Severe Proarrhythmic Potential of the Antiemetic Agents Ondansetron and Domperidone

Pilot Study on QTc Interval in Dogs Treated with Domperidone

Domperidone is used as an immunomodulatory drug for Leishmania infantum infection and disease in dogs. However, a pro-arrhythmic side effect, caused by prolonged QT intervals, is reported in humans. This pilot study evaluated the corrected QT (QTc) interval in dogs treated with domperidone for preventive or therapeutic management of leishmaniosis. The electrocardiogram and blood concentration of creatinine, urea nitrogen, sodium, potassium, and chloride were evaluated seven days before the start and on the last day of therapy in 17 dogs receiving domperidone for four weeks. In two dogs, the QTc interval was measured before and 2 h, 3 h, and 12 h after administration of the drug on the first day of treatment. After treatment, QTc measures and chloride concentrations increased significantly, although the QTc value slightly exceeded the upper reference limit only in one dog, and chloride concentrations were always normal. Creatinine concentrations significantly decreased after therapy. In the two dogs monitored at different times on the first day of treatment, QTc values were always normal. Domperidone caused a slight prolongation of QTc interval, and further studies should be made for a risk assessment in dogs with cardiac diseases, electrolytic imbalance, and in those receiving drugs increasing QT interval or competing with domperidone metabolism.

A patterned human primitive heart organoid model generated by pluripotent stem cell self-organization

Pluripotent stem cell-derived organoids can recapitulate significant features of organ development in vitro. We hypothesized that creating human heart organoids by mimicking aspects of in utero gestation (e.g., addition of metabolic and hormonal factors) would lead to higher physiological and anatomical relevance. We find that heart organoids produced using this self-organization-driven developmental induction strategy are remarkably similar transcriptionally and morphologically to age-matched human embryonic hearts. We also show that they recapitulate several aspects of cardiac development, including large atrial and ventricular chambers, proepicardial organ formation, and retinoic acid-mediated anterior-posterior patterning, mimicking the developmental processes found in the post-heart tube stage primitive heart. Moreover, we provide proof-of-concept demonstration of the value of this system for disease modeling by exploring the effects of ondansetron, a drug administered to pregnant women and associated with congenital heart defects. These findings constitute a significant technical advance for synthetic heart development and provide a powerful tool for cardiac disease modeling.

Multicenter, Randomized, Placebo-controlled Trial to Evaluate the Efficacy and Safety of a Controlled-release, Once-daily UIC201609/UIC201610 Combination Therapy for Functional Dyspepsia: Preliminary Study

Backgrounds/Aims

Functional dyspepsia is a disease involving a range of upper gastrointestinal symptoms derived from various pathophysiologies. Tablets containing a combination of rabeprazole and controlled-release (CR) mosapride were recently developed. To investigate a more effective treatment, this trial evaluated the efficacy and safety of UIC201609/UIC201610 as a preliminary study.

Methods

A multicenter, double-blind, randomized study was performed on 30 subjects. UIC201609/UIC201610 (combination of rabeprazole and CR mosapride) was the case group, and the two control groups were rabeprazole 10 mg once a day and mosapride 15 mg CR tablet once a day. As a primary efficacy endpoint of the study, the changes in the total score of eight items of the Nepean Dyspepsia Index-Korean version were analyzed at 2 weeks and 4 weeks. The outcomes regarding safety were collected.

Results

The total symptom score of Nepean Dyspepsia Index-Korean decreased in the rabeprazole single group (29.4±17.1), mosapride CR single group (33.4±15.6), and UIC201609/UIC201610 group (33.4±11.8) at 4 weeks without significant differences. On the other hand, the UIC201609/UIC201610 combination group showed more score reduction of pain in the upper abdomen, burning in the upper abdomen compared to each control group, but it did not reach statistical significance. No difference was found in safety analysis.

Conclusions

UIC201609/UIC201610 once daily showed some improvement in epigastric pain and dyspepsia in patients with functional dyspepsia, but there was no significance. Further study based on the advanced clinical trial design will be needed to confirm the efficacy of UIC201609/UIC201610 combination therapy in the future.

