5-HT(3)-receptor antagonists in the management of nausea and vomiting in cancer and cancer treatment

Overview of growth differentiation factor 15 (GDF15) in metabolic diseases

GDF15 is a stress response cytokine and a distant member of the transforming growth factor beta (TGFβ) superfamily, its levels increase in response to cell stress and certain diseases in the serum. To exert its effects, GDF15 binds to glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL), which was firstly identified in 2017 and highly expressed in the brain stem. Many studies have demonstrated that elevated serum GDF15 is associated with anorexia and weight loss. Herein, we focus on the biology of GDF15, specifically how this circulating protein regulates appetite and metabolism in influencing energy homeostasis through its actions on hindbrain neurons to shed light on its impact on diseases such as obesity and anorexia/cachexia syndromes. It works as an endocrine factor and transmits metabolic signals leading to weight reduction effects by directly reducing appetite and indirectly affecting food intake through complex mechanisms, which could be a promising target for the treatment of energy-intake disorders.

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.

Prolonged usage of fosaprepitant for prevention of delayed chemotherapy-induced nausea and vomiting(CINV) in patients receiving highly emetogenic chemotherapy

BACKGROUND

Even though chemotherapy-induced nausea and vomiting (CINV) can be well controlled in the acute phase, the incidence of delayed CINV remains high. In this study, we intend to investigate whether prolonged use of NK-1 receptor antagonist (RA) in addition to 5-HT3 RA and dexamethasone (DEX) was more effective in preventing delayed CINV.

METHODS

This randomised, open-label, controlled study was designed to compare the efficacy and safety of fosaprepitant 150 mg given on days 1,3 (prolonged group) versus on day 1 (regular group) in patients receiving highly emetogenic chemotherapy (HEC). All patients also treated with palonosetron on day 1 and DEX on days 1-3. The primary endpoint was the incidence of delayed nausea and vomiting. The second endpoint was AEs. All the above endpoints were defined according to CTCAE 5.0.

RESULTS

Seventy-seven patients were randomly assigned to prolonged group and seventy-nine to regular group. Prolonged group demonstrated superiority in controlling delayed CINV to regular group, with statistically significant lower incidence of nausea (6.17% vs 12.66%, P = 0.0056), and slightly lower incidence of grade 1 vomiting (1.62% vs 3.80%, P = 0.0953) in the delayed phase. In addition, prolonged use of fosaprepitant was safe. No significant difference was found between the two groups regarding constipation, diarrhea, hiccough, fatigue, palpitation and headache in delayed phase.

CONCLUSIONS

Prolonged use of fosaprepitant can effectively and safely prevent delayed CINV in patients receiving HEC.

Effectiveness of Palonosetron, 1-Day Dexamethasone, and Aprepitant in Patients Undergoing Carboplatin-Based Chemotherapy

INTRODUCTION

Dexamethasone (DEX)-sparing strategy with 5-hydroxytryptamine-3 receptor antagonist (5HT3RA) and aprepitant (APR), as triplet antiemetic prophylaxis, is associated with poor control of delayed chemotherapy-induced nausea and vomiting (CINV) in patients receiving carboplatin (CBDCA)-based chemotherapy. This study aimed to evaluate whether using palonosetron (PALO) as a 5HT3RA provides superior control with CINV than first-generation (1st) 5HT3RA in triplet antiemetic prophylaxis with a DEX-sparing strategy.

METHODS

Pooled patient-level data from a nationwide, multicenter, and prospective observational study were analyzed to compare the incidence of CINV between patients administered PALO and 1st 5HT3RA in combination with 1-day DEX and APR.

RESULTS

No significant differences were observed in the incidence of CINV, pattern of CINV, or severity of nausea by type of 5HT3RA in triplet antiemetic prophylaxis with DEX-sparing strategy. In both groups, the incidence of nausea gradually increased from day 3, peaked on day 4 or 5, and then declined slowly. The visual analog scale scores in the delayed phase remained high throughout the 7-day observation period.

CONCLUSION

Careful patient selection and symptom monitoring are needed when implementing the DEX-sparing strategy in triplet antiemetic prophylaxis for patients undergoing CBDCA-based chemotherapy. Furthermore, additional strategies may be needed to achieve better control of delayed CINV.

A positive feedback loop between tryptophan hydroxylase 1 and β-Catenin/ZBP-89 signaling promotes prostate cancer progression

Alterations in tryptophan (Trp) metabolism facilitate the continuous modulation of tumor progression, including tumor growth, distant metastasis, and chemoresistance development. Although there is a high correlation between Trp metabolism and tumor progression, it is unknown whether and how Trp metabolism affects the development of prostate cancer. In this study, we reported that the overexpression of Trp hydroxylase 1 (TPH1) caused the upregulation of Trp hydroxylation and mediated the production of 5-hydroxytryptamine (5-HT), contributing to tumor growth and poor prognosis in patients with prostate cancer. An increase in 5-HT levels triggered the activation of the Axin 1/β-catenin signaling pathway, thus enhancing cell proliferation and migration. Consequently, β-catenin cooperated with the Krüppel-type zinc finger family transcription factor ZBP-89 to upregulate TPH1 expression, further promoting Trp hydroxylation and forming the TPH1/5-HT/β-catenin/ZBP-89/THP1 positive feedback signaling loop. Interruption of the signaling loop by the THP1 inhibitor 4-chloro-dl-phenylalanine (PCPA) significantly improved anticancer effects and suppressed lung metastasis in prostate cancer–bearing mice. Our findings revealed a mechanism by which TPH1 promotes prostate cancer growth by inducing Trp hydroxylation and identified a novel THP1 target for an innovative prostate cancer therapeutic strategy.

