Stratified, randomized, double-blind comparison of intravenous ondansetron administered as a multiple-dose regimen versus two single-dose regimens in the prevention of cisplatin-induced nausea and vomiting

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

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors.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

A Randomized Open-Label Parallel-Group Study Comparing Ondansetron with Ondansetron plus Dexamethasone in Patients with Metastatic Breast Cancer Receiving High-Dose Epirubicin. A Hellenic Cooperative Oncology Group Study

AIMS AND BACKGROUND

The purpose of this multicenter randomized, open-label, parallel-group study was to assess whether the addition of low-dose dexamethasone to ondansetron results in improved control of chemotherapy-induced emesis in patients undergoing first-line chemotherapy with high-dose epirubicin.

METHODS & STUDY DESIGN

Patients were randomized to receive either 24 mg of ondansetron or 24 mg of ondansetron plus 8 mg of dexamethasone administered as an intravenous infusion 30 minutes prior to administration of chemotherapy. Both groups of patients received 8 mg of ondansetron given orally from day 2 to 5 two times daily. Fifty-three patients received ondansetron and 50 received ondansetron plus dexamethasone. The patients recorded nausea and the number of vomits and retches daily on diary cards.

RESULTS

Significantly more patients in the ondansetron plus dexamethasone group experienced neither vomiting nor retching during the first day of the first course of chemotherapy compared to those receiving ondansetron alone (79.6% vs 53.8%, P = 0.0062). Furthermore, there was a trend in favor of ondansetron plus dexamethasone in the control of nausea. There was no statistically significant difference between ondansetron plus dexamethasone versus ondansetron alone in protecting patients from emesis between days 2 and 5 of the first course of chemotherapy (66.7% vs 62.7%, P = 0.68). This was probably due to the small sample size. Ondansetron was well tolerated, with 15 patients (15%) reporting adverse events such as headache or constipation.

CONCLUSIONS

It appears that ondansetron given intravenously in combination with dexamethasone is more effective than ondansetron alone in the control of acute emesis in patients undergoing their first course of chemotherapy with high-dose epirubicin. No difference between the regimens was found with regard to nausea and delayed emesis control.

Prognostic factors for chemotherapy induced nausea and vomiting

PURPOSE

to review the topic of prognostic factors for chemotherapy-induced nausea and vomiting. Multiple patient factors such as age, gender and alcohol intake have been found that affect the likelihood of emesis with a given chemotherapy. Pharmacogenomics has also been explored as a cause for variation in emetic response. In theory these risk factors could be used to optimize antiemetic therapy for individual patients but guidelines for prophylactic antiemetics are based solely upon the type of chemotherapy administered. Attempts to identify subgroups of patients for whom guidelines recommendations are suboptimal have thus far been unsuccessful except for those with a poor experience in a previous cycle of the same chemotherapy. At present, there is no basis for deviating from evidence-based guidelines when prescribing antiemetics prior to the first cycle of chemotherapy.

Consensus recommendations for the prevention of vomiting and nausea following high-emetic-risk chemotherapy

In this update of our 2005 document, we used an evidence-based approach whenever possible to formulate recommendations, emphasizing the results of controlled trials concerning the best use of antiemetic agents for the prevention of emesis and nausea following anticancer chemotherapies of high emetic risk. A three-drug combination of a 5-hydroxytryptamine type 3 receptor (5-HT(3)) receptor antagonist, dexamethasone, and aprepitant beginning before chemotherapy and continuing for up to 4 days remains the standard of care. We address issues of dose, schedule, and route of administration of five selective 5-HT(3) receptor antagonists. We conclude that, for each of these five drugs, there is a plateau in therapeutic efficacy above which further dose escalation does not improve outcome. In trials designed to prove the equivalence of palonosetron to ondansetron and granisetron, palonosetron proved superior in emesis prevention, while adverse effects were comparable. Furthermore, for all classes of antiemetic agents, a single dose is as effective as multiple doses or a continuous infusion. The oral route is as efficacious as the intravenous route of administration.

[Management of chemotherapy-induced emesis: what is the standard after 20 years of clinical research]

BACKGROUND

The knowledge of the importance, the physiopathological mechanisms, and the management of the chemotherapy-induced emesis has increased exponentially during the last 20 years. High-dosage metoclopramide (MCP) therapy has been introduced in the eighties and serotonine type-3 receptor antagonists (5-HT(3) antagonists) have been used since the late eighties and early nineties. Due to both classes of substances the results of the antiemetic therapies have improved drastically. After 20 years of intensive clinical research it seems to be appropriate to come to an intermediate conclusion.

