Potential Roles of 5-HT3 Receptor Antagonists in Reducing Chemotherapy-induced Peripheral Neuropathy (CIPN).

5-HT3 receptor antagonists corresponding to ondansetron, granisetron, tropisetron, and palonosetron are clinically accustomed to treating nausea and emesis in chemotherapy patients. However, current and previous studies reveal novel potentials of those ligands in other diseases involving the nervous system, such as addiction, pruritus, and neurological disorders, such as anxiety, psychosis, nociception, and cognitive function. This review gathers existing studies to support the role of 5-HT3 receptors in CIPN modulation. It has been reported that chemotherapy drugs increase the 5-HT content that binds with the 5-HT3 receptor, which later induces pain. As also shown in pre-clinical and clinical studies that various neuropathic pains could be blocked by the 5-HT3 receptor antagonists, we proposed that 5-HT3 receptor antagonists via 5- HT3 receptors may also inhibit neuropathic pain induced by chemotherapy. Our review suggests that future studies focus more on the 5-HT3 receptor antagonists and their modulation in CIPN to reduce the gap in the current pharmacotherapy for cancer-related pain.

Effects of 5-HT3 receptor antagonists on cisplatin-induced kidney injury.

Nausea, vomiting, and renal injury are the common adverse effects associated with cisplatin. Cisplatin is excreted via the multidrug and toxin release (MATE) transporter, and the involvement of the MATE transporter in cisplatin-induced kidney injury has been reported. The MATE transporter is also involved in the excretion of ondansetron, but the effects of 5-HT3 receptor antagonists used clinically for cisplatin-induced renal injury have not been elucidated. Therefore, the aim of this study was to investigate the effects of 5-HT3 receptor antagonists in a mouse model of cisplatin-induced kidney injury and to validate the results using medical big data analysis of more than 1.4 million reports and a survey of 3000 hospital medical records. The concomitant use of a first-generation 5-HT3 receptor antagonist (ondansetron, granisetron, or ramosetron) significantly increased cisplatin accumulation in the kidneys and worsened renal damage. Conversely, the concomitant use of palonosetron had no effect on renal function compared with the use of cisplatin alone. Furthermore, an analysis of data from the US Food and Drug Administration Adverse Event Reporting System and retrospective medical records revealed that the combination treatment of cisplatin and a first-generation 5-HT3 receptor antagonist significantly increased the number of reported renal adverse events compared with the combination treatment of cisplatin and a second-generation 5-HT3 receptor antagonist. These results suggest that compared with the first-generation antagonists, second-generation 5-HT3 receptor antagonists do not worsen cisplatin-induced acute kidney injury. The findings should be validated in a prospective controlled trial before implementation in clinical practice.

A phase 1 pharmacokinetic study of oral NEPA, the fixed combination of netupitant and palonosetron, in Chinese healthy volunteers.

PURPOSE: Oral NEPA, the only fixed-combination antiemetic, is composed of the neurokinin-1 receptor antagonist netupitant (300 mg) and the 5-hydroxytryptamine-3 receptor antagonist palonosetron (0.50 mg). This study was conducted to evaluate the pharmacokinetic profile of netupitant and its main metabolites M1 and M3, and palonosetron in Chinese subjects. Oral NEPA tolerability and safety were also analyzed. METHODS: This was a single-center, single-dose phase 1 study in healthy, adult Chinese volunteers. Eligible subjects received oral NEPA, and blood samples were collected on day 1 predose and at various time points up until day 10 postdose. Pharmacokinetic parameters were analyzed using noncompartmental methods. For safety assessments, adverse events (AEs) were monitored during the study. RESULTS: In total 18 Chinese healthy volunteers received oral NEPA. Netupitant mean maximum plasma concentration (Cmax) [± standard deviation] of 698 ± 217 ng/mL was reached at 3-6 h, with a mean total exposure (AUC0-inf) of 22,000 ± 4410 h·ng/mL. For palonosetron, a mean Cmax of 1.8 ± 0.252 ng/mL was reached at 2-6 h postadministration, with a mean AUC0-inf of 81.0 ± 14.0 h·ng/mL. The most common treatment-related AEs in > 2 subjects were constipation (n = 9) and tiredness (n = 3). No severe AEs were observed, and no subject withdrew due to AEs. CONCLUSION: Following single-dose administration of oral NEPA in Chinese subjects, the pharmacokinetic profiles of the NEPA components were mostly similar to those reported previously in Caucasians. NEPA was well tolerated with a safety profile in line with that observed in pivotal trials in Caucasians.