Phytochemicals in Chemoprevention: A Cost-Effective Complementary Approach

Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.

Impact of genetic factors on platinum-induced gastrointestinal toxicity

Severe gastrointestinal (GI) toxicity is a common side effect after platinum-based chemotherapy. The incidence and severity of GI toxicity vary among patients with the same chemotherapy. Genetic factors involved in platinum transport, metabolism, detoxification, DNA repair, cell cycle control, and apoptosis pathways may account for the interindividual difference in GI toxicity. The influence of gene polymorphisms in the platinum pathway on GI toxicity has been extensively analyzed. Variations in study sample size, ethnicity, design, treatment schedule, dosing, endpoint definition, and assessment of toxicity make it difficult to precisely interpret the results. Hence, we conducted a review to summarize the most recent pharmacogenomics studies of GI toxicity in platinum-based chemotherapy and identify the most promising avenues for further research.

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.

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.

GDF15 Induces Anorexia through Nausea and Emesis

Growth differentiation factor 15 (GDF15) is a cytokine that reduces food intake through activation of hindbrain GFRAL-RET receptors and has become a keen target of interest for anti-obesity therapies. Elevated endogenous GDF15 is associated with energy balance disturbances, cancer progression, chemotherapy-induced anorexia, and morning sickness. We hypothesized that GDF15 causes emesis and that its anorectic effects are related to this function. Here, we examined feeding and emesis and/or emetic-like behaviors in three different mammalian laboratory species to help elucidate the role of GDF15 in these behaviors. Data show that GDF15 causes emesis in Suncus murinus (musk shrews) and induces behaviors indicative of nausea/malaise (e.g., anorexia and pica) in non-emetic species, including mice and lean or obese rats. We also present data in mice suggesting that GDF15 contributes to chemotherapy-induced malaise. Together, these results indicate that GDF15 triggers anorexia through the induction of nausea and/or by engaging emetic neurocircuitry.

Delineating the Site of Interaction of the 5-HT3A Receptor with the Chaperone Protein RIC-3

The serotonin type 3A (5-HT_3A) receptor is a homopentameric cation-selective member of the pentameric ligand-gated ion channel (pLGIC) superfamily. Members of this superfamily assemble from five subunits, each of which consists of three domains: extracellular (ECD), transmembrane (TMD), and intracellular domain (ICD). Previously, we have demonstrated that the 5-HT_3A-ICD is required for the interaction between 5-HT_3A and the chaperone protein resistance to inhibitors of choline esterase (RIC-3). Additionally, we have shown that 5-HT_3A-ICD fused to maltose-binding protein (MBP) directly interacts with RIC-3, without the involvement of other protein(s). To elucidate the molecular determinants of this interaction, we developed different MBP-fused 5-HT_3A-ICD constructs by deleting large segments of its amino acid sequence. We expressed seven engineered ICDs in Escherichia coli and purified them to homogeneity. Using a RIC-3 affinity pull-down assay, the interaction between MBP-5HT_3A-ICD constructs and RIC-3 was investigated. In summary, we identify a 24-amino-acid-long segment of the 5-HT_3A-ICD as a molecular determinant for the interaction between the 5-HT_3A-ICD and RIC-3.

The effect of ginger (Zingiber officinale) on chemotherapy-induced nausea and vomiting in breast cancer patients: A systematic literature review of randomized controlled trials

Breast cancer is the most commonly diagnosed cancer and is the leading cause of mortality due to all types of cancers among the female population worldwide. Results of clinical trials investigating the effect of ginger on chemotherapy-induced nausea and vomiting (CINV) in breast cancer patients are inconsistent. This study was aimed at obtaining a comprehensive overview of the current evidence regarding the effectiveness of ginger as an antiemetic modality for controlling CINV in breast cancer patients. All published randomized controlled trials in English were systematically searched on Google Scholar, PubMed, Scopus, and Cochrane search databases up to June 2018. The outcome variable of interest was severity and the frequency of nausea and vomiting in patients. A total of 50 studies were found through search databases. After excluding duplicates, the 42 remaining studies were screened, and finally, nine trials were included, which were published between 2012 and 2017. Two studies have examined the effect of ginger on the frequency of nausea, five studies on the frequency of vomiting, seven studies on the severity of nausea, and three studies on severity of vomiting. A study evaluated the effectiveness of ginger in improving dietary intake in CINV. Our investigation suggests that ginger may reduce nausea in the acute phase of chemotherapy in patients with breast cancer. The effect of ginger on nausea and vomiting in other conditions requires more high-quality clinical trials.

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.

