Influence of rabeprazole and lansoprazole on the pharmacokinetics of tacrolimus in relation to CYP2C19, CYP3A5 and MDR1 polymorphisms in renal transplant recipients

Pharmacomicrobiomics: Immunosuppressive Drugs and Microbiome Interactions in Transplantation

The human microbiome is associated with human health and disease. Exogenous compounds, including pharmaceutical products, are also known to be affected by the microbiome, and this discovery has led to the field of pharmacomicobiomics. The microbiome can also alter drug pharmacokinetics and pharmacodynamics, possibly resulting in side effects, toxicities, and unanticipated disease response. Microbiome-mediated effects are referred to as drug-microbiome interactions (DMI). Rapid advances in the field of pharmacomicrobiomics have been driven by the availability of efficient bacterial genome sequencing methods and new computational and bioinformatics tools. The success of fecal microbiota transplantation for recurrent Clostridioides difficile has fueled enthusiasm and research in the field. This review focuses on the pharmacomicrobiome in transplantation. Alterations in the microbiome in transplant recipients are well documented, largely because of prophylactic antibiotic use, and the potential for DMI is high. There is evidence that the gut microbiome may alter the pharmacokinetic disposition of tacrolimus and result in microbiome-specific tacrolimus metabolites. The gut microbiome also impacts the enterohepatic recirculation of mycophenolate, resulting in substantial changes in pharmacokinetic disposition and systemic exposure. The mechanisms of these DMI and the specific bacteria or communities of bacteria are under investigation. There are little or no human DMI data for cyclosporine A, corticosteroids, and sirolimus. The available evidence in transplantation is limited and driven by small studies of heterogeneous designs. Larger clinical studies are needed, but the potential for future clinical application of the pharmacomicrobiome in avoiding poor outcomes is high.

Assessment of Clinically Relevant Drug Interactions by Online Programs in Renal Transplant Recipients

BACKGROUND

Potential drug-drug interactions (pDDIs) with immunosuppressive drugs are frequently observed in renal transplant recipients. Drug interaction programs are acknowledged as a fundamental tool to alert physicians to pDDIs, but there is a high concern about variation among different programs in terms of quality and reliability of information.

OBJECTIVES

To (a) characterize the difference in severity levels of pDDIs with tacrolimus and cyclosporine provided by 3 drug interaction programs and (b) identify clinically relevant DDIs with these immunosuppressive drugs in renal transplant recipients.

METHODS

This study was conducted in a nephrology outpatient clinic at the University Research & Training Hospital between November 2017 and February 2018. A clinical pharmacist attended clinic visits with physicians and evaluated drug interactions. Micromedex, Medscape, and Lexicomp drug interaction programs were used to identify pDDIs and their severities. Furthermore, Drug Interaction Probability Scale (DIPS) criteria were applied to identify clinically relevant drug interactions seen in clinic patients. Finally, a clinical pharmacist intervened to manage clinically relevant drug interactions identified by DIPS.

RESULTS

80 patients (54 under tacrolimus; 26 under cyclosporine treatment) were included in this study. The 3 drug interaction programs generated 648 pDDIs, 63 of which were different drug interaction pairs. Ninety-eight pDDIs were common to all 3 drug interaction programs. Sixty-three different drug interaction pairs were evaluated according to severity level, and 3 drug interaction pairs were at the same level (moderate) among the programs. The Fleiss' kappa overall interrater agreement was poor. The kappa revealed a moderate agreement for interaction pairs with a "severe" rating and a slight agreement for interaction pairs with a "major" rating. According to the DIPS evaluation, 11 pDDIs were classified as "possible," and the percentage of clinically relevant drug-drug interactions was 4.0% (10/248), 4.2% (11/265), and 8.2% (11/135) for Medscape, Lexicomp, and Micromedex, respectively. Although daily doses of immunosuppressive drugs were not changed, the blood concentrations of these drugs increased after administration of an interacting drug. As a result, in order to maintain normal therapeutic range of concentrations, dose reduction or drug change was applied where appropriate.

CONCLUSIONS

Interaction checker programs are commonly used by health institutions, since they provide quick and summarized information on mechanism and management of drug interactions, when no clinical pharmacist is present to interpret. However, the likelihood of detecting clinically relevant DDIs by interaction checker programs is relatively low, and there are inconsistencies among different programs. Individualized patient monitoring should be maintained by a multidisciplinary health care team that includes a clinical pharmacist, and decision making should be based on professional assessment of the renal transplant patient.

DISCLOSURES

No outside funding supported this study. The authors have no conflicts of interest to disclose.