Ondansetron for Acute Migraine in the Pediatric Emergency Department.

BACKGROUND: Migraine patients are commonly encountered in the pediatric emergency departments. Much of the research on migraine treatment regimens involves antidopaminergic antiemetics such as prochlorperazine and metoclopramide. Despite a comparably more favorable side effect profile, no migraine treatment research has included ondansetron, a selective type three 5-hydroxytryptamine receptor antagonist. Our primary objective was to determine if treatment regimens including ondansetron were successful in reducing verbal pain scores. METHODS: We retrospectively reviewed patients with migraine aged seven to 18 years who visited the pediatric emergency departments over a four-year period. Charts were reviewed for initial and discharge pain scores, pediatric emergency department revisits, neurology consultation, and opioid administration. The primary outcome was treatment success, defined as reduction in the verbal pain score of 50% or more. Secondary outcomes included adverse effects, receiving non-evidence-based treatment defined as receiving an opioid, neurology consultation rate, and pediatric emergency department revisit rate within 48 hours. RESULTS: Ninety-eight encounters were included: 42 received ondansetron, 22 received an antidopaminergic, and 34 received no antiemetic. Thirty-eight patients (90%) in the ondansetron group (95% confidence interval 81 to 99) reached treatment success. Pediatric emergency department revisits, opioid administration, neurology consultation, and treatment success were similar among the ondansetron and antidopaminergic groups. CONCLUSION: Ondansetron may be a useful medication in the treatment regimen of migraine patients in the pediatric emergency department. Preliminary data suggest that ondansetron is comparable to antidopaminergic agents.

Fluvoxamine combination therapy with tropisetron for obsessive-compulsive disorder patients: A placebo-controlled, randomized clinical trial.

BACKGROUND: About 50% of obsessive-compulsive disorder patients still suffer significant symptoms even after the recommended first-line therapy. This demonstrates the necessity to investigate strategies to improve alleviation of symptoms. OBJECTIVE: The main objective of this study was to investigate the efficacy of a 5-hydroxytryptophan 3 receptor antagonist, tropisetron, as an adjuvant therapy to selective serotonin reuptake inhibitors, in ameliorating obsessive-compulsive disorder symptoms. METHODS: Men and women between the ages of 18-60 years diagnosed with obsessive-compulsive disorder, based on DSM5, who had a Yale-Brown obsessive compulsive scale score of more than 21 were recruited in a double-blinded, parallel-group, placebo-controlled, clinical trial of 10 weeks to receive either tropisetron (5 mg twice daily) and fluvoxamine (100 mg daily initially followed by 200 mg daily after week 4) or placebo and fluvoxamine. The primary outcome of interest in this study was the Yale-Brown obsessive compulsive scale total score decrease from baseline. RESULTS: One hundred and eight participants were equally randomized into two groups; 48 participants in each group finished the trial. The Yale-Brown obsessive compulsive total score significantly dropped in both groups while the tropisetron group participants experienced a significantly higher decrease in their scores (Greenhouse-Geisser F(1.53-65.87)=3.516, p-value=0.04). No major adverse effect was observed in any of the groups. CONCLUSION: This trial showed a significant efficacy for tropisetron over placebo in treatment of obsessive-compulsive disorder symptoms when added to fluvoxamine.

Treatment of irritable bowel syndrome with diarrhoea using titrated ondansetron (TRITON): study protocol for a randomised controlled trial.

