Selective serotonin 5-HT3 receptor antagonists for postoperative nausea and vomiting: are they all the same?

A Cytotoxic Indazole-based Gold(III) Carboxamide Pincer Complex Targeting DNA Through Dual Binding Modes of Groove Binding and Alkylation

Gold(III) complexes have garnered increasing attention in drug delivery due to their structural and mechanistic similarities to cisplatin. This study investigates an indazole-based gold(III) carboxamide pincer complex, [N2·N6-bis(1-methyl-1H-indazol-3-yl)pyridine-2·6-dicarboxamide]gold(III) chloride (AuL), for its potential as an anticancer agent. Speciation analysis at physiological pH revealed that AuL predominantly exists as a neutral chlorinated species. The complex exhibited strong cytotoxicity against the MCF-7 breast cancer cell line, with an impressive IC50 value of 9 µM, while showing no significant activity against the HT-29 colon cancer cell line. Comprehensive analysis using electrophoresis, viscometry, ultraviolet-visible spectroscopy (UV-Vis), circular dichroism (CD), linear dichroism (LD) spectroscopy, and biomolecular simulations demonstrated that AuL binds to DNA via a dual mechanism, specifically minor groove binding and alkylation, with binding constants Ka1 = 1.48 × 109 M-1 and Ka2 = 6.59 × 105 M-1, respectively. Our data indicate that AuL initially binds to the minor groove of DNA, at which point a nucleobase substitutes the Cl ion, resulting in AuL binding directly to the DNA bases. In conclusion, the dual binding mode of AuL with DNA underscores its potential as a promising anticancer agent, opening new avenues for drug discovery and the development of metal-based therapeutics.

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.

Population pharmacokinetic analysis of transdermal granisetron in healthy Chinese and Caucasian volunteers

Granisetron patches are a prolonged delivery transdermal system that is used to prevent Chemotherapy-induced nausea and vomiting (CINV). To date, no pharmacokinetics comparison between Chinese and Caucasian populations has been conducted for granisetron patches. This study focused on the ethnic differences in pharmacokinetics (PK) of granisetron transdermal delivery system (GTDS) between Chinese and Caucasians and the influence of demographic covariates on pharmacokinetics (age, weight, height, body mass index, sex). To achieve this, blood concentration data were collected from 112 Caucasian healthy subjects participating in four clinical trials and 24 Chinese healthy subjects from one clinical trial, after a single application of the granisetron transdermal delivery system. A nonlinear mixed-effects model method of Phoenix NLME software was used to establish a population pharmacokinetic (Pop PK) model for Caucasian subjects. Bootstrap and visual predictive check (VPC) were used to validate the model. Based on the analysis a one-compartment model with first-order absorption and a first-order elimination well described the PK characteristics of GTDS. The apparent systemic clearance was determined to be 31316.3 mL/h and the central compartment volume of distribution was 6299.03 L. None of the five covariates (age, weight, height, body mass index, and sex) included in the Pop PK were significant covariates affecting PK. The final Pop PK model was used to simulate the Caucasian blood concentration by applying the dosing regimen used for the Chinese population. Comparison of the simulated Caucasian PK data with observed clinical PK data from Chinese healthy subjects revealed no significant differences in the main parameters, AUC_last and C_avg, between the two groups. These findings suggested that no dose adjustment was required when applied to the Chinese population. In conclusion, this Pop PK study comparing the transdermal patch in Chinese and Caucasian healthy subjects provided valuable insights for optimizing dosage across ethnicities.

Comparison of Intravenous Granisetron and Ondansetron on Hemodynamics and Sensory Motor Block After Spinal Anaesthesia With Hyperbaric Bupivacaine in Patients Undergoing Elective Surgery: A Randomized Double-Blind Study

BACKGROUND

Bezold Jarisch reflex (BJR) is mediated by peripheral serotonin receptor 5-HT₃ type. BJR and sympathetic blockade are important causes of hypotension and bradycardia after spinal anaesthesia. Premedication with serotonin receptor antagonists has a role in the attenuation of hemodynamic disturbances.

AIM

To compare the effect of intravenous granisetron and ondansetron on the hemodynamic and sensory-motor block after spinal anaesthesia with hyperbaric bupivacaine in patients undergoing elective surgery.

METHODOLOGY

Ninety patients posted for elective surgery under spinal anaesthesia were randomly divided into three groups of 30 each. Group A patients received ondansetron 4mg, group B received granisetron 1mg, and group C received normal saline intravenously. Hemodynamic variables such as heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and peripheral oxygen saturation, were recorded at baseline and then 2 minutes intervals for 20 minutes and thereafter every 5 minutes till the end of the surgery. The onset and duration of sensory and motor block were recorded at baseline and then every 2 minutes till the complete block was achieved.

RESULT

No patient was excluded from our study. During the intergroup comparison, heart rate and mean arterial pressure remained stable in group A compared to groups B and C. Time to reach peak sensory block level T4 was faster in group A compared to group B and group C. The rate of sensory block regression to two segments (T4 to T6) and thereafter up to T10, T12, and S1 was faster in group B compared to groups A and C. The attainment of complete motor block, Modified Bromage Score (MBS)=4 was faster in group A compared to group B and group C. The rate of motor block regression to MBS=3 and MBS=0 was faster in group B compared to group A and group C.

CONCLUSION

Premedication with ondansetron 4mg and granisetron 1mg intravenously significantly reduces ephedrine use. Ondansetron provides better hemodynamic stability, earlier onset of the sensory and motor blocks as well as prolonged duration of sensory and motor blocks, and duration of analgesia compared to granisetron.

A Randomised Controlled Trial to Compare the Effect of Ramosetron and Ondansetron in Prevention of Postoperative Nausea and Vomiting in Patients Undergoing Laparoscopic Gynaecological Procedures

Background and objective

The antiemetic drug is one of the most common armamentariums in an anaesthesiologist's pharmacopoeia to prevent postoperative nausea and vomiting (PONV). PONV is one of the usual side effects after general anaesthesia, especially in female patients (21%) and after laparoscopic surgery (60%). This study aimed to compare the efficacy of ondansetron with ramosetron.

Methodology

After institutional ethical clearance and informed written consent, one hundred female patients scheduled for laparoscopic gynaecological surgeries were selected for this prospective, double-blinded, randomised interventional study. These patients were further subdivided into two equal groups (50 in groups R and O). Group R received ramosteron 0.3mg, and group O received ondansetron 8mg 30 minutes before the end of surgery. Patients were assessed between 0-2, 2-6, 6-12 and 12-24 hrs in the postoperative period. The primary objective of this study was to compare the effect of a single dose of ramosetron (0.3mg) with a single dose of ondansetron (8mg) for the prevention of PONV after general anaesthesia in laparoscopic surgeries. The secondary goal was to record the time of occurrence of the first episode of PONV, the need for rescue antiemetics, patient satisfaction scores, and to look for any side effects.

Results

This study shows no significant difference in the reduction of PONV incidence between group O and group R in the first 24 hours of the postoperative period. The overall incidence of PONV was significantly higher in the early postoperative (0-6 hrs) than in the late postoperative period (6-24 hrs), i.e., 51% and 13%, respectively. The requirement of rescue antiemetic was higher in group O than in group R but not statistically significant. In our study, both groups had similar patient satisfaction scores. Headache was the most common side effect and was noted in 9% of the patient population.

Conclusion

We conclude that ramosetron is as effective as ondansetron in preventing the incidence and severity of PONV up to 24 hours postoperatively.

