Urinary serotonin metabolite excretion during cisplatin chemotherapy

A randomised clinical trial to study postoperative abdominal and shoulder tip pain following low and standard pressure laparoscopic cholecystectomy

Background

Laparoscopic cholecystectomy (LC) has become the gold standard for the management of symptomatic gallstone disease. The complications related to different pressure ranges of pneumoperitoneum have been studied widely with no definite conclusion till date. The current study was planned to determine the effect of standard versus low pressure laparoscopic cholecystectomy (LPLC) on postoperative abdominal and shoulder tip pain (STP).

Methods

The present randomised clinical trial included 84 patients divided into two groups: standard pressure laparoscopic cholecystectomy (SPLC) (13 mmHg) and LPLC (9 mmHg). The variables tested were abdominal pain at 3, 6, 12 and 24 h (by verbal rating scale), the incidence and intensity of STP, post-operative nausea and vomiting (PONV) and surgeon's comfort for the two techniques.

Results

The demographic characteristics of patients were similar in both groups. In LPP group, the postoperative abdominal pain at 6, 12 and 24 h was significantly less than SPLC; p = 0.02. Incidence of shoulder pain was significantly less in low pressure group (7.14%) compared with standard pressure (28.57%).

Conclusions

Low-pressure pneumoperitoneum (LPP) is safe and feasible surgery with reduced abdominal and STP.

Concomitant palonosetron ameliorates cisplatin-induced nephrotoxicity, nausea, and vomiting: a retrospective cohort study and pharmacovigilance analysis

Background

Cisplatin (CDDP)-induced nephrotoxicity is the most important complication of CDDP treatment. 5-Hydroxytryptamine type 3 receptor antagonists (5-HT₃RAs) are widely used to prevent chemotherapy-induced nausea and vomiting (CINV). However, in patients with the triple antiemetic (neurokinin-1 receptor antagonist, 5-HT₃RA, and dexamethasone) therapy, the advantage of palonosetron in comparison with other 5-HT₃RAs on CDDP-induced nephrotoxicity and CINV remains unclear. In the present study, we investigated the effect of palonosetron on CDDP-induced nephrotoxicity and CINV in patients with the triple antiemetic therapy by a retrospective cohort study and a pharmacovigilance analysis.

Methods

We retrospectively analyzed the effect of 5-HT₃RAs on the development of nephrotoxicity and CINV in 110 patients who received CDDP, fluorouracil, and triple antiemetic therapy for the treatment of esophageal cancer. Moreover, the effect of 5-HT₃RAs on CDDP-induced nephrotoxicity was validated in patients with the triple antiemetic therapy using the Japanese Adverse Drug Event Report (JADER) database.

Results

In a retrospective study, the incidence of nephrotoxicity (≥ grade 1) in patients receiving palonosetron (18%) was significantly lower than that in patients receiving ramosetron (another 5-HT₃RA) (36%, p = 0.044). Moreover, severe nephrotoxicity ≥ grade 3 was observed in one patient treated with ramosetron, whereas hematological toxicity was comparable between the two groups (p = 0.553). Furthermore, the incidence rate of CINV within 120 h following CDDP administration in patients treated with palonosetron (18%) was significantly lower than that in patients receiving ramosetron (39%, p = 0.026). JADER database analyses revealed that the reporting odds ratio of palonosetron for CDDP-induced acute kidney injury was 0.282 (95% confidence interval: 0.169–0.472).

Conclusions

The findings of the present study suggested a greater potential of palonosetron against CDDP-induced nephrotoxicity and CINV than other 5-HT₃RAs in patients with the triple antiemetic therapy.

Effect and Mechanism of Herbal Medicines on Cisplatin-Induced Anorexia

Cisplatin is a well-known chemotherapeutic agent used to treat various types of cancers; however, it can also induce anorexia, which results in reduced food intake, loss of body weight, and lower quality of life. Although drugs such as megestrol acetate and cyproheptadine are used to decrease this severe feeding disorder, they can also induce side effects, such as diarrhea and somnolence, which limit their widespread use. Various types of herbal medicines have long been used to prevent and treat numerous gastrointestinal tract diseases; however, to date, no study has been conducted to analyze and summarize their effects on cisplatin-induced anorexia. In this paper, we analyze 12 animal studies that used either a single herbal medicine extract or mixtures thereof to decrease cisplatin-induced anorexia. Among the herbal medicines, Ginseng Radix was the most used, as it was included in seven studies, whereas both Glycyrrhizae Radix et Rhizoma and Angelicae Gigantis Radix were used in four studies. As for the mechanisms of action, the roles of serotonin and its receptors, cytokines, white blood cells, ghrelin, and leptin were investigated. Based on these results, we suggest that herbal medicines could be considered a useful treatment method for cisplatin-induced anorexia.

Effectiveness and safety of combined neurokinin-1 antagonist aprepitant treatment for multiple-day anthracycline-induced nausea and vomiting

OBJECTIVE

To assess the safety and efficacy of combined neurokinin-1 antagonist aprepitant treatment for multiple-day anthracycline chemotherapy-induced nausea and vomiting.

METHODS

One hundred patients with breast cancer from department of Medical Oncology of Ordos Central Hospital from June 2015 to February 2018 were selected and randomize subdivided into 2 groups. All cases received anthracycline (30 mg/m²/d for pirarubicin or 45 mg/m²/d for epirubicin) and cyclophosphamide adjuvant chemotherapy, along with either the standard therapy (dexamethasone and tropisetron) or the combined aprepitant therapy (aprepitant plus dexamethasone and tropisetron). The results of the observation between groups were presented by complete response in the overall phase (OP, 0-120 hours), acute phase (AP, 0-24 hours) and delay phase (DP, 25-120 hours). The Kaplan-Meier curves were plotted to exhibit the first time of vomiting, Functional Living Index-Emesis of patients' quality of life, and therapy-related adverse effects (AEs).

RESULTS

The complete response of OP, AP, and DP were statistically different between aprepitant group and standard group (80.0% vs 48%, P = 0.001; 92.0% vs 74%, P = 0.017; 80.0% vs 48%, P = 0.001). The aprepitant group held a longer time reaching the first emesis after the relevant treatment than the standard group. The Functional Living Index-Emesis increased significantly in the aprepitant group compared with the standard group (24% vs 8.3%, P = 0.029). Fatigue and constipation were the only AEs of aprepitant, since no significant differences were observed in fatigue between the 2 groups (72% vs 70%, P = 0.826), while the incidence of constipation of aprepitant group was higher than the standard group (48% vs 28%, P = 0.039).

