with anti-cancer agents. We aim at reviewing current evidence on this possible interaction by dividing anti-cancer agents by class. Until further data is available, we encourage healthcare providers to limit unnecessary PPI overuse.

Alpha-lipoic acid: A promising adjuvant for nonsteroidal anti-inflammatory drugs therapy with improved efficacy and gastroprotection

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in a wide variety of diseases due to their analgesic and anti-inflammatory effects, but their usage have been limited due to significant ulcerogenic side effects. In the present study, we aimed to evaluate the effect of α-lipoic acid (ALA) treatment on the anti-inflammatory activity of indomethacin (Indo) as well as the possible therapeutic effect of ALA on high dose Indo-induced gastropathy in female mice. Mice were treated with Indo (5 or 30 mg/kg, p.o) alone or in combination with ALA (50, 100 or 200 mg/kg, i.p). in vivo anti-inflammatory effect was evaluated by formalin-induced paw edema measured as paw thickness and edema. Gastric damage was evaluated macroscopically and histologically by scoring mucosal hemorrhage, erosion, edema and inflammation. To our results, Indo was ineffective at 5 mg/kg, but co-treatment with Indo and ALA significantly reduced paw edema, implying that ALA augmented the anti-inflammatory effect of subtherapeutic dose of Indo. However, ALA was not able to induce a further increase in the anti-inflammatory effect of Indo at 30 mg/kg. Unlike the treatment with Indo at 5 mg/kg, Indo at 30 mg/kg caused severe gastric damage that prevented by co-treatment with ALA. These results suggest that combination of ALA with NSAIDs can both increase anti-inflammatory effect and prevent NSAIDs-induced gastric damage. ALA would be promising adjuvant that can reduce dose for effective NSAID therapy, which improves safety profile of NSAIDs especially in cases long-term administration of high dose needed.

A Study of Proton Pump Inhibitors and Other Risk Factors in Warfarin-Associated Gastrointestinal Bleeding

Background

Warfarin users are at increased risk for gastrointestinal bleeding (GIB). History of GIB, stroke, cardiovascular or chronic kidney disease, age greater than 65 years, and drug interaction with proton pump inhibitors (PPI) have previously been identified as risk factors for GIB in warfarin users. We hypothesized that concomitant use of warfarin and PPI would increase the incidence of GIB relative to warfarin use alone.

Methods

We did a retrospective review of medical records of 626 patients taking warfarin for at least two weeks. Parameters including age, concomitant medication use (non-steroidal anti-inflammatory drugs (NSAID), aspirin, selective serotonin reuptake inhibitors (SSRIs), PPI, and anti-platelet drug), history of GIB, chronic renal failure (CRF), and peptic ulcer disease (PUD) prior to warfarin use were analyzed.

Results

Variables that increase the likelihood of bleeding in warfarin users included aspirin, PPI, history of PUD, history of previous GIB, CRF, and elevated prothrombin time (PT)/international normalized ratio (INR) values. Concomitant antiplatelet use showed a slight increase in GIB but this was not statistically significant (p=0.082). NSAID use and SSRI use were not associated with a higher risk of GIB among warfarin users. Patients who are on PPI and warfarin simultaneously are more likely to be on acetylsalicylic acid (ASA) or have a history of PUD, GIB, or CRF, all of which are associated with increased incidences of GIB.

Conclusions

Although concomitant use of warfarin and PPI appears to be associated with an increased incidence of GIB, these patients are more likely to have other risk factors that also increase the risk of a GIB outcome. Therefore, the interaction between PPI and warfarin is clinically insignificant.

Potential proton pump inhibitor-related adverse effects

Proton pump inhibitors (PPIs) are one of the most common medications taken by patients worldwide. PPIs are used to treat acid-related disorders, including gastroesophageal reflux disease, peptic ulcer disease, Helicobacter pylori infection, and nonsteroidal anti-inflammatory drug/stress ulceration. For some of these diseases, long-term treatment is necessary. With such prolonged use, concern and investigation into potential adverse effects has increased. In addition, data are available regarding potential anticancer effects of PPIs, especially regarding solid tumors. The aim of this review is to assess the literature on PPIs with regard to common concerns, such as drug-drug interactions, the intestinal microbiome, dementia and central nervous system disease, and osteoporosis, as well as to highlight potential negative and positive impacts of the drug in cancer.