Cisapride Use in Pediatric Patients With Intestinal Failure and Its Impact on Progression of Enteral Nutrition

OBJECTIVE

Gastrointestinal dysmotility is common in patients with pediatric intestinal failure (PIF), leading to delays in advancement of enteral nutrition (EN). Few studies have been published regarding the safety and efficacy of cisapride for improvement of enteral tolerance and ability to wean parenteral nutrition. Our objective was to describe a single center experience on the use of cisapride in patients with PIF.

METHODS

Retrospective chart review of patients was performed. Demographic, intestinal anatomy, and outcome data were collected. Percentage of EN before initiation of cisapride, progression of EN at 3 and 6 months, and ability to wean parenteral nutrition after initiation of cisapride were calculated.

RESULTS

Prokinetics were used in 61 of 106 patients (56.6%); 29 of 60 patients (48.3%) failed to progress EN on other prokinetics and started on cisapride. Before cisapride the progress of EN plateaued for a mean of 42.3 (standard deviation [SD] 60.2) days. The rate of feed progression was 0.14% (SD 0.19)/day pre-cisapride and 0.69%/day (SD 0.31) after cisapride initiation (P < 0.001). Percentage of EN improved significantly from baseline to 3 months postinitiation (23.9% vs 79.4%, respectively; P < 0.001). Electrocardiogram was performed on initiation of cisapride and after every dose change. Medication was discontinued in 2 of 29 (6.8%).

CONCLUSION

This retrospective study suggests that cisapride may be beneficial in PIF patients who fail to progress EN on first line prokinetics. The most significant period of improvement occurs within 3 months of cisapride initiation. Cardiac side effects in our cohort were lower than previously reported; however, cardiac monitoring is still recommended.

COVID-19 and Gastrointestinal Disease: Implications for the Gastroenterologist

BACKGROUND

COVID-19 was initially considered a respiratory disease but the SARS-CoV-2 virus can lead to serious systemic consequences affecting major organs including the digestive system.

SUMMARY

This review brings new clinically important information for the gastroenterologist. This includes: the mechanisms of tissue damage seen with the SARS-CoV-2 virus; the consequences of immunosuppression in patients with inflammatory bowel disease (IBD) and chronic liver disease with the additional risks of decompensation in patients with cirrhosis; the impact of COVID-19 on gastrointestinal emergencies, on gastrointestinal endoscopy, diagnosis and treatments. These highlight the need to understand the clinical pharmacology, toxicology and therapeutic implications of drugs commonly used by gastroenterologists and their links with COVID-19. Key Messages: Any part of the digestive system may be affected by the SARS-CoV-2 virus, and those with pre-existing disease are at greatest risk of adverse outcomes. The risk for drug-drug interactions is considerable in patients seriously ill with COVID-19 who often require mechanical ventilation and life support. Some repurposed drugs used against SARS-CoV-2 can cause or aggravate some of the COVID-19-related gastrointestinal symptoms and can also induce liver injury. Ongoing clinical studies will hopefully identify effective drugs with a more favourable risk-benefit ratio than many initially tried treatments.

Propofol abolishes torsade de pointes in different models of acquired long QT syndrome

There is conflicting evidence regarding the impact of propofol on cardiac repolarization and the risk of torsade de pointes (TdP). The purpose of this study was to elucidate the risk of propofol-induced TdP and to investigate the impact of propofol in drug-induced long QT syndrome. 35 rabbit hearts were perfused employing a Langendorff-setup. 10 hearts were perfused with increasing concentrations of propofol (50, 75, 100 µM). Propofol abbreviated action potential duration (APD₉₀) in a concentration-dependent manner without altering spatial dispersion of repolarization (SDR). Consequently, no proarrhythmic effects of propofol were observed. In 12 further hearts, erythromycin was employed to induce prolongation of cardiac repolarization. Erythromycin led to an amplification of SDR and triggered 36 episodes of TdP. Additional infusion of propofol abbreviated repolarization and reduced SDR. No episodes of TdP were observed with propofol. Similarly, ondansetron prolonged cardiac repolarization in another 13 hearts. SDR was increased and 36 episodes of TdP occurred. With additional propofol infusion, repolarization was abbreviated, SDR reduced and triggered activity abolished. In this experimental whole-heart study, propofol abbreviated repolarization without triggering TdP. On the contrary, propofol reversed prolongation of repolarization caused by erythromycin or ondansetron, reduced SDR and thereby eliminated drug-induced TdP.