5-HT3 receptor antagonists decrease the prevalence of postoperative delirium in older patients undergoing orthopedic lower limb surgery

BACKGROUND

Delirium is an important postoperative complication. Recent research suggested that 5-hydroxytryptamine 3 (5-HT₃) receptor antagonists may have clinical effect in the treatment and prevention of delirium. We investigated the association between 5-HT₃ receptor antagonists and the occurrence of postoperative delirium (POD).

METHODS

Retrospectively, the electronic medical records were reviewed in patients aged ≥ 65 years who underwent orthopedic lower limb surgery under regional anesthesia (spinal or combined spinal-epidural anesthesia) and administered intravenous 0.075 mg palonosetron or 0.3 mg ramosetron prior to the end of surgery between July 2012 and September 2015. POD incidence and anesthesia-, surgery-, and patient-related factors were evaluated. To investigate the association between 5-HT₃ receptor antagonists and the occurrence of POD, multivariable logistic regression analysis was performed.

RESULTS

Of the 855 patients included, 710 (83%) were administered 5-HT₃ receptor antagonists. POD was confirmed in 46 (5.4%) patients. 5-HT₃ receptor antagonists reduced the POD incidence by 63% (odds ratio [OR] 0.37; 95% confidence interval [CI], 0.15-0.94; P = 0.04). Moreover, the POD incidence decreased by 72% (OR 0.28, 95% CI 0.10-0.77, P = 0.01) when palonosetron was administered. Other identified risk factors for POD were emergency surgery, older age, hip surgery, lower body mass index, and intraoperative propofol sedation.

CONCLUSION

5-HT₃ receptor antagonists may be related with a significantly reduced risk for POD in older patients undergoing orthopedic lower limb surgery. Notably, palonosetron was more effective for POD prevention.

Involvement of 5-Serotonin and Substance p Pathways in Dichroa Alkali Salt-Induced Acute Pica in Rats

Dichroa alkali salt (DAS) is the active ingredient of Changshan, a traditional Chinese antimalarial medicine. However, owing to its vomiting side effects, its clinical use is limited. Recently, DAS-induced vomiting has attracted broad attention; however, the mechanisms involved have not yet been elucidated. The present study aimed to explore DAS induced vomiting and decipher the potential role of the 5-serotonin (5-HT) and substance p (SP) signaling pathways. We used a combination of approaches in the context of a rat pica model, such as immunoblot analysis, HPLC-ECD, ELISA, quantitative real-time PCR, pharmacological inhibition, and immunohistochemistry assays. We demonstrated that DAS contributed to Changshan-induced vomiting via the activation of the 5-HT and SP signaling pathways. DAS could induce a dose-dependent kaolin intake in the rat pica model. Moreover, DAS caused a similar profile as Cisplatin (DDP): “low-dose double-peak, high-dose single-peak pica phenomenon”. Interestingly, treatment with DAS stimulated the peripheral ileum and central medulla oblongata and augmented the release of 5-HT, SP, and preprotachykinin-A and the expression of 5-HT₃ and NK₁ receptors in the two issues in acute phase. Additionally, the 5-HT₃ and NK₁ receptor antagonists effectively alleviated DAS-induced kaolin intake and significantly reduced DAS-induced 5-HT and SP levels in the two issues in acute phase. Similar responses were not observed in the context of dopamine receptor inhibition. This study innovatively revealed that the 5-HT and SP-mediated vomiting network plays an important role in DAS-induced acute vomiting; of note, ondansetron, and aprepitant can effectively antagonize DAS-induced vomiting. Our results suggest a potential therapeutic strategy (based on drugs approved for human use) to prevent the DAS-associated adverse reactions.

Application of the HPLC Method in Parenteral Nutrition Assessment: Stability Studies of Ondansetron

Ondansetron (OND) is a serotonin type 3 receptor antagonist that exhibits antiemetic activity. From the clinical point of view, vomiting and nausea prevention is an important task. Anticancer treatment and recovery impact the patient’s overall state by affecting appetite, well-being, and physical activity, and consequently, nutrition quality. Depending on the patient’s indication and condition, parenteral nutrition is administered to meet full nutritional requirements. In addition, antiemetic drugs can be added to the parenteral nutrition (PN) admixture to treat chemo- or radio-therapy-induced nausea and vomiting. However, adding any medication to the PN admixture can result in the instability of the composition in the overall admixture. This study aimed to develop the HPLC method of determination of OND in Lipoflex special, one of the most popular, ready-to-use PN admixtures. The proposed HPLC method and the sample preparation procedure were suitable for analyzing OND in PN admixture stored under various conditions, such as exposure to sunlight and temperature. It was found that the decomposition of OND during the seven-day storage did not exceed 5% and did not depend on external factors. Based on the conducted research, it is recommended to add OND to Lipoflex special, and it is possible to store such an admixture for seven days.

Granisetron, a selective 5-HT3 antagonist, reduces L-3,4-dihydroxyphenylalanine-induced abnormal involuntary movements in the 6-hydroxydopamine-lesioned rat

Administration of L-3,4-dihydroxyphenylalanine (L-DOPA) provides Parkinson's disease patients with effective symptomatic relief. However, long-term L-DOPA therapy is often marred by complications such as dyskinesia. We have previously demonstrated that serotonin type 3 (5-HT3) receptor blockade with the clinically available and highly selective antagonist ondansetron alleviates dyskinesia in the 6-hydroxydopamine (6-OHDA)-lesioned rat. Here, we sought to explore the antidyskinetic efficacy of granisetron, another clinically available 5-HT3 receptor antagonist. Rats were rendered hemi-parkinsonian by 6-OHDA injection in the medial forebrain bundle. Following induction of stable abnormal involuntary movements (AIMs), granisetron (0.0001, 0.001, 0.01, 0.1 and 1 mg/kg) or vehicle was acutely administered in combination with L-DOPA and the severity of AIMs, both duration and amplitude, was determined. We also assessed the effect of granisetron on L-DOPA antiparkinsonian action by performing the cylinder test. Adding granisetron (0.0001, 0.001, 0.01, 0.1 and 1 mg/kg) to L-DOPA resulted in a significant reduction of AIMs duration and amplitude, with certain parameters being reduced by as much as 38 and 45% (P < 0.05 and P < 0.001, respectively). The antidyskinetic effect of granisetron was not accompanied by a reduction of L-DOPA antiparkinsonian action. These results suggest that 5-HT3 blockade may reduce L-DOPA-induced dyskinesia without impairing the therapeutic efficacy of L-DOPA. However, a U-shaped dose-response curve obtained with certain parameters may limit the therapeutic potential of this strategy and require further investigation.

Structure, dynamics and lipid interactions of serotonin receptors: excitements and challenges

Serotonin (5-hydroxytryptamine, 5-HT) is an intrinsically fluorescent neurotransmitter found in organisms spanning a wide evolutionary range. Serotonin exerts its diverse actions by binding to distinct cell membrane receptors which are classified into many groups. Serotonin receptors are involved in regulating a diverse array of physiological signaling pathways and belong to the family of either G protein-coupled receptors (GPCRs) or ligand-gated ion channels. Serotonergic signaling appears to play a key role in the generation and modulation of various cognitive and behavioral functions such as sleep, mood, pain, anxiety, depression, aggression, and learning. Serotonin receptors act as drug targets for a number of diseases, particularly neuropsychiatric disorders. The signaling mechanism and efficiency of serotonin receptors depend on their amazing ability to rapidly access multiple conformational states. This conformational plasticity, necessary for the wide variety of functions displayed by serotonin receptors, is regulated by binding to various ligands. In this review, we provide a succinct overview of recent developments in generating and analyzing high-resolution structures of serotonin receptors obtained using crystallography and cryo-electron microscopy. Capturing structures of distinct conformational states is crucial for understanding the mechanism of action of these receptors, which could provide important insight for rational drug design targeting serotonin receptors. We further provide emerging information and insight from studies on interactions of membrane lipids (such as cholesterol) with serotonin receptors. We envision that a judicious combination of analysis of high-resolution structures and receptor-lipid interaction would allow a comprehensive understanding of GPCR structure, function and dynamics, thereby leading to efficient drug discovery.

