Clotrimazole troches induce supratherapeutic blood levels of sirolimus and tacrolimus in an allogeneic hematopoietic cell-transplant recipient resulting in acute kidney injury

Drug Interactions and Safe Prescription Writing for Liver Transplant Recipients

Immunosuppression optimization is central to graft function in liver transplant recipients. Post-transplantation patients develop new onset or worsening metabolic syndrome, are prone to atypical infections, and are at higher risk of developing cardiac and brain-related clinical events. In this context, liver transplant recipients are at risk of using multiple comedications alongside immunosuppressants. It is imperative for the transplant physician to understand the various drug-drug interactions that potentially reduce or promote toxicity of immunosuppression, as well as associated synergistic or antagonistic effects on extrahepatic organ systems. This comprehensive review discusses drug-drug interactions in liver transplant recipients and the impact and role of complementary and alternative medicines among individuals on immunosuppression.

Acute Kidney Injury after Bone Marrow Transplantation in Patients with Lymphomas and Leukemias

Introduction: Hematologic malignancies, including lymphomas and leukemias, may be treated with autologous or allogeneic bone marrow transplantation. However, these approaches can increase the risk of infection, sepsis, graft-versus-host disease, and nephrotoxicity, possibly resulting in acute kidney injury (AKI). Objective: To evaluate AKI in patients with lymphomas or leukemia submitted to bone marrow transplantation (BMT). Method: Retrospective, observational cohort study of cases from a database of 256 patients (53.9% males) hospitalized for BMT between 2012 and 2014 at a cancer hospital in Sao Paulo, Brazil. Of these, 79 were selected randomly for analysis. Demographic data, length of hospitalization, and associated morbidities were recorded. AKI was identified according to Kidney Diseases Improving Global Outcomes (KDIGO) criteria. Results: The most frequent diagnoses for the 79 cases were non-Hodgkin’s lymphoma (30.4%), acute myeloid leukemia (26.6%), and Hodgkin’s lymphoma (24.1%). The probability of 100 days-survival after BMT was 81%, and three years after BMT was 61%. In-hospital mortality was significantly higher among patients who presented AKI during hospitalization (p<0.001). However, there was no difference in overall life expectancy (p=0.770). Conclusion: A significant prevalence of AKI was found in patients with leukemia or lymphoma while they were hospitalized for BMT, resulting in significantly increased rates of in-hospital mortality. The presence of AKI during hospitalization was not associated with a subsequent reduction in life expectancy.

Impact of Clotrimazole Fungal Prophylaxis on Tacrolimus Exposure in Kidney Transplant Recipients: A Retrospective Study

Tacrolimus, an immunosuppressant prescribed to reduce the risk of organ rejection, is metabolized by cytochrome P450 and is a substrate for P-glycoprotein. Many medications affect tacrolimus concentrations, making it difficult to maintain exposure within its narrow therapeutic index. Clotrimazole troches, prescribed to posttransplant recipients immediately for the first 30 days for oral candidiasis prevention, are considered nonsystemic. However, data suggest a potential drug interaction, affecting tacrolimus exposure. To assess the magnitude of the effect of clotrimazole on tacrolimus trough levels, 97 kidney transplant recipients, on a stable dose of tacrolimus, were retrospectively evaluated. Tacrolimus trough concentrations were analyzed 7 and 14 days before and after discontinuation of clotrimazole. The median change in tacrolimus trough level was -1.3 ng/mL (confidence interval, -2.5, -1.0; P < .001) at day 7 and -2.8 ng/mL (confidence interval, -3.3, -1.6; P < .001) at day 14 after clotrimazole discontinuation, from a median baseline of 8.9 ng/mL. Overall, a reduction in tacrolimus level was observed in 60% of patients after discontinuation of clotrimazole. When assessing the effect of race and sex, no influence was found on the degree of change in tacrolimus level after clotrimazole discontinuation. In conclusion, clotrimazole exerts a significant interaction on tacrolimus where close monitoring of tacrolimus trough levels after discontinuation of clotrimazole is warranted.

Drug interactions between tacrolimus and clotrimazole troche: a data mining approach followed by a pharmacokinetic study

PURPOSE

This study investigated the effects of clotrimazole troche on the risk of transplant rejection and the pharmacokinetics of tacrolimus.