METHOD

With the aid of an overview and a new analysis of the literature published on this topic so far, the current state of research is shown (including the fields in which further improvement will be necessary), and suggestions are made, wherever it seemed possible, to attain the "gold standard" in antiemetic therapy.

RESULTS AND CONCLUSIONS

In connection with all highly or very highly emetogenic chemotherapies, an antiemetic prophylaxis should be initiated on the day of therapy, especially when using platinum or most of the cyclophosphamide-based regimes for cancer treatment. The recommended prophylaxis consists of a combination of 5-HT(3) antagonists with a corticosteroid. To combat the so-called delayed emesis on the days following therapy, all patients should undergo an oral corticoid therapy, possibly in combination with MCP (especially platinum-therapy patients), less frequently with 5-HT(3) antagonists. With these means of prophylaxis emesis can be prevented/avoided completely in most patients, and nausea can at least be reduced. It is sufficient to administer a single dose of 5-HT(3) antagonists prior to chemotherapy. For ondansetron and granisetron, the best documented substances within this class of drugs, 8 mg (ondansteron) and 3 mg (granisetron) are considered standard dosages. Among the corticoids, most data have been accumulated for dexamethasone. A standard dose of 10 to 20 mg can be administered prior to chemotherapy. Right after and especially on the days following chemotherapy higher dosages seem to be indicated.

PROSPECT

Further therapy improvements, especially concerning emesis and nausea on the days following chemotherapy, are necessary and are currently object of clinical research.

Effectiveness of a single-day three-drug regimen of dexamethasone, palonosetron, and aprepitant for the prevention of acute and delayed nausea and vomiting caused by moderately emetogenic chemotherapy

PURPOSE

Chemotherapy-induced nausea and vomiting includes both Acute (0-24 h) and Delayed (24-120 h) components with different physiologic mechanisms. A combination of a serotonin antagonist, a corticosteroid, and an NK-1 antagonist has proven effective against this problem. However, standard antiemetic regimens require administration over 3-4 days after chemotherapy. The present study evaluated a more convenient single-day three-drug antiemetic regimen for patients receiving moderately emetogenic chemotherapy.

MATERIALS AND METHODS

Chemotherapy-naïve patients with solid tumors receiving cyclophosphamide and/or doxorubicin were eligible. Patients could not have pre-existing etiologies for vomiting. Prior to chemotherapy, patients received a single dose of aprepitant 285 mg p.o., dexamethasone 20 mg p.o., and palonosetron 0.25 mg i.v. A daily patient diary recording episodes of emesis and severity of nausea was then kept for 5 days. Any further antiemetics were considered rescue medication.

RESULTS

Forty-one eligible and evaluable patients (40 women, one man) with breast cancer were entered on study. Most were receiving adjuvant chemotherapy. Complete Response (no vomiting, no rescue medication) was seen in 51% of patients, including 76% with Complete Response for the Acute period and 66% for the Delayed period. No emesis was reported for 100% of patients in the Acute period and 95% in the Delayed period. No Nausea was seen in 32% of patients. No untoward toxicities were seen.

CONCLUSION

A single-day three-drug antiemetic regimen is feasible and effective for protection against both Acute and Delayed vomiting after moderately emetogenic chemotherapy. Formal comparison to a standard multi-day antiemetic regimen is warranted.

A meta-analysis comparing the efficacy of four 5-HT3-receptor antagonists for acute chemotherapy-induced emesis

GOALS OF WORK

Comparing antiemetic efficacy of different 5-HT(3)-receptor antagonists (5-HT(3)RAs) is difficult due to inter-study variability. Therefore, a meta-analysis was performed to comparatively evaluate dolasetron, granisetron, ondansetron and tropisetron for acute chemotherapy-induced nausea and vomiting (CINV).

PATIENTS AND METHODS

Comparisons between 5-HT(3)RAs were based on 44 randomized studies (including 12,343 patients) identified by MEDLINE, CANCERLIT or EMBASE searches and subcategorized by chemotherapy type (cisplatin- or non-cisplatin-based).

