Perioperative doses of ondansetron or dolasetron do not lengthen the QT interval

Elucidating effects of environmental exposure using human‐induced pluripotent stem cell disease modeling

Induced pluripotent stem cells (iPSCs) are a powerful modeling system for medical discovery and translational research. To date, most studies have focused on the potential for iPSCs for regenerative medicine, drug discovery, and disease modeling. However, iPSCs are also a powerful modeling system to investigate the effects of environmental exposure on the cardiovascular system. With the emergence of e‐cigarettes, air pollution, marijuana use, opioids, and microplastics as novel cardiovascular risk factors, iPSCs have the potential for elucidating the effects of these toxins on the body using conventional two‐dimensional (2D) arrays and more advanced tissue engineering approaches with organoid and other three‐dimensional (3D) models. The effects of these environmental factors may be enhanced by genetic polymorphisms that make some individuals more susceptible to the effects of toxins. iPSC disease modeling may reveal important gene–environment interactions that exacerbate cardiovascular disease and predispose some individuals to adverse outcomes. Thus, iPSCs and gene‐editing techniques could play a pivotal role in elucidating the mechanisms of gene–environment interactions and understanding individual variability in susceptibility to environmental effects.

Investigation role of ondansetron on long QT interval among non-cardiac patients

Background

Ondansetron is one of the commonly prescribed anti-emetic in emergency department however, high dose of the drug is associated with prolonged QT interval. This study was designed to evaluate the effect of ondansetron on prolongation of QT interval among patients referred to our emergency department.

Methods

In this cross-sectional study patients referred to the emergency department of Imam Reza hospital from June 2019 to December 2019 were included. Before the administration of ondansetron 12-lead electrocardiography was performed in all the patients. 4 mg of i.v. ondansetron was administered to these patients and ECG was obtained again. QT interval was calculated automatically from the system from these electrocardiographs. Demographic data of these patients along with QT interval findings was recorded in the questionnaire and analyzed statistically using SPSS software.

Results

A total of 55 patients were included with the mean age of 58 ± 13 years, where 36 were females (65.5%) and 19 were males (34.5%). The mean QT interval before and after injection of 4 mg intravenous ondansetron was not statistically significant, p-value = 0.073. Similarly, QT interval before and after the administration of the drugs was also not significantly different among females and males, p = 0.479 and p = 0.078, respectively. The age of the patients was also not associated with prolonged QT interval, p = 0.948.

Conclusions

The findings of our study indicated that 4 mg i.v. administration of ondansetron among non-cardiac patients referred to emergency department is not associated with QT interval prolongation.

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Ondansetron is one of the commonly prescribed anti-emetic in emergency department.

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High dose of the drug is associated with prolonged QT interval.

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The findings indicated that 4 mg i.v. administration of ondansetron among non-cardiac patients.

Perioperative Implications of the 2020 American Heart Association Scientific Statement on Drug-Induced Arrhythmias-A Focused Review

The recently released American Heart Association (AHA) scientific statement on drug-induced arrhythmias discussed medications commonly associated with bradycardia, supraventricular tachycardias, and ventricular arrhythmias. The foundational data for this statement were collected from general outpatient and inpatient populations. Patients undergoing surgical and minimally invasive treatments are a unique subgroup, because they may experience hemodynamic changes associated with anesthesia and their procedure, receive multiple drug combinations not given in either inpatient or outpatient settings, or experience postprocedural inflammatory syndromes. Accordingly, the generalizability of the AHA scientific statement to this perioperative population is unclear. This focused review highlights important aspects of the new AHA scientific statement and their application to the perioperative setting. The authors review medications frequently encountered and given by anesthesiologists and their risk of drug-induced arrhythmias and discuss common anesthetic and adjunctive medications and their associated risks of bradycardia, atrial fibrillation, torsades de pointes, and drug-induced Brugada syndrome. In many instances, the risk of arrhythmia reported by the AHA scientific statement in the general population appeared to be higher than found in perioperative arenas. Furthermore, the authors discuss the arrhythmia risk of additional medications commonly ordered or administered by anesthesiologists that are not included in the AHA scientific statement. As patient and procedural complexity increases and novel anesthetic combinations propagate, further research and observational studies will be required to delineate further perioperative risks for drug-induced arrhythmia.

