Ondansetron clinical pharmacokinetics

Anti-Emetics in Children Receiving Chemotherapy for Solid Tumors and Leukemia: Pharmacology and Optimization of Therapy for Nausea and Vomiting

The management of chemotherapy-induced nausea and vomiting (CINV) in children remains challenging due to differences in the chemotherapy regimens, their relative emetogenicity compared to that in adults and differences in drug metabolism and the available formulations. The common four classes of anti-emetics used for the treatment and prophylaxis of CINV in children include dexamethasone, neurokinin-1 receptor antagonists, 5-hydroxytryptamine-3 receptor antagonists (5HT3RAs), and olanzapine. The appropriate dose of dexamethasone for CINV prophylaxis in children is unknown, with a significant variability in dosage ranging between 6 and 32 mg/m2/day. The dose of dexamethasone is decreased by 30% when this drug is combined with (fos)aprepitant in children, in contrast to a decrease of 50% required in adults. The use of aprepitant in younger children (<12 years) is often hampered by the non-availability of oral suspension formulations in many countries; alternatively, 80 mg capsules are administered for 1-3 days in certain institutes to children weighing between 15 and 40 kg. Among the different 5HT3RAs, palonosetron is comparatively metabolized faster in children than in adults, requiring a higher dosage for similar efficacy to that achieved in adults. Olanzapine is a newer agent, used in doses between 0.1 and 0.14 mg/kg/day in children, with good anti-emetic efficacy, but has sedation and hyperglycemia as concerning adverse effects. Drug interactions between anti-emetics and between anti-emetics and chemotherapy/supportive agents (azole antifungals, cyclosporine, arsenic trioxide), especially QTc prolongation, should be considered during prescription.

Comparison of the ED50 of prophylactic butorphanol in preventing morphine-induced pruritus with or without palonosetron: a prospective, double-blinded, randomized dose-response trial using an up-down sequential allocation method

BACKGROUND

Butorphanol has been used to reduce the incidence and severity of neuraxial morphine-induced pruritus. Palonosetron is a commonly used antiemetic for the prevention of postoperative nausea and vomiting. The aim of our study was to compare the effective dose in 50% of subjects (ED50) of intravenous butorphanol infusion with or without a single intravenous bolus of palonosetron for preventing pruritus induced by epidural administration of morphine.

METHODS

A total of 120 parturients were randomly assigned to receive an intravenous bolus injection of palonosetron plus continuous infusion of butorphanol (Group P + B) or an intravenous bolus of saline plus continuous infusion of butorphanol (Group B) after epidural administration of morphine. The antipruritic effect was graded as satisfactory (numerical rating scale (NRS) of pruritus ≤3) or unsatisfactory (NRS >3) within 48 h after morphine treatment. The first patient in each group received butorphanol infusion at a rate of 4 µg/kg/h. The infusion dose for each subsequent patient in the corresponding group was increased by 0.2 µg/kg/h after an unsatisfactory response or decreased by 0.2 µg/kg/h after a satisfactory response. The ED50 was calculated for each group and compared using up-down sequential analysis.

RESULTS

The ED50 (mean [95% confidence interval (CI)]) of the dose of intravenous butorphanol infusion for preventing moderate to severe pruritus was lower in Group P + B (3.29 µg/kg/min [3.25-3.34 µg/kg/min]) than in Group B (3.57 µg/kg/min [3.47-3.67 µg/kg/min]) (p < 0.05).

CONCLUSIONS

Under the conditions of the present study, a prophylactic use of 0.25 mg palonosetron reduced the ED50 of prophylactic infusion of butorphanol by approximately 8% to achieve a satisfactory antipruritic effect after epidural morphine for post-caesarean analgesia.

Palonosetron versus ondansetron for prophylaxis of postoperative nausea and vomiting in laparoscopic cholecystectomy: a non-inferiority randomized controlled trial

BACKGROUND

We tested the hypothesis that, within the margin of 15% of risk difference, palonosetron is not inferior to ondansetron in reducing the incidence of postoperative nausea and vomiting (PONV) in laparoscopic cholecystectomy.

METHODS

We conducted a double-blind, non-inferiority, randomized, controlled trial of 212 patients aged 18 to 65 years undergoing laparoscopic cholecystectomy under general anesthesia in two secondary care hospitals. Patients were randomly assigned to receive either palonosetron (0.075.ßmg) or ondansetron (8.ßmg) intravenously at induction of anesthesia. Ondansetron (8.ßmg) was also administered 8 and 16.ßhours postoperatively. All anesthetic and surgical procedures were standardized. Patients were evaluated for 24.ßhours postoperatively for the occurrence of PONV.

RESULTS

A high incidence of PONV was observed at 2...6.ßhours postoperatively, with a rate of 36.8% (95% confidence interval [CI] 28.2...46.3) in the palonosetron group, as compared to 43.4% (95% CI 34.4...52.9) in the ondansetron group. The risk difference (95% CI) between palonosetron and ondansetron for PONV was 0 (-10.9 to 10.9) at 0...2.ßhours, -6.6 (-19.4 to 6.5) at 2...6.ßhours, -0.9 (-11.0 to 9.2) at 6...12.ßhours, and -2.8 (-9.6 to 3.6) at 12...24.ßhours. There was no statistically significant difference between the palonosetron and ondansetron groups in the use of rescue medication (dimenhydrinate). There were no adverse events associated with the medications under study.

CONCLUSION

Palonosetron is not inferior to ondansetron in patients at risk of PONV undergoing laparoscopic cholecystectomy, providing a good option for PONV prophylaxis, as it can be administered in a single dose.

Pharmacological Treatment of Acute Unilateral Vestibulopathy: A Review

There have been few investigations on the epidemiology, etiology, and medical management of acute unilateral vestibulopathy (AUV). Short-term pharmaceutical resolutions include vestibular symptomatic suppressants, anti-emetics, and some cause-based therapies. Anticholinergics, phenothiazines, antihistamines, antidopaminergics, benzodiazepines, and calcium channel antagonists are examples of vestibular suppressants. Some of these medications may show their effects through multiple mechanisms. In contrast, N-acetyl-L-leucine, Ginkgo biloba, and betahistine improve central vestibular compensation. Currently, AUV pathophysiology is poorly understood. Diverse hypotheses have previously been identified which have brought about some causal treatments presently used. According to some publications, acute administration of anti-inflammatory medications may have a deleterious impact on both post-lesional functional recovery and endogenous adaptive plasticity processes. Thus, some authors do not recommend the use of corticosteroids in AUV. Antivirals are even more contentious in the context of AUV treatment. Although vascular theories have been presented, no verified investigations employing anti-clotting or vasodilator medications have been conducted. There are no standardized treatment protocols for AUV to date, and the pharmacological treatment of AUV is still questionable. This review addresses the most current developments and controversies in AUV medical treatment.

A Physiologically Based Pharmacokinetic Model to Predict Systemic Ondansetron Concentration in Liver Cirrhosis Patients

INTRODUCTION

Ondansetron is a drug that is routinely prescribed for the management of nausea and vomiting associated with cancer, radiation therapy, and surgical operations. It is mainly metabolized in the liver, and it might accumulate in patients with hepatic impairment and lead to unwanted adverse events.

METHODS

A physiologically based pharmacokinetic (PBPK) model was developed to predict the exposure of ondansetron in healthy and liver cirrhosis populations. The population-based PBPK simulator PK-Sim was utilized for simulating ondansetron exposure in healthy and liver cirrhosis populations.

RESULTS

The developed model successfully described the pharmacokinetics of ondansetron in healthy and liver cirrhosis populations. The predicted area under the curve, maximum systemic concentration, and clearance were within the allowed twofold range. The exposure of ondansetron in the population of Child-Pugh class C has doubled in comparison to Child-Pugh class A. The dose has to be adjusted for liver cirrhosis patients to ensure comparable exposure to a healthy population.