MAIN RESULTS

When all studies were combined, granisetron was equivalent to ondansetron (n = 27), and showed an advantage vs tropisetron (p = 0.018; n = 12). Ondansetron vs tropisetron (n = 11) and ondansetron vs dolasetron (n = 3) revealed equivalence in each comparison. An advantage for 3 mg granisetron vs 8 mg ondansetron was found in non-cisplatin-based studies (p = 0.015; n = 6). Overall equivalence was seen between ondansetron, 24 or 32 mg, and granisetron, 2 or 3 mg, for all studies (n = 13). There was a possible advantage for higher (24 or 32 mg) vs lower (8 mg) ondansetron dose regimens with cisplatin-based trials (n = 6). No differences were seen between 3 and 1 mg granisetron doses (n = 6).

CONCLUSIONS

Efficacy of 5-HT(3)RAs for preventing CINV following cisplatin- and non-cisplatin-based chemotherapy is comparable, with the exception of granisetron vs tropisetron. Some differences were noted in dosing subanalyses.

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.

Prevención y control de las náuseas y los vómitos inducidos por quimioterapia

Nausea and vomiting are considered one of the most distressing side-effects of chemotherapy. Complete control of acute and delayed emesis improves quality of life and increases adherence to treatment. The frequency of nausea and vomiting depends primarily on the emetogenic potential of the chemotherapeutic agents used. With the standard antiemetic therapy (5HT-3 receptor antagonists in combination with dexamethasone) approximately 13% of patients receiving chemotherapy have vomiting in the acute phase and almost 50% in the delayed phase. A new group of antiemetic drugs, the neurokinin-1 receptor antagonists, in combination with standard therapy significantly improves emesis protection in the acute and in the delayed phase, although control of nausea is not so effective. Nowadays chemotherapy-induced emesis still occurs. Recent developments in antiemetic therapy and responsibility to achieve the best control of nausea and vomiting in patients receiving chemotherapy justified a review of this problem, which is frequently underestimated by physicians and nurses.

5-hydroxytryptamine type-3 receptor antagonists for chemotherapy-induced and radiotherapy-induced nausea and emesis: can we safely reduce the dose of administered agents?

BACKGROUND

Nausea and emesis as a consequence of chemotherapy or radiotherapy can have an adverse effect on patients' quality of life during cancer treatment and may last for > 5 days after administration. Guidelines suggest that, used at appropriate doses, the 5-hydroxytryptamine type-3 (5-HT3) receptor antagonists--which are considered the antiemetic "gold standard" when they are administered in combination with corticosteroids--demonstrate equivalent efficacy and safety. However, due to financial considerations, these agents often are used at lower doses than recommended.

METHODS

A literature review of relevant publications pertaining to the control of chemotherapy-induced nausea and emesis and dosing issues of the 5-HT3 receptor antagonists was undertaken to provide a comprehensive review of dosing issues relevant to the 5-HT3 receptor antagonists.

RESULTS

The issue of "down dosing" was particularly pertinent because of the nature of the 5-HT3 receptor antagonist dose-response curve: A steep dose-response profile within a narrow dose range suggests that antiemetic control will be lost suddenly after dose deescalation. However, the array of predisposing and confounding patient factors indicates that it is unlikely that a loss of antiemetic control will be apparent across a population; rather, individuals will experience loss of control as the dose is reduced below threshold. Of the 4 5-HT3 receptor antagonists currently licensed in the United States (granisetron, ondansetron, dolasetron, and palonosetron), ondansetron is used sometimes at lower than optimal doses, and there is evidence to suggest that even the approved oral dose of dolasetron may be suboptimal.

CONCLUSIONS

Suboptimal dosing not only will be detrimental to patients' quality of life but, ultimately, will prove counterproductive in terms of hospital resources, and it will add to the already significant socioeconomic burden associated with cancer therapy. Therefore, the dose of antiemetic agent administered should be sufficiently high to ensure good emesis control across the whole patient population.

Optimising antiemetic therapy: what are the problems and how can they be overcome?

BACKGROUND

Management of chemotherapy- or radiotherapy-induced emesis has improved significantly following the introduction of the 5-HT3-receptor antagonists. Prophylactic use of these agents is recommended for the prevention of both chemotherapy- and radiotherapy-induced nausea and vomiting, given with a corticosteroid. Despite these advances, nausea and vomiting remain among the most feared and debilitating adverse effects of cytotoxic therapy. The shift towards a more elderly population of patients with cancer presents additional considerations for supportive care, with an emphasis on achieving control of nausea and vomiting, whilst minimising toxicity and avoiding drug-drug interactions. This review presents some of the key issues for consideration in optimising antiemetic therapy. The PubMed search engine was used to search for relevant literature (up to December 2004) and relevant international congress materials collected during 2003 and 2004.

