Acute calcineurin inhibitor overdose: analysis of cases reported to a national poison center between 1995 and 2011

Metabolic network and proteomic expression perturbed by cyclosporine A to model microbe Escherichia coli

Cyclosporine A (CsA) is a model drug that has caused great concern due to its widespread use and abuse in the environment. However, the potential harm of CsA to organisms also remains largely unknown, and this issue is exceptionally important for the health risk assessment of antibiotics. To address this concern, the crosstalk between CsA stress and cellular metabolism at the proteomic level in Escherichia coli was investigated and dissected in this study. The results showed that CsA inhibited E. coli growth in a time-dependent manner. CsA induced reactive oxygen species (ROS) overproduction in a dose- and time-dependent manner, leading to membrane depolarization followed by cell apoptosis. In addition, translation, the citric acid cycle, amino acid biosynthesis, glycolysis and responses to oxidative stress and heat were the central metabolic pathways induced by CsA stress. The upregulated proteins, including PotD, PotF and PotG, controlled cell growth. The downregulated proteins, including SspA, SspB, CstA and DpS, were regulators of self-feedback during the starvation process. And the up- and downregulated proteins, including AtpD, Adk, GroS, GroL and DnaK, controlled energy production. These results provide an important reference for the environmental health risk assessment of CsA.

The Many Faces of Calcineurin Inhibitor Toxicity-What the FK?

Calcineurin inhibitors (CNIs) are both the savior and Achilles' heel of kidney transplantation. Although CNIs have significantly reduced rates of acute rejection, their numerous toxicities can plague kidney transplant recipients. By 10 years, virtually all allografts will have evidence of CNI nephrotoxicity. CNIs have been strongly associated with hypertension, dyslipidemia, and new onset of diabetes after transplantation-significantly contributing to cardiovascular risk in the kidney transplant recipient. Multiple electrolyte derangements including hyperkalemia, hypomagnesemia, hypercalciuria, metabolic acidosis, and hyperuricemia may be challenging to manage for the clinician. Finally, CNI-associated tremor, gingival hyperplasia, and defects in hair growth can have a significant impact on the transplant recipient's quality of life. In this review, the authors briefly discuss the pharmacokinetics of CNI and discuss the numerous clinically relevant toxicities of commonly used CNIs, cyclosporine and tacrolimus.

Successful Treatment of Life-Threatening Small Bowel Bleeding With Thalidomide After Living Donor Kidney Transplantation: A Case Report

Gastrointestinal bleeding after kidney transplantation is a complication that can occur from immunosuppressant use. We present a case of refractory small bowel bleeding treated successfully with thalidomide after multiple failed attempts of conventional treatment. A 65-year-old male patient with diabetic nephropathy underwent living donor kidney transplantation. The surgery was uneventful, however, he developed immunosuppressant-induced melena with unstable vital signs 11 days later. There were a total of 4 bleeding episodes until the 90th postoperative day, and he received a total of 290 units of red blood cell transfusion during this period. Endoscopic clipping, transarterial embolization, and 2 surgical interventions failed to stop the bleeding. A trial of thalidomide 100 mg per day finally stopped the bleeding and the patient was discharged on the 110th postoperative day with a functioning renal graft. This case shows that thalidomide can be a safe option to treat immunosuppressant-induced refractory gastrointestinal bleeding in the setting of kidney transplantation. Additionally, this is the first case that reports the survival of a renal graft after more than 3000 mL of transfusion.

Tacrolimus: 20 years of use in adult kidney transplantation. What we should know about its nephrotoxicity

Tacrolimus (or FK506), a calcineurin inhibitor (CNI) introduced in field of transplantation in the 1990s, is the cornerstone of most immunosuppressive regimens in solid organ transplantation. Its use has revolutionized the future of kidney transplantation (KT) and has been associated with better graft survival, a lower incidence of rejection, and improved drug tolerance with fewer side effects compared to cyclosporine. However, its monitoring remains complicated and underexposure increases the risk of rejection, whereas overexposure increases the risk of adverse effects, primarily nephrotoxicity, neurotoxicity, infections, malignancies, diabetes, and gastrointestinal complaints. Tacrolimus nephrotoxicity can be nonreversible and can lead to kidney graft loss, and its diagnosis is therefore best made with reference to the clinical context and after exclusion of other causes of graft dysfunction. Many factors contribute to its development including: systemic levels of tacrolimus; local renal exposure to tacrolimus; exposure to metabolites of tacrolimus; local susceptibility factors for CNI nephrotoxicity independent of systemic or local tacrolimus levels, such as the age of a kidney; local renal P-glycoprotein, local intestinal and hepatic cytochrome P450A3, and renin angiotensin system activation. The aim of this review is to describe the pharmacokinetics, pharmacodynamics, and mechanisms of acute and chronic tacrolimus nephrotoxicity in adult KT.