CONCLUSION

In this study, the developed PBPK model has described the pharmacokinetics of ondansetron successfully. The PBPK model has been successfully evaluated to be used as a tool for dose adjustments in liver cirrhosis patients.

Efficacy and safety of ondansetron for morning sickness in pregnancy: a systematic review of clinical trials

Background: Ondansetron is a selective antagonist of the serotonin 5-HT3 receptor that is commonly used to treat morning sickness. It is estimated that 70%-80% of pregnant women suffer from morning sickness, a condition characterized by nausea and vomiting. However, it is still controversial regarding its safety during pregnancy, and continued research will be necessary to fully understand the risks and benefits associated with its use. Therefore, we aimed to identify and provide details of the efficacy and safety of ondansetron in clinical trials. Methods: A search was conducted of the ClinicalTrials.gov database on 13 April 2023, using the search term "ondansetron and pregnancy." Inclusion and exclusion criteria were defined to identify relevant clinical trials. The inclusion criteria encompassed clinical trials related to pregnancy that utilized ondansetron as a treatment, while other clinical trials were excluded from consideration. All data extractions such as study title, study status, study type, intervention details, and outcome were collected. Results: A total of 18 clinical trials were identified, of which only 6 focused on studying the effects of ondansetron. Their respective study titles, statuses, conditions, interventions, outcome measures, and enrollment sizes have been written in detail. The information collected from these trials will contribute to our understanding of the potential benefits and risks of ondansetron in the context of pregnancy and its complications. Conclusion: Ondansetron has been shown to be an effective treatment for nausea and vomiting, including pregnancy-related morning sickness. Further research is needed to better understand the potential risks and benefits associated with its use in pregnant women. Systematic Review Registration: ClinicalTrials.gov, identifier.

Preoperative versus intraoperative antiemetic strategies in patients undergoing laparoscopic cholecystectomy: A randomised double-blind study

BACKGROUND

Previous studies have determined ondansetron's efficacy in preventing and treating postoperative nausea and vomiting (PONV). However, evidence regarding the timing of drug administration in relation to the surgical procedure remains vague.

OBJECTIVE

To compare the preoperative and intraoperative administration of ondansetron on the incidence of PONV.

DESIGN

Single-centred, randomised, double-blind trial. Patients were recruited between November 2018 and April 2021. Follow-up for PONV and retching was up to 24 h.

SETTING

Aretaieio University Hospital, Greece.

PATIENTS

A total of 121 patients undergoing elective laparoscopic cholecystectomy gave written consent.

INTERVENTIONS

Patients were randomly allocated to the preoperative or the intraoperative group. The preoperative group received 4 mg of ondansetron dissolved in 100 ml of 0.9% saline 1 hour before induction of anaesthesia and 100 ml of 0.9% saline 30 min before end of surgery. The intraoperative group received 100 ml of 0.9% saline 1 h before induction of anaesthesia and 4 mg of ondansetron dissolved in 100 ml of 0.9% saline 30 min before end of surgery.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of nausea and/or vomiting combined at 24 h.

RESULTS

No difference was found between the two groups regarding either the incidence of nausea and vomiting at 24 h (1.7% for the preoperative group versus 5.3% for the intraoperative group, P  = 0.31) or the incidence of nausea, vomiting and retching combined (5.3% for the preoperative group versus 10.5% for the intraoperative group, P  = 0.30). There was no difference between the groups in the pain intensity at rest or with coughing in the post anaesthesia care unit, at 4, 8 and 24 h postoperatively ( P  = 0.961, 0.929, 0.748 and 0.883 at rest, and 0.974, 0.220, 0.235 and 0.317 with coughing, respectively).

CONCLUSION

Under the current study design, we found no difference in the incidence of PONV between the administration of ondansetron 1 h before induction of anaesthesia and the intraoperative administration of ondansetron 30 min before the end of surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03023306.

Research progress of indole-fused derivatives as allosteric modulators: Opportunities for drug development

Allosteric modulation is a direct and effective method for regulating the function of biological macromolecules, which play vital roles in various cellular activities. Unlike orthosteric modulators, allosteric modulators bind to sites distant from the protein's orthosteric/active site and can have specific effects on the protein's function or activity without competing with endogenous ligands. Compared to traditional orthosteric modulators, allosteric modulators offer several advantages, including reduced side effects, greater specificity, and lower toxicity, making them a promising strategy for developing novel drugs. Indole-fused architectures are widely distributed in natural products and bioactive drug leads, displaying diverse biological activities that attract the interest of both chemists and biologists in drug discovery. Currently, an increasing number of indole-fused compounds have exhibited potent activities in allosteric modulation. In this review, we provide a brief summary of examples of allosteric modulators based on the indole-fused complex architecture, highlighting the strategies for drug design/discovery and the structure-activity relationships of allosteric modulators from the perspective of medicinal chemistry.

Investigating the relevance of CYP2J2 inhibition for drugs known to cause intermediate to high risk torsades de pointes

Cardiac cytochrome P450 2J2 (CYP2J2) metabolizes endogenous polyunsaturated fatty acid, arachidonic acid (AA), to bioactive regioisomeric epoxyeicosatrienoic acid (EET) metabolites. This endogenous metabolic pathway has been postulated to play a homeostatic role in cardiac electrophysiology. However, it is unknown if drugs that cause intermediate to high risk torsades de pointes (TdP) exhibit inhibitory effects against CYP2J2 metabolism of AA to EETs. In this study, we demonstrated that 11 out of 16 drugs screened with intermediate to high risk of TdP as defined by the Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative are concurrently reversible inhibitors of CYP2J2 metabolism of AA, with unbound inhibitory constant (K_i,AA,u) values ranging widely from 0.132 to 19.9 µM. To understand the physiological relevancy of K_i,AA,u, the in vivo unbound drug concentration within human heart tissue (C_u,heart) was calculated via experimental determination of in vitro unbound partition coefficient (K_puu) for 10 CYP2J2 inhibitors using AC16 human ventricular cardiomyocytes as well as literature-derived values of fraction unbound in plasma (f_u,p) and plasma drug concentrations in clinical scenarios leading to TdP. Notably, all CYP2J2 inhibitors screened belonging to the high TdP risk category, namely vandetanib and bepridil, exhibited highest K_puu values of 18.2 ± 1.39 and 7.48 ± 1.16 respectively although no clear relationship between C_u,heart and risk of TdP could eventually be determined. R values based on basic models of reversible inhibition as per FDA guidelines were calculated using unbound plasma drug concentrations (C_u,plasma) and adapted using C_u,heart which suggested that 4 out of 10 CYP2J2 inhibitors with intermediate to high risk of TdP demonstrate greatest potential for clinically relevant in vivo cardiac drug-AA interactions. Our results shed novel insights on the relevance of CYP2J2 inhibition in drugs with risk of TdP. Further studies ascertaining the role of CYP2J2 metabolism of AA in cardiac electrophysiology, characterizing inherent cardiac ion channel activities of drugs with risk of TdP as well as in vivo evidence of drug-AA interactions will be required prior to determining if CYP2J2 inhibition could be an alternative mechanism contributing to drug-induced TdP.