Nausea and Vomiting in 2021: A Comprehensive Update

GOAL

A comprehensive review of treatments for nausea and vomiting (N/V).

BACKGROUND

N/V are common symptoms encountered in medicine. While most cases of acute N/V related to a specific cause can be straightforward to manage, other cases of acute N/V such as chemotherapy-induced N/V and especially chronic unexplained N/V can be difficult to control, leading to a significant decline in the patient's quality of life and increased cost of medical care from repeated hospitalizations.

STUDY

Traditional management has relied on pharmacotherapy which may be inadequate in a certain proportion of these patients. Many of the medications used in the management of N/V have significant side effect profiles making the need for new and improved interventions of great importance.

RESULTS

This review covers a broad review of the pathophysiology of N/V, pharmacotherapy, including safety concerns and controversies with established pharmaceuticals, newer immunotherapies, bioelectrical neuromodulation (including gastric electrical stimulation), behavioral and surgical therapies, and complementary medicine.

CONCLUSION

On the basis of emerging understandings of the pathophysiology of N/V, improved therapies are becoming available.

The effects of ondansetron versus dexamethasone on electrocardiographic markers of ventricular repolarization in children undergoing cochlear implant

INTRODUCTION

Congenital hearing loss is associated with cardiac rhythm disturbances namely long Q-T syndrome. This study was designed to investigate the effect of anti-emetic doses of ondansetron and dexamethasone on ECG recordings in children undergoing cochlear implant surgery.

METHODS

Sixty-three pediatric patients scheduled for elective cochlear implantation were enrolled in the study. Two patients were excluded as their baseline ECG showed long QT syndrome. Anesthesia was induced with fentanyl, propofol and atracurium and maintained with propofol. Dexamethasone 0.1 mg.kg^-1or ondansetron 0.2 mg.kg^-1was randomly administered for the participants approximately 30 min before the end of surgery. ECG recording was performed 15 min after induction of anesthesia and 15 min after dexamethasone/ondansetron administration. RR interval, QRS duration, QT interval, and Tp-e interval were measured by a blinded cardiologist.

RESULTS

Ondansetron resulted in no significant changes in RR, JTc and QTc intervals; while prolongedTp-e interval. Multivariable logistic regression analysis showed that use of ondansetron was an independent predictor of QTc prolongation after adjustment for age, gender and baseline QTc (OR = 17.94, CI 95% 1.97-168.70, p = 0.011). The incidence of postoperative retching/vomiting in ondansetron group was significantly lower than dexamethasone group. (3.2% vs. 26.7%, p = 0.011).

CONCLUSION

The risk of arrhythmias with the use of ondansetron in otherwise healthy candidates of cochlear implant is very low. However, the drug may induce significant changes in ECG parameters. The clinical significance of these changes in patients with cardiac conduction abnormalities should be investigated in further studies.

Perianesthesia Implications and Considerations for Drug-Induced QT Interval Prolongation

Prolongation of the QT interval can predispose patients to fatal arrhythmias such as torsade de pointes. While arrhythmias can occur spontaneously in patients with a genetic predisposition, drugs such as ondansetron and droperidol, which are frequently used in the perioperative period, have been implicated in the prolongation of the QT interval. As the list of medications that cause QT prolongation grows, anesthesia providers and perioperative nurses must be informed regarding the importance of the QT interval. This article reviews the physiology and measurement of the QT interval, the risk factors of QT prolongation, the mechanism of drug-induced QT prolongation, and perioperative considerations for patient care.

Effect of a single dose of i.v. ondansetron on QTc interval in emergency department patients

PURPOSE

Results of a study to determine whether i.v. administration of a single dose of 4 mg of ondansetron was associated with QT interval prolongation in emergency department (ED) patients are reported.

METHODS

In a prospective observational study conducted at an urban academic medical center ED, a convenience sample of adult ED patients treated with ondansetron 4 mg i.v. were enrolled. A 12-lead electrocardiogram (ECG) was obtained immediately before and 5 minutes after ondansetron administration. Measurements of heart rate-corrected QT interval (QTc measurements) provided by ECG machines were evaluated. An electrophysiologist analyzed all ECGs for adverse electrical events and verified the accuracy of QTc values. The primary objective was to measure the QTc change from baseline after ondansetron administration. The secondary objective was to describe adverse electrical cardiac events. Interactions between ondansetron and patients' home medications or ED-provided medications were analyzed.