Prediction of pharmacokinetic clearance and potential Drug-Drug interactions for omeprazole in the horse using in vitro systems

Horses are exposed to various kinds of medication, however, there are limited determinations of plasma clearance (CL_p) for the drugs used due to the high cost of equine in vivo studies.Many of the CL_p values generated come from the equine sports industry for determining drug plasma screening limits in the control of medications at the time of competition.The kinetics of omeprazole metabolism were investigated in freshly isolated and cryopreserved equine hepatocytes and hepatic microsomes (n = 3 horses).The V_max, K_m and intrinsic clearance (CL_int) of omeprazole were determined via the substrate depletion method as well as K_m values for the formation of three metabolites.The CL_int values were extrapolated to in vivo hepatic plasma clearance (CL_H) using the well stirred and parallel tube models.Cl_p for omeprazole was successfully predicted using freshly isolated or cryopreserved equine hepatocytes, while microsomes under-predicted.Equine microsomes were used to perform a drug-drug interaction (DDI) study between omeprazole and chloramphenicol. The average inhibitor constant K_i, assuming competitive inhibition, was 15.4 ± 5 µM.To the authors' knowledge, this is the first report showing the successful extrapolation of drug CL_p in the horse using equine hepatocytes and the prediction of a DDI using microsomes.

Tacrolimus Concentration in Saliva of Kidney Transplant Recipients: Factors Influencing the Relationship with Whole Blood Concentrations

OBJECTIVE

The objective of this study was to examine the association between tacrolimus concentration in oral fluids and in whole blood and to investigate the various factors that influence this relationship.

PATIENTS AND METHODS

Forty-six adult kidney transplant recipients were included in the study. Study A (ten patients) included the collection of several paired oral fluid samples by passive drool over a 12-h post-dose period. Study B (36 patients) included the collection of oral fluids pre-dose and at 2 h after the tacrolimus dose under three conditions: un-stimulated, after stimulation with a tart candy, and after mouth rinsing. The tacrolimus concentration in oral fluids was measured by a specially developed sensitive and specific liquid chromatography mass spectrometry method. A salivary transferrin concentration of >1 mg/dL was used as a cut-off value for oral fluid blood contamination.

RESULTS

Rinsing the oral cavity before sampling proved to provide the most suitable sampling strategy giving a correlation coefficient value of 0.71 (p = 0.001) between the tacrolimus concentration in oral fluids and the tacrolimus concentration in whole blood at trough. Mean and 95% confidence interval of tacrolimus concentration in oral fluids at the pre-dose concentration for samples collected after mouth rinsing was 584 (436, 782) pg/mL. The ratio of the tacrolimus concentration in oral fluids to the tacrolimus concentration in whole blood (*100) was 11% (95% confidence interval 9-13) for all sampling times. Oral fluid pH or weight of a saliva sample did not influence the tacrolimus concentration in oral fluids. Tacrolimus distribution into oral fluids exhibited a delay with a pronounced counter-clockwise hysteresis with respect to the time after dose. A multivariate analysis of variance revealed that the tacrolimus concentration in oral fluids is related to the tacrolimus concentration in whole blood and tacrolimus plasma-binding proteins including albumin and cholesterol.

CONCLUSION

An optimal sampling strategy for the determination of the tacrolimus concentration in oral fluids was established. Measuring the tacrolimus concentration in oral fluids appears to be a feasible and non-invasive method for predicting the concentration of tacrolimus in whole blood.

Prescribing of proton pump inhibitors for gastrointestinal bleeding prophylaxis in the Lebanese outpatient setting: patterns, compliance with guidelines and risks

Objectives

To determine patterns of proton pump inhibitor (PPIs) prescribing for gastrointestinal bleeding prophylaxis (GIBP) in the Lebanese outpatient setting, to assess their compliance with guidelines for approved GIBP indications and to delineate independent factors that are associated with non-compliance.