Ondansetron: recommended antiemetics for patients with acute pancreatitis? a population-based study

Objective: Ondansetron administration is a common antemetic of acute pancreatitis therapy in the intensive care unit (ICU), but its actual association with patients' outcomes has not been confirmed. The study is aimed to determine whether the multiple outcomes of ICU patients with acute pancreatitis could benefit from ondansetron. Methods: 1,030 acute pancreatitis patients diagnosed in 2008-2019 were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database as our study cohort. The primary outcome we considered is the 90-day prognosis, and secondary outcomes included in-hospital survival and overall prognosis. Results: In MIMIC-IV, 663 acute pancreatitis patients received ondansetron administration (OND group) during their hospitalization, while 367 patients did not (non-OND group). Patients in the OND group presented better in-hospital, 90-day, and overall survival curves than the non-OND group (log-rank test: in-hospital: p < 0.001, 90-day: p = 0.002, overall: p = 0.009). After including covariates, ondansetron was associated with better survival in patients with multiple outcomes (in-hospital: HR = 0.50, 90-day: HR = 0.63, overall: HR = 0.66), and the optimal dose inflection points were 7.8 mg, 4.9 mg, and 4.6 mg, respectively. The survival benefit of ondansetron was unique and stable in the multivariate analyses after consideration of metoclopramide, diphenhydramine, and prochlorperazine, which may also be used as antiemetics. Conclusion: In ICU acute pancreatitis patients, ondansetron administration was associated with better 90-day outcomes, while results were similar in terms of in-hospital and overall outcomes, and the recommended minimum total dose might be suggested to be 4-8 mg.

Embryo-fetal safety evaluation of ondansetron in rats

BACKGROUND

Ondansetron is a 5HT3 receptor antagonist, used to mitigate the effects of nausea and vomiting after chemotherapy or surgery. Since nausea and vomiting are common experiences during the first trimester of pregnancy, this antiemetic has been the main drug used during this period.

METHODS

To evaluate the effects of ondansetron on the embryo-fetal development, which are still very contradictory, pregnant rats were exposed to therapeutic doses of ondansetron (1.7 or 2.5 mg/kg) daily, from gestational day (GD) 6 to 15.

RESULTS

No clinical signs of toxicity were observed in dams during the treatment. Although the hemato-biochemical parameters were similar among the groups, histological changes, as well as a reduction in the weight of kidney were found in the treated dams. After fetal examination, no visceral and skeletal abnormalities were observed in treated fetuses.

CONCLUSION

In conclusion, therapeutic doses of ondansetron have low teratogenic potential in rats. These data provide important information about the drug safety during pregnancy.

Intranasal ondansetron microemulsion counteracting the adverse effects of cisplatin: animal study

BACKGROUND

Cisplatin is considered one of the most effective and commonly used chemotherapeutic drugs, but despite its high therapeutic effectiveness, most patients treated with cisplatin suffer from nausea and vomiting, neurotoxic side effects, and cerebral psychiatric disorders such as depression. Therefore, the aim of the current work was to explore whether a selective 5-HT₃ receptor antagonist (Ondansetron) administered via the oral route or intranasally in microemulsion form would alleviate cisplatin's adverse effects.

METHODS

The selected ondansetron microemulsion was characterized in vitro for particle size, polydispersity, zeta potential, morphology, and nasal permeation, and in vivo in terms of anti-emetic and antidepressant activity, with the assessment of biochemical markers in brain homogenates.

RESULTS

Results revealed that both orally administered ondansetron and intranasally administered microemulsion were able to counteract the pica effect by increasing food consumption, water intake, and decreasing kaolin intake. They were also able to increase BDNF, normalize IL-6, increase serotonin, and normalize NOx, MDA, GSSH/GSH as well as 8OHdG levels in rats' brain homogenates. The intranasal ondansetron microemulsion displayed superiority compared to oral conventional ondansetron in terms of increasing food intake, reduction of stomach content, and normalization of serotonin turnover.

CONCLUSION

Ondansetron microemulsion can be administered by an alternative route of administration (intranasal) rather than oral, for patients on cisplatin chemotherapy.

Safety evaluation of ondansetron after gestational exposure on male reproductive parameters in rats

Ondansetron is a 5HT3 receptor antagonist widely used to treat hyperemesis gravidarum, although its safety is still questionable. Since 5HT3 receptors, which are the target of this drug, can interfere with brain development through changes in neurotransmitter levels, this study evaluated whether the prenatal exposure to this drug could compromise reproductive and behavioral parameters in male offspring. Pregnant rats were treated with ondansetron (1.7 and 2.5 mg/kg/body weight; gavage), from gestational day 1-21. No exposure-related changes in clinical signs, body weight, food consumption, pregnancy length, and necropsy findings were observed in dams. Ondansetron exposure did not alter the anogenital distance or age of preputial separation in male offspring. Similarly, males exposed to therapeutic doses of ondansetron did not exhibit changes in play behavior. In adulthood, there were no changes in sperm parameters, as well as in testosterone level, sexual behavior and fertility. Furthermore, ondansetron did not interfere with testicular and epididymal histology, and with androgen receptor expression in hypothalamus. In conclusion, prenatal exposure to ondansetron did not cause maternal toxicity, as well as did not interfere with reproductive parameters of male offspring, indicating its safety after gestational exposure in rats.

Prophylactic antiemetics for adults receiving intravenous opioids in the acute care setting

BACKGROUND

Physicians often prescribe opioids for pain in the acute care setting. Nausea and vomiting are well-described adverse events, occurring in over one-third of patients. Prophylactic antiemetics may be one option to reduce opioid-associated nausea and vomiting. However, these medications also have their own adverse effects, so it is important to understand their efficacy and safety prior to routine use. This is a review of randomized controlled trials comparing prophylactic antiemetics versus placebo or standard care for preventing opioid-associated nausea and vomiting.

OBJECTIVES

To assess the effects of prophylactic antiemetics for nausea and vomiting in adults (aged 16 years or older) receiving intravenous opioids in the acute care setting.

SEARCH METHODS

We searched CENTRAL (the Cochrane Library), MEDLINE (OVID), Embase (OVID) from inception to January 2022, and Google Scholar (17 January 2022). We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and screened reference lists.

SELECTION CRITERIA

We included randomized controlled trials of prophylactic antiemetics versus placebo or standard care in adults prior to receiving an intravenous opioid.

DATA COLLECTION AND ANALYSIS

Two review authors (MG, JNC) independently determined the eligibility of each study according to the inclusion criteria. Two review authors (MG, GDP) then independently extracted data, assessed risk of bias, and determined the certainty of evidence using GRADE. Our primary outcomes were the occurrence of nausea, vomiting, and adverse events. Secondary outcomes included nausea severity, number of vomiting episodes, and number of participants requiring antiemetic rescue therapy. We presented outcomes as risk ratios (RR) for dichotomous data (e.g. presence of vomiting, presence of nausea, number of participants requiring rescue medication, adverse events) and mean difference (MD) or standardized mean difference for continuous data (e.g. number of vomiting episodes, nausea severity) with 95% confidence intervals (CI).

MAIN RESULTS

We included three studies involving 527 participants (187 women and 340 men) with a mean age of 42 years.  All studies used intravenous metoclopramide (10 mg) as the intervention and a placebo for the comparator. No studies assessed any other antiemetic or compared the intervention to standard care. Compared to placebo, metoclopramide did not reduce vomiting (RR 1.18, 95% CI 0.26 to 5.32; low-certainty evidence) or nausea (RR 0.55; 95% CI 0.15 to 2.03; low-certainty evidence) and there was no difference in adverse events (RR 2.34, 95% CI 0.47 to 11.61; low-certainty evidence).  No data were available regarding the number of vomiting episodes. Metoclopramide did reduce the severity of nausea compared with placebo (MD -0.49, 95% CI -0.75 to -0.23; low-certainty evidence) but did not reduce the need for rescue medication (RR 1.86, 95% CI 0.17 to 20.16; low-certainty evidence).  Two studies were at unclear risk of bias for random sequence generation, one for blinding of outcome assessors, one for incomplete outcome data, and two for selective reporting. The studies were at low risk of bias for all remaining components.