CONCLUSION

Combined aprepitant therapy is efficient and safe in the multiple-day anthracycline chemotherapy-induced nausea and vomiting control and is recommended for the clinical use.

Diversity of enteroendocrine cells investigated at cellular and subcellular levels: the need for a new classification scheme

Enteroendocrine cells were historically classified by a letter code, each linked to a single hormone, deduced to be the only hormone produced by the cell. One type, the L cell, was recognised to store and secrete two products, peptide YY (PYY) and glucagon-related peptides. Many other exceptions to the one-cell one-hormone classifications have been reported over the last 40 years or so, and yet the one-hormone dogma has persisted. In the last 6 years, a plethora of data has appeared that makes the concept unviable. Here, we describe the evidence that multiple hormone transcripts and their products reside in single cells and evidence that the hormones are often, but not always, processed into separate storage vesicles. It has become clear that most enteroendocrine cells contain multiple hormones. For example, most secretin cells contain 5-hydroxytryptamine (5-HT), and in mouse many of these also contain cholecystokinin (CCK). Furthermore, CCK cells also commonly store ghrelin, glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1), neurotensin, and PYY. Several hormones, for example, secretin and 5-HT, are in separate storage vesicles at a subcellular level. Hormone patterns can differ considerably between species. Another complication is that relative levels of expression vary substantially. This means that data are significantly influenced by the sensitivities of detection techniques. For example, a hormone that can be detected in storage vesicles by super-resolution microscopy may not be above threshold for detection by conventional fluorescence microscopy. New nomenclature for cell clusters with common attributes will need to be devised and old classifications abandoned.

Evaluation of a Neurokinin-1 Antagonist in Preventing Multiple-day Cisplatin-induced Nausea and Vomiting

Objective

To perform a prospective non-randomized comparison of the effectiveness and safety of combined neurokinin-1 antagonist aprepitant treatment with the standard multiple-day cisplatin regimen for the prevention of cisplatin-induced nausea and vomiting (CINV).

Methods

Patients being administered 3-day cisplatin-based chemotherapy (25 mg/m²/d) who had never received aprepitant were given either the standard regimen (tropisetron and dexamethasone) or the aprepitant regimen (aprepitant plus tropisetron and dexamethasone). The primary endpoint was the complete response (CR) in the overall phase (OP, 0–120 h) between the combined aprepitant triple regimen group and the standard group. Secondary endpoints were the CR in the acute phase (AP, 0–24 h) and delay phase (DP, 25–120 h) between the two groups. The first time of vomiting was also compared by Kaplan–Meier curves. The impact of CINV on the quality of life was assessed by the Functional Living Index-Emesis (FLIE). Aprepitant-related adverse effects (AEs) were also recorded.

Results

A CR was achieved by 80.0% in the aprepitant group compared with 56.0% in the standard group during the OP (P =0.018)as well as during the DP. However, during the AP, the aprepitant and standard therapy groups achieved identical CR rates (98.0%, P =1.000). A longer time to first emesis was documented for the aprepitant group than for the standard group. No effect of CINV on quality of life as assessed by FLIE was reported by 44.7% of aprepitant therapy patients and 24.0% of standard therapy patients (P=0.035). The main aprepitant-related AEs were fatigue and constipation, but there was no significant difference between groups.

Conclusion

Combined aprepitant therapy is recommended for the prevention of multiple-day CINV because of its improved CINV control rate and safety.

This CE is published through an unrestricted educational grant from Bristol-Myers Squibb

Credit

This lesson is good for 0.2 CE units, with a passing grade of 70%.

Goal

The goal of this program is to inform the participant of costeffective ways to prevent, identify, and manage nausea and vomiting induced by antineoplastic agents.

Objectives

At the completion of this program the participant will be able to: 1. List antineoplastic agents associated with a high incidence of nausea and vomiting. 2. Identify patient-specific risk factors for developing chemotherapyinduced nausea and vomiting (CINV) and how these factors may influence treatment of this syndrome. 3. Compare the three major types of CINV, including the pathophysiologic mechanism, time of onset, and symptom duration of each type. 4. Explain the mechanism of action and appropriate place in therapy for each type of antiemetic agent. 5. Differentiate between pharmacologic regimens for the prevention and treatment of CINV in adults. 6. Identify drug-specific factors that must be considered in developing a formulary management strategy for the antiemetic agents. 7. Describe specific information that the pharmacist can share with patients to help them understand and manage CINV.

The anti-asthmatic drug pranlukast suppresses the delayed-phase vomiting and reverses intracellular indices of emesis evoked by cisplatin in the least shrew (Cryptotis parva)

The introduction of second generation serotonin 5-HT₃ receptor (5-HT₃) antagonist palonosetron combined with long-acting substance P neurokinin NK₁ receptor (NK₁) antagonists (e.g. netupitant) has substantially improved antiemetic therapy against early- and delayed-phases of emesis caused by highly emetogenic chemotherapeutics such as cisplatin. However, the improved efficacy comes at a cost that many patients cannot afford. We introduce a new class of antiemetic, the antiasthmatic leukotriene CysLT1 receptor antagonist pranlukast for the suppression of cisplatin-evoked vomiting. Pranlukast (10mg/kg) by itself significantly reduced the mean frequency of vomits (70%) and fully protected least shrews from vomiting (46%) during the delayed-phase of cisplatin (10mg/kg)-evoked vomiting. Although, pranlukast tended to substantially reduce both the mean frequency of vomits and the number of shrews vomiting during the early-phase, these reductions failed to attain significance. When combined with a first (tropisetron)- or a second (palonosetron)-generation 5-HT₃ receptor antagonist, pranlukast potentiated their antiemetic efficacy during both phases of vomiting. In addition, pranlukast by itself prevented several intracellular signal markers of cisplatin-evoked delayed-vomiting such as phosphorylation of ERK1/2 and PKA. When pranlukast was combined with either palonosetron or tropisetron, these combinations suppressed the evoked phosphorylation of: i) ERK1/2 during both acute- and delayed-phase, ii) PKCα/β at the peak acute-phase, and iii) PKA at the peak delayed-phase. The current and our published findings suggest that overall behavioral and intracellular signaling effects of pranlukast via blockade of CysLT1 receptors generally appear to be similar to the NK₁ receptor antagonist netupitant with some differences.

5-Hydroxyindoleacetic acid and substance P profiles in patients receiving emetogenic chemotherapy

Background. Even though direct cause and effect has not been proved, clinical evidence suggests serotonin and substance P (SP) are involved in the emetic response following chemotherapy. Because of several parallels, we hypothesized that SP release, like serotonin, may be propagated by chemotherapy and both substances can be measured in biological fluids, and correlated with a particular phase of emesis.