Association of Genetic Variants in CYP3A4, CYP3A5, CYP2C8, and CYP2C19 with Tacrolimus Pharmacokinetics in Renal Transplant Recipients

BACKGROUND

Our study aimed to investigate the pharmacogenetics of cytochrome P3A4 (CYP3A4), CYP3A5, CYP2C8, and CYP2C19 and their influence on TAC Pharmacokinetics (PKs) in short-term renal transplant recipients.

METHODS

A total of 105 renal transplant recipients were enrolled. Target Sequencing (TS) based on next-generation sequencing technology was used to detect all exons, exon/intron boundaries, and flanking regions of CYP3A4, CYP3A5, CYP2C8, and CYP2C19. After adjustment of Minor Allele Frequencies (MAF) and Hardy-Weinberg Equilibrium (HWE) analysis, tagger Single-nucleotide Polymorphisms (SNPs) and haplotypes were identified. Influence of tagger SNPs on TAC concentrations was analyzed.

RESULTS

A total of 94 SNPs were identified in TS analysis. Nine tagger SNPs were selected, and two SNPs (rs15524 and rs4646453) were noted to be significantly associated with TAC PKs in short-term post-transplant follow-up. Measurement time points of TAC, body mass index (BMI), usage of sirolimus, and incidence of Delayed Graft Function (DGF) were observed to be significantly associated with TAC PKs. Three haplotypes were identified, and rs15524-rs4646453 was found to remarkably contribute to TAC PKs. Recipients carrying H2/H2 (GG-AA) haplotype also showed significantly high weight- and dose-adjusted TAC concentrations in posttransplant periods of 7, 14, and 30 days and 3 and 6 months.

CONCLUSIONS

Two tagger SNPs, namely, rs15524 and rs4646453, are significantly related to the variability of TAC disposition, and TAC measurement time points, BMI, usage of sirolimus, and incidence of DGF contribute to this influence. Recipients carrying H2/H2 (GG-AA) haplotype in rs15524-rs4646453 may require a low dosage of TAC during 1-year follow-up posttransplant.

Proton pump inhibitors and adverse effects in kidney transplant recipients: A meta-analysis

BACKGROUND

The adverse renal effects of proton pump inhibitors (PPIs) are increasingly recognized in both the general population and patients with chronic kidney disease. Several pharmacokinetic studies have also raised concerns regarding the interaction between PPIs and immunosuppressive drugs in transplant patients. Whether the adverse effects of PPIs have a clinical significance in kidney transplant recipients remains unclear. We performed this meta-analysis to assess the risk of adverse effects in kidney transplant recipients on PPI compared with those without PPI exposure.

AIM

To investigate the risk of acute rejection, graft loss, hypomagnesemia, renal dysfunction, and overall mortality in kidney transplant recipients on PPI compared with those without PPI exposure.

METHODS

A systematic review was conducted in MEDLINE, EMBASE, and Cochrane databases from inception through October 2018 to identify studies that evaluated the adverse effects of PPIs in kidney transplant recipients, including biopsy-proven acute rejection, graft loss, hypomagnesemia, renal function, and overall mortality. Effect estimates from the individual studies were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird. The protocol for this meta-analysis is registered with PROSPERO, No. CRD42018115676.

RESULTS

Fourteen observational studies with 6786 kidney transplant recipients were enrolled. No significant association was found between PPI exposure and the risk of biopsy-proven acute rejection at ≥ 1 year [pooled odds ratio (OR), 1.25; 95% confidence interval (CI), 0.82-1.91, I² = 55%], graft loss at 1 year (pooled OR = 1.30, 95%CI: 0.75-2.24, I² = 0%) or 1-year mortality (pooled OR = 1.53, 95%CI: 0.90-2.58, I² = 34%). However, PPI exposure was significantly associated with hypomagnesemia (pooled OR = 1.56, 95%CI: 1.19-2.05, I² = 27%). Funnel plots and Egger regression asymmetry test were performed and showed no publication bias.

CONCLUSION

PPI use was not associated with significant risks of higher acute rejection, graft loss, or 1-year mortality. However, the risk of hypomagnesemia was significantly increased with PPI use. Thus, future studies are needed to assess the impact of PPIs on long-term outcomes.