Recent advances with 5-HT3 modulators for neuropsychiatric and gastrointestinal disorders

Serotonin (5-hydroxytryptophan [5-HT]) is a biologically active amine expressed in platelets, in gastrointestinal (GI) cells and, to a lesser extent, in the central nervous system (CNS). This biogenic compound acts through the activation of seven 5-HT receptors (5-HT_1-7 Rs). The 5-HT₃ R is a ligand-gated ion channel belonging to the Cys-loop receptor family. There is a wide variety of 5-HT₃ R modulators, but only receptor antagonists (known as setrons) have been used clinically for chemotherapy-induced nausea and vomiting and irritable bowel syndrome treatment. However, since the discovery of the setrons in the mid-1980s, a large number of studies have been published exploring new potential applications due their potency in the CNS and mild side effects. The results of these studies have revealed new potential applications, including the treatment of neuropsychiatric disorders such as schizophrenia, depression, anxiety, and drug abuse. In this review, we provide information related to therapeutic potential of 5-HT₃ R antagonists on GI and neuropsychiatric disorders. The major attention is paid to the structure, function, and pharmacology of novel 5-HT₃ R modulators developed over the past 10 years.

Tropisetron ameliorates cyclophosphamide-induced hemorrhagic cystitis in rats

Hemorrhagic cystitis is one of the most important complications of cyclophosphamide, a drug widely used in cancer chemotherapy and bone marrow transplantation. 5-HT₃ antagonists are anti-emetic agents and have been shown to have notable anti-inflammatory and antioxidant properties. This study was designed to investigate the possible protective effects of tropisetron against cyclophosphamide-induced hemorrhagic cystitis in rats. Hemorrhagic cystitis was induced in female rats by cyclophosphamide (270 mg/kg). Tropisetron (2.5, 5 and 7.5 mg/kg), granisetron (2.5 and 5 mg/kg), and ondansetron (5 mg/kg) were injected 15 min before, 4 and 8 h after cyclophosphamide. To evaluate the role of alpha7 nicotinic acetylcholine receptor (α7nAChR), its antagonist, methyllycaconitine (5 mg/kg) was administered 30 min before tropisetron. After 24 h, animals were killed under anesthesia. Macroscopic and histological changes were evaluated. Malondialdehyde (MDA), glutathione (GSH) and Evans blue were measured spectrophotometrically. Furthermore, the protein levels of p38 mitogen-activated protein kinases (P38 MAPK), p-P38, signal transducer and activator of transcription 3 (STAT3), p-STAT3 and Poly (ADP-ribose) polymerase (PARP) were determined using Western blot. Cyclophosphamide administration significantly induced histopathological damages and increased MDA, p-p38/p38, p-STAT3/STAT3, and PARP levels compared with the saline group. Tropisetron treatment diminished histopathological injuries as well as MDA level, and STAT3 activity compared to cyclophosphamide treated rats. Co-administration of methyllycaconitine with tropisetron, partially or completely reversed the protective effects of tropisetron. Our results showed that prophylactic administration of tropisetron markedly ameliorated the cyclophosphamide-induced bladder hemorrhage and inflammation in rats. These effects of tropisetron were α7nAChR dependent.

The Contribution of Serotonergic Receptors and Nitric Oxide Systems in the Analgesic Effect of Acetaminophen: An Overview of the Last Decade

Acetaminophen is a widely used analgesic and antipyretic agent. It is also available in over the counter formulations, which has increased its wide use. There have been many studies to date that have aimed to evaluate the mechanism of the analgesic action of acetaminophen. Additional to the inhibition of the cyclooxygenase pathway in the central nervous system, the involvement of opioidergic, cannabinoidergic, dopaminergic, cholinergic, and nitrergic systems as well as the contribution of descending pain inhibitory systems like the bulbospinal serotonergic pathway has been proposed as possible mechanisms of the analgesic action of acetaminophen. In this review, we aimed to collect the data from studies revealing the contribution of the central serotonergic system and the role of central nervous system-located serotonergic receptor subtypes in the analgesic effect of acetaminophen. While doing this, we mainly focused on the research that has been performed in the last ten years and tried to link the previous data with the lately added results. In addition to serotonergic system involvement, we also reviewed the role of nitric oxide in the analgesic action of acetaminophen, especially with the new findings reported over the last decade.

The Role of Descending Pain Modulation in Chronic Primary Pain: Potential Application of Drugs Targeting Serotonergic System

Chronic primary pain (CPP) is a group of diseases with long-term pain and functional disorders but without structural or specific tissue pathologies. CPP is becoming a serious health problem in clinical practice due to the unknown cause of intractable pain and high cost of health care yet has not been satisfactorily addressed. During the past decades, a significant role for the descending pain modulation and alterations due to specific diseases of CPP has been emphasized. It has been widely established that central sensitization and alterations in neuroplasticity induced by the enhancement of descending pain facilitation and/or the impairment of descending pain inhibition can explain many chronic pain states including CPP. The descending serotonergic neurons in the raphe nuclei target receptors along the descending pain circuits and exert either pro- or antinociceptive effects in different pain conditions. In this review, we summarize the possible underlying descending pain regulation mechanisms in CPP and the role of serotonin, thus providing evidence for potential application of analgesic medications based on the serotonergic system in CPP patients.

Pharmacogenetics of Postoperative Nausea and Vomiting

Postoperative nausea and vomiting (PONV) remains one of the most common adverse effects of anesthesia, affecting up to 80% of high-risk patients within 24 hours after surgery. Patient-related factors, surgical procedure, and perioperative medications such as opioids determine a patient's risk for PONV. To prevent and manage PONV, ondansetron, a 5-hydroxytryptamine type 3 (5-HT₃) receptor antagonist, is frequently administered. Ondansetron is metabolized predominantly by hepatic cytochrome P450 (CYP2D6) enzymes, encoded by the CYP2D6 gene, whereas most of the effects of opioids are exerted at the opioid mu-1 receptor, encoded by the OPRM1 gene. Genetic polymorphisms of the CYP2D6 and OPRM1 genes may have a role in interindividual variation in the occurrence of PONV. Specifically, the occurrence of the G-allele produced by the OPRM1 A118G appears to be protective against PONV, whereas CYP2D6 ultrarapid metabolism increases the risk for PONV. The Clinical Pharmacogenetics Implementation Consortium guidelines provide CYP2D6-guided therapeutic recommendations for ondansetron. However, further studies are needed to investigate the role of genetic polymorphism in the occurrence of PONV and response to antiemetics.

Rapid structure identification of nineteen metabolites of ondansetron in human urine using LC/MSn

Ondansetron, a 5-hydroxytryptamine type 3 (5-HT₃ ) receptor antagonist, is regarded as an excellent candidate to treat chemotherapy- and radiotherapy-induced nausea and vomiting. To better understand the metabolic profiles of ondansetron in human urine, the metabolites were analyzed using liquid chromatography/mass spectrometry (LC/MSⁿ ). Urine samples were collected after oral administration of 8 mg ondansetron to healthy volunteers. Then samples were treated by solid-phase extraction and detected with LC/MSⁿ . Besides ondansetron, in human urine, a total of 19 metabolites including 13 new metabolites were detected and identified via comparing the retention time and product ion spectra with those of reference standards isolated and characterized. The results showed that ondansetron was metabolized via hydroxylation, glucuronidation, sulfation and minor N-demethylation in human. LC/MSⁿ was demonstrated to be useful and sensitive in the metabolic study of ondansetron.