Methods. Urinary 5-hydroxyindoleacetic acid (5-HIAA) was assessed by HPLC; serum and urine SP were measured by immunoassay. In addition to construction of neurotransmitter profiles, all SP data were grouped according to cisplatin dosages, = or>75 mg/m 2 versus <75 mg/m2, and phase of emesis, acute versus delayed. Analyses of these data were performed by repeated measures analysis of variance.

Results. Samples were collected over a 72-hour period from 26 adult patients who received cisplatin-( n=13) or non-cisplatin-containing ( n=13) chemotherapy. Mean baseline 5-HIAA: creatinine ratios were 5.23 and 5.16 in females and males, respectively; mean baseline SP levels were 392 and 181 pg/mL in females and males, respectively. Comparisons between SP data stratified by cisplatin dosage and emetic phase were significantly different, P <0.0001.

Conclusions. Laboratory studies provide additional evidence that serotonin and SP are involved primarily, though not exclusively, in acute and delayed vomiting, respectively.

Comparison between 5-day aprepitant and single-dose fosaprepitant meglumine for preventing nausea and vomiting induced by cisplatin-based chemotherapy

Purpose

We aimed to compare the preventive effect of 5-day administration of aprepitant with single administration of fosaprepitant meglumine against nausea and vomiting symptoms due to highly emetogenic chemotherapy regimens comprising cisplatin (CDDP).

Methods

Subjects were inpatients who underwent chemotherapy for gastric cancer, esophageal cancer, lung cancer, or head and neck cancer with a regimen comprising 60 mg/m² or higher dose of CDDP. In this randomised, open-label, controlled study, the subjects were assigned to a group given aprepitant for 5 days or a group given a single administration of fosaprepitant meglumine. The nausea and vomiting symptoms that emerged within 7 days after the first CDDP administration were investigated with a questionnaire form; the results were compared between the two groups. Risk factors affecting nausea and vomiting symptoms were also investigated.

Results

Of the 101 patients enrolled, 93 patients were included (48 in the 5-day aprepitant group and 45 in the single fosaprepitant meglumine group). No significant intergroup differences in the complete response rate or the complete control rate were found over the entire period. The nausea score tended to increase from day 3 in both groups, but no significant intergroup difference was observed. Furthermore, the investigation of risk factors affecting moderate or severe nausea symptoms indicated that the fosaprepitant meglumine administration was not a risk factor.

Conclusions

Single administration of fosaprepitant meglumine was not inferior to 5-day administration of aprepitant for preventing acute and delayed nausea and vomiting symptoms occurring after administration of CDDP (60 mg/m² or higher).

Comparison of low and standard pressure gas injection at abdominal cavity on postoperative nausea and vomiting in laparoscopic cholecystectomy

Background and Objective: Postoperative nausea and vomiting (PONV) is the main concern for 40-70% of patients undergoing laparoscopic cholecystectomy. Our objective was to compare carbon dioxide gas at low pressure and standard pressure for the occurrence of PONV on patients undergoing laparoscopic cholecystectomy.

Methods: This double- blind trial was conducted on 50 women patients aged between 18 to 60 years with acute cholecystectomy. The patients were divided into two groups: low pressure (LP) (received LP gas, 7-9 mmHg) and standard pressure (SP) (received SP gas, 14-15 mmHg). Nausea and vomiting in patients at hours 0-4, 4-8, 8-12, 12-24 after the surgery were recorded.

Results: The frequency of PONV in the LP and SP groups did not demonstrate statistically significant different (P > 0.05). Nevertheless the frequency of shoulder pain after 4 hours at the LP group compared with SP group was significantly different (P < 0.023).

Conclusions: The use of low pressure gas compared to standard pressure gas to create pneumoperitoneum could not reduce the PONV whereas the frequency of shoulder pain in LP group was reduced. Low pressure gas was associated with reduction of surgeon visibility and subsequently more prolonged surgery duration.

Clinical practice guidelines on antiemetics in oncology

The tolerability of chemotherapy has been significantly improved by the advent of effective drugs and protocols for the amelioration of chemotherapy-induced nausea and vomiting. Variables such as the timing of nausea and vomiting (acute, delayed or anticipatory) and the emetogenicity of the chemotherapy must be taken into account in developing guidelines for antiemetic prophylaxis and treatment. Although there are a number of 5-hydroxytryptamine antagonists available, the clinical differences between them are small. The use of drugs with a different mechanism of action, such as the recently introduced neurokinin-1 receptor antagonist aprepitant, may be a useful adjunct to 5-hydroxytryptamine-3 receptor antagonists or steroid prophylaxis. The addition of aprepitant to standard antiemetic regimens increases the proportion of complete responses to antiemetic therapy. For the use of highly emetogenic chemotherapy in oncology a combination of 5-hydroxytryptamine-3 receptor antagonist, dexamethasone and aprepitant is recommended in the acute phase, and dexamethasone plus aprepitant during the subsequent days (many patients do not have their symptoms controlled by 5-hydroxytryptamine-3 receptor antagonist and steroid alone). In either case, lorazepam can be added as required. For moderately emetogenic chemotherapy, a regimen of 5-hydroxytryptamine, dexamethasone and aprepitant is recommended in the acute phase, followed by aprepitant alone in the delayed phase. Alternatively, a 5-hydroxytryptamine-3 receptor antagonist and dexamethasone can be used in the acute phase, followed by dexamethasone for prophylaxis in the delayed phase. For chemotherapy with a low emetogenicity, either dexamethasone, metoclopramide, prochlorperazine or triethyperazine alone is recommended. No prophylaxis is generally required during the delayed phase and indeed may not be necessary during the acute phase either.

Prevention of chemotherapy-induced nausea and vomiting and the role of neurokinin 1 inhibitors: from guidelines to clinical practice in solid tumors

A significant proportion of cancer patients experience nausea or vomiting during the course of their disease, either because of the cancer itself or because of the treatment received. Highly or moderately emetogenic drugs are part of the standard chemotherapy regimens frequently used in patients with lung cancer, breast cancer, ovarian cancer, and several other common solid tumors. In this review, we describe the impact of nausea and vomiting in patients receiving chemotherapy, and the main progress achieved in the prophylaxis of chemotherapy-induced nausea and vomiting with the introduction of neurokinin 1 inhibitors. The adherence to existing guidelines is particularly important to avoid suboptimal prophylaxis and maximize patients' outcome. This review is focused on lung, breast, ovarian, and colorectal cancer, which are among the solid tumors characterized by a numeric and clinical relevance of the chemotherapy-induced nausea and vomiting issue because of the wide use of highly and/or moderately emetogenic chemotherapy regimens.