Inosine Monophosphate Dehydrogenase Pharmacogenetics in Hematopoietic Cell Transplantation Patients

We evaluated inosine monophosphate dehydrogenase (IMPDH) 1 and IMPDH2 pharmacogenetics in 247 recipient-donor pairs after nonmyeloablative hematopoietic cell transplant (HCT). Patients were conditioned with total body irradiation + fludarabine and received grafts from related or unrelated donors (10% HLA mismatch), with postgraft immunosuppression of mycophenolate mofetil (MMF) with a calcineurin inhibitor. Recipient and donor IMPDH genotypes (rs11706052, rs2278294, rs2278293) were not associated with day 28 T cell chimerism, acute graft-versus-host disease (GVHD), disease relapse, cytomegalovirus reactivation, nonrelapse mortality, or overall survival. Recipient IMPDH1 rs2278293 genotype was associated with a lower incidence of chronic GVHD (hazard ratio, .72; P = .008) in nonmyeloablative HCT recipients. Additional studies are needed to confirm these results with the goal of identifying predictive biomarkers to MMF that lower GVHD.

Pharmacogenetics of drug-drug interaction and drug-drug-gene interaction: a systematic review on CYP2C9, CYP2C19 and CYP2D6

Currently, most guidelines on drug-drug interaction (DDI) neither consider the potential effect of genetic polymorphism in the strength of the interaction nor do they account for the complex interaction caused by the combination of DDI and drug-gene interaction (DGI) where there are multiple biotransformation pathways, which is referred to as drug-drug-gene interaction (DDGI). In this systematic review, we report the impact of pharmacogenetics on DDI and DDGI in which three major drug-metabolizing enzymes - CYP2C9, CYP2C19 and CYP2D6 - are central. We observed that several DDI and DDGI are highly gene-dependent, leading to a different magnitude of interaction. Precision drug therapy should take pharmacogenetics into account when drug interactions in clinical practice are expected.

Hepatic drug interaction between tacrolimus and lansoprazole in a bone marrow transplant patient receiving voriconazole and harboring CYP2C19 and CYP3A5 heterozygous mutations

BACKGROUND

A drug interaction between oral tacrolimus (TAC) and lansoprazole (LAN) has been reported in patients with CYP2C19 hetero/homozygous mutations and the CYP3A5 *3/*3 genotype. A PubMed search (implemented March 16, 2011) using search terms drug interaction, tacrolimus, and lansoprazole failed to identify drug interactions in CYP3A5 extensive metabolizers and parenterally administered TAC.

OBJECTIVE

The purpose of this study was to report a case of drug interaction between intravenously administered TAC and LAN in a patient being treated with voriconazole (VCZ) and harboring CYP2C19 and CYP3A5 heterozygous mutations.

CASE SUMMARY

An 18-year-old Japanese man weighing 53 kg with an anaplastic large cell lymphoma received continuous IV administration of TAC as post-transplantation prophylaxis against graft-versus-host disease (GVHD) after an allogeneic bone marrow transplantation (BMT). He began receiving IV LAN 60 mg/d and VCZ 400 mg/d initiated the day before BMT. His blood TAC concentrations were within the range of 9-16 ng/mL from post-BMT day 5 to 26. The engraftment of the donor's hematopoietic cells was observed on day 17. The LAN dose was reduced to 15 mg/d PO on day 26, and the blood TAC concentration subsequently decreased to 6.6 ng/mL, with GVHD-related symptoms emerging on day 28. Consequently, the plasma VCZ concentration also decreased from 5.0 ng/mL to 2.5 ng/mL after reducing the LAN dose. VCZ was switched to liposomal amphotericin B on day 48. Thereafter, the blood TAC concentration decreased to 4.4 ng/mL on day 51. Ultimately, the patient died on day 77 because of the recurrence and progression of lymphoma. Other drugs taken were acyclovir, ursodeoxycholic acid, cefepime, meropenem, vancomycin, lenograstim, and dopamine hydrochloride. The genotyping analyses using the pre-BMT and post-engraftment (day 33) samples indicated that both were CYP2C19 *1/*2, CYP3A5 *1/*3 and CYP2C9 *1/*1. The calculated Drug Interaction Probability Score between TAC and LAN was 6, indicating a probable interaction. TAC and VCZ concentrations were measured by an affinity column-mediated immunometric assay and HPLC, respectively. Mutant alleles were examined using the multiplex extension of unlabeled oligonucleotide primers with fluorescently labeled dideoxynucleoside triphosphates.

CONCLUSIONS

In a BMT patient with CYP2C19 and CYP3A5 heterozygous mutations, blood TAC concentration decreased after reducing the LAN dose, which appeared to be caused by a reduction in plasma VCZ concentration.