Measurement and Management of QT Interval Prolongation for General Physicians

One of the more challenging aspects of ECG interpretation is measurement and interpretation of the QT interval. This interval represents the time taken for the ventricles to completely repolarise after activation. Abnormal prolongation of the QT interval can lead to torsades de pointes, a form of potentially life-threatening polymorphic ventricular tachycardia (VT). Detection of a prolonged QT interval is essential as this can be a reversible problem, particularly in the context of the use of a variety of commonly prescribed medications in the hospital setting. Automated ECG printouts cannot be relied upon to diagnose QT interval prolongation; thus, the onus is on the clinician to identify it. This is a difficult task, as the normal QT interval is typically measured relative to the heart rate. Therefore, the QT interval often requires "correction" for the current heart rate, in order to correctly stratify the risk of torsades de pointes. A wealth of correctional formulae have been derived, but none has proven superior. We present an approach to the ECG in this context, and a step-by-step guide to manually measuring and correcting the QT interval, and an approach to management in common hospital-based clinical scenarios.

Clinical Practice Guidelines for Functional Dyspepsia in Korea

Functional dyspepsia (FD) is a chronic upper gastrointestinal (GI) symptom complex that routine diagnostic work-up, such as endoscopy, blood laboratory analysis, or radiological examination, fails to identify a cause. It is highly prevalent in the World population, and its response to the various available therapeutic strategies is only modest because of the heterogenous nature of its pathogenesis. Therefore, FD represents a heavy medical burden for healthcare systems. We constituted a guideline development committee to review the existing guidelines on the management of functional dyspepsia. This committee drafted statements and conducted a systematic review and meta-analysis of various studies, guidelines, and randomized control trials. External review was also conducted by selected experts. These clinical practice guidelines for FD were developed based on evidence recently accumulated with the revised version of FD guidelines released in 2011 by the Korean Society of Neurogastroenterology and Motility. These guidelines apply to adults with chronic symptoms of FD and include the diagnostic role of endoscopy, Helicobacter pylori screening, and systematic review and meta-analyses of the various treatment options for FD (proton pump inhibitors, H.pylori eradication, and tricyclic antidepressants), especially according to the FD subtype. The purpose of these new guidelines is to aid the understanding, diagnosis, and treatment of FD, and the targets of the guidelines are clinicians, healthcare workers at the forefront of patient care, patients, and medical students. The guidelines will continue to be revised and updated periodically.

Effect of Chronic Domperidone Use on QT Interval: A Large Single Center Study

GOALS

The goal of this study was to determine the effect and safety of domperidone on QTc interval at the commonly prescribed doses of 30 to 80 mg daily.

BACKGROUND

Domperidone is a dopamine receptor antagonist used for the treatment of gastroparesis. However, it has been associated with QT prolongation, ventricular arrhythmias, and sudden cardiac death.

STUDY

This study analyzed patients prescribed domperidone for treatment of gastroparesis between January 2012 and September 2017 at a single center. This study reviewed EKGs, primarily the QTc interval, taken at baseline, 2 to 6 months after initiation of domperidone, 6 to 12 months after initiation, and ≥12 months after initiation. Concurrent QTc prolonging medications were recorded for each patient. The primary endpoint was QTc prolongation >500 ms. Secondary endpoints were QTc >450 ms for males, a QTc>470 ms for females, QTc prolongation ≥20 ms above baseline, and QTc prolongation >60 ms above baseline.

RESULTS

In total, 246 patients were included for analysis (age, 46.3±17.4 y; F 209). EKGs were available for all 246 patients before treatment, 170 patients at 2 to 6 months, 135 at 6 to 12 months, and 152 patients at least 1 year after domperidone initiation.Of 246 subjects, 15 patients (6.1%, 9 female) had clinically important QTc prolongation; 11 had QTc >450 ms for males or >470 ms for females; none had QTc prolongation >500 ms; 5 (2.0%) had >60 ms over baseline and 61 (24.7%) patients had QTc increase of ≥20 ms but <60 ms from baseline.