Managing hyperemesis gravidarum: a multimodal challenge

Up to 90% of pregnant women experience nausea and vomiting. When prolonged or severe, this is known as hyperemesis gravidarum (HG), which can, in individual cases, be life threatening. In this article the aetiology, diagnosis and treatment strategies will be presented based on a selective literature review. Treatment strategies range from outpatient dietary advice and antiemetic drugs to hospitalization and intravenous (IV) fluid replacement in persistent or severe cases. Alternative methods, such as acupuncture, are not yet evidence based but sometimes have a therapeutic effect.In most cases, the condition is self limiting and subsides by around 20 weeks gestation. More severe forms require medical intervention once other organic causes of nausea and vomiting have been excluded. In addition, a psychosomatic approach is often helpful.In view of its potential complexity, general practitioners and obstetricians should be well informed about HG and therapy should be multimodal.

Chemotherapy-induced nausea and vomiting: antiemetic trials that impacted clinical practice

Objective. To review the scientific evidence related to serotonin and substance P and the clinical impact targeting these two neurotransmitters have had managing chemotherapy-induced nausea and vomiting (CINV).

Data Source. A PubMed search (January 1968 to December 2008), restricted to English-language publications, was conducted using the key words antiemetics, cancer chemotherapy, cisplatin, serotonin, substance P, NK1, and 5-HT3. Abstracts emanating from the meetings of the American Society of Clinical Oncology and Multinational Association of Supportive Care in Cancer during the period May 2000 to June 2008 were also reviewed.

Data Synthesis. Two important outcomes emanated from well-conducted antiemetic clinical trials (Table 1): first, evidence that serotonin and substance P are major mediators of acute and delayed symptoms and second, improved, though not complete, control of CINV.

Conclusion. Serotonin-type 3 and neurokinin-1 receptor antagonists are the most effective agents currently available. In most cases, these agents are used in conjunction with glucocorticoids. The use of these three types of agents is incorporated into current clinical practice guidelines. Further understanding of the biological and biochemical basis of nausea and vomiting may enhance management of this potentially debilitating adverse effect.

Comparative activity of antiemetic drugs

Nausea and vomiting continues to be an important problem for cancer patients receiving chemotherapy. Chemotherapy-induced nausea and vomiting (CINV) are classified as acute, occurring within the first 24h, or delayed, occurring after the first 24h. A number of antiemetic agents are available for the management of nausea and vomiting, including 5-HT3-receptor-antagonists, corticosteroids, NK-1-receptor-antagonists, dopamine-receptor antagonists, benzodiazepines, neuroleptics and cannabinoids. With modern antiemetic therapy, vomiting can be prevented in 70-80% of patients, whereas the control of nausea remains suboptimal. The development of acute emesis is known to depend on serotonin. The pathophysiology of delayed emesis is less well understood, and multiple mechanisms may contribute, including substance P. Here, the most recent developments in the antiemetic therapy, including new antiemetic drugs and the latest guidelines for antiemetic prophylaxis, are reviewed.

Health outcomes and cost-effectiveness of aprepitant in outpatients receiving antiemetic prophylaxis for highly emetogenic chemotherapy in Germany

BACKGROUND

Chemotherapy-induced nausea and vomiting (CINV) remains a major adverse effect of cancer therapy. We aimed to determine outcomes associated with use of aprepitant in outpatients undergoing highly emetogenic chemotherapy in Germany from a patient's and payer's perspective.

METHODS

A decision-analytic model compared an aprepitant regimen (aprepitant/ondansetron/dexamethasone) to a control regimen (ondansetron/dexamethasone) over a five days period. Clinical results and resource utilisation observed in aprepitant phase III clinical trials were assigned German unit cost data.

RESULTS

Complete response over one chemotherapy cycle was observed in 68% of patients in the aprepitant group (N=514) compared to 48% of patients in the control group (N=518). Patients were estimated to have gained an equivalent of 15 additional hours of perfect health per cycle (0.63 quality-adjusted life days) with aprepitant-based regimen compared to control regimen. Cost per quality-adjusted life year gained with aprepitant was estimated at euro28,891.

CONCLUSIONS

Aprepitant substantially improved CINV-related health outcomes in patients undergoing highly emetogenic chemotherapy. Incremental benefits materialised in a cost-effective fashion.

Gastrointestinal toxicity of chemotherapeutic agents

Chemotherapy-induced toxicities commonly occur in sites within the gastrointestinal (GI) tract and account for dose-limiting effects. These toxicities are major contributing factors to dose reduction, delays, and cessation of cancer treatment. Through intensive therapies including surgery, combination chemotherapy, hormonal therapy, and targeted therapy, an increasing number of patients with cancer are experiencing improved survival and long-term disease-free survival, as well as palliation of disease-related symptoms. Thus, GI toxicities should be predicted and appropriate interventions initiated to prevent them when possible and provide effective supportive measures and comprehensive follow-up care. This review will discuss the etiology, incidence, prevention, and treatment of GI toxicities of cancer chemotherapy.

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

The 5-HT(3)-receptor antagonists, considered as 'gold standard' therapy for cancer patients, are generally perceived to have similar efficacy and safety profiles, andmost antiemetic guidelines do not distinguish between agents. However, important pharmacological differences exist between agents, which may translate into potential benefits for some patients. In particular, 5-HT(3)-receptor antagonists vary in the nature of their receptor antagonism and plasma half-lives, possibly leading to differences in duration of action. Agents with a longer duration of action provide antiemetic protection throughout the acute emetic period (24 h) with a single daily dose, whereas shorter-acting agents, e.g. ondansetron, may require multiple dosing for full efficacy. Differences also exist between agents in their hepatic metabolism and cardiovascular safety, which may present particular problems for elderly patients who often receive additional medications for comorbid conditions, increasing the risk of drug-drug interaction. Recent antiemetic guidelines from the National Comprehensive Cancer Network recommend preferential use of palonosetron for moderately emetogenic chemotherapy; however, this agent is newly approved and key clinical questions remain unanswered by clinical trial data. Selection of an appropriate 5-HT(3)-receptor antagonist should be based on proven efficacy and safety, as well as on the individual characteristics of the patient.

Aprepitant: A Novel Antiemetic for Chemotherapy-Induced Nausea and Vomiting

OBJECTIVE:

To evaluate the safety and efficacy of aprepitant in the prevention of acute and delayed chemotherapy-induced nausea and vomiting (CINV).