Use of Direct Oral Anticoagulants in Patients with Cancer: Practical Considerations for the Management of Patients with Nausea or Vomiting

Direct oral anticoagulants (DOACs) have proven efficacy and safety and are approved for use in the prevention and treatment of thromboembolic events in patients with venous thromboembolism (VTE) and those with atrial fibrillation (AF). There is no clear guidance on the use of DOACs in the significant proportion of these patients who have or will develop concomitant cancer. The occurrence of nausea and vomiting in these patients, despite implementation of guideline-recommended antiemetic strategies, is a particular concern because it may affect oral drug intake and consequently outcomes with anticoagulation therapy.Here, we review recent data on the incidence and management of cancer-associated nausea and vomiting and the current evidence and guidance relating to the use of DOACs in patients with cancer. On the basis of this evidence, an international working group of experts in the fields of cancer-associated thrombosis/hemostasis, hematology, and oncology discussed key issues related to the use of DOACs in patients with VTE or AF and cancer who are at risk of nausea and vomiting and developed some consensus recommendations. We present these consensus recommendations, which outline strategies for the use and management of anticoagulants, including DOACs, in patients with VTE or AF and cancer for whom oral drug intake may pose challenges. Guidance is provided on managing patients with gastrointestinal obstruction or nausea and vomiting that is caused by cancer treatments or other cancer-related factors.The recommendations outlined in this review provide a useful reference for health care professionals and will help to improve the management of anticoagulation in patients with VTE or AF and cancer.

IMPLICATIONS FOR PRACTICE

Direct oral anticoagulants (DOACs) offer several advantages over traditional anticoagulants, including ease of administration and the lack of need for routine monitoring. However, the management of patients with an indication for anticoagulation and concomitant cancer, who are at high risk of thromboembolic events, presents several challenges for administering oral therapies, particularly with regard to the risk of nausea and vomiting. In the absence of robust data from randomized trials and specific guidelines, consensus recommendations were developed for healthcare professionals regarding the use of DOACs in patients with cancer, with a focus on the management of patients who are at risk of nausea and vomiting.

Clinical Update on Palonosetron in the Management of Chemotherapy-Induced Nausea and Vomiting

The need to control chemotherapy-induced nausea and vomiting is continuously stimulating research to find better options for the optimal antiemetic care. Palonosetron is different from conventional serotonin receptor antagonists not only by the fact of having a longer half-life but also by higher binding affinity for serotonin receptors. It is the first agent in the class which is approved for preventing both delayed and acute emesis induced by moderately emetogenic chemotherapy. Recent studies using palonosetron-based antiemetic regimens, as well as in the clinical setting of multiple-day chemotherapy, have been reported. Palonosetron plus dexamethasone given as a pre-treatment infusion was effective for preventing acute and delayed emesis after moderately emetogenic chemotherapy. Palonosetron in combination with dexamethasone and aprepitant was highly effective in preventing emesis in the days following administration of moderately emetogenic chemotherapy. Treatment was well tolerated, with no unexpected adverse events. Multiple-day dosing of palonosetron plus dexamethasone was safe and effective for prevention of emesis induced by 5-day cisplatin-based chemotherapy. There was no evidence of cumulative toxicity when palonosetron was given three times over 5 days. Further evidence from ongoing clinical trials with palonosetron with or without dexamethasone will be available soon. Palonosetron represents an useful addition to the therapeutic armamentarium for the management of chemotherapy-induced nausea and vomiting. Further studies are needed to assess the effectiveness of palonosetronin combination with dexamethasone compared with that of older serotonin receptor antagonists combined with dexamethasone. However, palonosetron may offer advantages of convenience over the short-acting older antagonists due to its ability to be given as a single intravenous dose prior to chemotherapy.

Delayed Chemotherapy-Induced Nausea and Vomiting: Pathogenesis, Incidence, and Current Management

Even when chemotherapy-induced nausea and vomiting (CINV) can be effectively controlled in the acute phase, it may still occur in the delayed phase. Identifying at-risk patients is complex and requires consideration of clinical, personal, demographic, and behavioral factors. Delayed CINV has a significant detrimental effect on patients' daily life and is responsible for significant healthcare resource utilization. Patients who do not experience acute CINV are not necessarily exempt from delayed CINV, and healthcare professionals have been shown to underestimate the incidence of delayed CINV. Failure to protect against CINV during the first cycle of chemotherapy is the most significant independent risk factor for delayed CINV during subsequent cycles. Addition of a neurokinin-1 receptor antagonist to antiemetic prophylactic regimens involving a 5-hydroxytryptamine type 3 receptor antagonist and a corticosteroid helps to ameliorate delayed CINV, particularly vomiting. Netupitant and rolapitant are second-generation neurokinin-1 receptor antagonists that provide effective prophylaxis against delayed chemotherapy-induced vomiting and also have an antinausea benefit. All of the neurokinin-1 receptor antagonists with the exception of rolapitant inhibit or induce cytochrome P450 3A4 (CYP3A4), and a reduced dose of dexamethasone (a CYP3A4 substrate) should be administered with aprepitant or netupitant; by contrast, this is not necessary with rolapitant. Here we review specific challenges associated with delayed CINV, its pathophysiology, epidemiology, treatment, and outcomes relative to acute CINV, and its management within the larger context of overall CINV.

Carbon monoxide contributes to the constipating effects of granisetron in rat colon

AIM

To investigate the mechanisms underlying the potential contribution of the heme oxygenase/carbon monoxide (HO/CO) pathway in the constipating effects of granisetron.