BACKGROUND: Irritable bowel syndrome with diarrhoea (IBS-D) affects up to 4% of the general population. Symptoms include frequent, loose, or watery stools with associated urgency, resulting in marked reduction of quality of life and loss of work productivity. Ondansetron, a 5HT3 receptor antagonist, has had an excellent safety record for over 20 years as an antiemetic, yet is not widely used in the treatment of IBS-D. It has, however, been shown to slow colonic transit and in a small randomised, placebo-controlled, cross-over pilot study, benefited patients with IBS-D. METHODS: This trial is a phase III, parallel group, randomised, double-blind, multi-centre, placebo-controlled trial, with embedded mechanistic studies. Participants (n = 400) meeting Rome IV criteria for IBS-D will be recruited from outpatient and primary care clinics and by social media to receive either ondansetron (dose titrated up to 24 mg daily) or placebo for 12 weeks. Throughout the trial, participants will record their worst abdominal pain, worst urgency, stool frequency, and stool consistency on a daily basis. The primary endpoint is the proportion of "responders" in each group, using Food and Drug Administration (FDA) recommendations. Secondary endpoints include pain intensity, stool consistency, frequency, and urgency. Mood and quality of life will also be assessed. Mechanistic assessments will include whole gut transit, faecal tryptase and faecal bile acid concentrations at baseline and between weeks 8 and 11. A subgroup of participants will also undergo assessment of sensitivity (n = 80) using the barostat, and/or high-resolution colonic manometry (n = 40) to assess motor patterns in the left colon and the impact of ondansetron. DISCUSSION: The TRITON trial aims to assess the effect of ondansetron across multiple centres. By defining ondansetron's mechanisms of action we hope to better identify patients with IBS-D who are likely to respond. TRIAL REGISTRATION: ISRCTN, ISRCTN17508514 , Registered on 2 October 2017.

Prophylactic Effects of Ephedrine, Ondansetron and Ringer on Hemodynamic Changes during Cesarean Section under Spinal Anesthesia - a randomized clinical trial.

BACKGROUND: Hemodynamic change during spinal anaesthesia for cesarean section is prevalent. OBJECTIVE: Comparing the prophylactic effects of ephedrine, ondansetron and ringer on hemodynamic changes in patients undergoing cesarean section with spinal anaesthesia. MATERIAL AND METHODS: This randomized clinical trial was carried out on pregnant women undergoing elective cesarean sec-tion referred to teaching hospitals of Mashhad, Iran. Patients allocated to three groups of intravenous ondansetron (O) (4 mg, 5 min),intramuscular ephedrine (E) (25 mg, 25 min) and ringer (R) (500 ml, 20 min) prior to spinal anaesthesia. Anaesthesia inducted with 10-15 mg of bupivacaine. Vital signs were recorded every 3 minutes for 18 minutes including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate (PR), pulse oximetry (SpO2). RESULTS: Ninety patients with a mean age of 29.4 ± 5.4 years were studied in three groups of O (n = 30), E (n = 30), R (n = 30). Results showed a statistically significant difference in the incidence rate of hypotension 12 minutes after spinal anaesthesia in the three groups, but no statistically significant difference was found in the rest of minutes among the three groups. Dur-ing follow-up minutes, bradycardia was observed in only one patient (1.1%) of Group O and no cases of this sign were observed in other minutes and other groups. CONCLUSION: Intramuscular administration of ephedrine 25 minutes prior to the spinal anaesthesia leads to better prevention of systolic blood pressure changes compared with intravenous ondansetron and ringer, while administration of ondansetron and ringer had the same effects on reducing hemodynamic changes.

Nephrotoxicity Evaluation on Cisplatin Combined with 5-HT3 Receptor Antagonists: A Retrospective Study.