Methods

A community-based multicentre cross-sectional study was conducted. Eligible patients were those who presented to the community pharmacy setting with a PPI prescription for GIBP. Prescriptions were reviewed by a clinical pharmacist to ascertain their compliance with guidelines approved for GIBP indications. Several variables were tested to determine independent factors that were associated with guidelines non-compliance.

Key findings

Of the 720 reviewed PPI prescriptions, 297 (41.25%) were found to be compliant with guidelines approved for GIBP indications. The presence of two or more comorbid conditions, prescribing initiated by a primary care physician, patients taking three or more medications, and prescribing of NSAIDs including low-dose aspirin were found to be independent factors that were significantly associated with PPI prescribing non-compliance (P ≤ 0.05). PPIs were also inappropriately coprescribed with corticosteroids (102 (24.1%)), selective serotonin reuptake inhibitors (SSRIs) (48 (11.4%)), amoxicillin-clavulanic acid (20 (4.7%)) and bisphosphonates (13 (3.1%)) for GIBP.

Conclusion

This study demonstrated that PPIs were appropriately prescribed for GIBP in less than the half of the study patients. The need for improvement of clinical practice in this regard is therefore indispensable since inappropriate prescribing is costly and put the patient at risk for adverse health outcomes. Strategies to alter inappropriate prescribing may include education, guidelines awareness and decision support systems.

Exploiting Cysteine Residues of SLC Membrane Transporters as Targets for Drugs

The observation that cysteine is the top gainer amino acid during evolution attracted the attention of scientists dealing with protein chemistry. The thiol group of cysteine, indeed, is a potential site for several types of reactions with variable specificity and strength. This feature proved to be promising also in the field of membrane transporters that represent boundary proteins fundamental for cell homeostasis. These proteins are classified, according to the driving force for transport, in primary or secondary active transporters. Another frequently used classification is nowadays based on phylogenesis. Two major groups are identified that take into account both criteria: the ABC and the SLC transporters, the second being much more numerous. The cellular localization of the transporters makes them very attractive for drug design. Moreover, the presence of at least one cysteine residue in all the annotated SLC transporters, so far, highlights the possibility of using the thiol (SH) residue for covalent drug targeting. Even if a delay exists in this research field due to the scarce knowledge of structure/function relationships, the setup of novel experimental tools for studying SLC proteins of plasma and organelle membranes opens an important perspective in pharmacology.

Effects of medicines used to treat gastrointestinal diseases on the pharmacokinetics of coadministered drugs: a PEARRL Review

OBJECTIVES

Drugs used to treat gastrointestinal diseases (GI drugs) are widely used either as prescription or over-the-counter (OTC) medications and belong to both the 10 most prescribed and 10 most sold OTC medications worldwide. The objective of this review article is to discuss the most frequent interactions between GI and other drugs, including identification of the mechanisms behind these interactions, where possible.

KEY FINDINGS

Current clinical practice shows that in many cases, these drugs are administered concomitantly with other drug products. Due to their metabolic properties and mechanisms of action, the drugs used to treat gastrointestinal diseases can change the pharmacokinetics of some coadministered drugs. In certain cases, these interactions can lead to failure of treatment or to the occurrence of serious adverse events. The mechanism of interaction depends highly on drug properties and differs among therapeutic categories. Understanding these interactions is essential to providing recommendations for optimal drug therapy.

SUMMARY

Interactions with GI drugs are numerous and can be highly significant clinically in some cases. While alterations in bioavailability due to changes in solubility, dissolution rate, GI transit and metabolic interactions can be (for the most part) easily identified, interactions that are mediated through other mechanisms, such as permeability or microbiota, are less well-understood. Future work should focus on characterising these aspects.

Effects of proton pump inhibitors, esomeprazole and vonoprazan, on the disposition of proguanil, a CYP2C19 substrate, in healthy volunteers

AIMS

Vonoprazan, a new class of potassium-competitive proton pump inhibitors has been found to attenuate the antiplatelet function of clopidogrel in a recent clinical study, despite weak in vitro activity against CYP2C19. To elucidate the mechanism of this interaction, the present study investigated the effects of esomeprazole and vonoprazan on the pharmacokinetics of proguanil, a CYP2C19 substrate.