AUTHORS' CONCLUSIONS

There was no evidence that prophylactic metoclopramide affected the risk of vomiting, nausea, or the need for rescue medication when provided prior to intravenous opioids in the acute care setting. There was a clinically insignificant difference in nausea severity when comparing prophylactic metoclopramide with placebo. Overall, the evidence was of low certainty. Future research could better delineate the effects of prophylactic antiemetics on specific populations, and new studies are needed to evaluate the use of other prophylactic antiemetic agents, for which there were no data.

Association between early ondansetron administration and in-hospital mortality in critically ill patients: analysis of the MIMIC-IV database

Background

While ondansetron (OND) is widespread availability, the contribution of OND to improve patient outcomes among intensive care unit (ICU) patients has not been examined. This study aimed to illustrate the association between early OND use and in-hospital mortality in critically ill patients and investigate whether this association differed according to OND dose.

Methods

The MIMIC-IV database was employed to identify patients who had and had not received OND. Statistical approaches included multivariate logistic regression, propensity score matching (PSM), and propensity score-based inverse probability of treatment weighting (IPTW) models to ensure the robustness of our findings.

Results

In total, 51,342 ICU patients were included. A significant benefit in terms of in-hospital mortality was observed in the OND patients compared to the non-OND group in the early stage [odds ratio (OR) = 0.75, 95% CI 0.63–0.89, p < 0.001]. In the circulatory system group, the early OND administration was associated with improved in-hospital mortality in ICU patients (OR 0.48, 95% CI 0.34–0.66; P < 0.001). The risk of in-hospital mortality was also lower in early OND users than in non-OND users both in the medical admission group and the surgical ICU admission group, and ORs were 0.57 (95% CI 0.42–0.76; P < 0.001) and 0.79 (95% CI 0.62–0.91; P < 0.001), respectively.

A positive role of daily low- and moderate-dose OND treatment in early-stage was showed on the in-hospital mortality in PSM cohort, and the ORs were 0.75 (95% CI 0.62–0.90; P < 0.001) and 0.63 (95% CI 0.43–0.91; P < 0.001), respectively. The relationship between the daily low- and moderate-dose of OND and in-hospital mortality was also significant in ICU patients with cardiovascular diseases, and ORs were 0.51(95% CI 0.36–0.73; P < 0.001), and 0.26(95% CI 0.11–0.65; P < 0.001), respectively. Daily low-to-moderate dose of OND was also associated with in-hospital mortality in ICU entire cohort.

Conclusions

Early OND use is closely associated with lower in-hospital mortality in ICU patients. Daily low-to-moderate dose of OND application is protective against in-hospital mortality. This association is more evident in the circulatory system group.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03401-y.

Synthesis Strategies and Medicinal Value of Pyrrole and its Fused Heterocyclic Compounds

For several decades, interest in pyrrole and pyrrolopyrimidine derivatives increases owing to their biological importance, such as anti-tumor, anti-microbial, anti-inflammatory, anti-diabetic, anti-histaminic, anti-malarial, anti-Parkinson, antioxidant and anti-viral, specially recently against COVID-19. These tremendous biological features motivated scientists to discover more pyrrole and fused pyrrole derivatives, owing to the great importance of the pyrrole nucleus as a pharmacophore in many drugs, and motivated us to present this article, highlighting on the different synthetic pathways of pyrrole and its fused compounds specially pyrrolopyrimidine, as well as their medicinal value from 2017 till 2021.

Palliative care for children and young people with stage 5 chronic kidney disease

Death from stage 5 chronic kidney disease (CKD 5) in childhood or adolescence is rare, but something that all paediatric renal physicians and most paediatricians will encounter. In this paper, we present the literature on three key areas of palliative care practice essential to good clinical management: shared decision-making, advance care planning, and symptom management, with particular reference to CKD 5 where kidney transplant is not an option and where a decision has been made to withdraw or withhold dialysis. Some areas of care, particularly with regard to symptom management, have not been well-studied in children and young people (CYP) with CKD 5 and recommendations with regard to drug choice and dose modification are based on adult literature, known pharmacokinetics, and clinical experience.

The effect of oral ondansetron on QT interval in children with acute gastroenteritis; a retrospective observational study

Background

In mildly to moderately dehydrated patients with acute gastroenteritis (AGE), oral rehydration therapy (ORT) is the treatment of choice. Though ondansetron is a very effective antiemetics and leads to succeed ORT, there have been reports QT prolongation in patients using it. We investigated the effect of oral ondansetron on QT interval in mildly to moderately dehydrated children with AGE.

Methods

This retrospective observational study was conducted in a single pediatric emergency department (ED) of a tertiary university hospital. We collected the medical records of patients with a primary diagnosis of AGE who received oral ondansetron and underwent an electrocardiogram between January 2017 and June 2018. A pediatric emergency physician calculated the corrected QT interval (QTc) by Bazett’s method, and the calculations were reviewed by a pediatric cardiologist. QTc values before (preQTc) and after (postQTc) ondansetron administration were analyzed. ΔQTc was calculated as the change from preQTc to postQTc. We also investigated any cardiac complications from oral ondansetron.

Results

Total 80 patients were included. The mean age of the patients was 53.31 ± 32.42 months, and 45% were male. The mean dose of oral ondansetron was 0.18 ± 0.04 mg/kg. The mean interval from administration of ondansetron to performance of the electrocardiogram was 65 ± 26 min. The mean preQTc was 403.3 ± 24.0 ms, and the mean postQTc was 407.2 ± 26.7 ms. Two patients had a preQTc ≥460 ms, and one patient had a postQTc ≥460 ms. ΔQTc was ≥30 ms in seven patients (8.8%). No ΔQTc was ≥60 ms. No pre- or postQTc was ≥500 ms. No patient had a fatal cardiac arrhythmia after taking ondansetron.

Conclusion

Oral administration of a single dose of ondansetron in children with AGE did not cause high-risk QTc prolongation or fatal arrhythmia.

Benefit-Risk Assessment of Off-Label Drug Use in Children: The Bravo Framework

A drug is granted a license for use after a thorough assessment of risks and benefits based on high-quality scientific proof of its efficacy and safety. Many drugs that are relevant to children are not licensed for use in this population implying that a thorough assessment of risks and benefits in the pediatric population has not been made at all, implying a negative risk-benefit balance in children, or implying insufficient information to establish the risk-benefit balance. Use of drugs without positive assessment of risks and benefits exposes children to potential lack of efficacy, unknown toxicity, and harm. To aid guideline committees and individual prescribers, we here present a tutorial of the Benefit and Risk Assessment for Off-label use (BRAvO) decision framework. This pragmatic framework offers a structured assessment of benefits and risks of off-label drug use, including a clinical pharmacological based approach to age-appropriate dose selection. As proof of concept and to illustrate the practical use, we have applied the framework to assess benefits and risks of off-label use of ondansetron for gastroenteritis-induced nausea and vomiting. The framework could also guide decisions on off-label use in other special populations (e.g., pregnant women, elderly, obese, or critically ill patients) where off-label drug use is frequent, thereby contributing to effective and safe pharmacotherapy.