DATA SOURCES:

MEDLINE and PubMed database searches were conducted from 1966 to May 2004 using the following search terms: aprepitant, Emend, substance P, neurokinin-1, chemotherapy, nausea, vomiting, L-754,030, and MK-869.

STUDY SELECTION AND DATA EXTRACTION:

Large, randomized Phase II and III clinical trials examining the use of aprepitant for CINV, as well as all published drug interaction studies with aprepitant, were included and reviewed. Data lacking in published trials were supplemented with the manufacturer product information.

DATA SYNTHESIS:

The pharmacokinetics of aprepitant are favorable for once-daily oral dosing. Based on the results of published clinical trials, aprepitant appears to augment the effects of corticosteroids and 5-HT3 antagonists when given prior to highly emetogenic chemotherapy, including cisplatin. Aprepitant appears to have the most benefit in the prevention of delayed CINV and in preventing emesis rather than nausea. Data in pediatric patients, patients undergoing stem-cell transplantation, and those receiving multiple-day or moderately emetogenic chemotherapy are lacking. Common adverse effects are limited to hiccups, asthenia, and diarrhea. More serious but rare adverse effects include neutropenia. Because aprepitant is a CYP3A4 substrate, a 3A4 inhibitor and inducer, and a 2C9 inducer, close monitoring for drug interactions is warranted.

CONCLUSIONS:

Triple antiemetic therapy with aprepitant, a corticosteroid, and a 5-HT3 antagonist appears to provide improved efficacy in the prevention of emesis in patients receiving highly emetogenic chemotherapy. Due to its novel mechanism of action and demonstrated efficacy in this combination, aprepitant should be considered for formulary addition.

Open-label, randomized comparison of the efficacy of intravenous dolasetron mesylate and ondansetron in the prevention of acute and delayed cisplatin-induced emesis in cancer patients

PURPOSE

The aim of this study is to compare the antiemetic efficacy and tolerability of intravenous dolasetron mesylate and ondansetron in the prevention of acute and delayed emesis.

MATERIAL AND METHODS

From April 2002 through October 2002, a total of 112 patients receiving cisplatin- based combination chemotherapy were randomized to receive a single i.v. dose of dolasetron 100 mg or ondansetron 8 mg, 30 minutes before the initiation of chemotherapy. In the ondansetron group, two additional doses of ondansetron 8 mg were given at intervals of 2 to 4 hours. To prevent delayed emesis, dolasetron 200 mg p.o. daily or ondansetron 8 mg p.o. bid was administered from the 2(nd) days to a maximum of 5 days. The primary end point was the proportion of patients that experienced no emetic episodes and required no rescue medication (complete response, CR) during the 24 hours (acute period) and during Day 2 to Day 5+/-2 days (delayed period), after chemotherapy. The secondary end points included the incidence and severity of emesis.

RESULTS

105 patients were evaluable for efficacy. CR rates during the acute period were 36.0% for a single dose of dolasetron 100 mg, and 43.6% for three doses of ondansetron 8 mg. CR rates during the delayed period were 8.0% and 10.9%, respectively. There was no significant difference in the efficacy between the two groups. Adverse effects were mostly mild to moderate and not related to study medication.

CONCLUSIONS

A single i.v. dose of dolasetron 100 mg is as effective as three i.v. doses of ondansetron 8 mg in preventing acute and delayed emesis after cisplatin-based chemotherapy, with a comparable safety profile.

[Vomiting after gynecologic laparoscopy and under general anesthesia is associated with changes in excretion of serotonin metabolites]

INTRODUCTION

The efficacy of 5-HT(3)-receptor antagonists suggests a role of serotonin in the pathogenesis of postoperative nausea and vomiting (PONV). However, studies investigating the relationship between the turnover of serotonin and PONV were contradictory. Therefore we carried out a pilot study in order to find out whether results can be obtained that would justify further studies on a larger scale.

METHODS

A total of 22 patients scheduled for elective gynaecological laparoscopy were enrolled. A balanced anaesthesia using sufentanil, etomidate, cisatracurium, isoflurane and nitrous oxide was administered and 5-hydroxyindoleaceticacid (5-HIAA) concentrations in the urine were measured within the 24 h after surgery.

RESULTS

Only the patients that vomited postoperatively had a significant change in the concentrations of 5-HIAA over the time course investigated. However, comparison of urinary 5-HIAA concentrations of the group comprising patients that vomited with those that had no PONV did not reveal a significant difference.

CONCLUSIONS

Results of this study support further investigation of the relationship between serotonin and PONV and suggest that there may in fact be an association between PONV and increased serotonin turnover.

Pharmacokinetics of granisetron in adults and children with malignant diseases

Granisetron (GRN) is widely used for patients with various cancers who suffer from chemotherapy-induced vomiting and nausea. The, pharmacokinetics of GRN has not been fully evaluated in such patients, however, and its dosage regimen is still controversial. In this study, we determined GRN levels in serum and urine from lung cancer patients and children suffering from cancer after intravenous infusion. In lung cancer patients, the interindividual variations in t(1/2beta), area under the concentration-time curve (AUC), and Vd(beta) were relatively smaller than expected from previous reports on healthy subjects, while t(1/2beta) was prolonged more than 5-fold in healthy subjects. Urinary excretion of unchanged GRN in lung cancer patients was ca. 15% of dose, consistent with previous reports, and one individual demonstrated an even higher urinary excretion (ca. 45%). The pharmacokinetic parameters of GRN in child cancer patients varied markedly among individuals, and some child patients had smaller t(1/2beta) than adult patients. In these cases, GRN should be administered at shorter intervals. These results suggested that a pharmacokinetic study of GRN was necessary for planning a dosage regimen and managing chemotherapy-induced vomiting and nausea.

Cisplatin-induced emesis in the cat: effect of granisetron and dexamethasone

The emetic action of cisplatin was investigated in the cat using a closed circuit video recording system. In initial investigations, cisplatin 3 and 5 mg/kg, i.v. induced emesis over a 2-day period following a latency of 17.6+/-9.6 and 15.6+/-7.8 h, respectively. The anti-emetic efficacy of granisetron and dexamethasone was investigated in the cisplatin 5 mg/kg, i.v.-induced emesis model. In these experiments, cisplatin induced 47.0+/-14.0 and 20.0+/-9.0 retches+vomits on days 1 and 2, respectively, following a latency of 2.4+/-0.4 h. Granisetron (1 mg/kg, i.m.) administered three times per day reduced significantly the retching+vomiting response induced by cisplatin on days 1 and 2 by 100.0% (P<0.05) and 75.0% (P<0.05), respectively; dexamethasone (0.01-1 mg/kg, i.m.) administered three times per day reduced significantly the retching+vomiting response by 68.8-100.0% (P<0.05) and 33.3-100.0% (P<0.05) on days 1 and 2, respectively. The emetic action of cisplatin 7.5 mg/kg, i.v. was also investigated. This dose of cisplatin-induced emesis following a latency of 1.2+/-0.2 h and comprised 119.0+/-20.8 retches+vomits over a 24-h period. Granisetron and dexamethasone antagonized the emesis occurring in the first 3-h period (P<0.05) but were less effective to antagonize the subsequent emetic response (P0.05). The pharmacological sensitivity of low dose cisplatin-induced emesis in the cat is variable but unique and not representative of the clinical situation.