METHODS

Seven healthy male volunteers (CYP2C19 extensive metabolizers) received a single oral administration of 100 mg proguanil/250 mg atovaquone (control phase), oral esomeprazole (20 mg) for 5 days followed by proguanil/atovaquone (esomeprazole phase) and oral vonoprazan (20 mg) for 5 days followed by proguanil/atovaquone (vonoprazan phase). Concentrations of proguanil and its metabolite, cycloguanil, in plasma and urine in each phase were determined using liquid chromatography-tandem mass spectrometry.

RESULTS

Coadministration with proton pump inhibitors resulted in increase and decrease in the area under the plasma concentration-time curve (AUC) of proguanil and cycloguanil, respectively, significantly reducing their AUC ratio (cycloguanil/proguanil) to 0.317-fold (95% confidence interval [CI] 0.256-0.379) and 0.507-fold (95% CI 0.409-0.605) in esomeprazole phase and vonoprazan phase, respectively. Esomeprazole and vonoprazan also significantly reduced the apparent formation clearance (cumulative amount of cycloguanil in urine divided by AUC of proguanil) to 0.324-fold (95% CI 0.212-0.436) and 0.433-fold (95% CI 0.355-0.511), respectively, without significant changes in renal clearance of proguanil and cycloguanil.

CONCLUSIONS

Although further studies are needed, both esomeprazole and vonoprazan potentially inhibit CYP2C19 at clinical doses, suggesting caution in the coadministration of these drugs with CYP2C19 substrates.

Pantoprazole Does not Affect Serum Trough Levels of Tacrolimus and Everolimus in Liver Transplant Recipients

Background: Liver transplant recipients are frequently treated with proton pump inhibitors. Drug interactions have been described especially with respect to omeprazole. Due to the lower binding capacity of pantoprazole to CYP2C19 this drug became preferred and became the most used proton pump inhibitor in Germany. The data on the influence of pantoprazole on immunosuppressive drugs in liver transplant recipients a very scarce.

Methods: The authors performed a single center analysis in liver transplant recipients on the effect of pantoprazole on the serum trough levels of different immunosuppressants. The trough levels were compared over a period of 1 year before and after start or stop of a continuous oral co-administration of 40 mg pantoprazole once daily.

Results: The serum trough levels of tacrolimus (n = 30), everolimus (n = 7), or sirolimus (n = 3) remain constant during an observation period of at least 1 year before and after co-administration of pantoprazole. None of the included patients needed a change of dosage of the observed immunosuppressants during the observation period.

Conclusions: The oral co-administration of pantoprazole is safe in immunosuppressed liver transplant recipients according to the serum trough levels of tacrolimus, everolimus, and sirolimus. This analysis provides first data on the influence of pantoprazole on immunosuppressive drugs in liver transplant recipients.

Decorporation potential of lansoprazole against radiothallium (201Tl) in internally contaminated BALB/c mice and New Zealand White rabbits

INTRODUCTION:

This study examined the decorporation potential of lansoprazole (LNP) as radioactivity decorporation agent for radiothallium (²⁰¹Tl) in internally contaminated BALB/c mice and New Zealand White rabbits using radiometry and gamma scintigraphy.

METHODS:

Animals were divided into three groups, that is, control, pretreatment-1 (1X LNP), and pretreatment-2 (2X LNP). Mice received LNP intraperitoneally, while in rabbits LNP was given through oral route 0.5 and 1.5 h before radiothallium administration, respectively. Mice and rabbits used in the experiment were administered 1.48 and 11.1 MBq radiothallium (²⁰¹TlCl) through intravenous and oral route, respectively. Once started as prophylactic, LNP was continued as therapeutic twice a day till the end of study period. Radiometry and gamma scintigraphy were used to monitor radiothallium retention and uptake patterns in animals. Gamma scintigraphic images of rabbits were taken at different time intervals up to 72 h and were analyzed for comparative uptake pattern of ²⁰¹TlCl in all the groups.