METHODS

For in vivo studies, gastrointestinal motility was evaluated in male rats acutely treated with granisetron [25, 50, 75 μg/kg/subcutaneous (sc)], zinc protoporphyrin IX [ZnPPIX, 50 μg/kg/intraperitoneal (ip)] and hemin (50 μmol/L/kg/ip), alone or in combination. For in vitro studies, the contractile neurogenic response to electrical field stimulation (EFS, 3, 5, 10 Hz, 14 V, 1 ms, pulse trains lasting 10 s), as well as the contractile myogenic response to acetylcholine (ACh, 0.1-100 μmol/L) were evaluated on colon specimens incubated with granisetron (3 μmol/L, 15 min), ZnPPIX (10 μmol/L, 60 min) or CO-releasing molecule-3 (CORM-3, 100, 200, 400 μmol/L) alone or in combination. These experiments were performed under co-treatment with or without atropine (3 μmol/L, a muscarinic receptor antagonist) or N^G-nitro-L-Arginine (L-NNA, 100 μmol/L, a nitric oxide synthase inhibitor).

RESULTS

Administration of granisetron (50, 75 μg/kg) in vivo significantly increased the time to first defecation (P = 0.045 vs vehicle-treated rats), clearly suggesting a constipating effect of this drug. Although administration of ZnPPIX or hemin alone had no effect on this gastrointestinal motility parameter, ZnPPIX co-administered with granisetron abolished the granisetron-induced constipation. On the other hand, co-administration of hemin and granisetron did not modify the increased constipation observed under granisetron alone. When administered in vitro, granisetron alone (3 μmol/L) did not significantly modify the colon’s contractile response to either EFS or ACh. Incubation with ZnPPIX alone (10 μmol/L) significantly reduced the colon’s contractile response to EFS (P = 0.016) but had no effect on contractile response to ACh. Co-administration of ZnPPIX and atropine (3 μmol/L) abolished the ZnPPIX-mediated decrease in contractile response to EFS. Conversely, incubation with CORM-3 (400 μmol/L) alone increased both the contractile response to EFS at 10 Hz (10 Hz: 71.02 ± 19.16 vs 116.25 ± 53.70, P = 0.01) and the contractile response to ACh (100 μmol/L) (P = 0.012). Co-administration of atropine abolished the CORM-3-mediated effects on the EFS-mediated response. When granisetron was co-incubated in vitro with ZnPPIX, the ZnPPIX-mediated decrease in colon contractile response to EFS was lost. On the other hand, co-incubation of granisetron and CORM-3 (400 μmol/L) further increased the colon’s contractile response to EFS (at 5 Hz: P = 0.007; at 10 Hz: P = 0.001) and to ACh (ACh 10 μmol/L: P = 0.001; ACh 100 μmol/L: P = 0.001) elicited by CORM-3 alone. L-NNA co-administered with granisetron and CORM-3 abolished the potentiating effect of CORM-3 on granisetron on both the EFS-induced and ACh-induced contractile response.

CONCLUSION

Taken together, findings from in vivo and in vitro studies suggest that the HO/CO pathway is involved in the constipating effects of granisetron.

The Human Serotonin Type 3 Receptor Gene (HTR3A-E) Allelic Variant Database

Serotonin type 3 (5-HT₃ ) receptors are ligand-gated ion channels formed by five subunits (5-HT3A-E), which are encoded by the HTR3A, HTR3B, HTR3C, HTR3D, and HTR3E genes. Functional receptors are pentameric complexes of diverse composition. Different receptor subtypes confer a predisposition to nausea and vomiting during chemotherapy, pregnancy, and following surgery. In addition, different subtypes contribute to neurogastroenterologic disorders such irritable bowel syndrome (IBS) and eating disorders as well as comorbid psychiatric conditions. 5-HT₃ receptor antagonists are established treatments for emesis and IBS and are beneficial in the treatment of psychiatric diseases. Several case-control and pharmacogenetic studies have demonstrated an association between HTR3 variants and psychiatric and neurogastroenterologic phenotypes. Recently, their potential as predictors of nausea and vomiting and treatment of psychiatric disorders became evident. This information is now available in the serotonin receptor 3 HTR3 gene allelic variant database (www.htr3.uni-hd.de), which contains five sub-databases, one for each of the five different serotonin receptor genes HTR3A-E. Information on HTR3 variants, their functional relevance, associated phenotypes, and pharmacogenetic data such as drug response and side effects are available. This central information pool should help clinicians as well as scientists to evaluate their findings and to use the relevant information for subsequent genotype-phenotype correlation studies and pharmacogenetic approaches.

Synthesis and evaluation of (S)-[(18)F]fesetron in the rat brain as a potential PET imaging agent for serotonin 5-HT3 receptors

Serotonin 5-HT3 receptors are involved in various brain functions including as an emesis target during cancer chemotherapy. We report here the development of (S)-2,3-dimethoxy-5-(3'-[(18)F]fluoropropyl)-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide ([(18)F]fesetron) as a potential PET imaging agent for serotonin 5-HT3 receptors. By radiolabeling((S)-2,3-dimethoxy-5-(3'-tosyloxypropyl)-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide) with fluorine-18, (S)-[(18)F]fesetron was obtained in 5 to 10% decay-corrected yields and with specific activities >74GBq/μmol at the end of radiosynthesis. PET imaging in rats showed low uptake of [(18)F]fesetron in the brain with retention of binding in the striatal and cerebellar regions. Using colliculi as a reference region, ratios were 3.4 for striata and 2.5 for cerebellum. Ex vivo brain PET analysis displayed binding of [(18)F]fesetron in the hippocampus, striatum and cerebellar regions. Cerebellar regions corresponded to area postrema and nucleus tract solitaris known to contain 5-HT3 receptors. Dorsal hippocampus showed the highest uptake with ratio of >17 with respect to colliculi, while area postrema and striata had ratios of >10. Thus, [(18)F]fesetron exhibited a unique binding profile to rat brain regions known to contain significant amounts of serotonin 5-HT3 receptors. However, the very low brain uptake limits its usefulness as a PET radiotracer in this animal model.