METHODS

The data mining approach was used to investigate whether the use of clotrimazole increased the risk of transplant rejection in patients receiving tacrolimus therapy. Patient data were acquired from the US Food and Drug Administration's Adverse Event Reporting System (FAERS) from the first quarter of 2004 to the end of 2017. Next, we retrospectively investigated the effect of clotrimazole troche on tacrolimus pharmacokinetics in seven patients who underwent heart transplantation between March and December 2017.

RESULTS

The FAERS subset data indicated a significant association between transplant rejection and tacrolimus with clotrimazole [reporting odds ratio 1.92, 95% two-sided confidence interval (95% CI) 1.43-2.58, information component 0.81, 95% CI 0.40-1.23]. The pharmacokinetic study demonstrated a significant correlation between trough concentration (C₀) and area under the concentration-time curve of tacrolimus after discontinuation of clotrimazole (R² = 0.60, P < 0.05) but not before its discontinuation. Furthermore, the median clearance/bioavailability of tacrolimus after discontinuation of clotrimazole was 2.2-fold greater than that before its discontinuation (0.27 vs. 0.59 L/h/kg, P < 0.05). The median C₀ decreased from 10.7 ng/mL on the day after discontinuation of clotrimazole to 6.5 ng/mL at 1 day and 5.3 ng/mL at 2 days after its discontinuation.

CONCLUSION

Immediate dose adjustments of tacrolimus may be beneficial to avoid transplant rejection when clotrimazole troche is added or discontinued.

Interactions between anti-infective agents and immunosuppressants-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation provide an update on potential drug-drug interactions between anti-infectives and immunosuppressants, which are most notable with calcineurin and mTOR inhibitors. Drug-drug interactions may occur through pharmacokinetic mechanisms leading to altered drug concentrations of either the anti-infective or immunosuppressive drug, or by pharmacodynamic interactions increasing or decreasing the efficacy or toxicity of the medications. Many of the significant pharmacokinetic interactions occur through inhibition or induction of the cytochrome 3A4 system by anti-infective agents leading to increased or decreased immunosuppressive agent levels, respectively. The membrane transporter P-glycoprotein is also often involved in drug interactions. Since the last iteration of these guidelines, multiple new hepatitis C virus direct-acting antivirals have become available for use in SOT recipients. Of these agents, some are substrates of cytochrome and drug transporter systems, while others inhibit these systems and may affect immunosuppressive agents. Due to the high risk for drug-drug interactions in the solid organ transplant population, practitioners must be aware of potential interactions and be vigilant in monitoring and adjusting drug dosing when appropriate.

Impact of the CYP3A5*1 Allele on the Pharmacokinetics of Tacrolimus in Japanese Heart Transplant Patients

BACKGROUND AND OBJECTIVE

Tacrolimus, a major immunosuppressant used after transplantation, is associated with large interindividual variation involving genetic polymorphisms in metabolic processes. A common variant of the cytochrome P450 (CYP) 3A5 gene, CYP3A5*3, affects blood concentrations of tacrolimus. However, tacrolimus pharmacokinetics at the early stage of transplantation have not been adequately studied in heart transplantation. We retrospectively examined the impact of the CYP3A5 genotype on tacrolimus pharmacokinetics at the early stage of heart transplantation.

METHODS

The tacrolimus pharmacokinetic profile was obtained from 65 patients during the first 5 weeks after heart transplantation. Differences in the patients' characteristics and tacrolimus pharmacokinetic parameters between the CYP3A5 expresser (*1/*1 or *1/*3 genotypes) and non-expresser (*3/*3 genotype) groups were assessed by the Chi-square test, Student's t test, or Mann-Whitney U test.

RESULTS

The CYP3A5 *1/*1, *1/*3, and *3/*3 genotypes were detected in 5, 22, and 38 patients, respectively. All patients started clotrimazole therapy approximately 1 week after starting tacrolimus. Apparent clearance and dose/weight to reach the target trough concentration (C₀) were significantly higher in the expresser group than in the non-expresser group (0.32 vs. 0.19 L/h/kg, p = 0.0003; 0.052 vs. 0.034 mg/kg/day, p = 0.0002); there were no significant differences in the area under the concentration-time curve from 0 to 12 h (AUC_0-12) and concentrations at any sampling time point between the two groups.