RESULTS:

LNP treatment significantly increased the ²⁰¹Tl elimination over untreated control and considerably reduced the retention of ²⁰¹Tl in various tissues and organs. Decrease in radiothallium uptake up to 40% was observed in LNP-treated mice as compared to untreated control. While in rabbits, whole-body radioactivity burden at 72 h was found to be 31.24%, 26%, and 18.54% in untreated control, 9 and 18 mg/kg LNP-treated groups, respectively.

CONCLUSION:

LNP exhibited dose-dependent decorporation potential to effectively enhance the elimination of ²⁰¹Tl in mice and rabbits experimentally contaminated with ²⁰¹TlCl.

Incidence of complications in men undergoing transurethral resection of the prostate

Objectives

To examine the link between medication use and the risk of bleeding complications following transurethral resection of the prostate from the second postoperative day until hospital discharge.

Method

Using a retrospective observational study design, the medical records of all patients who underwent transurethral resection of the prostate over a 24-month period were examined. Comprehensive data regarding patients’ medication history, comorbidities and complications that occurred either during or after surgery were collected from medical records. Inferential statistical analysis was used to examine associations between demographic and medication variables and the risk of complications.

Results

Complications arising after surgery occurred in 48/135 (36%) of patients. The most common complications postoperatively were hematuria, occurring in 41/48 (85%) and hematuria with clot retention, occurring in 24/48 (50%) of patients who suffered complications. There was a significant association between the number of medications prescribed and postoperative complications; for hematuria, χ2 (12) = 21.50, p = 0.04; and for hematuria with clot retention χ2 (12) = 24.97, p = 0.015.

Conclusions

Demographic data relating to patients’ age, comorbid state and the number of standard medications prescribed is associated with an increase in macroscopic hematuria and macroscopic hematuria with clot retention after transurethral resection of the prostate. These findings emphasize the importance of nursing practice in both preoperative and postoperative care of patients undergoing surgery. Nurses need to be very vigilant in assessing patients at risk of increased bleeding from a transurethral resection of the prostate by examining their medication regimen.

Use of clopidogrel and proton pump inhibitors after a serious acute coronary event: Risk of coronary events and peptic ulcer bleeding

Some pharmacokinetic studies have reported that proton pump inhibitors (PPIs) reduce the activity of clopidogrel, but the results of studies assessing clinical outcomes in patients receiving both drugs are inconsistent. We have therefore carried out a population-based cohort study with nested case–control analysis, in order to evaluate changes in the risk of cardiovascular and peptic ulcer bleeding (PUB) events associated with PPI use in patients receiving clopidogrel. A total of 42,542 patients aged 50–84 years in 2000–2007 who survived an acute coronary event were identified in two UK-based primary care databases (The Health Improvement Network and the General Practice Research Database). Individuals were followed up to identify incident cases of non-fatal myocardial infarction/coronary death (n = 2,546) and PUB (n = 194). Controls were frequency matched to cases by age, sex and calendar year. Compared with PPI non-use, current continuous PPI use was not associated with a significant change in risk of non-fatal myocardial infarction/coronary death among current continuous users of clopidogrel monotherapy (relative risk [RR], 1.06; 95% confidence interval [95% CI], 0.47 to 2.36) or dual antiplatelet therapy (DAT; RR, 0.80; 95% CI, 0.47 to 1.37) who initiated their antiplatelet therapy shortly after their coronary event. Among patients prescribed DAT at the start date, the RR of PUB events associated with current PPI use initiated at the start date was 0.66 (95% CI, 0.27 to 1.60).