OBJECTIVE: 5-HT3 receptor antagonist (ondansetron) has been reported to have nephrotoxic effect when combined with cisplatin in mice; however, little evidence exists in explaining its nephrotoxic effects on patients. The aim of this present study was to investigate whether 5-HT3 receptor antagonist could enhance or aggravate the incidence of cisplatin-induced nephrotoxicity in patients. METHODS: We retrospectively reviewed 600 tumor patients which were treated with cisplatin (⩾60 mg/m2) as a first-time chemotherapy and combined with 5-HT3 receptor antagonist (i.e., ondansetron, tropisetron, or ramosetron, each kind of 5-HT3 receptor antagonist contains 200 cases) between January 2010 and December 2015. Cisplatin dosing, the baseline creatinine clearance, and other independent risk factors such as patient's age, sex, PS score, and weight associated with nephrotoxicity were evaluated in a multivariable model. RESULTS: The incidence of Grade ⩾ 2 serum creatinine elevation in cisplatin + ondansetron group was significantly higher than cisplatin + tropisetron group (P = 0.04), but no significant difference was found between cisplatin + ondansetron group and cisplatin + ramosetron group (P = 0.3). It was also found that cisplatin dosage and tumor type were independent risk factors in the development of nephrotoxicity. CONCLUSION: Higher cisplatin dosage and regular use of ondansetron combined with cisplatin are more likely to increase the incidence of nephrotoxicity; tropisetron showed the relatively mild effect on kidney function, suggesting that tropisetron is a preferable alternative in the process of cisplatin chemotherapy.

Ramosetron for the treatment of irritable bowel syndrome with diarrhea: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Ramosetron is a potent and selective serotonin type 3 receptor antagonist. This meta-analysis aimed to analyze the efficacy and safety of ramosetron for irritable bowel syndrome with diarrhea (IBS-D). METHODS: Pubmed, MEDLINE, EMBASE and the Cochrane Library were searched for randomized controlled trials investigating the efficacy and safety of ramosetron for IBS-D. Risk of bias was assessed as described in the Cochrane handbook. A random effects model was used to calculate the effects of ramosetron vs placebo on symptomatic improvements, including relief of overall IBS symptoms, relief of abdominal discomfort/pain, improvement in abnormal bowel habits, and improvement in stool consistency, expressed as pooled relative risks (RRs) with 95% confidence interval (CI). Adverse events data were also summarized with RRs. RESULTS: Four randomized controlled trials involving 1623 participants were included. Compared with placebo, ramosetron could lead to relief of overall IBS symptoms (RR 1.70; 95%CI 1.48, 1.95), relief of abdominal discomfort/pain (RR 1.41; 95%CI, 1.24, 1.59), improvement in abnormal bowel habits (RR 1.72; 95%CI, 1.50, 1.98) and improvement in stool consistency (RR 1.71; 95%CI 1.40, 2.08). Ramosetron could lead to relief of overall IBS symptoms in both male and female patients (RR; 95%CI: 1.94; 1.58, 2.38 and 1.49; 1.25, 1.79). The RR (95%CI) for reported adverse events of ramosetron vs placebo was 1.10 (0.97, 1.26) across all studies. No serious adverse events (e.g., ischemic colitis) were reported. The incidences of hard stool and constipation were higher in ramosetron group compared with placebo group (RR; 95%CI: 4.74; 3.00, 7.51 and 2.53; 1.57, 4.10, respectively). CONCLUSIONS: Ramosetron had beneficial effects to both male and female IBS-D patients. Treatment with ramosetron could cause more hard stool and constipation, without severe adverse events.

Efficacy and Safety of Serotonin Receptor Ligands in the Treatment of Irritable Bowel Syndrome: A Review.