Using known drug interactions to manage supratherapeutic calcineurin inhibitor concentrations

OBJECTIVES

To summarize the available body of evidence guiding the management of supratherapeutic concentrations of calcineurin inhibitors (CNI) using cytochrome P450 (CYP450) enzyme inducers.

METHODS

A nondate restricted literature search within MEDLINE, Embase, and Scopus was performed using the terms "cyclosporine," "tacrolimus," "calcineurin inhibitor," "toxicity," "pharmacokinetics," "carbamazepine," "rifampin," "phenytoin," and "phenobarbital." Additional references were identified from a review of all included citations. All English-language reports that describe the management of supratherapeutic CNI concentrations with interventions targeting metabolic induction using CYP450 enzyme inducers were evaluated.

RESULTS

A total of 10 publications were identified in which a CYP450 enzyme inducer was utilized intentionally to enhance CNI clearance in the setting of supratherapeutic concentrations; 7 case reports describe the use of phenytoin and 3 case reports describe the use of phenobarbital. Patient demographics, dosing strategies employed, and reported efficacy across this series of publications are heterogeneous; however, both agents appear to be well-tolerated when used in this setting.

CONCLUSIONS

There is a paucity of published data on the use of CYP450 enzyme inducers for the management of supratherapeutic CNI concentrations. While routine use of this approach cannot be recommended, thorough risk-benefit analyses should be performed in the management of each such clinical scenario.

Association Between Readmission After Liver Transplant and Adverse Immunosuppressant Reactions: A Prospective Cohort With a 1-Year Follow-up

OBJECTIVE

To measure the association between readmission after liver transplantation and corresponding adverse drug reactions.

METHODS

A total of 48 patients undergoing liver transplantation were prospectively followed for 1 year. Of these, 23 were readmitted and evaluated by a pharmacist for causes of adverse drug reaction. The detection of adverse drug reactions was based on a combination of clinical interviews and physical and laboratory exams. Adverse reactions were defined in accordance with the Naranjo algorithm.

RESULTS

A total of 67.6% of all readmissions were related to adverse drug reactions, with tacrolimus accounting for 80% of the drug reactions. The most common cause of readmission was infection (48.6%), followed by procedure-related reasons (29.7%). Of all patients requiring admission, 39.1% had Model for End-stage Liver Disease (MELD) scores below 21 at the time of transplantation, 17.4% had MELD scores between 21 and 29, and 43.5% had MELD scores above 29. Most (66.7%) of those readmitted more than twice had MELD scores above 29.

CONCLUSION

Adverse drug reactions related to immunosuppressants frequently lead to readmission among liver transplant patients, and in our series tacrolimus was the most frequently associated drug.

Accidental Overdose of Oral Cyclosporine in Haematopoietic Stem Cell Transplantation: A Case Report and Literature Review

A 26-year-old woman developed symptoms of acute toxicity during cyclosporine (CsA) therapy for graft-versus-host disease prophylaxis. The standard regimen included CsA in a dose of 1.5 mg/kg (120 mg) every 12 h, but, as a medication error, she received a high dose of 500 mg of oral CsA. After 2 h, she developed nausea and vomiting and, subsequently, flushing, chest tightness, tremor and vertigo. Laboratory and clinical examinations revealed high blood CsA concentrations (1000 ng/mL after 12 h) with a mild increase in blood pressure. Therefore, the patient was diagnosed with an acute CsA overdose. Before confirmation of the overdose by measurement of drug concentrations, the second dose was administered at its routine time because of uncertainty about the aetiology of the symptoms. The third dose was withheld, and the patient was monitored closely for clinical and laboratory presentations until the time when the abnormalities were relieved. CsA administration was then resumed with the correct prescription. The patient was discharged with successful engraftment and normal biochemical laboratory results after 1 month. Evaluation with the Naranjo assessment score indicated a probable relationship between the patient's symptoms and overdosage with the suspected drug. Currently, detailed presentations of acute CsA toxicity cases due to overdose are limited in the medical literature. Evaluation of the patient's medical and laboratory records, with cooperation of all responsible clinical staff, along with a review of the literature, were very helpful in discovery of the toxicity incident. Vigilance of health care providers with regard to medication errors and early detection of toxicity symptoms can decrease CsA-related morbidity and mortality in the future.