Absence of influence of concomitant administration of rabeprazole on the pharmacokinetics of tacrolimus in adult living-donor liver transplant patients: a case-control study

This study assesses the effects of rabeprazole on the pharmacokinetics of tacrolimus, considering the cytochrome P450 (CYP) 2C19 and CYP3A5 genotypes of living-donor liver transplant patients (native intestine) and their corresponding donors (graft liver). We examined the concentration/dose ratio of tacrolimus in transplant patients treated with (n=17) or without (n=38) rabeprazole at 10 mg/day on postoperative days 22-28. A stratified analysis revealed no significant differences between the control and rabeprazole groups in the median (range) concentration/dose ratio of tacrolimus [(ng/mL)/(mg/day)] for CYP2C19 extensive/intermediate metabolizers [2.71 (1.00-6.15) versus 2.55 (0.96-9.25); P=0.85] and for poor metabolizers [4.92 (2.44-7.00) versus 3.82 (2.00-7.31); P=0.68], respectively. Even based on the classification of CYP2C19 genotypes of donors, no significant difference in the concentration/dose ratio of tacrolimus was found for the two groups (CYP2C19 extensive/intermediate metabolizers, P=0.52; poor metabolizers, P=0.51). The same was observed for CYP3A5(*)1 carriers (P=0.97 for native intestine; P=0.87 for graft liver) and CYP3A5(*)3/(*)3 carriers (P=0.89 for native intestine; P=0.56 for graft liver). These findings suggest a safer dosing and monitoring of tacrolimus coadministered with rabeprazole early on after liver transplantation regardless of the CYP2C19 and CYP3A5 genotypes of transplant patients and their donors.

Proton pump inhibitors reduce mycophenolate exposure in heart transplant recipients-a prospective case-controlled study

This prospective study investigates the impact of proton pump inhibitors (PPI) on mycophenolic acid (MPA) pharmacokinetics in heart transplant recipients receiving mycophenolate mofetil (MMF) and tacrolimus. MPA plasma concentrations at baseline (C(0 h)), 30 min (C(0.5 h)), 1(C(1 h)) and 2 h (C(2 h)) were obtained by high-performance liquid chromatography (HPLC) in 22 patients treated with pantoprazole 40 mg and MMF 2000 mg. Measurements were repeated 1 month after pantoprazole withdrawal. A four-point limited-sampling strategy was applied to calculate the MPA area under the curve (MPA-AUC). Predose MPA concentrations with PPI were 2.6 +/- 1.6 mg/L versus 3.4 +/- 2.7 mg/L without PPI (p = ns). Postdose MPA concentrations were lower with PPI at C(0.5 h) (8.3 +/- 5.7 mg/L vs. 18.3 +/- 11.3 mg/L, p = 0.001) and C(1 h) (10.0 +/- 5.6 mg/L vs. 15.8 +/- 8.4 mg/L, p = 0.004), without significant differences at C(2 h) (8.3 +/- 6.5 mg/L vs. 7.6 +/- 3.9 mg/L). The MPA-AUC was significantly lower with PPI medication (51.2 +/- 26.6 mg x h/L vs. 68.7 +/- 30.3 mg x h/L; p = 0.003). The maximum concentration of MPA (MPA-C(max)) was lower (12.2 +/- 7.5 mg/L vs. 20.6 +/- 9.3 mg/L; p = 0.001) and the time to reach MPA-C(max) (t(max)) was longer with PPI (60.0 +/- 27.8 min vs. 46.4 +/- 22.2 min; p = 0.05). This is the first study to document an important drug interaction between a widely used immunosuppressive agent and a class of drugs frequently used in transplant patients. This interaction results in a decreased MMF drug exposure which may lead to patients having a higher risk for acute rejection and transplant vasculopathy.

Proton pump inhibitors: an update of their clinical use and pharmacokinetics

BACKGROUND

Proton pump inhibitors (PPIs) represent drugs of first choice for treating peptic ulcer, Helicobacter pylori infection, gastrooesophageal reflux disease, nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal lesions (complications), and Zollinger-Ellison syndrome.

RESULTS

The available agents (omeprazole/esomeprazole, lansoprazole, pantoprazole, and rabeprazole) differ somewhat in their pharmacokinetic properties (e.g., time-/dose-dependent bioavailability, metabolic pattern, interaction potential, genetic variability). For all PPIs, there is a clear relationship between drug exposure (area under the plasma concentration/time curve) and the pharmacodynamic response (inhibition of acid secretion). Furthermore, clinical outcome (e.g., healing and eradication rates) depends on maintaining intragastric pH values above certain threshold levels. Thus, any changes in drug disposition will subsequently be translated directly into clinical efficiency so that extensive metabolizers of CYP2C19 will demonstrate a higher rate of therapeutic nonresponse.