5-HT3 Antagonist Ondansetron Increases apoE Secretion by Modulating the LXR-ABCA1 Pathway

Apolipoprotein E (apoE) is linked to the risk for Alzheimer’s disease (AD) and thus has been suggested to be an important therapeutic target. In our drug screening effort, we identified Ondansetron (OS), an FDA-approved 5-HT3 antagonist, as an apoE-modulating drug. OS at low micromolar concentrations significantly increased apoE secretion from immortalized astrocytes and primary astrocytes derived from apoE3 and apoE4-targeted replacement mice without generating cellular toxicity. Other 5-HT3 antagonists also had similar effects as OS, though their effects were milder and required higher concentrations. Antagonists for other 5-HT receptors did not increase apoE secretion. OS also increased mRNA and protein levels of the ATB-binding cassette protein A1 (ABCA1), which is involved in lipidation and secretion of apoE. Accordingly, OS increased high molecular weight apoE. Moreover, the liver X receptor (LXR) and ABCA1 antagonists blocked the OS-induced increase of apoE secretion, indicating that the LXR-ABCA1 pathway is involved in the OS-mediated facilitation of apoE secretion from astrocytes. The effects of OS on apoE and ABCA1 were also observed in human astrocytes derived from induced pluripotent stem cells (iPSC) carrying the APOE ε3/ε3 and APOE ε4/ε4 genotypes. Oral administration of OS at clinically-relevant doses affected apoE levels in the liver, though the effects in the brain were not observed. Collectively, though further studies are needed to probe its effects in vivo, OS could be a potential therapeutic drug for AD by modulating poE metabolism through the LXR-ABCA1 pathway.

Comparison of ramosetron and ondansetron for the treatment of established postoperative nausea and vomiting after laparoscopic surgery: a prospective, randomized, double-blinded multicenter trial

Background

Postoperative nausea and vomiting (PONV) is a common complication after surgery, which increases physical and psychological discomfort and delays recovery. The aim of this study was to test the hypothesis that ramosetron is comparable to ondansetron for the treatment of established PONV after laparoscopic surgery using a prospective, randomized, double-blinded, noninferiority study.

Methods

Patients who had at least two risk factors of PONV and underwent laparoscopic surgery under general anesthesia were assessed for eligibility. Patients who developed PONV within the first 2 h after anesthesia received ondansetron (4 mg) or ramosetron (0.3 mg) intravenously in a randomized double-blind manner. Patients were then observed for 24 h after drug administration. The incidence of nausea and vomiting, severity of nausea, rescue antiemetic necessity, and adverse effects at 0–2 or 2–24 h after drug administration was evaluated. The primary endpoint was the rate of patients exhibiting a complete response, defined as no emesis and no further rescue antiemetic medication for 24 h after drug administration.

Results

Among the 583 patients, 210 (36.0%) developed PONV and were randomized to either the ondansetron (n=105) or ramosetron (n=105) group. Patient’s characteristics were similar between the groups. The complete response rate was 44.1% in the ondansetron group and 52.9% in the ramosetron group after 24 h of initial antiemetic administration. The incidence of adverse events was not different between the groups.

Conclusion

We found evidence to support the noninferiority of ramosetron (0.3 mg) compared to ondansetron (4 mg) for the treatment of established PONV in moderate to high-risk patients undergoing laparoscopic surgery.

Comparative efficacy of ramosetron and ondansetron in preventing postoperative nausea and vomiting: An updated systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Postoperative nausea and vomiting is a distressing complication of surgery, and 5-HT3 receptor antagonists are often prescribed to prevent it. Ondansetron is the agent typically administered to prevent postoperative nausea and vomiting. Although ramosetron has a longer duration of action than ondansetron, it remains unclear whether ramosetron is the more effective medication. We performed an updated meta-analysis on the comparative efficacy of ramosetron and ondansetron in preventing postoperative nausea and vomiting.

METHODS

We searched six databases for all trials that randomly assigned patients to ramosetron or ondansetron groups. The primary outcome was postoperative nausea or vomiting in the early, late, and next-day periods. The secondary outcomes were side effects of the medications. We used the random-effects model to combine the results. Trial sequential analyses were performed to correct for repetitive testing in the updated meta-analysis.

RESULTS

Twenty-seven randomized controlled trials with 3,811 patients were included in the meta-analysis. The combined results of ramosetron vs. ondansetron efficacy in preventing postoperative nausea and vomiting were as follows: Risk ratio [95% confidence interval] = 0.82 [0.69-0.98] for early postoperative nausea, 0.76 [0.65-0.89] for late postoperative nausea, 0.69 [0.57-0.84] for next-day postoperative nausea, 0.78 [0.63-0.98] for early postoperative vomiting, 0.57 [0.45-0.72] for late postoperative vomiting, and 0.61 [0.43-0.86] for next-day postoperative vomiting. Dizziness was significantly lower in ramosetron groups than in ondansetron groups (risk ratio [95% confidence interval] = 0.81 [0.66-0.98]). Trial sequential analysis revealed that the results for late postoperative nausea, late postoperative vomiting, and next-day postoperative nausea were conclusive.

CONCLUSIONS

Ramosetron is more effective in preventing late postoperative nausea, late postoperative vomiting, and next-day postoperative nausea than ondansetron. The incidence of dizziness may be lower in patients receiving ramosetron than in patients receiving ondansetron.

TRIAL REGISTRATION

University hospital Medical Information Network Clinical Trials Registry: UMIN000022980.

Postoperative nausea and vomiting: physiopathology, risk factors, prophylaxis and treatment

Recognising the importance of the prevention and early treatment of postoperative nausea and vomiting (PONV) is essential to avoid postoperative complications, improve patient satisfaction and enable the development of major outpatient surgery and fast-track surgery. The topic of PONV might seem to have become stagnant, but we are moving forward. New concepts and problems like post-discharge nausea and vomiting, new risk factors and new drugs are appearing. However, there continue to be mistaken notions about PONV, such as the association between PONV and post-anaesthesia care unit stays, or assuming that it is a risk factore characteristic of the patient, anaesthesia or surgery when it is not. Perhaps, now is the moment to tackle PONV in a different manner, implementing guidelines and going for more aggressive prophylaxis in some groups of patients. We present an extensive review of this topic.

Polymorphisms in CYP1A1 and CYP3A5 Genes Contribute to the Variability in Granisetron Clearance and Exposure in Pregnant Women with Nausea and Vomiting

BACKGROUND

Nausea and vomiting affect up to 90% of pregnant women. Granisetron is a potent and highly selective serotonin receptor antagonist and is an effective antiemetic. Findings from a prior study in pregnant women demonstrated a large interindividual variability in granisetron exposure. Granisetron is primarily metabolized by the cytochrome P450 (CYP) enzymes CYP1A1 and CYP3A and is likely a substrate of the ABCB1 transporter. Single-nucleotide polymorphisms (SNPs) in CYP3A, CYP1A1, and ABCB1 can alter drug metabolism.

OBJECTIVE

This study evaluated the influence of polymorphisms in CYP3A4, CYP3A5, CYP1A1, and ABCB1 on the pharmacokinetic properties of granisetron in pregnant women.

METHODS

The study enrolled 16 pregnant women (gestational age of 12-19 wks). All patients had nausea and vomiting and were treated with granisetron 1 mg. Granisetron plasma concentrations were determined using liquid chromatography tandem-mass spectrometry. The patients' genotype was determined using TaqMan SNP Genotyping Assays. The Hardy-Weinberg equilibrium was assessed by comparing observed and expected genotype frequencies, using the exact test. Intravenous granisetron clearance was used as the dependent variable for analysis of associations.