Potential implications of DMET ontogeny on the disposition of commonly prescribed drugs in neonatal and pediatric intensive care units

Introduction: Pediatric patients, especially neonates and infants, are more susceptible to adverse drug events as compared to adults. In particular, immature small molecule drug metabolism and excretion can result in higher incidences of pediatric toxicity than adults if the pediatric dose is not adjusted.Area covered: We reviewed the top 29 small molecule drugs prescribed in neonatal and pediatric intensive care units and compiled the mechanisms of their metabolism and excretion. The ontogeny of Phase I and II drug metabolizing enzymes and transporters (DMETs), particularly relevant to these drugs, are summarized. The potential effects of DMET ontogeny on the metabolism and excretion of the top pediatric drugs were predicted. The current regulatory requirements and recommendations regarding safe and effective use of drugs in children are discussed. A few representative examples of the use of ontogeny-informed physiologically based pharmacokinetic (PBPK) models are highlighted.Expert opinion: Empirical prediction of pediatric drug dosing based on body weight or body-surface area from the adult parameters can be inaccurate because DMETs are not mature in children and the age-dependent maturation of these proteins is different. Ontogeny-informed-PBPK modeling provides a better alternative to predict the pharmacokinetics of drugs in children.

Does Intravenous Ondansetron Affect the Intestinal Motility Pattern in Healthy Donkeys (Equus asinus)?

The current study was undertaken to investigate the effect of intravenous administration of ondansetron on the small and large intestinal motility in donkeys (Equus asinus) using non-invasive transabdominal ultrasonography. The current prospective, randomized, placebo-controlled, crossover study was conducted on thirty healthy donkeys (15 males and 15 females). The selected donkeys underwent two trials; the first was performed by intravenous administration of saline solution as a placebo, while the second was carried out by intravenous administration of ondansetron hydrochloride. The contractility of selected portions of both the small intestine (duodenum and jejunum) and the large intestine (left colon, right colon, and cecum) was counted over a period of 3 minutes before administration (zero time) and at 15, 30, 60, 90, 120, 180, and 240 minutes after administration. The results of this study showed that ondansetron significantly altered the small and large intestinal contractility compared to normal saline. Intravenous administration of ondansetron induced a significant decrease in the duodenal, jejunal and cecal contractility compared to placebo at 30, 60, 90, and 120 minutes after administration. Likewise, ondansetron induced a significant decrease in the left colon and right colon contractility when compared with placebo at 30, 60, 90, 120, and 180 minutes following administration. Ondansetron can be used as a highly specific and selective serotonin 5-HT₃ receptor antagonist for reducing the small and large intestinal motility in donkeys, and is therefore highly suggested for treating spasmodic colic in equine.

RETRACTED: Pluronic® F127 stabilized reduced graphene oxide hydrogel for transdermal delivery of ondansetron: Ex vivo and animal studies

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors. Significant similarities were noticed post-publication between this article and an article submitted to the journal on the same day, by an apparently unrelated research group: Qiang Li, Fangmei Li, Xixi Qi, Fuqiao Wei, Hongxiao Chen and Ting Wang, Colloids and Surfaces B: Biointerfaces 195 (2020) 111246 https://doi.org/10.1016/j.colsurfb.2020.111246. Moreover, the authors did not respond to the journal request to comment on these similarities and to provide the raw data, and the Editors decided to retract the article. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and genuine. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Preparation of an oil suspension containing ondansetron hydrochloride as a sustained release parenteral formulation

Ondansetron hydrochloride (ODS) is a selective 5-hydroxytryptamine type 3 antagonist for nausea and emesis prevention in neoplastic patients. To reduce dosing frequency and side effects and improve patient compliance, a sustained release parenteral formulation of ODS was developed. Microparticles of methylcellulose (MC) and ODS were prepared using the spray-drying method and suspended in oils to form oil suspensions. The formulations were evaluated for residual moisture, drug content, size distribution, DSC, XRD, FTIR, SEM, drug release, and pharmacokinetic studies. The effects of polymers and oils on the drug release were evaluated. MC showed the most prominent sustained release effect among various polymers examined with the optimum MC/ODS ratio of 2:1 (w/w). The particle size of the produced microparticles was in the mean diameter of approximately 3 μm. Physicochemical characterization suggested that ODS existed in an amorphous matrix within the microparticles and interacted with MC via hydrogen bonds. Corn oil was selected as the appropriate oil for suspension due to the sustained release of ODS and the appropriate viscosity. The optimized sustained release formulation of ODS was the corn oil suspension of spray-dried microparticles containing MC and ODS (2:1, w/w). It showed an in vitro drug sustained release up to 120 h, while the oil suspension of ODS without any polymer released the drug within 2 h. Following subcutaneous administration in rats, the optimized formulation could prolong the drug release until 72 h with the enhanced bioavailability in comparison with the ODS solution. The oil suspension of spray-dried microparticles might be an efficient approach for prolongation of the drug effect in the management of nausea and emesis. Graphical abstract.

Pharmacokinetic profile of the selective 5-HT3 receptor antagonist ondansetron in the rat: an original study and a minireview of the behavioural pharmacological literature in the rat

The availability of agonists and antagonists to modulate the activity of the 5-hydroxytryptamine (5-HT) type 3 (5-HT3) receptor has renewed interest in its role as a therapeutic target. Ondansetron is a highly selective 5-HT3 receptor antagonist that is well tolerated as an anti-emetic for patients undergoing chemotherapy. Preclinical studies in rat have shown the effects of small doses of ondansetron on cognition, behavioural sensitisation, and epilepsy. However, the pharmacokinetic (PK) profile of ondansetron in rat has not been described, which limits the translational relevance of these findings. Here, we aim to determine, in the rat, the PK profile of ondansetron in the plasma and to determine associated brain levels. The plasma PK profile was determined following acute subcutaneous administration of ondansetron (0.1, 1, and 10 μg/kg). Brain levels were measured following subcutaneous administration of ondansetron at 1 μg/kg. Plasma and brain levels of ondansetron were determined using high-performance liquid chromatography – tandem mass spectrometry. Following administration of all three doses, measured ondansetron plasma levels (≈30–3000 pg/mL) were below levels achieved with doses usually administered in the clinic, with a rapid absorption phase and a short half-life (≈30–40 min). We also found that brain levels of ondansetron at 1 μg/kg were significantly lower than plasma levels, with brain to plasma ratios of 0.45 and 0.46 in the motor and pre-frontal cortices. We discuss our findings in the context of a minireview of the literature. We hope that our study will be helpful to the design of preclinical studies with therapeutic end-points.

Single-dose of ondansetron for vomiting in children and adolescents with acute gastroenteritis-an updated systematic review and meta-analysis

This review aimed to meta-analyze evidence of efficacy and safety of one single dose of ondansetron for vomiting in children and adolescents with acute gastroenteritis. Database searches of MEDLINE (PubMed), Scopus (Elsevier), Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov up to November 2019 were performed. Only randomized clinical trials versus placebo were considered. Fixed and random effect models were used for the analyses of pooled data. Thirteen randomized clinical trials (2146 patients) were finally included. One single dose of ondansetron showed to produce (1) higher chance of vomiting cessation within 8 h (RR 1.41, 95% CI 1.19-1.68; low-quality evidence); (2) lower chances of oral rehydration therapy failure (RR 0.43, 95% CI 0.34-0.55; high-quality evidence), intravenous hydration needs (RR 0.44, 95% CI 0.34-0.57; high-quality evidence), and hospitalization rates within 8 h (RR 0.49, 95% CI 0.32-0.75; high-quality evidence); and (3) no statistically significant differences in return visits to emergency department (RR 1.14, 95% CI 0.74-1.76; high-quality evidence) compared with placebo. Further studies are necessary to better assess long term efficacy and safety of ondansetron in this context.Conclusions: Mixed evidence was found via few studies about the efficacy and safety of a single dose of ondansetron in the pediatric population.What is known:• Ondansetron use for vomiting in pediatric acute gastroenteritis is increasing worldwide.• Actual convictions come from studies evaluating one and more than one dose of the drug.What is new:• This is the first review to collect data about the effects of one single dose of ondansetron on strong and temporally homogeneous clinical outcomes.• This study supports the use of one dose of ondansetron in pediatric acute gastroenteritis.• Further studies are necessary to assess its long-term efficacy and safety.