BACKGROUND: Irritable bowel syndrome (IBS) is a chronic, recurrent bowel disorder with an unknown etiology, which is most likely multifactorial. Increased mucosal permeability, visceral hypersensitivity and activation status of intestinal mucosal immune cells cause changes in gastrointestinal (GI) motility, secretion and sensation observed in the course of IBS. Permanent, cumbersome symptoms, such as diarrhea, constipation and abdominal pain greatly lower the quality of life of IBS patients. On this basis, according to the Rome IV criteria, different forms of IBS can be distinguished. OBJECTIVE: This article focuses on the role of serotonin system in the pathophysiology of IBS as a potential therapeutic target. We shortly describe several molecules, associated with serotonin receptors, mainly 5-HT3 receptor antagonists and 5-HT4 receptor agonists, that are used in the treatment of motility disorders and visceral pain in IBS patients. We summarize the findings obtained in the clinical trials and elaborate on the safety of the serotonin ligands. Although the majority of serotonin receptor ligands relieve global symptoms, there are also some adverse effects, which can be dangerous for patients. RESULTS AND CONCLUSION: We postulate that currently, among all serotonin-targeting compounds, ramosetron is the best treatment option for IBS-D patients, due to its exceptional efficacy in both genders as well as good tolerability. Whereas, tegaserod is highly recommended for IBS-C sufferers. Nevertheless, numerous studies on the new serotonin receptor ligands are conducted to ensure the delivery of novel compounds with improved efficacy and safety profiles.

Comparative safety and effectiveness of serotonin receptor antagonists in patients undergoing chemotherapy: a systematic review and network meta-analysis.

BACKGROUND: Although serotonin (5-HT3) receptor antagonists are effective in reducing nausea and vomiting, they may be associated with increased cardiac risk. Our objective was to examine the comparative safety and effectiveness of 5-HT3 receptor antagonists (e.g., dolasetron, granisetron, ondansetron, palonosetron, tropisetron) alone or combined with steroids for patients undergoing chemotherapy. METHODS: We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from inception until December 2015 for studies comparing 5-HT3 receptor antagonists with each other or placebo in chemotherapy patients. The search results were screened, data were abstracted, and risk of bias was appraised by pairs of reviewers, independently. Random-effects meta-analyses and network meta-analyses (NMAs) were conducted. RESULTS: After screening 9226 citations and 970 full-text articles, we included 299 studies (n = 58,412 patients). None of the included studies reported harms for active treatment versus placebo. For NMAs on the risk of arrhythmia (primary outcome; three randomized controlled trials [RCTs], 627 adults) and mortality (secondary outcome; eight RCTs, 4823 adults), no statistically significant differences were observed between agents. A NMA on the risk of QTc prolongation showed a significantly greater risk for dolasetron + dexamethasone versus ondansetron + dexamethasone (four RCTs, 3358 children and adults, odds ratio 2.94, 95% confidence interval 2.13-4.17). For NMAs on the number of patients without nausea (44 RCTs, 11,664 adults, 12 treatments), number of patients without vomiting (63 RCTs, 15,460 adults, 12 treatments), and number of patients without chemotherapy-induced nausea or vomiting (27 RCTs, 10,924 adults, nine treatments), all agents were significantly superior to placebo. For a NMA on severe vomiting (10 RCTs, 917 adults), all treatments decreased the risk, but only ondansetron and ramosetron were significantly superior to placebo. According to a rank-heat plot with the surface under the cumulative ranking curve results, palonosetron + steroid was ranked the safest and most effective agent overall. CONCLUSIONS: Most 5-HT3 receptor antagonists were relatively safe when compared with each other, yet none of the studies compared active treatment with placebo for harms. However, dolasetron + dexamethasone may prolong the QTc compared to ondansetron + dexamethasone. All agents were effective for reducing risk of nausea, vomiting, and chemotherapy-induced nausea or vomiting. TRIAL REGISTRATION: This study was registered at PROSPERO: ( CRD42013003564 ).

Combination of 5-HT3 Antagonist and Dexamethasone Is Superior to 5-HT3 Antagonist Alone for PONV Prophylaxis After Laparoscopic Surgeries: A Meta-analysis.