CONCLUSION

Similar concentration-time curves for tacrolimus were obtained in the expresser and non-expresser groups by dose adjustment based on therapeutic drug monitoring. These results demonstrate the importance of the CYP3A5 genotype in tacrolimus dose optimization based on therapeutic drug monitoring after heart transplantation.

Drug-drug interactions in patients receiving hematopoietic stem cell transplantation

INTRODUCTION

Recipients of hematopoietic stem cell transplantation (HSCT) are exposed to numerous drugs in both pre- and post-transplantation period, which creates an opportunity for drug-drug interactions (DDIs); if clinically relevant DDIs happen, the risk of adverse treatment outcomes is increased. Areas covered: This review is focused on DDIs in recipients of HSCT that were observed and published as clinical trials, case series or case reports. Relevant publications were found by the systematic search of the following online databases: MEDLINE, SCOPUS, EBSCO, and SCINDEX. Expert opinion: The most important DDIs involve cytostatic or immunosuppressant drug on one side, and antimicrobial drugs on the other. The majority of clinically relevant interactions have pharmacokinetic character, involving drug metabolizing enzymes in the liver. Antifungal azoles inhibit metabolism of many cytostatic and immunosuppressant drugs at cytochromes and increase their plasma concentrations. Macrolide antibiotics and fluoroqunolones should be avoided in HSCT recipients, as they have much larger potential for DDIs than other antibiotic groups. HSCT recipients increasingly receive new immunomodulating drugs, and further observational studies are needed to reveal unsuspected DDIs with clinical relevance.

Effects of clotrimazole troches on tacrolimus dosing in heart transplant recipients

BACKGROUND

Tacrolimus is a cornerstone of immunosuppression after transplantation but is highly susceptible to changes from interacting variables and has a narrow therapeutic index. Clotrimazole troches are commonly used as a non-systemic antifungal to prevent oral candidiasis. Studies suggest that clotrimazole troches, though minimally absorbed systemically, may affect tacrolimus concentrations by inhibition of metabolic enzyme activity in the intestines. However, the magnitude of the impact of clotrimazole on tacrolimus dosing requirements to maintain goal levels is not well described.

METHODS

To assess this, tacrolimus dose adjustments and trough concentrations were retrospectively examined in 95 heart transplant recipients before and after the discontinuation of clotrimazole.

RESULTS

The median percent tacrolimus dose change was an increase of 66.7% (IQR 28.6%, 100%) after clotrimazole discontinuation, and the median trough concentration percent change from baseline to the first trough after clotrimazole discontinuation (in the absence of a dose change) was -42.5% (IQR -52.3%, -30.9%). Five cases of allograft rejection were observed.

CONCLUSION

In conclusion, clotrimazole troches exert a meaningful interaction with tacrolimus that requires close monitoring and dose adjustment. The data from this single-center study provide novel information that could guide providers on the degree of tacrolimus dose adjustment needed when discontinuing clotrimazole prophylaxis after heart transplantation.

An Unusual Manifestation of Calcineurin Inhibitor-Induced Pain Syndrome in Kidney Transplantation: A Case Report and Literature Review

Patient: Female, 23

Final Diagnosis: Calcineurin inhibitor-induced pain syndrome

Symptoms: Back pain

Medication: —

Clinical Procedure: Supportive treatment

Specialty: Transplantology

Common oral complications of head and neck cancer radiation therapy: mucositis, infections, saliva change, fibrosis, sensory dysfunctions, dental caries, periodontal disease, and osteoradionecrosis

Patients undergoing radiation therapy for the head and neck are susceptible to a significant and often abrupt deterioration in their oral health. The oral morbidities of radiation therapy include but are not limited to an increased susceptibility to dental caries and periodontal disease. They also include profound and often permanent functional and sensory changes involving the oral soft tissue. These changes range from oral mucositis experienced during and soon after treatment, mucosal opportunistic infections, neurosensory disorders, and tissue fibrosis. Many of the oral soft tissue changes following radiation therapy are difficult challenges to the patients and their caregivers and require life-long strategies to alleviate their deleterious effect on basic life functions and on the quality of life. We discuss the presentation, prognosis, and management strategies of the dental structure and oral soft tissue morbidities resulting from the administration of therapeutic radiation in head and neck patient. A case for a collaborative and integrated multidisciplinary approach to the management of these patients is made, with specific recommendation to include knowledgeable and experienced oral health care professionals in the treatment team.