CONCLUSIONS

This update of pharmacokinetic, pharmacodynamic, and clinical data will provide the necessary guide by which to select between the various PPIs that differ-based on pharmacodynamic assessments-in their relative potencies (e.g., higher doses are needed for pantoprazole and lansoprazole compared with rabeprazole). Despite their well-documented clinical efficacy and safety, there is still a certain number of patients who are refractory to treatment with PPIs (nonresponder), which will leave sufficient space for future drug development and clinical research.

Rabeprazole: a second-generation proton pump inhibitor in the treatment of acid-related disease

Rabeprazole is a proton pump inhibitor (PPI) presenting a very advantageous pharmacodynamic and pharmacokinetic profile over older PPIs. In particular, this drug has a very fast onset of action, due to a short activation time and a very high pKa, and may therefore be defined as a 'second generation' PPI. The aim of this article is to provide an update on the pharmacology and clinical profile of rabeprazole and its use in acid-related disorders, with a particular focus on its role in gastroesophageal reflux disease; in the treatment and prevention of duodenal and gastric ulcers and Zollinger-Ellison syndrome; in the therapy of the extraesophageal manifestations of gastroesophageal reflux disease (in particular the respiratory and ear, nose and throat ones); and in the eradication of Helicobacter pylori.

Clinical efficacy of esomeprazole in the prevention and healing of gastrointestinal toxicity associated with NSAIDs in elderly patients

NSAIDs are widely prescribed for the treatment of pain, inflammation and rheumatic disorders, but their use is associated with adverse gastrointestinal effects, ranging from dyspeptic symptoms and peptic ulcers to more serious complications. Elderly patients are at high risk of experiencing NSAID-induced gastrointestinal tract injury and should be considered candidates for prophylactic pharmacological therapy. In studies conducted in adult patients, proton pump inhibitors (PPIs) such as esomeprazole have been shown to prevent or reduce NSAID-induced gastrointestinal injury. The beneficial effects of esomeprazole can be ascribed largely to its ability to maintain sustained inhibition of gastric acid secretion, although there is evidence to suggest that pharmacodynamic properties unrelated to acid inhibition may also contribute to the gastroprotective effects of this agent. Although there are limited data on the use of esomeprazole specifically in elderly patient populations, studies of patients at high risk of NSAID-induced gastrointestinal toxicity because of advanced age indicate that this PPI is both effective and well tolerated when administered in conjunction with NSAIDs. Thus, esomeprazole can be regarded as a useful option for prophylactic therapy in elderly patients receiving long-term NSAID therapy.

Influence of lansoprazole and rabeprazole on mycophenolic acid pharmacokinetics one year after renal transplantation

Peptic ulcer disease is a common complication after organ transplantation, and long-term administration of antiulcer agents is needed in many renal transplant recipients. Although several drug interactions with mycophenolic acid (MPA), the active metabolite of the prodrug mycophenolate mofetil (MMF), have been reported, little is known about the interaction between MPA and proton pump inhibitors (PPIs). The present study investigated the drug interaction between MMF and lansoprazole or rabeprazole and the impact of cytochrome (CYP) 2C19, and multidrug resistance (MDR)1 C3435T polymorphisms on these drug interactions at 1 year after renal transplantation. Retrospectively, 61 recipients were divided into 3 groups: MMF and tacrolimus as combination immunosuppressive therapy, together with either 30 mg lansoprazole (n = 22) or 10 mg rabeprazole (n = 17), or without PPI (n = 22). One year after transplantation, plasma concentrations of MPA were measured by high-performance liquid chromatography. The mean dose-unadjusted and -adjusted Cmax of MPA with 30 mg lansoprazole were significantly lower than those without PPI (11.8 vs. 17.8 microg/mL, P = 0.0197, and 22.6 vs. 33.1 ng/mL/mg MMF, P = 0.0222, respectively). In recipients having the CYP2C19 *1/*2+*1/*3 or MDR1 C3435T CC genotype, the mean dose-adjusted AUC0-12 of MPA with 30 mg lansoprazole was significantly smaller than that with 10 mg rabeprazole or without PPI. The plasma concentration of MPA was influenced by 30 mg lansoprazole but not 10 mg rabeprazole. Because of the greater gastric acid secretion-inhibitory effect of 30 mg lansoprazole in recipients having the CYP2C19 *1/*2+*1/*3 (intermediate metabolizer) or MDR1 C3435T CC genotype, the elution and hydrolysis of MMF might be decreased. Although the clinical relevance might be minor, the fact that administration of 30 mg lansoprazole in patients having the CYP2C19 *2 or *3 allele or the MDR1 C3435T CC genotype diminishes the absorption of MPA in the maintenance stage after renal transplantation should be taken into consideration with regard to the MPA pharmacokinetics.