Can 5-HT3 antagonists contribute toward the treatment of schizophrenia?

In one of his earlier papers, Lex Cools stated that the 'concept of an impaired balance between the in series connected […] dopamine system, […] 5-HT system and […] noradrenaline system offers a single coherent and integrated theory of schizophrenia' (Cools, 1975). Since then, considerable attention has focused on the interaction between dopamine and 5-HT and it is now well accepted that most antipsychotics (especially the second-generation drugs) modulate both dopaminergic and serotonergic receptors. However, the vast majority of research has focused on the 5-HT1A, 5-HT2A and 5-HT2C receptors. In the present paper, we review the literature pertaining to the 5-HT3 receptor, the only ionotropic 5-HT receptor. We discuss both the interactions between 5-HT3 receptors and dopamine, and the animal and human literature investigating the role of 5-HT3 receptors in schizophrenia. The results show that the interactions between 5-HT3 receptors and dopamine are complex, but that 5-HT3 receptors do not have a strong influence on the positive symptoms of schizophrenia. However, when added to standard antipsychotic medication, several recent studies have found that 5-HT3 receptor antagonists can induce a statistically significantly improvement in negative and cognitive symptoms. The implications of these findings in relation to animal modelling and drug development are discussed.

Effects of inhaled ginger aromatherapy on chemotherapy-induced nausea and vomiting and health-related quality of life in women with breast cancer

OBJECTIVE

To assess the efficacy of inhaled ginger aromatherapy on nausea, vomiting and health-related quality of life (HRQoL) in chemotherapy breast cancer patients.

DESIGN

Single-blind, controlled, randomized cross-over study. Patients received 5-day aromatherapy treatment using either ginger essential oil or fragrance-matched artificial placebo (ginger fragrance oil) which was instilled in a necklace in an order dictated by the treatment group sequence.

SETTING

Two oncology clinics in the East Coast of Peninsular Malaysia.

MAIN OUTCOME MEASURES

VAS nausea score, frequency of vomiting and HRQoL profile (EORTC QLQ-C30 scores).

RESULTS

Sixty female patients completed the study (age=47.3±9.26 years; Malay=98.3%; on highly emetogenic chemotherapy=86.7%). The VAS nausea score was significantly lower after ginger essential oil inhalation compared to placebo during acute phase (P=0.040) but not sustained for overall treatment effect (treatment effect: F=1.82, P=0.183; time effect: F=43.98, P<0.001; treatment×time effect: F=2.04; P=0.102). Similarly, there was no significant effect of aromatherapy on vomiting [F(1, 58)=0.29, P=0.594]. However, a statistically significant change from baseline for global health status (P<0.001) was detected after ginger essential oil inhalation. A clinically relevant 10 points improvement on role functioning (P=0.002) and appetite loss (P<0.001) were also documented while patients were on ginger essential oil.

CONCLUSION

At present time, the evidence derived from this study is not sufficiently convincing that inhaled ginger aromatherapy is an effective complementary therapy for CINV. The findings for HRQoL were however encouraging with significant improvement in several domains.

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.

Palonosetron plus dexamethasone in highly emetogenic chemotherapy: pooled data from two Phase III trials

Aim: Data from two randomized trials were pooled to further characterize the effectiveness of palonosetron combined with dexamethasone in the setting of highly emetogenic chemotherapy. Patients & methods: The analysis included 1411 patients who were randomized to receive palonosetron or ondansetron/granisetron intravenously on day 1 plus either 1-day or 3-day dexamethasone dosing. The primary end point was complete response (no vomiting and no rescue antiemetics over days 1–5) in cycle one. Data across the studies were analyzed by the Mantel–Haenszel method. Results: The vast majority of patients received either cisplatin (62%) or anthracycline plus cyclophosphamide (34%). The palonosetron regimen provided a 12 percentage-point improvement in the rate of overall complete response compared with the control regimen (49.2 vs 37.3%; odds ratio: 1.65; 95% CI: 1.33–2.04; p < 0.0001). The frequency of no delayed nausea at all daily periods was consistently higher in the palonosetron group. Conclusion: The current analysis confirmed that palonosetron plus dexamethasone improved control of highly emetogenic chemotherapy-induced nausea and vomiting throughout 5 days postchemotherapy to a significantly greater extent than the combination including older 5-HT3 antagonists.