SCOPE

While the early stages of nausea and vomiting are 5-HT-mediated, identification of a role for substance P in late emesis has led to the development of the NK1-receptor antagonist, aprepitant. As a new agent, the clinical profile of aprepitant is still being explored, including its interaction with concomitant medications. Patients who achieve good control of acute and late-acute nausea and vomiting have a reduced risk of experiencing delayed onset symptoms, emphasising the importance of prophylactic management with effective agents. Although the 5-HT3-receptor antagonists are widely considered to have equivalent efficacy, they vary in half-life and the nature of antagonism at receptors. Their metabolic profiles also differ, with cytochrome P450 (CYP) metabolism affecting their propensity for drug-drug interactions. Several sets of guidelines are available that outline recommendations for selection and use of antiemetic therapy. However, under-use of 5-HT3 receptor antagonists has been reported in both the radiotherapy and chemotherapy settings, and some commonly used doses may be suboptimal.

CONCLUSION

In optimising antiemetic therapy, wider implementation of guidelines is desirable, as is consideration of each patient's individual needs. Safety and tolerability of supportive care medications should be a key consideration, and cardiovascular warnings and the possibility of drug-drug interactions should be given sufficient consideration, particularly in view of the older age of the population with cancer.

Is there a pharmacological basis for differences in 5-HT3-receptor antagonist efficacy in refractory patients?

5-HT3-receptor antagonists are the current antiemetic 'gold standard' for chemotherapy- and radiotherapy-induced nausea and vomiting. Interestingly, studies have shown that patients experiencing poor control of acute chemotherapy-induced nausea and vomiting with one antiemetic therapy may respond well to another agent, including a drug of the same class. This review examines pharmacological differences between the 5-HT3-receptor antagonists in order to determine potential reasons for their differing efficacy, particularly in relation to refractory emesis. Differences in drug metabolism by the cytochrome P450 system, inadequate dosing of the respective agents, differences in onset and duration of action, and effects on serotonin release and reuptake are discussed.

Consensus proposals for the prevention of acute and delayed vomiting and nausea following high-emetic-risk chemotherapy

This paper uses an evidence-based approach whenever possible to formulate recommendations, emphasizing the results of controlled trials concerning the best use of antiemetic agents. We address issues of dose, schedule, and route of administration of five selective 5-HT(3) antagonists. We conclude that for each of these five drugs, there is a plateau in therapeutic efficacy above which further dose escalation does not improve outcome. Furthermore, for all classes of antiemetic agents, a single dose is as effective as multiple doses or a continuous infusion. The oral route is as efficacious as the intravenous route of administration, even with chemotherapy of high emetic risk. Selective antagonists of the type 3 serotonin receptor (5-HT(3)) in combination with dexamethasone and aprepitant are the standard of care for the prevention of emesis following chemotherapy of high emetic risk.

Efficacy, safety and pharmacokinetics of palonosetron in patients receiving highly emetogenic cisplatin-based chemotherapy:a dose-ranging clinical study

BACKGROUND

Although currently available 5-hydroxytryptamine type 3 receptor (5-HT3) antagonists are effective, not all patients receiving these agents achieve adequate control of chemotherapy-induced nausea and vomiting (CINV). Palonosetron, a potent and highly selective 5-HT3 antagonist with a strong affinity for 5-HT3 and a prolonged plasma elimination half-life, may provide a longer duration of action than other approved agents.

PATIENTS AND METHODS

One hundred and sixty-one patients were randomly assigned to receive a single intravenous bolus dose of palonosetron (0.3, 1, 3, 10, 30 or 90 microg/kg) before administration of highly emetogenic chemotherapy, with no pretreatment with corticosteroids.

RESULTS

The four highest doses of palonosetron were similarly effective during the first 24 h, producing clearly higher complete response (CR) (no emesis, no rescue medication) rates in the 3, 10, 30 and 90 microg/kg groups (46%, 40%, 50% and 46%, respectively) than in the 0.3-1 microg/kg group (24%) of evaluable patients (n = 148). The 3 microg/kg dose was identified as the lowest effective dose. A single dose of palonosetron showed prolonged efficacy in preventing delayed emesis, with approximately one-third of patients who received palonosetron 10 or 30 microg/kg maintaining a CR throughout the 7-day period following chemotherapy administration. Dose-proportional increases in pharmacokinetic parameters and a long plasma half-life (43.7-128 h) were observed. Palonosetron was well-tolerated, with no dose-response effect evident for the incidence or intensity of adverse events.