INTRODUCTION: 5-Hydroxytryptamine type 3 (5-HT3) receptor antagonists are the most commonly used drugs for postoperative nausea vomiting (PONV) prophylaxis. Dexamethasone is another antiemetic with proven efficacy in reducing PONV. The aim of this study was to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare the combination of dexamethasone and 5-HT3 antagonist versus a 5-HT3 antagonist alone as prophylaxis of PONV in laparoscopic surgical patients. METHODS: PubMed, PubMed Central, and CENTRAL databases were searched to identify those randomized trials that compared a 5-HT3 antagonist with the 5-HT3 antagonist and dexamethasone combination for PONV prophylaxis after laparoscopic surgeries. RESULTS: Data from 17 RCTs that evaluated 1402 patients were included. Results from our meta-analysis show that the combination of dexamethasone and a 5-HT3 receptor antagonist is more effective in preventing PONV than the 5-HT3 antagonist alone (odds ratio 0.38, 95% confidence interval [CI] 0.27-0.54; number needed to treat = 6.6), with no statistical heterogeneity (I = 0) among studies. The need for rescue antiemetic is also decreased in patients receiving the combination (odds ratio 0.21, 99% CI 0.10-0.46; number needed to treat = 6), although data are insufficient to detect any significant difference in incidence of adverse effects. In addition, patients in the combination group complained of less pain after 24 hours (Weighted Mean Difference -0.67, 99% CI -1.27 to -0.08). CONCLUSION: Combination of a 5-HT3 receptor antagonist and dexamethasone is significantly more effective than 5-HT3 antagonist alone in preventing PONV after laparoscopic surgeries, with possible improvement in postoperative analgesia.

Ondansetron and pregnancy: possible congenital heart defects.

Two cohort studies, including more than 2500 pregnant women exposed to ondansetron in early pregnancy, have raised concerns over an increased risk of congenital heart defects.

Ramosetron Reduces Symptoms of Irritable Bowel Syndrome With Diarrhea and Improves Quality of Life in Women.

BACKGROUND & AIMS: Previous studies have indicated that serotonin-3-receptor antagonists might have a sex-specific effect in patients with irritable bowel syndrome with diarrhea (IBS-D). Alosetron has been approved for the treatment of only women, and ramosetron has been approved for the treatment for only men. We performed a randomized, placebo-controlled, phase 3 study to determine whether ramosetron reduces symptoms of IBS-D in women. METHODS: We performed a prospective study of 576 female outpatients with IBS-D (according to the Rome III criteria), from February 2013 through February 2014, at 70 academic Gastroenterology Departments in Japan. After a 1-week baseline period, subjects received either 2.5 µg ramosetron (n = 292) or placebo (n = 284) once daily for 12 weeks. Primary end points were the monthly rates of response for relief from overall IBS symptoms and increased stool consistency at the last evaluation point. Quality of life (QOL) also was quantified. RESULTS: A significantly higher proportion of patients given ramosetron reported global improvement (50.7%; 95% confidence interval [CI], 44.8-56.6) than patients given placebo (32.0%; 95% CI, 26.7-37.8)--a difference of 18.6% (95% CI, 10.7-26.5; P < .001). The relative risk was 1.58 (95% CI, 1.29-1.94) and the number needed to treat was 6 (95% CI, 4-10). A significantly higher proportion of patients in the ramosetron group reported increased stool consistency (40.8%; 95% CI, 35.1%-46.6%) than in the placebo group (24.3%; 95% CI, 19.4%-29.7%)--a difference of 16.5% (95% CI, 8.9%-24.0%; P < .001). Patients receiving ramosetron had significant reductions in abdominal pain and discomfort (P = .001) and greater improvement in QOL (P = .002) compared with placebo. Ramosetron induced constipation in 11.0% of patients. CONCLUSIONS: In a randomized, placebo-controlled study of 576 women with IBS-D, 2.5 µg ramosetron per day reduced symptoms and increased stool consistency and QOL. Clinicaltrials.gov no: NCT01870895.

Effects of Palonosetron on Perioperative Cardiovascular Complications in Patients Undergoing Noncardiac Surgery With General Anesthesia: A Retrospective Cohort Study.