CONCLUSIONS

Domperidone at the conventionally used doses to treat gastroparesis (30 to 80 mg/d) was associated with QTc prolongation in only 6% of patients with no QT interval reaching the point considered to be clinically significant. These data suggest that domperidone can be safely prescribed at doses of 30 to 80 mg daily for the treatment of gastroparesis.

Additive Proarrhythmic Effect of Combined Treatment with QT-Prolonging Agents

Drug combinations may elevate the risk of proarrhythmia. The aim of the present study was to investigate whether combinations of non-cardiovascular agents induce an additive increase in the proarrhythmic risk. In 12 female rabbit hearts, a drug combination of cotrimoxazole (300 µM), ondansetron (5 µM) and domperidone (1 µM) was infused after obtaining baseline data. In another 13 hearts, a combination of cotrimoxazole (300 µM), ondansetron (5 µM) and erythromycin (300 µM) was infused. Monophasic action potentials and ECG displayed a significant QT prolongation in all groups. This was accompanied by a significant increase in action potential duration. Of note, addition of each drug resulted in a further increase in the QT interval. Furthermore, a significant elevation of spatial dispersion of repolarization was observed. Lowering of potassium concentration in bradycardic AV-blocked hearts provoked early afterdepolarizations and torsade de pointes (TDP) in both study groups. Under baseline conditions, no episodes of TDP recorded. After administration of the first agent, TDP occurred in 5 of 12 hearts (37 episodes) and 5 of 13 hearts (26 episodes), respectively. After additional infusion of the second drug, TDP were recorded in 7 of 12 hearts (55 episodes) and 8 of 13 hearts (111 episodes). After additional infusion of the third drug, TDP occurred in 11 of 12 hearts (118 episodes) and 9 of 13 hearts (88 episodes). Combined treatment with several non-cardiovascular QT-prolonging agents resulted in a remarkable occurrence of proarrhythmia. An additive and significant prolongation of cardiac repolarization combined with an increased spatial dispersion of repolarization represents the underlying electrophysiological mechanism.

Ondansetron and teratogenicity in rats: Evidence for a mechanism mediated via embryonic hERG blockade

The potent hERG channel blocking drug ondansetron is used off-label for treatment of nausea and vomiting in early pregnancy. Some human epidemiological studies have associated ondansetron with fetal cardiovascular defects and orofacial clefts. This study investigated the effects of ondanestron on embryonic heart rhythm of gestational day (GD) 13 rat embryos in vitro and then integrated the results with published animal teratology, and animal and human pharmacokinetic studies to perform a risk evaluation. Ondansetron caused concentration dependent bradycardia and arrhythmia. Cardiovascular malformations in rats occurred at exposures slightly higher than those in early human pregnancy. Together the results suggest that ondansetron can have teratogenic potential in rats and humans mediated via hERG block and severe heart rhythm disturbances in the embryo. The risk may be increased in human pregnancy if additional risk factors are present such as hypokalemia.

Prokinetics in the Management of Functional Gastrointestinal Disorders

PURPOSE OF REVIEW

The goal of this review is to review the current status of prokinetics and to place it in historical context. Impaired motility and thus propulsion have long been thought to play important roles in the pathogenesis of a number of gastrointestinal disorders including gastroesophageal reflux disease (GERD), gastroparesis, chronic idiopathic pseudo-obstruction, and constipation. Historically, disordered motility was also thought to contribute to a number of functional gastrointestinal disorders such as functional dyspepsia (FD) and irritable bowel syndrome (IBS).

RECENT FINDINGS

As we learn more of the pathophysiology of FD, IBS, GERD, constipation, and gastroparesis, the limitations of a therapeutic strategy based on the stimulation of motility (i.e., the use of a prokinetic) have become apparent and the disappointments of the past explained. The development of prokinetic drugs has also been hampered by the non-selective nature of many of the agents studied to date which resulted in some unexpected side effects. There is still an unmet need for an effective and safe prokinetic, but drug development in this area must be mindful of the challenges of the area and the need for selectivity for a given target receptor.