CONCLUSIONS

Palonosetron is an effective and well-tolerated agent for the prevention of CINV following highly emetogenic chemotherapy, with 3 and 10 microg/kg identified as the lowest effective palonosetron doses.

Chemotherapy-induced nausea and vomiting: the importance of acute antiemetic control

Nausea and vomiting are two of the most feared side effects of cancer chemotherapy and radiotherapy. Chemotherapy-induced nausea and vomiting can be broadly categorized as acute (occurring within 24 hours of therapy), delayed (persisting for 6-7 days after therapy), or anticipatory (occurring prior to chemotherapy administration). Breakthrough and refractory nausea and vomiting describe the symptoms of uncontrolled emesis. Evidence suggests that good control of nausea and vomiting during the acute period correlates with the control of delayed emesis. Conversely, protection failure during the first 24 hours has a high predictive value for delayed emesis in the same cycle. The 5-HT(3)-receptor antagonists, regarded as the 'gold standard' in antiemetic therapy, are the first-line treatment for moderately and highly emetogenic chemotherapy and radiotherapy regimens in adults and children. Evidence suggests that the 5-HT(3)-receptor antagonists administered in combination with corticosteroids afford the best protection from symptoms of acute emesis and, by extrapolation, the most effective prevention of delayed emesis. Antiemetic therapeutic guidelines stress that the goal of therapy is to prevent cytostatic-induced nausea and vomiting. Therefore, the prophylactic use of the most effective antiemetic regimen-taking into consideration the emetogenicity of the chemotherapy and individual patient characteristics-must be adhered to in order to prevent acute, delayed, and anticipatory nausea and vomiting.

Benefits and risks of newer treatments for chemotherapy-induced and postoperative nausea and vomiting

Nausea and vomiting are common adverse effects of chemotherapy, radiation therapy, anaesthesia and surgery. The incidence of chemotherapy-induced nausea and vomiting (CINV) is estimated to vary from 30 to 90%, depending on the type of chemotherapeutic agent used. Radiation-induced emesis varies with anatomical site radiated but is estimated to have an overall incidence of approximately 40%. The incidence of postoperative nausea and vomiting (PONV) depends on the type of anaesthesia and surgery, but overall is estimated to be 20-30%. Evidence-based medicine and meta-analysis have been used to direct medical therapy to help determine equivalence, optimal dose, timing, safety and efficacy of antiemetic medications. Concepts such as the number needed to treat and number needed to harm are helpful to guide the clinician regarding the benefits and risks of a particular treatment. The serotonin 5-HT(3) receptor antagonists ondansetron, granisetron, tropisetron and dolasetron have been important additions to the antiemetic armamentarium. The 5-HT(3) receptor antagonists are similar in chemical structure, efficacy and adverse effect profile. They appear to have no important differences among themselves in clinical outcomes for CINV and PONV. Headache, dizziness, constipation and diarrhoea are their most common adverse effects, and when they occur they are usually mild and easily managed. Haemodynamic changes and extrapyramidal adverse effects are uncommon. ECG changes such as prolonged corrected QT (QTc) interval are infrequent, dose-related and overall judged to be clinically insignificant. As most studies with the 5-HT(3) antagonists have been conducted on relatively healthy patients, caution should be exercised when these drugs are used in susceptible patients with co-morbidities. The clinician must weigh the benefit of administering an antiemetic for CINV or PONV against the risk of occurrence of an adverse event.

Granisetron vs ondansetron: is it a question of duration of 5-HT3 receptor blockade?

British Journal of Cancer (2002) 86, 1662–1663. DOI: 10.1038/sj/bjc/6600313www.bjcancer.com

© 2002 Cancer Research UK

Prospective evaluation of antiemetic outcome following high-dose chemotherapy with hematopoietic stem cell support

Considerable progress has been made in improving the control of chemotherapy-induced emesis. The impact of available antiemetic options for patients receiving stem cell transplants is unclear, as few prospective data have been collected. We prospectively evaluated antiemetic outcome in patients receiving stem cell transplantation over a 7-day period following the initiation of chemotherapy. The primary endpoints were the number of emetic episodes and the extent of nausea measured on a four-point scale. Eighty-two patients were evaluated. Ninety-five percent of patients had nausea during the first week of treatment; 80% had at least one emetic episode. The percentage of patients with emesis was as follows: day 1: 13%, day 2: 21%, day 3: 30%, day 4: 38%, day 5: 44%, day 6: 39%, day 7: 18%. In multivariate analysis, gender, emesis with prior chemotherapy, history of morning or motion sickness, type of transplant (auto vs allo), use of total body irradiation, or use of dexamethasone did not effect emesis control. Most patients receiving high-dose chemotherapy experience incompletely controlled emesis. Control of nausea and emesis progressively worsened with each subsequent day following initiation of chemotherapy, reaching a nadir on day 5. New treatment approaches are needed to improve emesis control in this patient population.