RESULTS

Of 16 patients, 25% were homozygous for the allele variant CYP3A5*3 and had a significantly lower granisetron clearance and increased area under the plasma concentration-versus-time curve (AUC) compared with nonhomozygous patients. Approximately one-third of patients (n=5) were carriers for the allele variant CYP1A1*2A and had a significantly higher granisetron clearance and decreased AUC. We did not find significant differences in the AUC or clearance for any SNPs in CYP3A4 and ABCB1 genes.

CONCLUSIONS

Polymorphisms in CYP3A5 and CYP1A1 account for some of the variability in systemic clearance and exposure of granisetron in pregnant women.

Ramosetron versus ondansetron for postoperative nausea and vomiting in strabismus surgery patients

Background

Postoperative nausea and vomiting (PONV) is one of the most common adverse outcomes after strabismus surgery. The primary outcome of this prospective, randomized, double-blind study was to compare the incidences of nausea or vomiting, and patient satisfaction of ondansetron and ramosetron after strabismus surgery under general anesthesia. The secondary outcome was to investigate whether the number of involved extraocular muscles (EOMs) in strabismus surgery was related to PONV.

Methods

One hundred and five patients (aged 18–60 years) undergoing strabismus surgery were allocated randomly to one of the three groups: placebo, ondansetron, or ramosetron. Patients received 2 ml placebo, 4 mg ondansetron, or 0.3 mg ramosetron at the end of surgery. Each of the three groups was subdivided into two subgroups according to the number of EOMs involved in the surgery: subgroup S, single-muscle correction; subgroup M, multiple-muscle correction. The incidences of nausea or vomiting, and patient satisfaction at 2, 24 and 48 h after surgery were analyzed as primary outcome. With regard to subgroups S and M in the placebo, ondansetron and ramosetron groups, incidences of nausea or vomiting, and patient satisfaction at 2, 24 and 48 h after surgery were analyzed as seconadary outcome.

Results

The incidence of nausea was significantly lower in the ramosetron group at 2 h (9.4 %) than in the placebo (45.2 %) and ondansetron (34.7 %) groups (P < 0.05). The incidence of nausea was also significantly lower in the ramosetron group at 24 h than in the other groups (P < 0.05). Patients in the ramosetron group were more satisfied at 2 h (8.11 ± 0.98) and 24 h (8.50 ± 0.67) after surgery than those in the other groups (P < 0.05). With regard to subgroups S and M in the placebo, ondansetron and ramosetron groups, there were no significant differences in either the incidence of nausea or patient satisfaction.

Conclusion

Ramosetron has superior antiemetic activity to ondansetron in adult strabismus surgery patients. The number of EOMs involved in strabismus surgery was not related to the incidence of PONV.

Trial registration

Clinical Research Information Service (CRiS) Identifier: KCT0000688. Date of registration: 27 February 2013.

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

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

Efficacy of palonosetron in postoperative nausea and vomiting (PONV)-a meta-analysis

INTRODUCTION

Palonosetron is a second-generation 5-HT3 receptor antagonist with proposed higher efficacy and sustained action for prophylaxis of postoperative nausea and vomiting (PONV).

METHODS

Randomized controlled trials involving adult population undergoing elective surgery under general anesthesia comparing palonosetron to placebo, ramosetron, granisetron, and ondansetron were included. Data were extracted for vomiting incidence (VI), complete response (no nausea/vomiting; Complete Response [CR]), and rescue antiemetic need. This was categorized as early phase (24 hours postoperative for ramosetron and 6 hours for rest) and delayed phase (48 hours for ramosetron and 24 hours for rest). VI and CR were used as markers of drug efficacy. Any adverse effects were evaluated.

RESULTS

Twenty-two trials (4 with 3 groups) were included (comparing palonosetron to placebo in 5, ramosetron in 5, granisetron in 4, and ondansetron in 12 subgroups). Palonosetron demonstrated statistical superiority over placebo for VI and CR, both early/delayed PONV prevention. For delayed phase, palonosetron surpassed ramosetron in all 3 variables; however, none of the variables attained statistical significance during early phase. In early phase, palonosetron had better VI and CR than did granisetron; however, variables other than CR (better for palonosetron) failed to achieve statistical significance for delayed phase. All 3 outcomes were significantly better for palonosetron compared with ondansetron in delayed phase, but statistical superiority could only be demonstrated for VI in early phase. Being inconsistently documented across trials, nausea scores could not be evaluated.

CONCLUSION

Palonosetron is as safe as and more effective than placebo, ramosetron, granisetron, and ondansetron in preventing delayed PONV. For early PONV, it has higher efficacy over placebo, granisetron, and ondansetron.

Population pharmacokinetics and prophylactic anti-emetic efficacy of ramosetron in surgical patients

AIMS

This study characterized the pharmacokinetics of ramosetron and compared prophylactic anti-emetic efficacy with that of ondansetron in a large population.

METHODS

Fifty-eight patients consented to the pharmacokinetic analysis and were assigned randomly to receive 0.3, 0.45 or 0.6 mg ramosetron after induction of anaesthesia. Blood samples were acquired at preset intervals. Non-compartmental and population pharmacokinetic analyses were performed. In total, 1102 patients consented to the evaluation of prophylactic anti-emetic efficacy and were allocated randomly to receive 0.3 mg ramosetron or 4 mg ondansetron at the end of surgery. An additional 16 mg ondansetron were mixed in the intravenous patient-controlled analgesia pump of the ondansetron group. Post-operative nausea and vomiting (PONV) were evaluated 6, 24 and 48 h post-operatively using the Rhodes index of nausea, vomiting and retching (RINVR). Administration of rescue anti-emetics and adverse events were evaluated.

RESULTS

The pharmacokinetic parameter estimates were V1 (l) = 5.12, V2 (l) = 108, CL (l⋅min(-1) ) = 0.08 + (59⋅age(-1) ) × 0.09, Q (l⋅min(-1) ) = 1.42. The incidences of PONV in the ramosetron and ondansetron groups were 77 (13.9%) and 113 (20.6%) and 44 (7.9%) and 66 (12.0%) at 24 and 48 h post-operatively, respectively (P = 0.004, 0.030). RINVR was significantly lower in the ramosetron than the ondansetron group 24 and 48 h post-operatively (P = 0.003, 0.025). Use of rescue anti-emetics and incidence of adverse events were comparable.

CONCLUSIONS

A two compartment mammillary model was used to describe ramosetron pharmacokinetics. Prophylactic anti-emetic efficacy of ramosetron was significantly better 24 and 48 h post-operatively than that of ondansetron, particularly when the Apfel score was ≥ 3.

Effect of Palonosetron, Dexamethasone, or Palonosetron and Dexamethasone in Postoperative Nausea and Vomiting in Highly Susceptible Thyroidectomy Patients: A Randomized Trial

Our study aimed to compare the efficacy of dexamethasone added to palonosetron to both palonosetron and dexamethasone monotherapy for preventing postoperative nausea and vomiting in highly susceptible patients receiving opioid-based, intravenous patient-controlled analgesia after thyroidectomy. Nonsmoking women who underwent total thyroidectomy were randomly allocated to either the dexamethasone group (Group D), the palonosetron group (Group P), or to the dexamethasone plus palonosetron group (Group DP). The severity of nausea and pain, the number of episodes of vomiting, the administrations of rescue anti-emetics, and the side effects of the antiemetics were documented in the recovery room at 2, 4, 8, 12, 24, and 48 hours after surgery. The severity of nausea was lowest in Group DP, followed by Group P and Group D. But there was an overall difference only between Group D and Group DP. The overall differences in the time to the first administration of the rescue antiemetic were observed in a Kaplan-Meier analysis (P = 0.017), noting a significant difference between Group D and Group DP (P = 0.003). The combination of dexamethasone and palonosetron decreased the severity of nausea and increased the time to the first antiemetic dose compared with using dexamethasone or palonosetron alone in nausea-susceptible patients undergoing thyroidectomy.