Range of therapeutic prothipendyl and prothipendyl sulfoxide concentrations in clinical blood samples

Due to a lack of reference blood concentrations in the literature, the forensic evaluation of prothipendyl findings in blood samples is difficult. Interpretations with regard to the assessment of blood concentrations as well as an estimation of the ingested prothipendyl amounts were often vague. To describe a concentration range in clinical samples, prothipendyl and prothipendyl sulfoxide concentrations were determined in serum samples of 50 psychiatric patients receiving 40 mg, 80 mg, or 160 mg doses of prothipendyl. The analyses of prothipendyl and prothipendyl sulfoxide were carried out using validated methods of high performance liquid chromatography coupled to triple quadrupole mass spectrometry (LC-QQQ-MS), respectively. 40 mg doses caused average prothipendyl serum concentrations of 18.0 ng/mL (1 hour after intake) and 7.9 ng/mL (10.5 hours after intake), while 80 mg doses caused averages of 42.6 ng/mL and 15.2 ng/mL at the mentioned times of sampling. Irrespective of the given dose, prothipendyl concentrations below 30 ng/mL were observed in 80% of the patient samples taken 1 hour after ingestion as well as in 90% of the samples collected 10.5 hours after administration. Serum concentrations of the Phase I metabolite prothipendyl sulfoxide averaged 4.3 ng/mL (1 hour after intake) and 3.6 ng/mL (10.5 hours after intake). Possible drug-drug interactions regarding absorption and metabolism of prothipendyl are discussed. Results of the herein presented study are useful for the interpretation of analytical prothipendyl findings in forensic toxicology. The utility of the described concentration range is demonstrated by discussing two death cases involving prothipendyl findings.

Impact of the CYP2C19 genotype on voriconazole exposure in adults with invasive fungal infections

OBJECTIVES

Voriconazole, a first-line agent for the treatment of invasive fungal infections (IFIs), is metabolized by CYP2C19. A significant proportion of patients fail to achieve therapeutic trough concentrations with standard weight-based voriconazole dosing, placing them at increased risk for treatment failure, which can be life threatening. We sought to test the association between the CYP2C19 genotype and subtherapeutic voriconazole concentrations in adults with IFIs.

PATIENT AND METHODS

Adults receiving weight-based voriconazole dosing for the treatment of IFIs were genotyped for the CYP2C19*2, *3, and *17 polymorphisms, and CYP2C19 metabolizer phenotypes were inferred. Steady-state voriconazole trough plasma concentrations and the prevalence of subtherapeutic troughs (<2 mg/l) were compared between patients with the CYP2C19*17/*17 (ultrarapid metabolizer, UM) or *1/*17 (rapid metabolizer, RM) genotype versus those with other genotypes. Logistic regression, adjusting for clinical factors, was performed to estimate the odds of subtherapeutic concentrations.

RESULTS

Of 70 patients included (mean age 52.5±18 years), 39% were RMs or UMs. Compared with patients with the other phenotypes, RMs/UMs had a lower steady-state trough concentration (4.26±2.2 vs. 2.86±2.3, P=0.0093) and a higher prevalence of subtherapeutic troughs (16 vs. 52%, P=0.0028), with an odds ratio of 5.6 (95% confidence interval: 1.64-19.24, P=0.0044).

CONCLUSION

Our findings indicate that adults with the CYP2C19 RM or UM phenotype are more likely to have subtherapeutic concentrations with weight-based voriconazole dosing. These results corroborate previous findings in children and support the potential clinical utility of CYP2C19 genotype-guided voriconazole dosing to avoid underexposure in RMs and UMs.

Data-driven prediction of adverse drug reactions induced by drug-drug interactions

Background

The expanded use of multiple drugs has increased the occurrence of adverse drug reactions (ADRs) induced by drug-drug interactions (DDIs). However, such reactions are typically not observed in clinical drug-development studies because most of them focus on single-drug therapies. ADR reporting systems collect information on adverse health effects caused by both single drugs and DDIs. A major challenge is to unambiguously identify the effects caused by DDIs and to attribute them to specific drug interactions. A computational method that provides prospective predictions of potential DDI-induced ADRs will help to identify and mitigate these adverse health effects.

Method

We hypothesize that drug-protein interactions can be used as independent variables in predicting ADRs. We constructed drug pair-protein interaction profiles for ~800 drugs using drug-protein interaction information in the public domain. We then constructed statistical models to score drug pairs for their potential to induce ADRs based on drug pair-protein interaction profiles.