We retrospectively investigated whether palonosetron administered during the induction of general anesthesia is associated with an increased risk of perioperative cardiovascular complications in a single tertiary center cohort consisting of 4,517 palonosetron-exposed patients and 4,517 propensity score-matched patients without palonosetron exposure. The primary endpoint was a composite of perioperative cardiovascular complications, including intraoperative cardiac arrhythmia, intraoperative cardiac death, and myocardial injury within the first postoperative week, and there was no significant difference between the groups (odds ratio [OR] = 1.04; 95% confidence interval [CI] = 0.92-1.19). As secondary endpoints, intraoperative cardioversion, cardiac compression, use of cardiovascular drugs, postoperative hospital stay, and in-hospital mortality showed no differences between the groups. However, the palonosetron group showed decreased intraoperative hypotension (OR = 0.88; 95% CI = 0.79-0.97) and length of postoperative intensive care unit (ICU) stay (4.26 ± 9.86 vs. 6.14 ± 16.75; P = 0.026). Palonosetron did not increase the rate of perioperative cardiovascular complications, and can therefore be used safely during anesthetic induction.

Interventions to decrease the risk of adverse cardiac events for patients receiving chemotherapy and serotonin (5-HT3) receptor antagonists: a systematic review.

BACKGROUND: Patients may experience nausea and vomiting when undergoing chemotherapy or surgery requiring anesthesia. Serotonin 5-hydroxytryptamine 3 (5-HT3) receptor antagonists are effective antiemetics, yet may cause adverse cardiac events, such as arrhythmia. We aimed to identify interventions that mitigate the cardiac risk of 5-HT3 receptor antagonists. METHODS: Electronic databases, trial registries, and references were searched. Studies on patients undergoing chemotherapy or surgery examining interventions to monitor cardiac risk of 5-HT3 receptor antagonists were included. Search results were screened and data from relevant studies were abstracted in duplicate. Risk of bias of included studies was assessed using the Cochrane Effective Practice and Organisation of Care (EPOC) group's risk-of-bias tool. Due to a dearth of included studies, meta-analysis was not conducted. RESULTS: Two randomized clinical trials (RCT) and 1 non-randomized clinical trial (NRCT) were included after screening 7,637 titles and abstracts and 1,554 full-text articles. Intravenous administration of different dolasetron doses was examined in the NRCT, while dolasetron versus ondansetron and palonosetron versus ondansetron were examined in the RCT. Electrocardiogram (ECG) was the only intervention examined to mitigate cardiac harm. No differences in ECG evaluations were observed between dolasetron or palonosetron versus ondansetron after 15 minutes, 24 hours, and 1 week post-administration in the 2 RCTs. Four deaths were observed in one RCT, which were deemed unrelated to palonosetron or ondansetron administration. Minor increases in PR and QT intervals were observed in the NRCT for dolasetron dosages greater than 1.2 mg/kg 1-2 hours post-administration, but were deemed not clinically relevant. CONCLUSIONS: ECG monitoring of chemotherapy patients administered with 5-HT3 receptor antagonists did not reveal clinically significant differences in arrhythmia between the medications at the examined time periods. The usefulness of ECG to monitor chemotherapy patients administered with 5-HT3 receptor antagonists remains unclear, as all patients received ECG monitoring. TRIAL REGISTRATION: PROSPERO registry number: CRD42013003565.

Analgesic interaction between ondansetron and acetaminophen after tonsillectomy in children: the Paratron randomized, controlled trial.