Gynecologic laparoscopic surgery is not associated with an increase of serotonin metabolites excretion

Gynecologic laparoscopic surgery is associated with a high incidence of postoperative nausea and vomiting (PONV). The specific antagonists of the 5-hydroxytryptamine-3 (5-HT3) receptor have been progressively introduced in anesthesiology to prevent or treat PONV. Although a large increase of serotonin has been documented after cisplatin treatment, the link between serotonin and PONV in surgery/anesthesiology is unknown. In a prospective study, we compared the excretion of the serotonin metabolite 5-hydroxyindoacetic acid (5-HIAA) in 40 women undergoing either gynecologic laparoscopic surgery (laparoscopy group) or traditional open laparotomy surgery (laparotomy group). Premedication, anesthetic technique, and postoperative pain treatment were standardized. The excretion of 5-H IAA corrected to creatinine was measured in all patients immediately after the induction of anesthesia and was repeated regularly until 9 h after induction. The excretion of 5-HIAA/creatinine was similar in the two groups; no increase was observed in either group. The incidence of nausea and vomiting was 40% and 35%, respectively, in the laparoscopy group versus 60% and 15%, respectively, in the laparotomy group (not significantly different). The excretion of 5-HIAA/creatinine was comparable in patients of both groups among those who vomited and those who did not. We conclude that the creation of a pneumoperitoneum during gynecologic laparoscopic surgery is not associated with an increase of 5-HIAA excretion. PONV after gynecologic laparoscopic surgery is not explained by an increase of serotonin secretion.

IMPLICATIONS

The mechanism leading to the high incidence of postoperative nausea and vomiting after gynecologic laparoscopic surgery is unknown. The excretion of the serotonin metabolite 5-hydroxyindoacetic acid did not increase during the creation of the pneumoperitoneum and the first 9 h postoperatively. Increase of serotonin secretion from the gut may not explain postoperative nausea and vomiting associated with this surgery.

Effects of granisetron and its combination with dexamethasone on cisplatin-induced delayed emesis in the ferret

1. Granisetron and its combination with dexamethasone for the treatment of delayed emesis following cisplatin (CDDP) administration were investigated using ferrets. 2. CDDP-induced emesis was significantly inhibited in both the granisetron group and the combined granisetron and dexamethasone group during the acute and delayed phase in terms of total emesis, latency to first emesis and duration of emesis. 3. Food and water consumption in the combined group of ferrets was significantly increased as compared with the CDDP control group. 4. 5-Hydroxytryptamine (5-HT) level was increased in the ileum and the 5-hydroxyindole acetic acid (5-HIAA) level was increased in the area postrema of ferrets after 3 days of CDDP administration. It is suggested that the antiemetic activity of granisetron and/or dexamethasone is not related to 5-HT levels in delayed emesis. 5. Both granisetron and its combination with dexamethasone are effective in CDDP-induced emesis, but combination treatment is more effective than granisetron alone for the duration of emesis in the delayed phase.

5-HT3 receptor antagonists for the prevention of chemotherapy-induced nausea and vomiting. A comparison of their pharmacology and clinical efficacy

In the mid-1980s it was discovered that serotonin (5-hydroxytryptamine; 5-HT) was at least partially responsible for producing chemotherapy-induced nausea and vomiting. It was therefore realised that serotonin receptor blockade with serotonin 5-HT3 receptor antagonists could inhibit chemotherapy-induced nausea and vomiting. 5-HT3 antagonists have different chemical structures and receptor binding affinity. Granisetron, dolasetron and its major metabolite are pure 5-HT3 antagonists, while ondansetron and tropisetron are weak antagonists at the 5-HT4 receptor. Ondansetron has also been demonstrated to bind at other serotonin receptors and to the opioid mu receptor. The half-lives of granisetron, tropisetron and the active metabolite of dolasetron are 2 to 3 times longer than that of ondansetron. These observations initially suggested that more frequent ondansetron administration would be required; however, it has now been shown that receptor blockade does not correlate with elimination half-life and all 5-HT3 antagonists can be effectively administered once daily. Clinical trials have been conducted that directly compare the 5-HT3 antagonists. To compare these studies, it is necessary to assess trial design, including known risk factors for the development of chemotherapy-induced nausea and vomiting, and response criteria. Stratification for risk factors, use of strict efficacy criteria and randomisation to a blinded trial using an appropriate comparative regimen are essential for a well designed antiemetic trial. Comparative clinical trials using various doses, routes and regimens of administration have been conducted with 5-HT3 antagonists. Despite some trial design shortcomings, most of the studies show equal efficacy between the agents, especially in moderately emetogenic chemotherapy and mild, infrequently occurring adverse effects. The addition of steroids also appears to improve outcome. However, since many doses and regimens of ondansetron were used, further study is needed to determine the optimal regimen. The efficacy of 5-HT3 antagonists in controlling delayed nausea and vomiting from chemotherapy is less well studied. Further, there is no good scientific rationale for the use of 5-HT3 antagonists in controlling delayed nausea and vomiting since serotonin has not been shown to be released during the delayed phase. In fact, most studies show no benefit or modest benefit of 5-HT3 antagonists over placebo. Because the 5-HT3 antagonists perform similarly in the clinical setting, pharmacological differences do not seem to translate into therapeutic differences. There is also no appreciable difference in the incidence or severity of adverse effects among the 5-HT3 antagonists. Determination of clinical use may then be driven by cost.

Urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion during multiple-day high-dose chemotherapy

Highly emetogenic drugs such as cisplatin induce an increase in the urinary 5-hydroxyindoleacetic acid (5-HIAA) level, the main metabolite of serotonin (5-HT), within the first 24 h following a single infusion, thus providing a possible cause for acute emesis and an explanation for the action of 5-HT3 antagonists. No further excretion peaks have been observed, suggesting that additional or serotonin-independent mechanisms cause delayed emesis. Our aim was to study the mechanisms behind emesis seen during a highly emetogenic chemotherapy regimen given as a continuous infusion over several days. Seven women treated with a 4-day high-dose chemotherapy (HDCT) regimen for breast cancer entered the study. Pooled urine samples were collected prior to and during chemotherapy for determining 5-HIAA excretion. An excretion peak in the urinary 5-HIAA level was observed within the first 24 h with no further peaks thereafter. Thus, the mechanisms behind the emesis experienced during this highly emetogenic multiple-day chemotherapy regimen from days 2-3 onwards would appear to be at least partially serotonin independent and would not be expected to be completely relieved by 5-HT3 antagonists alone.

Effects of a 5-HT1A receptor agonist on acute and delayed cyclophosphamide-induced vomiting

LY228729 [(-)-4(dipropylamino)-1,3,4,5-tetrahydrobenz-[c,d]indole-6-carboxa mide]], an agonist at the 5-HT1A subtype of 5-HT receptor, was studied as an antiemetic in pigeons dosed with a highly emetic oncolytic agent, cyclophosphamide. An intramuscular injection of 0.32 mg/kg of LY228729 administered 15 min prior to the intravenous injection of 200 mg/kg of cyclophosphamide totally prevented the acute emetic response induced by cyclophosphamide. When used as a rescue therapy in a separate group of pigeons, LY228729 (0.32 mg/kg, i.m.) prevented further emetic episodes when it was administered after vomiting had already been induced by cyclophosphamide. Injections of LY228729 given at intervals over the next 2 d also attenuated the delayed emetic response induced by cyclophosphamide. LY228729 appears to be a broad spectrum antiemetic agent that is effective against the anticipatory, the acute and the delayed stages of emesis induced by oncolytic agents.

Hyperemesis gravidarum: is serotonin implicated?

Serotonin excretion was investigated in the nausea and vomiting associated with hyperemesis gravidarum. Urinary hydroxyindoleacetic acid was measured in 13 gravid women with hyperemesis gravidarum, 10 gravid women without nausea and vomiting, and 10 nongravid women of similar age not taking contraceptive pills. No significant difference in the urinary excretion of hydroxyindoleacetic acid was found among the groups. Hyperemesis gravidarum is not associated with an increase of serotonin secretion.

An overview of randomised studies comparing 5-HT3 receptor antagonists to conventional anti-emetics in the prophylaxis of acute chemotherapy-induced vomiting

Ten years after it was demonstrated in the ferret that cisplatin-induced emesis could be blocked by the selective 5-HT3 receptor antagonist MDL 72222, 5-HT3 receptor antagonists have become routine anti-emetic agents for chemotherapy-induced emesis. However, although in association with highly emetogenic, mainly cisplatin-containing regimens, the use of these agents is well justified, the net benefit of 5-HT3 receptor antagonists in association with moderately emetogenic regimens has not been that well clarified. Here, we present an overview of 30 randomised studies comparing 5-HT3 antagonists with the conventional anti-emetics in the prophylaxis of acute vomiting induced by cytotoxic chemotherapy. A meta-analysis showed that 5-HT3 antagonists reduce the risk of acute vomiting in comparison to conventional anti-emetics both with cisplatin treatments (15 trials; odds ratio 0.60; 95% confidence interval 0.51-0.70) and with moderately emetogenic treatments (11 trials; odds ratio 0.47; 95% confidence interval 0.39-0.58). The risk of acute vomiting seems to be further reduced when 5-HT3 antagonists are combined with dexamethasone.

The action of the NK1 tachykinin receptor antagonist, CP 99,994, in antagonizing the acute and delayed emesis induced by cisplatin in the ferret

1. The anti-emetic effects of the NK1 tachykinin receptor antagonist, CP 99,994 (10 mg kg-1) were investigated in the ferret using a cisplatin-induced acute (day 1) and delayed (day 2 and 3) retching and vomiting model. 2. With a single cisplatin (10 mg kg-1) emetogenic challenge, the i.p. administration of CP 99,994 given as a single injection immediately following the first emetic episode, promptly abolished the retching and vomiting for a 4 h period. CP 99,994 was as efficacious as ondansetron (1.0 mg kg-1). The general toxicity of cisplatin 10 mg kg-1 precluded its use in studies of delayed emesis. 3. With a single cisplatin (5 mg kg-1) emetogenic challenge, the single administration of either CP 99,994 (10 mg kg-1) or ondansetron (1.0 mg kg-1) immediately following the first emetic episode markedly reduced or abolished the retching and vomiting for 4 h. Such single treatments failed to modify significantly the intensity of delayed emesis appearing on the second and third day. 4. With a cisplatin (5 mg kg-1) emetogenic challenge, administration of CP 99,994 (10 mg kg-1) at 8 hourly intervals, the first injection being administered 30 s post cisplatin, was associated with 4 or more abolitions of emesis during both the acute and delayed phase. A 4 hourly administration of CP 99,994 for 20 h during delayed emesis completely abolished the retching and vomiting. 5. It is concluded that cisplatin 5 mg kg-1 provides an emetogenic challenge causing an acute and delayed phase of retching and vomiting and that CP 99,994 can abolish both phases. The results may be relevant to the understanding and treatment of chemotherapy-induced emesis in man.

Role of 5-hydroxytryptamine3 (5-HT3) antagonists in the prevention of emesis caused by anticancer therapy

Most anticancer drugs are cytotoxic and produce various side-effects, among which nausea and vomiting are almost ubiquitous and usually extremely distressing to the patient. Cancer chemotherapy elicits two main phases of vomiting: an intense, acute phase of vomiting that occurs almost immediately following anti-cancer therapy and a milder, delayed phase of nausea and vomiting of longer duration. The mechanisms underlying the induction of nausea and vomiting after cancer chemotherapy are poorly understood but may be mediated by serotonin (5-hydroxytryptamine or 5-HT), particularly in the acute phase. Serotonin activates 5-HT3 receptors, which function as ligand-gated ion channels located either in the periphery and/or in the central nervous system to produce emesis, among other effects. The peripheral 5-HT3 receptors may be pharmacologically distinct from the central 5-HT3 receptors and may exhibit some association with GTP-binding proteins. In addition, different populations may exist as distinct subtypes of the same receptor. The 5-HT3 receptor antagonist ondansetron (GR 38032F) is effective in preventing the emesis induced by cytotoxic agents currently used in the treatment of many forms of cancer. Ondansetron has, comparatively, a much higher efficacy in the treatment of acute emesis following cancer chemotherapy than it does in the delayed phase, suggesting that the late phase of emesis may be mediated by other distinct mechanisms.