Acute sirolimus overdose: a multicenter case series

BACKGROUND

There are few data relating to sirolimus overdose in the medical literature. Our objectives were to describe all cases of overdose with sirolimus reported to Swiss, German and Austrian Poisons Centres between 2002-2013.

METHODS

An observational case-series analysis was performed to determine circumstances, magnitude, management and outcome of sirolimus overdose.

RESULTS

Five cases of acute sirolimus overdose were reported--three in young children and two in adults. Four were accidental and one was with suicidal intent. Two patients developed symptoms probably related to sirolimus overdose: mild elevation of alkaline phosphatase, fever and gastroenteritis in a 2.5-year-old male who ingested 3 mg, and mild changes in total cholesterol in an 18-year-old female after ingestion of 103 mg. None of these events were life-threatening. Serial blood concentration measurements were performed starting 24 h after ingestion of 103 mg in a single case, and these followed a similar pharmacokinetic time-course to measurements taken after dosing in the therapeutic range.

CONCLUSIONS

Acute sirolimus overdose occurred accidentally in the majority of cases. Even large overdoses appeared to be well-tolerated, however children might be at greater risk of developing complications. Further study of sirolimus overdose is needed.

Acute mycophenolate overdose: case series and systematic literature analysis

BACKGROUND

Literature regarding acute human toxicity of mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) is limited.

OBJECTIVES

Our objectives were to describe all cases of overdose with MMF or EC-MPS reported to the Swiss Toxicological Information Centre (STIC) or in the literature between 1995 and 2013. Therefore, we performed an observational case-series and systematic literature search to determine circumstances, magnitude, management and outcome of overdose with MMF or EC-MPS.

RESULTS

Of 152,762 reports to STIC, 15 (7 pediatric) involved overdose with MMF (n = 13) or EC-MPS (n = 2). Three cases from other centers were identified from a systematic literature search. The magnitude of overdose ranged from 1.2 to 16.7 (median 2.9) times usual dose. Six (33%) MMF overdoses had attributable symptoms, which included abdominal pain, vomiting, headache and dizziness. The majority of findings were minor, although a 9-fold MMF overdose caused hypotension 8 h after ingestion and a 12.5-fold overdose caused leukopenia after 5 days. Symptoms did not occur in patients who took 2.5 times or less of their usual MMF dose. Gastrointestinal decontamination measures with activated charcoal were undertaken in one-third of cases.

CONCLUSIONS

Acute MMF and EC-MPS overdoses had a favorable outcome in all cases reported to STIC and in the literature.

Acute thiopurine overdose: analysis of reports to a National Poison Centre 1995-2013

Literature regarding acute human toxicity of thiopurines is limited to a handful of case reports. Our objectives were to describe all cases of overdose with thiopurines reported to the Swiss Toxicological Information Centre between 1995–2013. A retrospective analysis was performed to determine circumstances, magnitude, management and outcome of overdose with these substances. A total of 40 cases (14 paediatric) were reported (azathioprine, n = 35; 6-mercaptopurine, n = 5). Of these, 25 were with suicidal intent, 12 were accidental and 3 were iatrogenic errors. The magnitude of overdose ranged from 1.5 to 43 (median 8) times the usual dose in adults. Twelve cases (30%) had attributable symptoms. The majority of these were minor and included gastrointestinal complaints and liver function test and blood count abnormalities. Symptoms were experienced by patients who took at least 1.5-times their usual daily thiopurine dose. Overdoses over two or more consecutive days, even if of modest size, were less well tolerated. One case of azathioprine and allopurinol co-ingestion over consecutive days led to agranulocytosis. Decontamination measures were undertaken in 11 cases (10 activated charcoal, 1 gastric lavage) and these developed fewer symptoms than untreated patients. This study shows that acute overdoses with thiopurines have a favourable outcome in the majority of cases and provides preliminary evidence that gastrointestinal decontamination with activated charcoal may reduce symptom development after overdose of these substances if patients present to medical services soon after ingestion.

Hepatotoxicity and drug interactions in liver transplant candidates and recipients

In this article the medications that have been shown to increase rates of drug-induced liver injury in patients with cirrhosis and the important drug-drug interactions in recipients of liver transplantation are reviewed. In general, the risk of drug-induced liver injury in patients with cirrhosis does not seem to be higher when compared with the noncirrhotic population. There are, however, 2 classes of agents that have been implicated-medications used to treat tuberculosis and medications used to treat human immunodeficiency virus infection. However, with careful monitoring, even significant interactions can be effectively managed.