Comparison of a new sublingual sedation troche with midazolam, ketamine, and ondansetron with intravenous sedation and the effects on vital signs

PURPOSE

To compare effects of the MKO Melt (midazolam 3 mg, ketamine 25 mg, and ondansetron 2 mg) with intravenous (IV) sedation on vital signs of patients who underwent cataract surgery.

SETTING

Two private ophthalmology practices in Sioux Falls, South Dakota, USA.

DESIGN

Retrospective analysis.

METHODS

Preoperative, intraoperative, and postoperative vital signs were compared between individuals who underwent cataract surgery and received exclusively either MKO (n = 991) or traditional IV methods (n = 120) for sedation. Clinical significance was defined as a 5 mm Hg change in blood pressure, 3 beats per minute (bpm) change in heart rate, a change of 2 respirations per minute, or a change of 3% in O2 saturation. MKO Melt but not IV sedation was given before the reported preoperative vital signs.

RESULTS

There were 1111 patients included in this study. Preoperative systolic blood pressure (SBP) was 133.7 ± 15.6 mm Hg in the MKO group and 139.6 ± 17.3 mm Hg in the IV group (P = .0001). Postoperative SBP was 130.8 ± 12.9 mm Hg in the MKO group and 135.8 ± 19.3 mm Hg in the IV group (P < .01). Postoperative heart rate was 66.3 ± 10.4 bpm in the MKO group compared with 69.8 ± 10.5 bpm in the IV group (P < .001). No other clinically and statistically significant differences were found. The mean number of melts used was 1.5.

CONCLUSIONS

Clinically and statistically significant improvements in preoperative and postoperative SBP and postoperative heart rate were observed in patients who received MKO Melt. The MKO Melt was safe, effective, and well tolerated and a viable alternative to IV sedation.

Pharmacogenetics of antiemetics for chemotherapy-induced nausea and vomiting: A systematic review and meta-analysis

A substantial proportion of cancer patients experience chemotherapy-induced nausea and vomiting (CINV) despite the use of antiemetic drugs. Prevalent genetic polymorphisms involved in antiemetic drug metabolism, drug transport and receptor pathways likely affect the effectiveness of antiemetics. Knowledge on which polymorphisms to integrate into individualised clinical care is needed. We did a systematic review evaluating the association between polymorphisms and effectiveness of antiemetics in cancer patients receiving moderately to highly emetogenic chemotherapy. Twenty studies n = 2331 evaluated eight polymorphisms in five candidate genes involved in 5-HT₃ antagonist pathways. HTR3C C1214G increased the risk of acute chemotherapy-induced vomiting in the dominant model (odds ratio (OR) = 2.67, 95 % confidence interval (CI): 1.08-6.63). ABCB1 C3435T reduced the risk of acute CINV in the recessive model (OR = 0.60, 95 % CI: 0.44-0.81). Future studies should evaluate candidate genes that affect pharmacogenetics of other antiemetics beside 5-HT₃ antagonists.

Hyper-serotonergic state determines onset and progression of idiopathic Parkinson's disease

Despite decades of research on Parkinson's disease (PD), the etiology of this disease remains unclear. The present manuscript introduces a new hypothesis proposing a hyper-serotonergic state as the main mechanism leading to axonal impairment both in dopaminergic and serotonergic neurons in PD. The strong serotonergic connection between the raphe nuclei and the dorsal raphe nuclei with the basal ganglia, all important brain structures associated with the pathophysiology of PD, emphasize a potential role for this neurotransmitter in PD. Importantly, a hyper-serotonergic state can lead to axonal growth impairment, an effect that seems to be selective to axons that can respond to this neurotransmitter. Serotonin seems to be a promising candidate to explain several of the poorly understood early symptoms of PD, including sleep impairment, anxiety, altered gastrointestinal motility and hallucinations. The hypothesis proposed here emphasizes that a hyper-serotonergic state would initially cause disruption of axonal transportation, an acute state in which axonal changes are reversible and the neurodegenerative process can be halted. As the hyper-serotonergic state persists, the accumulation of neurotoxic products and a sustained impairment in axonal transportation would lead to axonal death and culminate in an irreversible neurodegenerative process. The potential implications of this hypothesis are discussed, as well as how future research can be employed to further elucidate the role of serotonin on PD progression.

A randomized study to compare palonosetron with ondansetron for prevention of postoperative nausea and vomiting following middle ear surgeries

Background and Aims:

Postoperative nausea and vomiting (PONV) has multifactorial etiology. It is a commonly encountered morbidity after anesthesia specially following middle ear surgery. Various antiemetic medications have been tried with mixed responses. Palonosetron is a newer 5-hydroxytryptamine (5-HT₃) receptor antagonist marketed for PONV prophylaxis. This study was designed to compare the efficacy of palonosetron and ondansetron in preventing PONV after middle ear surgeries.

Material and Methods:

One hundred patients of ASA class 1 or 2, aged 18 years and above, weighing between 40 and 90 kg scheduled for elective middle ear surgeries were randomly assigned into palonosetron group (n = 50) and ondansetron group (n = 50). Palonosetron was administered in dose of 1 mcg/kg maximum up to 75 mcg and ondansetron in dose of 0.1 mg/kg maximum up to 8 mg. Intraoperative monitoring of QTc interval was also done to see any significant change after the antiemetic administration. The incidence of nausea, vomiting, and side effects were recorded over 2, 12, and 24 hours postoperatively. All parameters were compared between the two groups as mean ± standard deviation and as count (%). Two sided P values of <0.05 were considered significant.

Results:

The incidence of PONV (P = 0.002), nausea (P = 0.0002) and vomiting (P = 0.006) was significantly lower in palonosetron group than in ondansetron group in 2- to 12-hour period. QTc interval prolongation, a known side effect of ondansetron was not found in palonosetron group intraoperatively.

Conclusion:

Palonosetron was found to be superior to ondansetron up to 12 hours after the surgery with no significant effect on QTc interval.

The Effect of Ondansetron on Acute Opioid Tolerance in Patients Receiving Intrathecal Opioids Prior to Cesarean Delivery

BACKGROUND

Multiple animal studies suggest that ondansetron ameliorates opioid-induced hyperalgesia and tolerance. In this study, we aimed to determine if the administration of ondansetron prior to spinal anesthesia would have an effect on intrathecal opioid-induced acute opioid tolerance, postoperative pain, and analgesic requirements in patients undergoing cesarean delivery with spinal anesthesia.

METHODS

Eighty-six patients undergoing elective cesarean delivery were recruited and randomly allocated to receive either 8 mg intravenous ondansetron (n = 44) or placebo (n = 42) in a prospective, double-blind design. All patients received spinal anesthesia consisting of 15 mg bupivacaine, 20 μg of fentanyl, and 100 μg of preservative-free morphine. We used linear mixed-effects models to assess the difference in pain and opioid consumption in the first 24 hours after surgery between the 2 groups.

RESULTS

No differences between the 2 groups were found in age, body mass index, American Society of Anesthesiologists physical status scores, duration of surgery, or sensory and motor block characteristics. There was no difference between the 2 groups in postoperative pain scores (P = 0.95) or opioid consumption (P = 0.68).

CONCLUSIONS

In patients undergoing cesarean delivery under spinal anesthesia with intrathecal opioids, the administration of ondansetron prior to spinal anesthesia did not significantly affect postoperative pain scores or opioid consumption. Thus, the administration of ondansetron did not have an effect on acute opioid tolerance in our study.

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.