Propofol in chemotherapy-associated nausea and vomiting

Propofol appears to possess antiemetic actions. Limited reports have shown benefit with its use as adjuvant therapy with highly emetogenic chemotherapy regimens and as monotherapy with moderately emetogenic chemotherapy. Adverse effects have been minimal. It should be noted that to date no Phase I dose ranging studies have been described; therefore, optimal dose and duration remain unknown. Results from well-designed, controlled clinical trials in large numbers of patients are needed to define the appropriate role of propofol in antiemetic therapy. Currently, propofol must be reserved for use in clinical trials or as adjuvant therapy for patients refractory to standard 5-HT3 antagonist and corticosteroid antiemetic prophylaxis.

The interaction of dexamethasone with ondansetron on drug-induced emesis in the ferret

The potential of dexamethasone (0.5-20 mg/kg i.p.) to antagonize the emesis induced by cisplatin (10 mg/kg i.v.), apomorphine (0.25 mg/kg s.c.), morphine (0.5 mg/kg s.c.) and copper sulphate (100 mg/kg intragastric) was investigated alone and in combination with ondansetron in the ferret. There was a trend for dexamethasone 0.1-5 mg/kg to reduce cisplatin-induced emesis and for 0.05-2.5 mg/kg to delay the onset of apomorphine-induced emesis but doses of dexamethasone up to 20 mg/kg were without effect to modify morphine- or copper sulphate-induced emesis. The combination of dexamethasone 2.5 mg/kg with ondansetron 0.1 mg/kg did not have additive effects to reduce cisplatin-induced emesis but did reduce significantly the total numbers of episodes recorded. Ondansetron 1 mg/kg was without effect to modify apomorphine-, morphine- or copper sulphate-induced emesis but the combination pretreatment of ondansetron 1 mg/kg with dexamethasone 2.5 and 5 mg/kg reduced significantly apomorphine-induced retching. Data are discussed in terms of the antiemetic effectiveness of dexamethasone to antagonize chemotherapy-induced emesis in man.

Serotonin metabolism following platinum-based chemotherapy combined with the serotonin type-3 antagonist tropisetron

The administration of platinum-based chemotherapy induces serotonin release from the enterochromaffin cells, causing nausea and vomiting. This study was conducted to evaluate parameters of serotonin metabolism following platinum-based chemotherapy given in combination with the serotonin type-3 antagonist tropisetron as an antiemetic agent. In nine chemotherapy-naive patients with disseminated germ-cell tumors, parameters of serotonin metabolism in both blood and urine were evaluated during two consecutive courses of platinum-based chemotherapy. Serotonin concentrations in platelet-rich plasma and platelet-poor plasma as well as urinary 5-hydroxyindoleacetic acid (5-HIAA) and serotonin levels were measured during the full length of the courses. By means of comparison with the antiemetic agent chlorpromazine, used on day 1 of the first course only, the effect of the serotonin type-3 antagonist tropisetron, the antiemetic agent used during the rest of the courses, on these parameters was studied. Clinical effects were also recorded. No change in the parameters of serotonin metabolism could be demonstrated during either course by the serotonin type-3 antagonist tropisetron. Also in vitro, no effect of tropisetron on the active serotonin uptake by platelets was found. Serotonin levels in platelets showed no correlation with emetic response. However, the platelet serotonin content decreased significantly between the first and the second course (P < 0.01). The significant reduction in platelet serotonin content observed between the first and the second course indicates a depletion of total body serotonin. The role of a serotonin type-3 antagonist might be affected by the altered serotonin equilibrium during later courses of chemotherapy.

The role of serotonin as a mediator of emesis induced by different stimuli

The aim of this work was to evaluate the impact of changes in serotonin metabolism on the pathophysiology of different types of emesis: pregnancy-induced emesis, emesis associated with inner-ear dysfunction, and cisplatin-induced emesis. The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin, was measured in 13 women with pregnancy-induced emesis, 12 patients who had nausea and vomiting following inner-ear dysfunctions, 27 patients with cisplatin-induced emesis and a control group of 21 women. 5-HIAA was measured with a fluorescence polarization immunoassay (Abbott) and corrected for varying urine concentrations. Both patients with emesis associated with inner-ear dysfunction and patients with pregnancy-associated emesis showed a similar 5-HIAA excretion pattern compared with the control group. No correlation between intensity of nausea or vomiting and changes in 5-HIAA excretion could be detected. In patients receiving cisplatin, the 5-HIAA excretion increased rapidly within the 12 h following cisplatin administration and returned to baseline levels after 24 h. There was a parallel increase of 5-HIAA excretion and numbers of emetic episodes in the first 12 h, but delayed emesis was not associated with elevated 5-HIAA excretion. Our results provide evidence that serotonin is involved in the pathophysiology of cisplatin-induced acute emesis. Cisplatin-induced delayed emesis, pregnancy-associated emesis, and emesis due to inner-ear dysfunction are not associated with elevated levels of 5-HIAA excretion. The serotonin pathway probably represents only one of many different afferent mechanisms capable of initiating the emesis cascade.

Delayed emesis following anticancer chemotherapy

As the control of acute chemotherapy-induced emesis has improved, delayed emesis (occurring 24 h or more after treatment) has become the most bothersome vomiting problem. Delayed vomiting occurs after treatment with many anticancer drugs, but has been most often studied following cisplatin or combinations of cyclophosphamide and anthracyclines. The mechanism of this phenomenon is unknown. Empirical trials of antiemetic agents effective in controlling acute emesis identified the combination of metoclopramide and dexamethasone as useful in lessening delayed emesis after displatin in a randomized, placebo-controlled study. The specific serotonin receptor (5-HT3) antagonist ondansetron yielded results equivalent to the prior placebo results in a phase II trial using identical methodology in similar patients given cisplatin. Following anthracycline and cyclophosphamide combination chemotherapy, the delayed vomiting prevention observed with dexamethasone alone exceeds that of ondansetron. These observations suggest that delayed emesis is primarily mediated by neurotransmitters other than serotonin. Since delayed emesis occurs more frequently in patients who experience nausea and vomiting on the day they receive chemotherapy, tested combination antiemetic regimens, employing a 5-HT3 antagonist (either granisetron, metoclopramide, ondansetron or tropisetron), dexamethasone, and a benzodiazepine (lorazepam and alprazolam) should be routinely employed. This approach provides the best protection for acute and delayed emesis. Further research, looking beyond the specific 5-HT3 antagonists, provides the best strategy to improve the control of delayed symptoms.