Assessment of Ondansetron-Associated Hypokalemia in Pediatric Oncology Patients

Objectives. Ondansetron is a 5-hydroxytryptamine (5-HT3, serotonin) receptor antagonist used as antiemetic prophylaxis preceding chemotherapy administration. Hypokalemia is a rare complication of ondansetron, which may be underreported due to confounding emesis and chemotherapy-induced tubulopathy. We performed a prospective cohort study to determine if ondansetron caused significant hypokalemia independently as a result of renal potassium wasting. Methods. Twelve patients were recruited, with ten completing the study. Blood and urine samples were collected before and after ondansetron administration in patients admitted for intravenous (IV) hydration and chemotherapy. Dietary histories and IV records were analyzed to calculate sodium and potassium balances. Results. We observed an expected drop in urine osmolality, an increase in urine sodium, but no statistically significant change in sodium or potassium balance before and after ondansetron. Conclusion. Ondansetron does not cause significant potassium wasting in appropriately hydrated and nutritionally replete patients. Careful monitoring of serum potassium is recommended in patients with chronic nutritional or volume status deficiencies receiving this medication.

Ginger (Zingiber officinale) reduces acute chemotherapy-induced nausea: a URCC CCOP study of 576 patients

PURPOSE

Despite the widespread use of antiemetics, nausea continues to be reported by over 70% of patients receiving chemotherapy.

METHODS

In this double blind, multicenter trial, we randomly assigned 744 cancer patients to four arms: 1) placebo, 2) 0.5 g ginger, 3) 1.0 g ginger, or 4) 1.5 g ginger. Nausea occurrence and severity were assessed at a baseline cycle and the two following cycles during which patients were taking their assigned study medication. All patients received a 5-HT(3) receptor antagonist antiemetic on Day 1 of all cycles. Patients took three capsules of ginger (250 mg) or placebo twice daily for 6 days starting 3 days before the first day of chemotherapy. Patients reported the severity of nausea on a 7-point rating scale ("1" = "Not at all Nauseated" and "7" = "Extremely Nauseated") for Days 1-4 of each cycle. The primary outcomes were to determine the dose and efficacy of ginger at reducing the severity of chemotherapy-induced nausea on Day 1 of chemotherapy.

RESULTS

A total of 576 patients were included in final analysis (91% female, mean age = 53). Mixed model analyses demonstrated that all doses of ginger significantly reduced acute nausea severity compared to placebo on Day 1 of chemotherapy (p = 0.003). The largest reduction in nausea intensity occurred with 0.5 g and 1.0 g of ginger (p = 0.017 and p = 0.036, respectively). Anticipatory nausea was a key factor in acute chemotherapy-induced nausea (p < 0.0001).

CONCLUSIONS

Ginger supplementation at a daily dose of 0.5 g-1.0 g significantly aids in reduction of the severity of acute chemotherapy-induced nausea in adult cancer patients.

An overview of the clinical use of ondansetron in preschool age children

The introduction of 5-HT₃ receptor antagonist has revolutionized the prevention and treatment of nausea and vomiting in preschool aged children. These distressing symptoms, arising from multiple etiologies such as anesthesia, chemotherapy, and viral infection, are a major concern of patients and their families. Clinical research has demonstrated the antiemetic effectiveness of ondansetron in children. Although most of these studies focus primarily on preventing vomiting across the pediatric age group, they provide strong evidence for the use of ondansetron in preschool age children. For children at high risk, pediatric practice guidelines recommend ondansetron in conjunction with other antiemetics to achieve complete control of symptoms.

Therapeutics of 5-HT3 receptor antagonists: current uses and future directions

The 5-Hydroxytryptamine3 (5-HT3) receptor is a member of the cys-loop family of ligand gated ion channels, of which the nicotinic acetylcholine receptor is the prototype. All other 5-HT receptors identified to date are metabotropic receptors. The 5-HT3 receptor is present in the central and peripheral nervous systems, as well as a number of non-nervous tissues. As an ion channel that is permeable to the cations, Na(+), K(+), and Ca(2+), the 5-HT3 receptor mediates fast depolarizing responses in pre- and post-synaptic neurons. As such, 5-HT3 receptor antagonists that are used clinically block afferent and efferent synaptic transmission. The most well established physiological roles of the 5-HT3 receptor are to coordinate emesis and regulate gastrointestinal motility. Currently marketed 5-HT3 receptor antagonists are indicated for the treatment of chemotherapy, radiation, and anesthesia-induced nausea and vomiting, as well as irritable bowel syndrome. Other therapeutic uses that have been explored include pain and drug addiction. The 5-HT3 receptor is one of a number of receptors that play a role in mediating nausea and vomiting, and as such, 5-HT3 receptor antagonists demonstrate the greatest anti-emetic efficacy when administered in combination with other drug classes.

Vomiting, diarrhea, constipation, and gastroenteritis

Diseases that cause vomiting, diarrhea, constipation, and gastroenteritis are major problems for populations worldwide. Patients, particularly infants, elderly, and immunocompromised individuals, may present at any point in a wide spectrum of disease states, underscoring the need for the clinician to treat these ailments aggressively. Several promising new treatment modalities, from oral rehydration solutions to antiemetic therapies, have been introduced over the past decade. Future directions include the use of probiotic agents and better tolerated rehydration solutions. Gastrointestinal disease will continue to be a focus worldwide in the search for better ways to cure illnesses associated with vomiting and diarrhea.