Results

We used extensive clinical database information to construct categorical prediction models for drug pairs that are likely to induce ADRs via synergistic DDIs and showed that model performance deteriorated only slightly, with a moderate amount of false positives and false negatives in the training samples, as evaluated by our cross-validation analysis. The cross validation calculations showed an average prediction accuracy of 89% across 1,096 ADR models that captured the deleterious effects of synergistic DDIs. Because the models rely on drug-protein interactions, we made predictions for pairwise combinations of 764 drugs that are currently on the market and for which drug-protein interaction information is available. These predictions are publicly accessible at http://avoid-db.bhsai.org. We used the predictive models to analyze broader aspects of DDI-induced ADRs, showing that ~10% of all combinations have the potential to induce ADRs via DDIs. This allowed us to identify potential DDI-induced ADRs not yet clinically reported. The ability of the models to quantify adverse effects between drug classes also suggests that we may be able to select drug combinations that minimize the risk of ADRs.

Conclusion

Almost all information on DDI-induced ADRs is generated after drug approval. This situation poses significant health risks for vulnerable patient populations with comorbidities. To help mitigate the risks, we developed a robust probabilistic approach to prospectively predict DDI-induced ADRs. Based on this approach, we developed prediction models for 1,096 ADRs and used them to predict the propensity of all pairwise combinations of nearly 800 drugs to be associated with these ADRs via DDIs. We made the predictions publicly available via internet access.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-017-0153-6) contains supplementary material, which is available to authorized users.

Successful treatment of a hemodialyzed patient with pure red cell aplasia associated with epoetin beta pegol therapy with cyclosporine

A 42-year-old man with end-stage renal failure had been receiving hemodialysis therapy since April 2009. Initially, darbepoetin alfa was administered to treat his renal anemia. After treatment was switched to epoetin beta pegol, the patient's hemoglobin levels rapidly decreased. He was diagnosed with pure red cell aplasia (PRCA) based on the results of a bone marrow examination. Epoetin beta pegol was strongly suspected to be the cause of the PRCA, and although he tested negative for anti-epoetin beta pegol antibodies, epoetin beta pegol was discontinued and cyclosporine therapy was initiated. Thereafter, his hemoglobin levels increased, and his anemia dramatically improved after 3 months.

The Oral β-Lactamase SYN-004 (Ribaxamase) Degrades Ceftriaxone Excreted into the Intestine in Phase 2a Clinical Studies

SYN-004 (ribaxamase) is a β-lactamase designed to be orally administered concurrently with intravenous β-lactam antibiotics, including most penicillins and cephalosporins. Ribaxamase's anticipated mechanism of action is to degrade excess β-lactam antibiotic that is excreted into the small intestine. This enzymatic inactivation of excreted antibiotic is expected to protect the gut microbiome from disruption and thus prevent undesirable side effects, including secondary infections such as Clostridium difficile infections, as well as other antibiotic-associated diarrheas. In phase 1 clinical studies, ribaxamase was well tolerated compared to a placebo group and displayed negligible systemic absorption. The two phase 2a clinical studies described here were performed to confirm the mechanism of action of ribaxamase, degradation of β-lactam antibiotics in the human intestine, and were therefore conducted in subjects with functioning ileostomies to allow serial sampling of their intestinal chyme. Ribaxamase fully degraded ceftriaxone to below the level of quantitation in the intestines of all subjects in both studies. Coadministration of oral ribaxamase with intravenous ceftriaxone was also well tolerated, and the plasma pharmacokinetics of ceftriaxone were unchanged by ribaxamase administration. Since ribaxamase is formulated as a pH-dependent, delayed-release formulation, the activity of ribaxamase in the presence of the proton pump inhibitor esomeprazole was examined in the second study; coadministration of these drugs did not adversely affect ribaxamase's ability to degrade ceftriaxone excreted into the intestine. These studies have confirmed the in vivo mechanism of action of ribaxamase, degradation of β-lactam antibiotics in the human intestine (registered at ClinicalTrials.gov under NCT02419001 and NCT02473640).