Investigational drug therapies in phase I and phase II clinical trials for alcohol use disorders

INTRODUCTION

Alcohol use disorder (AUD) is a complex psychiatric condition characterized by craving, compulsive seeking, loss of control of alcohol consumption as well as the emergence of negative emotional states during withdrawal. Despite the large socioeconomic burden of AUD, therapeutic treatment options lag behind.

AREAS COVERED

This review covers pharmacotherapies currently in phase I/II clinical trials for the treatment of AUDs listed on clinicaltrials.gov. We discuss drug therapies that modulate monoamine, GABA/Glutamate, neuropeptide and neuroimmune systems. We examine in depth preclinical and clinical evidence of a select range of these compounds and consider their utility in treating AUDs.

EXPERT OPINION

Current therapeutic options to treat AUD are inadequate at a population level. Currently there are 30 different compounds and one compound combination in phase I/II clinical trials for AUD. These compounds target various aspects of neurotransmitter signaling, neuroimmune modulation, and alcohol metabolism. Almost 75% of these compounds under trial are Food and Drug Administration (FDA) approved for other indications, which may save time and costs in treatment development. Further, development of therapeutics focused on genetic biomarkers and behavioral screening may improve how treatment decisions are made in the future on a case-by-case basis.

Pregnancy in a patient with congenital analbuminaemia

Congenital analbuminaemia is a rare autosomal recessive disorder that is characterised by a severe reduction or total absence of serum albumin. This condition has implications for therapeutics as a large proportion of commonly used drugs are plasma protein bound where albumin is the primary component of plasma protein. This is the first case report of pregnancy in a patient with congenital analbuminaemia in the medical literature. In the absence of drug dosage guidelines for patients with congenital analbuminaemia, a list of drugs which may be required for this patient during pregnancy, delivery and/or emergency situations were compiled by a multidisciplinary team. Our patient suffered from polyhydramnios during her pregnancy which was successfully managed with albumin transfusions and had a normal vaginal delivery with no complications in the intrapartum or postpartum period. The management and unique challenges of pregnancy in a patient with congenital analbuminaemia are discussed.

Fatal Cardiac Arrest in 2 Children: Possible Role of Ondansetron

INTRODUCTION

Ondansetron is commonly used to treat vomiting in gastroenteritis, but has a United States Food and Drug Administration black box warning for risk of Q wave to T wave time interval (QT) prolongation. We report 2 pediatric cases of fatal refractory cardiac arrest after administration of ondansetron.

CASES

A 10-year-old previously healthy boy presented to the emergency room with gastroenteritis symptoms. After intravenous fluids, morphine, antibiotics, and 2 doses of ondansetron, the patient became unresponsive with agonal respirations and a wide complex tachycardia consistent with ventricular tachycardia. In a second case, an 86-day-old infant with previously unidentified congenital cardiomyopathy presented to our emergency department with gastroenteritis symptoms. The patient received ondansetron and subsequently experienced repeated bouts of supraventricular tachycardia which progressed to ventricular fibrillation. Resuscitation efforts failed in each case, and both patients expired.

DISCUSSION

Ondansetron can cause dose-dependent QT prolongation effects, which are more clinically relevant when other proarrhythmic elements are present. There is very limited published experience on use of ondansetron in children younger than 2 years. Our 2 cases join 2 previous case reports of death after ondansetron administration for gastroenteritis. The pharmacology of ondansetron's cardiac effects and drug-induced QT prolongation is discussed.

CONCLUSIONS

Patients may have hidden risk factors that, together with ondansetron, could result in a proarrhythmic state that could lead to adverse effects, such as arrhythmias. Administration of ondansetron should be individualized and used cautiously in patients with risk factors for arrhythmia.

Inadvertent spinal injection of ondansetron

Cesarean sections under spinal anesthesia are now a daily occurrence in most tertiary hospitals. We report the first published case of inadvertent spinal injection of ondansetron without any neurological sequelae in a patient undergoing elective Cesarean section under spinal anesthesia. She did not experience any permanent neurological sequelae, and also did not exhibit any central neuraxial opioid side effects-nausea, vomiting or pruritus. Vigilance is essential to reduce the risk of wrong route delivery of drugs, especially when presented in very similar-looking 2 mL ampules as in our institution.

Ondansetron Exposure Changes in a Pregnant Woman

Pregnancy results in many physiologic changes that can alter the pharmacokinetic profiles of medications used during pregnancy. One of the primary factors leading to these pharmacokinetic changes is altered activity of drug-metabolizing enzymes. Ondansetron is a substrate of cytochrome P450 (CYP) 3A4 (primary metabolic pathway), 2D6, and 1A2, all of which are altered during pregnancy. We evaluated the pharmacokinetics of ondansetron at three different gestational time points in a 26-year-old, pregnant, Caucasian woman with normal liver and kidney function, who was maintained on ondansetron 8 mg administered orally 3 times/day throughout her pregnancy. Serial plasma samples were collected from the subject over one 8-hour dosing interval at 14, 24, and 35 weeks' gestation (representing early-, mid-, and late-pregnancy time points, respectively). Ondansetron plasma concentrations were determined using liquid chromatography-tandem mass spectrometry. Ondansetron area under the plasma concentration-time curve decreased progressively across gestation (634 ng hr/ml in early pregnancy, 553 ng hr/ml in mid-pregnancy, and 387 ng hr/ml in late pregnancy), with a corresponding increase in apparent oral clearance (12.6 L/hr in early-pregnancy, 14.5 L/hr in mid-pregnancy, and 20.7 L/hr in late-pregnancy). The decreased area under the plasma concentration-time curve and exposure to ondansetron across gestation is likely due to increased activity of CYP3A4 and CYP2D6 during pregnancy. We were not able to study this patient during the postpartum period; however, as with other CYP3A4 and CYP2D6 substrates, the apparent activities of these isoenzymes are likely return to baseline. To our knowledge, this is the first report to describe ondansetron pharmacokinetics across gestation. Additional pharmacokinetic and pharmacodynamic data are needed to confirm our results and to evaluate clinical impact; however, in the meantime, clinicians should be aware of these pharmacokinetic changes in ondansetron exposure during pregnancy.

Limited sampling pharmacokinetics of subcutaneous ondansetron in healthy geriatric cats, cats with chronic kidney disease, and cats with liver disease

Ondansetron, a 5-HT3 receptor antagonist, is an effective anti-emetic in cats. The purpose of this study was to compare pharmacokinetics of subcutaneous (SQ) ondansetron in healthy geriatric cats to cats with chronic kidney disease (CKD) or liver disease using a limited sampling strategy. 60 cats participated; 20 per group. Blood was drawn 30 and 120 min following one 2 mg (mean 0.49 mg/kg, range 0.27-1.05 mg/kg) SQ dose of ondansetron. Ondansetron concentrations were measured by liquid chromatography coupled to tandem mass spectrometry. Drug exposure represented as area under the curve (AUC) was predicted using a limited sampling approach based on multiple linear regression analysis from previous full sampling studies, and clearance (CL/F) estimated using noncompartmental methods. Kruskal-Wallis anova was used to compare parameters between groups. Mean AUC (ng/mL·h) of subcutaneous ondansetron was 301.4 (geriatric), 415.2 (CKD), and 587.0 (liver). CL/F (L/h/kg) of SQ ondansetron was 1.157 (geriatric), 0.967 (CKD), and 0.795 (liver). AUC was significantly higher in liver and CKD cats when compared to geriatric cats (P < 0.05). CL/F in liver cats was significantly decreased (P < 0.05) compared to geriatric cats. In age-matched subset analysis, AUC and CL/F in liver cats remained significantly different from geriatric cats.