Effects of OCT1 polymorphisms on the cellular uptake, plasma concentrations and efficacy of the 5-HT(3) antagonists tropisetron and ondansetron

After uptake into liver cells, the antiemetic drugs tropisetron and ondansetron undergo metabolic inactivation by cytochrome P450 2D6 (CYP2D6). We investigated whether the hepatic organic cation transporter 1 (OCT1; SLC22A1) mediates cellular uptake and whether common OCT1 loss-of-function polymorphisms affect pharmacokinetics and efficacy of both drugs. Both tropisetron and ondansetron inhibited ASP(+) uptake in OCT1-overexpressing HEK293 cells. Overexpression of wild-type, but not OCT1 loss-of-function variants, significantly increased tropisetron uptake. Correspondingly, patients with two loss-of-function OCT1 alleles had higher tropisetron plasma concentrations (n=59, P<0.04) and higher clinical efficacy (n=91, P=0.009) compared with carriers of fully active OCT1. Overexpression of OCT1 did not increase ondansetron uptake. Nevertheless, OCT1 genotypes correlated with pharmacokinetics (n=45, P<0.05) and clinical efficacy (n=222, P<0.02) of ondansetron, the effect size of OCT1 genotypes on pharmacokinetics and efficacy was greater for tropisetron than for ondansetron. In conclusion, in addition to the known effects of CYP2D6, OCT1 deficiency may increase efficacy of tropisetron and potentially of ondansetron by limiting their hepatic uptake.

5-HT(3) receptors: role in disease and target of drugs

Serotonin type 3 (5-HT(3)) receptors are pentameric ion channels belonging to the superfamily of Cys-loop receptors. Receptor activation either leads to fast excitatory responses or modulation of neurotransmitter release depending on their neuronal localisation. 5-HT(3) receptors are known to be expressed in the central nervous system in regions involved in the vomiting reflex, processing of pain, the reward system, cognition and anxiety control. In the periphery they are present on a variety of neurons and immune cells. 5-HT(3) receptors are known to be involved in emesis, pain disorders, drug addiction, psychiatric and GI disorders. Progress in molecular genetics gives direction to personalised medical strategies for treating complex diseases such as psychiatric and functional GI disorders and unravelling individual drug responses in pharmacogenetic approaches. Here we discuss the molecular basis of 5-HT(3) receptor diversity at the DNA and protein level, of which our knowledge has greatly extended in the last decade. We also evaluate their role in health and disease and describe specific case-control studies addressing the involvement of polymorphisms of 5-HT3 subunit genes in complex disorders and responses to drugs. Furthermore, we focus on the actual state of the pharmacological knowledge concerning not only classical 5-HT(3) antagonists--the setrons--but also compounds of various substance classes targeting 5-HT(3) receptors such as anaesthetics, opioids, cannabinoids, steroids, antidepressants and antipsychotics as well as natural compounds derived from plants. This shall point to alternative treatment options modulating the 5-HT(3) receptor system and open new possibilities for drug development in the future.

Polymorphism of human cytochrome P450 enzymes and its clinical impact

Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.

Treatment of nausea and vomiting in terminally ill cancer patients

Nausea and vomiting is a common and distressing symptom complex in patients with far-advanced cancer, affecting up to 60% of individuals at some stage of their illness. The current approach to the palliative care of patients with nausea and vomiting is based on identifying the cause, understanding its pathophysiology and knowing the pharmacology of the drugs available for its amelioration. The following six main syndromes are identified: gastric stasis, biochemical, raised intracranial pressure, vestibular, mechanical bowel obstruction and ileus. A careful history, focused physical examination and appropriate investigations are needed to elucidate the syndrome and its cause, so that therapy is rational. Drugs are the mainstay of treatment in terminal cancer, and the main classes of antiemetic agents are prokinetics, dopamine antagonists, antihistamines, anticholinergics and serotonin antagonists. Dexamethasone and octreotide are also used, especially in bowel obstruction. Non-drug measures are important in relieving the associated distress. Patients should be able to die comfortably, without tubes. Despite decades of practice affirming this approach, the evidence base is weak and well designed studies are urgently needed.

Serotonin type 3 receptor genes: HTR3A, B, C, D, E

The 5-HT3 receptor is a ligand-gated ion channel composed of five subunits. To date, five different human subunits are known, 5-HT3A–E, which are encoded by the serotonin receptor genes HTR3A, HTR3B, HTR3C, HTR3D and HTR3E, respectively. Functional receptors are pentameric complexes of diverse composition. Different receptor subtypes seem to be involved in chemotherapy-induced nausea and vomiting (CINV), irritable bowel syndrome and psychiatric disorders. 5-HT3 receptor antagonists are established in the therapy of CINV and irritable bowel syndrome. HTR3A and HTR3B polymorphisms may also contribute to the etiology of psychiatric disorders and serve as predictors in CINV and in the medical treatment of psychiatric patients.

Serotonin pharmacology in the gastrointestinal tract: a review

Serotonin (5-hydroxytryptamine or 5-HT) plays a critical physiological role in the regulation of gastrointestinal (GI) function. 5-HT dysfunction may also be involved in the pathophysiology of a number of functional GI disorders, such as chronic constipation, irritable bowel syndrome and functional dyspepsia. This article describes the role of 5-HT in the enteric nervous system (ENS) of the mammalian GI tract and the receptors with which it interacts. Existing serotonergic therapies that have proven effective in the treatment of GI functional disorders and the potential of drugs currently in development are also highlighted. Advances in our understanding of the physiological and pathophysiological roles of 5-HT in the ENS and the identification of selective receptor ligands bodes well for the future development of more efficacious therapies for patients with functional GI disorders.