Repeated tender point injections of granisetron alleviate chronic myofascial pain--a randomized, controlled, double-blinded trial

Background

Serotonin (5-HT) mediates pain by peripheral 5-HT₃-receptors. Results from a few studies indicate that intramuscular injections of 5-HT₃-antagonists may reduce musculoskeletal pain. The aim of this study was to investigate if repeated intramuscular tender-point injections of the 5-HT₃-antagonist granisetron alleviate pain in patients with myofascial temporomandibular disorders (M-TMD).

Methods

This prospective, randomized, controlled, double blind, parallel-arm trial (RCT) was carried out during at two centers in Stockholm, Sweden. The randomization was performed by a researcher who did not participate in data collection with an internet-based application (www.randomization.com). 40 patients with a diagnose of M-TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were randomized to receive repeated injections, one week apart, with either granisetron (GRA; 3 mg) or isotonic saline as control (CTR).

Results

The median weekly pain intensities decreased significantly at all follow-ups (1-, 2-, 6-months) in the GRA-group (Friedman test; P < 0.05), but not in the CTR-group (Friedman-test; P > 0.075). The numbers needed to treat (NNT) were 4 at the 1- and 6-month follow-ups, and 3.3 at the 2-month follow-up in favor of granisetron.

Conclusions

Repeated intramuscular tender-point injections with granisetron provide a new pharmacological treatment possibility for myofascial pain patients with repeated intramuscular tender-point injections with the serotonin type 3 antagonist granisetron. It showed a clinically relevant pain reducing effect in the temporomandibular region, both in a short- and long-term aspect.

Trial registration

European Clinical Trials Database 2005-006042-41 as well as at Clinical Trials NCT02230371.

Formulation of Convenient, Easily Scalable, and Efficient Granisetron HCl Intranasal Droppable Gels

Deacetylated gellan gum and two sodium alginate polymer types were used each at three concentrations in the suitable range for their sol-gel transition. The prepared nine droppable gels were evaluated in vitro, ex vivo through sheep nasal mucosa, as well as in vivo in comparison to drug solution given intravenously and orally at the same dose. The prepared formulas gelled instantaneously in simulated nasal fluid and the obtained gels sustained their shear thinning and thixotropic behavior up to 48 h. Polymer type and concentration had significant effects on the apparent viscosities and the in vitro release profile of granisetron from the prepared gels. The drug release data best fitted a modified Higuchi equation with initial burst and followed Fickian diffusion mechanism. A 0.5% gellan-gum-based formula sustained the in vitro drug release up to 3 h and enhanced the drug permeation without need for an enhancer. The histopatholgical study revealed the safety of the tested formula. Intranasal delivery recorded double the drug bioavailabilty in comparison to the oral route. It had an absolute bioavailability of 0.6539 and the maximum plasma drug concentration reached after 1.5 h. The developed formula could be promising for the management of chemotherapy-induced nausea and vomiting regarding its improved bioavailability, patient acceptability, and ease of production.

Palonosetron, Ondansetron, and Granisetron for antiemetic prophylaxis of postoperative nausea and vomiting - A comparative evaluation

Background:

Postoperative nausea and vomiting is commonly associated with adverse consequences and hamper the postoperative recovery in spite of the availability of many antiemetic drugs and regimens for its prevention. The study was aimed to compare the prophylactic effects of intravenously administered palonosetron, ondansetron, and granisetron on prevention of postoperative nausea and vomiting after general anesthesia.

Materials and Methods:

This prospective, double-blind study, comprised 120 adult consented patients of ASA grade I and II of either gender, was carried out after approval of Institutional Ethical Committee. Patients were randomized into three equal groups of 40 patients each in double-blind manner. Group P received inj. palonosetron (0.075 mg), group O received inj. ondansetron (4 mg), and group G received inj. granisetron (2 mg) intravenously five minutes before induction of anesthesia. The need for rescue antiemetic, episode of postoperative nausea and vomiting, and side effects were observed for 12 hours in the post-anesthesia care unit. At the end of study, results were compiled and statistical analysis was done by using ANOVA, Chi-square test, and Kruskal Wallis Test. Value of P < 0.05 was considered significant.

Results:

The incidence of nausea and vomiting was maximal during the first four hours postoperatively. The complete control of postoperative nausea and vomiting for first 12 hours was achieved in 30% patients of ondansetron group, 55% patients of granisetron group, and 90% patients of palonosetron group. Safety profile was more with palonosetron.

Conclusion:

Palonosetron was comparatively highly effective to prevent the PONV after anesthesia due to its prolonged duration of action than ondansetron and granisetron.

Inhibition of native 5-HT3 receptor-evoked contractions in guinea pig and mouse ileum by antimalarial drugs

Quinine, chloroquine and mefloquine are commonly used to treat malaria, however, with associated gastrointestinal (GI) side-effects. These drugs act as antagonists at recombinant 5-HT3 receptors and modulate gut peristalsis. These gastrointestinal side effects may be the result of antagonism at intestinal 5-HT3 receptors. Ileum from male C57BL/6 mice and guinea pigs was mounted longitudinally in organ baths. The concentration-response curves for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT were obtained with 5-HT (pEC50 = 7.57 ± 0.33, 12) more potent (P = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5) in mouse ileum. There was no difference in potency of 5-HT (pEC50 = 5.42 ± 0.15, n = 8) and 2-Me-5-HT (pIC50 = 5.01 ± 0.55, n = 11) in guinea pig ileum (P > 0.05). Quinine, chloroquine or mefloquine was applied for 10 min and inhibitions prior to submaximal agonist application. In mouse ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 4.9 ± 0.17, n = 7; 4.76 ± 0.14, n = 5; 6.21 ± 0.2, n = 4, correspondingly) with mefloquine most potent (P < 0.05). Quinine, chloroquine and mefloquine antagonised 2-me-5-HT-induced contractions (pIC50 = 6.35 ± 0.11, n = 8; 4.64 ± 0.2, n = 7; 5.11 ± 0.22, n = 6, correspondingly) with quinine most potent (P < 0.05). In guinea-pig ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 5.02 ± 0.15, n = 6; 4.54 ± 0.1, n = 7; 5.32 ± 0.13, n = 5) and 2-me-5-HT-induced contractions (pIC50 = 4.62 ± 0.25, n = 5; 4.56 ± 0.14, n = 6; 5.67 ± 0.12, n = 4) with chloroquine least potent against 5-HT and mefloquine most potent against 2-me-5-HT (P < 0.05). These results support previous studies identifying anti-malarial drugs as antagonists at recombinant 5-HT3 receptors and may also demonstrate the ability of these drugs to influence native 5-HT3 receptor-evoked contractile responses which may account for their associated GI side-effects.

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.

Effect of pretreatment with palonosetron on withdrawal movement associated with rocuronium injection

BACKGROUND

The main disadvantage of rocuronium is the pain associated with vascular injection. We evaluated the efficacy of palonosetron for reducing pain after rocuronium injection.