BACKGROUND: The mechanism of action of acetaminophen remains unclear. One hypothesis involves an interaction with the serotoninergic system. Antagonists to serotonin (5-HT)3 receptors (setrons) have antiemetic properties. Therefore, co-administration of acetaminophen and a setron could lead to a decrease or a loss of acetaminophen analgesic effects. The aim of this study was to demonstrate such an interaction. METHODS: Paratron is a prospective, randomized, controlled, double-blind, parallel group trial. All children aged 2-7 years (n = 69) scheduled for a tonsillectomy ± adenoidectomy received intraoperative acetaminophen with ondansetron or droperidol. Pain scores [Children's Hospital of Eastern Ontario Pain Scale (CHEOPS)], morphine consumption and the incidence of post-operative nausea and vomiting (PONV) were measured for 24 h following surgery. RESULTS: Pain scores were not different at all times between the groups but median morphine consumption (µg) in recovery was 322.5 [interquartile range (IQR) 0.0-500.0] and 0 (IQR 0-0) in the ondansetron (n = 35) and droperidol (n = 34) groups, respectively (p = 0.004). The percentages of patients who received morphine titration were 57.1% and 20.6% in the ondansetron and droperidol groups, respectively (p = 0.008). No significant difference was found for PONV. CONCLUSIONS: An interaction between acetaminophen and ondansetron is suggested, with children receiving three times more morphine during pain titration in the recovery room. More studies are necessary to evaluate whether this finding is clinically relevant enough to preclude the simultaneous perioperative administration of both drugs in the future.

Theoretical evaluation of antiemetic effects of 5-HT3 receptor antagonists for prevention of vomiting induced by cisplatin.

5-HT(3) receptor antagonists are widely used as antiemetic agents in clinical setting, of which palonosetron, with a long elimination half life (t(1/2)), has recently become available. It is important to evaluate the concentration of serotonin when investigating the antiemetic effects of 5-HT(3) receptor antagonists, as those effects are not based solely on the t(1/2) value. We theoretically evaluated the antiemetic effects of three 5-HT(3) receptor antagonists (granisetron, azasetron, palonosetron) on cisplatin-induced nausea and vomiting by estimating the time course of the 5-HT(3) receptor occupancy of serotonin. We estimated the 5-HT(3) receptor occupancy of serotonin in the small intestine, based on the time course of plasma concentration of each 5-HT(3) receptor antagonist and the time course of concentration of serotonin near the 5-HT(3) receptor in the small intestine after administration of cisplatin. The antiemetic effect of each 5-HT(3) receptor antagonist was evaluated based on the normal level of 5-HT(3) receptor occupancy of serotonin. Our results suggest that an adequate antiemetic effect will be provided when a dose of 75 mg/m(2) of cisplatin is given to patients along with any single administration of granisetron, azasetron, or palonosetron at a usual dose. On the other hand, the 5-HT(3) receptor occupancy of serotonin was found to be significantly lower than normal for several days after administration of palonosetron, as compared to granisetron and azasetron, indicating that constipation may be induced. Our results show that granisetron, azasetron, and palonosetron each have an adequate antiemetic effect after administration of 75 mg/m(2) of cisplatin.

5-Hydroxytryptamine3 receptor antagonists and cardiac side effects.

INTRODUCTION: 5-Hydroxytryptamine3-receptor antagonists (5-HT3-RA) are the most widely used antiemetics in oncology, and although tolerability is high, QTC prolongation has been observed in some patients. AREAS COVERED: The purpose of this article is to outline the risk of cardiac adverse events (AEs) from 5-HT3-RAs, with focus on the three most commonly used, ondansetron, granisetron and palonosetron. EXPERT OPINION: Most of the studies analyze electrocardiogram (ECG) changes after 5-HT3-RA administrations in healthy, young adults, or in noncancer patients to treat postoperative nausea and vomiting (PONV). Only a few studies have addressed ECG changes in cancer patients treated for chemotherapy-induced nausea and vomiting (CINV). Investigations in cancer patients are essential, because these patients are older and have a higher incidence of comorbidity, than those usually included in clinical trials. Furthermore, polypharmacy is frequent and drug-drug interactions between chemotherapy and other QTc-prolonging drugs may influence the pharmacokinetics and pharmacodynamics of the 5-HT3-RAs. During the next 10 - 15 years a huge increase in the number of cancer patients is expected, primarily in the group of 65-plus-year old. Therefore it will be crucial to address the incidence of cardiac AEs in cancer patients with known heart disease receiving chemotherapy and a 5-HT3 RA for the prophylaxis of CINV.