Ondansetron versus promethazine to treat acute undifferentiated nausea in the emergency department: a randomized, double-blind, noninferiority trial

OBJECTIVES

The authors sought to compare ondansetron and promethazine among emergency department (ED) patients with undifferentiated nausea. The hypothesis was that ondansetron was not inferior to promethazine and that rates of adverse effects were similar.

METHODS

This was a randomized double-blind noninferiority clinical trial conducted in an urban academic ED. A convenience sample of nonpregnant adults with at least 40 mm of self-reported nausea measured on a 100-mm visual analog scale (VAS) were enrolled. Patients who had already received more than 1 L of intravenous fluid or an antiemetic agent were excluded. Subjects were block-randomized in groups of 10 to either 4 mg of ondansetron or 25 mg of promethazine delivered intravenously. The primary outcome was change in nausea over 30 minutes. The authors used a 15-mm margin of noninferiority. Secondary endpoints included changes in anxiety, sedation, and other adverse effects. Analyses included t-tests, tests for proportions, and 95% confidence intervals (CIs).

RESULTS

A total of 120 subjects completed the study, 60 in each arm. Baseline nausea, anxiety, and sedation scores were similar. Ondansetron and promethazine reduced nausea similarly (ondansetron -34 mm, promethazine -36 mm; difference -2 mm; 95% CI = -13 to 8 mm). The reduction in anxiety was similar (ondansetron -13 mm, promethazine -14 mm; difference -1 mm; 95% CI = -10 to 10 mm). Promethazine was associated with significantly more sedation than ondansetron (ondansetron 5 mm, promethazine 19 mm; difference 14 mm; 95% CI = 5 to 24 mm). There were no cases of akathisia in the ondansetron group and 2 cases in the promethazine group.

CONCLUSIONS

Promethazine and ondansetron have similar efficacy in reducing nausea among ED patients. Change in anxiety was similar, but promethazine was associated with greater sedation.

Antiemetic placebo: Reduce adverse drug interactions between chemotherapeutic agents and antiemetic drugs in cancer patients

Cancer patients receiving chemotherapy often require a wide range of drugs to manage symptoms of their cancer. The adverse drug interactions are common in the field of medical oncology. Chemotherapy-induced nausea and vomiting (CINV) continues to have a considerable effect on the physical and psychological well-being of patients with cancer, despite significant advances in antiemetic drugs since the 1990s. Fortunately, evidence-based interventions suggested that to a certain extent antiemetic effects can be achieved by use of placebo appropriately. Placebo effect can be reinforced by conferring much meaning. Thus physician can replace antiemetic drugs with reinforced meaningful antiemetic placebo to get better prevention and treatment efficacy for CINV while reduce the unnecessary adverse drug interactions induced by antiemetic drugs and chemotherapeutic agents.

Ondansetron-associated hypokalemia in a 2-year-old with pre-B-cell ALL

Ondansetron is a commonly used medication in the treatment of nausea and vomiting arising from many etiologies, including chemotherapy. Although it is a highly safe drug, ondansetron use has been associated, rarely, with hypokalemia. However, it is unknown whether hypokalemia is due to the medication itself or to an underlying potassium disturbance caused by prior metabolic derangements, including vomiting. We relate a patient who presents with hypokalemia of unknown etiology, with evidence suggesting a possible relationship to ondansetron. We also present a proposed mechanism for this phenomenon.

Cancer rehabilitation: challenges, approaches, and new directions

Impairments and disability in cancer patients can be caused by the disease process or by its treatment, including the effects of surgery, chemotherapy, and radiation. The prevalence of all cancers, with an estimated 1.4 million new cases in 2006, the development of new treatment options, and improved outcomes have created a constantly growing population of cancer survivors whose function and quality of life have been affected by their diagnoses. This article reviews the theoretical framework, clinical interventions, and research initiatives pertinent to providing rehabilitation services for patients who have been diagnosed with cancer.

Pharmacology, pharmacogenetics, and clinical efficacy of 5-hydroxytryptamine type 3 receptor antagonists for postoperative nausea and vomiting

PURPOSE OF REVIEW

The use of selective 5-hydroxytryptamine type 3 receptor antagonists has improved the management of postoperative nausea and vomiting, but has not completely eliminated it. In this article, we discuss the pharmacology of 5-hydroxytryptamine type 3 receptor antagonists and the impact of pharmacogenetics on postoperative nausea and vomiting.

RECENT FINDINGS

Dolasetron, granisetron, ondansetron, palonosetron, and tropisetron have similar mechanisms of action but different pharmacokinetic and pharmacodynamic properties. Genetic polymorphism in the cytochrome P450 mono-oxygenase system, drug efflux transporter adenosine triphosphate-binding cassette subfamily B member 1 and 5-hydroxytryptamine type 3 receptor subunits also contribute to the interindividual variation in response to different 5-hydroxytryptamine type 3 receptor antagonists. These differences account for differences in the duration of action and clinical efficacy of these agents.

SUMMARY

Pharmacogenetics testing in patients may help differentiate responders to 5-hydroxytryptamine type 3 receptor antagonists from non-responders and allow the anesthesiologist to individualize antiemetic therapy. The cost-effectiveness of such screening in postoperative nausea and vomiting management has, however, not been evaluated. Given the multifactorial nature of postoperative nausea and vomiting, a multimodal approach to reduce or eliminate risk factors will be most successful in its management.