METHODS

EIGHTY PATIENTS SCHEDULED FOR ELECTIVE SURGERY WERE RANDOMLY DIVIDED INTO TWO GROUPS: Group C (normal saline 1.5 ml, n = 40) and Group P (palonosetron 0.075 mg, n = 40). Anesthesia was induced with thiopental 5 mg/kg and the test drug was injected over 10 seconds. Thirty seconds after the injection of the test drug, rocuronium 0.6 mg/kg was injected over 30 seconds and the response was recorded. Injection pain was graded using a 4-point scale. The grade was 0 points for no movement, 1 point for wrist movement, 2 points for elbow or shoulder movement, and 3 points for whole body movement. Mean arterial pressure and heart rate were recorded on arrival in the operating room and before and 30 seconds after rocuronim injection.

RESULTS

There was no significant difference in the grade 1 response between the two groups; however, the grade 2 and 3 responses in Group P were 5 (12.5%) and 4 (10%), respectively, which were significantly lower than in Group C, with 13 (32.5%) responses for each grade. There were no significant differences in hemodynamic changes within each group. However, the difference in mean arterial pressure before and after the injection of rocuronium was significantly larger in Group C compared to Group P.

CONCLUSIONS

Pretreatment with palonosetron 0.075 mg reduced the incidence and severity of withdrawal movement after rocuronium administration.

Evaluation of antiemetic effect of intravenous palonosetron versus intravenous ondansetron in laparoscopic cholecystectomy: a randomized controlled trial

OBJECTIVES

Incidence of postoperative nausea and vomiting (PONV), without active intervention, following laparoscopic cholecystectomy is unacceptably high. We evaluated the effectiveness of intravenous (IV) palonosetron in counteracting PONV during the first 24 hrs following laparoscopic cholecystectomy, using ondansetron as the comparator drug.

MATERIALS AND METHODS

In a randomized, controlled, single blind, parallel group trial, single pre-induction IV doses of palonosetron (75 mcg) or ondansetron (4 mg) were administered to adult patients of either sex undergoing elective laparoscopic cholecystectomy. There were 49 subjects per group. The pre-anesthetic regimen, anesthesia procedure and laparoscopic technique were uniform. The primary effectiveness measure was total number of PONV episodes in the 24 hrs period following end of surgery. The frequencies of individual nausea, retching and vomiting episodes, visual analog scale (VAS) score for nausea at 2, 6 and 24 hrs, use of rescue antiemetic (metoclopramide), number of complete responders (no PONV or use of rescue in 24 hrs) and adverse events were secondary measures.

RESULTS

There was no statistically significant difference between the groups in primary outcome. Similarly, the frequencies of nausea, retching and vomiting episodes, when considered individually, did not show significant difference. Nausea score was comparable at all time points. With palonosetron, 14 subjects (28.6%) required rescue medication while 13 (26.5%) did so with ondansetron. The number of complete responders was 14 (28.6%) and 16 (32.7%), respectively. Adverse events were few and mild. QTc prolongation was not encountered.

CONCLUSION

Palonosetron is comparable to ondansetron for PONV prophylaxis in elective laparoscopic cholecystectomy when administered as single pre-induction dose.

Comparison of the antiemetic effect of ramosetron with the combination of dexamethasone and ondansetron in middle ear surgery: A double-blind, randomized clinical study

Background:

Postoperative nausea and vomiting (PONV) is a frequent complication of middle ear surgery. Ondansetron has been shown to be effective for early PONV and dexamethasone has been shown to be effective for late PONV. Therefore, a combination of dexamethasone and ondansetron is commonly used for middle ear surgery. This study was conducted to compare the combination of ondansetron and dexamethasone with ramosetron for early and late PONV up to 48 h after middle ear surgery.

Methods:

One hundred and twenty adults scheduled for middle ear surgery were allocated to receive either dexamethasone 8 mg and ondansetron 4 mg (n=60) or ramosetron 0.3 mg (n=60). General anesthesia with inhalation agents was used for all the patients. The incidence and severity of PONV, administration of rescue antiemetic, and the side effects of the antiemetic were documented during the first 48 h after surgery.

Results:

The incidence of nausea was significantly lower in the dexamethasone and ondansetron group compared to the ramosetron group between 2 and 24 h. The complete response, which is patients with no nausea or vomiting, was significantly more in dexamethasone and ondansetron group compared to ramosetron group between 2 and 24 h and between 24 and 48 h (76% vs. 56%, P=0.02, 93% vs. 81%, P=0.05, respectively). Overall, complete response was more in dexamethasone and ondansetron group compared to ramosetron group (71% vs. 40%, P=0.01).

Conclusion:

The combination of dexamethasone and ondansetron is superior to ramosetron for prevention of PONV after middle ear surgeries.

Hemin and Zinc Protoporphyrin IX Affect Granisetron Constipating Effects In Vitro and In Vivo

Granisetron is a 5-HT3 receptors antagonist used in the management of emesis associated with anticancer chemotherapy. It affects intestinal motility with constipating effect. Since the pathway heme oxygenase/carbon monoxide (HO/CO) is involved in gastrointestinal motility, we evaluated the possible interplay between granisetron and agents affecting HO/CO pathways such as zinc protoporphyrin IX (ZnPPIX), an HO inhibitor, or hemin, an HO-1 inducer. ZnPPIX (10 µM) or hemin (10 µM), but not granisetron (0.1, 0.3, 1 µM), affected spontaneous basal activity recorded in rat duodenal strips, in noncholinergic nonadrenergic conditions. Granisetron restored spontaneous basal activity after ZnPPIX, but not after hemin. ZnPPIX decreased and hemin increased the inhibition of activity after electrical field stimulation (EFS), but they did not affect the contraction that follows the relaxation induced by EFS called off contraction. Granisetron did not alter the response to EFS per se but abolished both ZnPPIX and hemin effect when coadministered. In vivo study showed constipating effect of granisetron (25, 50, 75 µg/kg/sc) but no effect of either ZnPPIX (50 µg/kg/i.p.) or hemin (50 µM/kg/i.p.). When coadministered, granisetron effect was abolished by ZnPPIX and increased by hemin. Specimens from rats treated in vivo with hemin (50 µM/kg/i.p.) showed increased HO-1 protein levels. In conclusion, granisetron seems to interact with agents affecting HO/CO pathway both in vitro and in vivo.

Ramosetron, midazolam, and combination of ramosetron and midazolam for prevention of postoperative nausea and vomiting: A prospective, randomized, double-blind study

Objective

To compare the efficacy of ramosetron, midazolam, and the combination of ramosetron and midazolam in the prevention of postoperative nausea and vomiting (PONV) in female patients undergoing thyroidectomy.

Methods

Patients were randomized to receive 0.3 mg ramosetron (Group R), 75 µg/kg midazolam (Group M) or 0.3 mg ramosetron combined with 75 µg/kg midazolam (Group RM) before the induction of anaesthesia. PONV, use of rescue antiemetics, pain severity and fentanyl consumption were assessed for 24 h after thyroidectomy.

Results

A total of 100 patients were enrolled; 94 patients completed the study. The severity of nausea was statistically significantly reduced at 0–2 h in Group RM compared with Groups R and M, and at 2–6 h in Group RM compared with Group M. The incidence of retching and vomiting was significantly lower at 0–2 h, 2–6 h, 6–12 h in Group RM than in Group M, and lower in Group R than Group M at 6–12 h. The requirement for rescue antiemetics was significantly lower at 0–2 h in group RM than in group M.

Conclusion

The combination therapy of ramosetron and midazolam provided superior antiemetic efficacy compared with midazolam single therapy, but did not show any significant additional benefits compared with ramosetron single therapy.