The effect of ondansetron on the efficacy of postoperative tramadol: a systematic review and meta-analysis of a drug interaction

Several studies have investigated the presence of a drug interaction between tramadol and ondansetron that reduced the efficacy of tramadol postoperatively. Most of these studies were small and the results inconsistent, so we performed a systematic review and meta-analysis of randomised controlled trials comparing the cumulative dose of tramadol administered by patient-controlled analgesia within the first 24 h after surgery between subjects receiving tramadol alone and those who received tramadol with ondansetron. Six studies, with a total of 340 participants, met the selection criteria and were included in the meta-analysis. There was an increased tramadol requirement in patients receiving ondansetron. The standardised mean difference in tramadol requirements, expressed in terms of standard deviations (95% CI), was 1.03 (0.54-1.53) (p < 0.001) at 4 h, 0.66 (0.06-1.25) (p = 0.03) at 8 h, 0.86 (0.41-1.31) (p < 0.001) at 12 h and 0.45 (0.01-0.90) (p = 0.046) at 24 h postoperatively, where the mean pooled standard deviations were 79.5, 157.7, 238.1 and 289.4 mg at 4, 8, 12 and 24 h, respectively. There was a significant linear time effect over the 24 h, indicating that the effect of ondansetron on tramadol consumption diminished with time. The results support the presence of a drug interaction between tramadol and ondansetron in the early postoperative period that potentially decreases the effectiveness of tramadol.

Ondansetron pharmacokinetics in pregnant women and neonates: towards a new treatment for neonatal abstinence syndrome

Ondansetron is the drug of choice to prevent nausea in women undergoing cesarean surgery and can be used to prevent neonatal abstinence syndrome (NAS). The pharmacokinetics of ondansetron have not been characterized in pregnant women or in newborns. A nonlinear mixed-effects modeling approach was used to analyze plasma samples obtained from 20 nonpregnant and 40 pregnant women following a single administration of 4 or 8 mg ondansetron, from umbilical cord blood at delivery, and from neonates after birth. The analysis indicates that: ondansetron disposition is not affected by pregnancy (P > 0.05), but influenced by dose (P < 0.05), and is characterized by rapid transplacental transfer and longer elimination half-life in neonates compared to their mother. A dosing regimen for prevention of NAS was designed based on the model. The regimen involves IV administration of 4 mg to the mothers shortly before cord clamping, or oral administration of 0.07 mg/kg (or equivalently 0.04 mg/kg IV) to neonates.

Does ondansetron have an effect on intramuscular ketamine-associated vomiting in children? A prospective, randomised, open, controlled study

AIM

Ketamine is one of the most commonly used sedatives for facilitating painful procedures for paediatric patients in the emergency department (ED). However, the use of ketamine is associated with a common, though not serious, adverse event usually called ketamine-associated vomiting (KAV). The purpose of this study is to evaluate the anti-emetic effect of adjunctive ondansetron in paediatric patients receiving ketamine sedation in the ED.

METHODS

We conducted a prospective, randomised, open, controlled study in children from 1 to 18 years of age who had undergone intramuscular ketamine sedation in the ED. The patients were randomised into two groups: a ketamine-only group and a ketamine/ondansetron group. The patients in the first group received ketamine alone, while those in the second group received ketamine with oral ondansetron. The incidence of KAV was estimated in the ED and after discharge, and the time to resumption of a normal diet was measured after sedation.

RESULTS

A total of 237 patients were analysed. The incidence of KAV was 29.7% in the ketamine-only group and 25.2% in the ketamine/ondansetron group (P = 0.47). After administration of ketamine, the mean time to resumption of a normal diet was 8 h 54 min in the ketamine-only group and 8 h 39 min in the ketamine/ondansetron group (P = 0.67).

CONCLUSIONS

A relatively high rate of KAV (29.7%) was observed, and the time to resumption of a normal diet after ketamine sedation was rather long. It turned out that, however, the adjunctive administration of ondansetron did not effectively reduce the incidence of KAV.

Tolerability and pharmacokinetic properties of ondansetron administered subcutaneously with recombinant human hyaluronidase in minipigs and healthy volunteers

BACKGROUND

Subcutaneous ondansetron facilitated by recombinant human hyaluronidase PH20 (rHuPH20) is an alternative for treating nausea/vomiting in patients who cannot receive ondansetron by other routes of administration.

OBJECTIVE

Based on preclinical results in minipigs, a Phase I study was designed to assess the tolerability and pharmacokinetic properties of subcutaneous ondansetron + rHuPH20 compared with intramuscular, intravenous, or oral ondansetron monotherapy in healthy volunteers.

METHODS

In a crossover design, 3 minipigs were dosed with subcutaneous ondansetron 0.08 mg/kg + rHuPH20, or as intramuscular or intravenous monotherapy, for the evaluation of plasma ondansetron concentrations and local tolerability. In a randomized, open-label, 4-way crossover study, subjects received a randomized sequence of SC ondansetron 4 mg + rHuPH20, or ondansetron monotherapy IM (4 mg), IV (4 mg), or PO (8 mg), over 4 daily visits. Study participants included healthy volunteers aged 19 to 65 years with adequate venous access in both upper extremities and no history of QT-interval prolongation. Primary tolerability end points (administration-site observations, systemic adverse events [AEs], and subject-assessed pain) were assessed, and pharmacokinetic parameters (AUC, Cmax, Tmax, t½) were computed to compare relative rate and extent of systemic exposure. Results were described using summary statistics, and bioequivalence was determined with a linear mixed-effects model.

RESULTS

In the preclinical study, no adverse events or significant local reactions were observed. The Cmax (45.8 ng/mL at 0.08 hour) with subcutaneous administration + rHuPH20 was 83% greater and was achieved 68% faster than with intramuscular administration (Cmax = 25 ng/mL at 0.25 hour). In the clinical study, a total of 12 subjects (7 women, 5 men; white majority; mean age, 44.8) were randomized. The majority of AEs were at the injection site, mild in severity, and transient. After subcutaneous administration of ondansetron + rHuPH20, geometric mean Cmax was 35% higher than with intramuscular ondansetron, 43% lower than with intravenous ondansetron, and 126% higher than with oral ondansetron (corrected for dose). Bioequivalence tests demonstrated that systemic exposure after subcutaneous administration was similar to that after intramuscular or intravenous administration and significantly greater than that after oral administration.

CONCLUSIONS

Subcutaneous ondansetron + rHuPH20 was generally well-tolerated. Subcutaneous dosing resulted in an extent of systemic exposure similar to that with intramuscular or intravenous dosing and greater than that with oral administration, and may be an option for clinical administration of ondansetron. ClinicalTrials.gov identifier: NCT01572012.

Ondansetron: a review of pharmacokinetics and clinical experience in postoperative nausea and vomiting

INTRODUCTION

Postoperative nausea and vomiting (PONV) is associated with poor patient satisfaction and delayed recovery after general anesthesia. Multiple neurotransmitters are involved in the mediation of PONV but despite the introduction of new antiemetics, no completely effective drug exists for its prevention or treatment.

AREAS COVERED

This review provides a detailed description of ondansetron's chemistry, pharmacokinetics, pharmacodynamics, toxicity and a brief review of clinical trials involving ondansetron and the management of PONV. We searched reviews, meta-analysis and randomized controlled trials (Medline, Embase and article reference lists).

EXPERT OPINION

According to current literature, administering ondansetron 4 mg i.v. near the end of surgery provides sufficient protection against PONV in low- and moderate-risk patients, comparable to traditional antiemetics such as antihistamines and droperidol. High-risk patients require a multimodal approach since one quarter of them will not respond to monotherapy. In the future, transdermal formulation or formulations for nasal or buccal delivery will be available. The development of non-racemic mixture consisting of R-ondansetron would enhance the safety profile and probably the efficacy too.