RESULTS

Among patients included in the data analysis (n = 20), ondansetron administration was associated with a mean QTc increase of 16.2 msec (95% confidence interval, 4.2-28.2 msec; p = 0.01) and a median increase of 12 msec (interquartile range, 5.5-18.0 msec; p < 0.01). One patient had a significant cardiac event (pulseless electrical activity) that was likely unrelated to ondansetron use. The home medications of 9 patients (42.9%) were deemed to pose a risk of torsades de pointes, and 17 major QT-prolonging drug-drug interactions were identified.

CONCLUSION

Significant QTc prolongation occurred in ED patients receiving a single 4-mg i.v. dose of ondansetron. None of the patients had an ondansetron-related cardiac adverse event.

Providers' Response to Clinical Decision Support for QT Prolonging Drugs

Commonly used drugs in hospital setting can cause QT prolongation and trigger life-threatening arrhythmias. We evaluate changes in prescribing behavior after the implementation of a clinical decision support system to prevent the use of QT prolonging medications in the hospital setting. We conducted a quasi-experimental study, before and after the implementation of a clinical decision support system integrated in the electronic medical record (QT-alert system). This system detects patients at risk of significant QT prolongation (QTc>500ms) and alerts providers ordering QT prolonging drugs. We reviewed the electronic health record to assess the provider's responses which were classified as "action taken" (QT drug avoided, QT drug changed, other QT drug(s) avoided, ECG monitoring, electrolytes monitoring, QT issue acknowledged, other actions) or "no action taken". Approximately, 15.5% (95/612) of the alerts were followed by a provider's action in the pre-intervention phase compared with 21% (228/1085) in the post-intervention phase (p=0.006). The most common type of actions taken during pre-intervention phase compared to post-intervention phase were ECG monitoring (8% vs. 13%, p=0.002) and QT issue acknowledgment (2.1% vs. 4.1%, p=0.03). Notably, there was no significant difference for other actions including QT drug avoided (p=0.8), QT drug changed (p=0.06) and other QT drug(s) avoided (p=0.3). Our study demonstrated that the QT alert system prompted a higher proportion of providers to take action on patients at risk of complications. However, the overall impact was modest underscoring the need for educating providers and optimizing clinical decision support to further reduce drug-induced QT prolongation.

Local-anesthetic like inhibition of the cardiac sodium channel Nav1.5 α-subunit by 5-HT3 receptor antagonists

5-hydroxytryptamine 3 receptor (5-HT3 receptor) antagonists are administered for prevention and therapy of nausea and vomiting. Although regarded as safe therapeutics, they can also provoke arrhythmias by prolonging the QRS interval. However, the mechanisms mediating this cardiotoxicity are poorly understood. Here we investigated effects of 5-HT3 receptor antagonists on the cardiac Na(+) channel Nav1.5. We explored the interaction of dolasetron, tropisetron, granisetron and ondansetron on the human α-subunit Nav1.5 heterologously expressed in HEK293 cells. Sodium currents were explored by means of whole-cell patch clamp recordings. All four substances inhibited the Nav1.5 in a concentration and state-dependent manner. Dolasetron displayed the lowest blocking efficacy, and tropisetron was the most potent blocker with a half maximum blocking concentration of 18µM for tonic block of inactivated channels. Tropisetron was also the most potent use-dependent inhibitor, and it also induced a strong open -channel block. Both tonic and use-dependent block by tropisetron were abbreviated on the local-anesthetic insensitive mutant Nav1.5-F1760A. Co-administration of tropisetron and the local anesthetic bupivacaine or the hypnotic propofol augmented inhibition of Nav1.5. Our data demonstrate that 5-HT3 receptor antagonists induce a local-anesthetic like inhibition of Nav1.5, and that they display different blocking efficacies. Reports on a relevant cardiotoxicity of dolasetron as opposed to other 5-HT3 receptor antagonists do not seem to correlate with a block of Nav1.5. As inhibition of Nav1.5 was enhanced by propofol and bupivacaine however, it is possible that a combined administration of Na(+) channel blockers and 5-HT3 receptor antagonists can provoke arrhythmias.