The comparative study to evaluate the effect of palonosetron monotherapy versus palonosetron with dexamethasone combination therapy for prevention of postoperative nausea and vomiting

Background

5-hydroxytryptamine type 3 (5-HT3) receptor antagonists are effective and safe on postoperative nausea and vomiting (PONV). Palonosetron, the newest 5-HT3 antagonist, has potent antiemetic property. We hypothesized that a combination of palonosetron and dexamethasone could more decrease PONV than palonosetron alone.

Methods

Among the patients scheduled to undergo laparoscopic gynecologic surgery, mastoidectomy with tympanoplasty or thyroidectomy under general anesthesia, eighty four female patients with at least two PONV risk factors were enrolled in this study. They were received randomly 0.075 mg palonosetron and 4 mg dexamethasone (group C) or 0.075 mg palonosetron alone (group P). The severity of PONV using Rhodes index and the percentage of complete response during postoperative 24 hours were compared between groups.

Results

The frequency of mild/moderate/great/severe PONV based on Rhodes index were 9.8%/0%/0%/0% and 9.3%/2.3%/2.3%/0% in group P and group C, respectively. Complete response for PONV was observed in 90.2% and 86% of patients in group P and group C, respectively. The overall incidence of PONV in group P and C was 9.8% and 14%, respectively. There was no significant difference between the two groups.

Conclusions

There were no differences between palonosetron monotherapy and combination therapy of palonosetron and dexamethasone in patients with high emetogenic risk.

Comparison of ramosetron's and ondansetron's preventive anti-emetic effects in highly susceptible patients undergoing abdominal hysterectomy

Background

This study compared the preventive effects of ramosetron and ondansetron on postoperative nausea and vomiting (PONV) in highly susceptible patients undergoing abdominal hysterectomy.

Methods

In a prospective, randomized, double-blinded study, a total of 120 highly susceptible women (nonsmokers, those receiving opioid-based IV patient-controlled analgesia [PCA]) undergoing abdominal hysterectomy were included in the study. Patients were divided into 2 groups and each group received either 0.3 mg of ramosetron or 4 mg of ondansetron, IV. All patients received fentanyl-based IV PCA during the 48 h postoperative periods. The incidences of PONV and side effects of 5-HT₃ antagonists (headache and dizziness) were assessed at 3 intervals (<2 h, 2-24 h and 24-48 h) postoperatively.

Results

Patients in the ramosetron group showed a significantly higher ratio of complete response and lower incidence of nausea during the 24-48 h interval after surgery compared with those the ondansetron group.

Conclusions

Ramosetron (0.3 mg) is more effective in preventing delayed PONV in highly susceptible women undergoing abdominal hysterectomy compared with ondansetron (4 mg).

Efficacy of ramosetron in the treatment of male patients with irritable bowel syndrome with diarrhea: a multicenter, randomized clinical trial, compared with mebeverine

BACKGROUND

The 5-HT(3) receptor antagonists are known to be effective for the treatment of diarrhea-predominant irritable bowel syndrome (IBS), but not widely used yet. The aim of this study was to compare the efficacy and safety of ramosetron, a 5-HT(3) receptor antagonist, and mebeverine in male patients with IBS with diarrhea (IBS-D).

METHODS

This study was performed in a multicenter, randomized, open-label design. Data of 343 male patients with IBS-D who were randomized to either a 4-week treatment of ramosetron 5μg once daily or a 4-week treatment of mebeverine 135 mg three times daily were analyzed by the intent-to-treat analysis. The primary efficacy parameter was the proportion of patients with adequate relief of IBS symptoms at the last week of treatment. The secondary endpoints were changes in each symptom score and the safety profiles.

KEY RESULTS

The responder rates for global IBS symptoms, abdominal pain/discomfort and abnormal bowel habits in the ramosetron and mebeverine groups significantly increased during the treatment period. The severity scores of abdominal pain/discomfort and urgency, the stool form score, and the stool frequency in both treatment arms were significantly reduced, compared with the baselines. There were no significant differences in the responder rates (37%vs 38% on ITT analysis) and adverse event profiles between the ramosetron and mebeverine groups. Neither severe constipation nor ischemic colitis was reported by ramosetron-treated patients.

CONCLUSIONS & INFERENCES

Ramosetron 5μg once daily is as effective as mebeverine three times daily in male patients with IBS-D.

Serotonin receptor type 3 antagonists improve obesity-associated fatty liver disease in mice

Obesity is a major cause for nonalcoholic fatty liver disease (NAFLD). Previous studies suggested that alterations in intestinal motility and permeability contribute to the development of NAFLD. Serotonin and serotonin receptor type 3 (5-HT(3)R) are key factors in the regulation of intestinal motility and permeability. Therefore, we studied the effect of the 5-HT(3)R antagonists tropisetron and palonosetron on the development of NAFLD in leptin-deficient obese mice. Four-week-old ob/ob mice and lean controls were treated for 6 weeks orally with tropisetron or palonosetron at 0.2 mg/kg per day. We determined markers of liver damage and inflammation, portal endotoxin levels, and duodenal concentrations of serotonin, serotonin-reuptake transporter (SERT), occludin, and claudin-1. Tropisetron treatment significantly reduced liver fat content (-29%), liver inflammation (-56%), and liver cell necrosis (-59%) in ob/ob mice. The beneficial effects of tropisetron were accompanied by a decrease in plasma alanine aminotransferase and portal vein plasma endotoxin levels, an attenuation of enhanced MyD88 and tumor necrosis factor-α mRNA expression in the liver, and an increase of tight junction proteins in the duodenum. Tropisetron treatment also caused a reduction of elevated serotonin levels and an increase of SERT in the duodenum of ob/ob mice. Palonosetron had similar effects as tropisetron with regard to the reduction of liver fat and other parameters. Tropisetron and palonosetron are effective in attenuating NAFLD in a genetic mouse model of obesity. The effect involves the intestinal nervous system, resulting in a reduction of endotoxin influx into the liver and subsequently of liver inflammation and fat accumulation.

Serotonin augments gut pacemaker activity via 5-HT3 receptors

Serotonin (5-hydroxytryptamine: 5-HT) affects numerous functions in the gut, such as secretion, muscle contraction, and enteric nervous activity, and therefore to clarify details of 5-HT's actions leads to good therapeutic strategies for gut functional disorders. The role of interstitial cells of Cajal (ICC), as pacemaker cells, has been recognised relatively recently. We thus investigated 5-HT actions on ICC pacemaker activity. Muscle preparations with myenteric plexus were isolated from the murine ileum. Spatio-temporal measurements of intracellular Ca(2+) and electric activities in ICC were performed by employing fluorescent Ca(2+) imaging and microelectrode array (MEA) systems, respectively. Dihydropyridine (DHP) Ca(2+) antagonists and tetrodotoxin (TTX) were applied to suppress smooth muscle and nerve activities, respectively. 5-HT significantly enhanced spontaneous Ca(2+) oscillations that are considered to underlie electric pacemaker activity in ICC. LY-278584, a 5-HT(3) receptor antagonist suppressed spontaneous Ca(2+) activity in ICC, while 2-methylserotonin (2-Me-5-HT), a 5-HT(3) receptor agonist, restored it. GR113808, a selective antagonist for 5-HT(4), and O-methyl-5-HT (O-Me-5-HT), a non-selective 5-HT receptor agonist lacking affinity for 5-HT(3) receptors, had little effect on ICC Ca(2+) activity. In MEA measurements of ICC electric activity, 5-HT and 2-Me-5-HT caused excitatory effects. RT-PCR and immunostaining confirmed expression of 5-HT(3) receptors in ICC. The results indicate that 5-HT augments ICC pacemaker activity via 5-HT(3) receptors. ICC appear to be a promising target for treatment of functional motility disorders of the gut, for example, irritable bowel syndrome.