Randomized, double-blind, crossover, placebo-controlled trial of intravenous ondansetron for the prevention of intrathecal chemotherapy-induced vomiting in children

BACKGROUND

The purpose of this study was to determine the effectiveness of intravenous ondansetron in preventing vomiting after the administration of intrathecal chemotherapy in children.

PATIENTS AND METHODS

Twenty-six children (ages 18 mo to 15 y) receiving intrathecal chemotherapy with either methotrexate or the combination of methotrexate, hydrocortisone, and Ara-C for the prophylactic treatment of central nervous system leukemia were randomly assigned to receive an infusion of normal saline or ondansetron at one of two doses (0.15 or 0.45 mg/kg) 30 minutes before undergoing the procedure. One hundred forty-six infusions were administered (51 placebo, 47 at the lower ondansetron dose, and 48 at the higher dose). Each patient acted as his or her own control, and each patient was studied at least three times.

RESULTS

Twenty-three of 26 patients (88.5%) had postprocedural vomiting on at least one occasion. At least one episode of vomiting occurred during the 24 hours after the procedure in fifty-two of the procedures (35.6%). The incidence of vomiting was significantly greater after infusion of placebo than after either low-dose or high-dose ondansetron. The likelihood of severe vomiting was even more significantly reduced by the preadministration of ondansetron. Almost all of the intrathecal treatments associated with severe vomiting occurred after the infusion of placebo.

CONCLUSIONS

Vomiting induced by intrathecal chemotherapy can be greatly reduced by the intravenous administration of ondansetron before the procedure, and severe vomiting can be virtually eliminated.

Stratified administration of serotonin 5-HT3 receptor antagonists (setrons) for chemotherapy-induced emesis. Economic implications

The serotonin 5-HT3 receptor antagonists or 'setrons' have become the standard of care for the prevention of chemotherapy-induced emesis (CIE) and are first-line therapy for acute CIE in healthcare organisations worldwide. However, their superior efficacy versus standard antiemetics comes at a significant cost. Currently, 3 agents are available in the US: ondansetron, granisetron and dolasetron. The most important treatment-related factor contributing to CIE is the emetogenicity of chemotherapy. The ability to customise, or stratify, the setron dose to match the emetogenic challenge of the chemotherapy administered has potential benefits, both clinically and economically. In adults, there is an appreciable amount of clinical literature addressing stratified administration; however, the amount of 'hard' economic data is rather limited. Intuitively, if clinical outcomes are equivalent, then stratified administration should be associated with economic benefits, as it generally promotes the use of doses lower than those recommended by the manufacturer. The literature strongly substantiates this for ondansetron, but is not as favourable for granisetron or dolasetron. As the rationale and justification for dose stratification is contained in the clinical literature, the authors have reviewed the pertinent literature supporting the clinical and economic benefits of dose stratification in both adult and paediatric patients. The authors also provide a discussion of various additional strategies that can be employed to ensure the appropriate and cost-effective use of setrons in real-world practice settings. These strategies include the use of lower doses than recommended by manufacturers, use for acute versus delayed phase emesis, enhancing the antiemetic efficacy by the addition of a corticosteroid, use of oral versus injectable formulations (when appropriate) and the implementation and use of local, national and international drug use guidelines.

Randomized, multicenter comparison of oral granisetron and oral ondansetron for emetogenic chemotherapy

STUDY OBJECTIVES

To compare the antiemetic effectiveness and safety of oral granisetron plus dexamethasone with those of oral ondansetron plus dexamethasone administered before emetogenic chemotherapy.

DESIGN

Randomized, prospective, multicenter, open-label study.

SETTINGS

University-teaching hospital and veterans health care system.

PATIENTS

Sixty-one chemotherapy-naïve patients scheduled to receive emetogenic antineoplastic agents.

INTERVENTION

A single-dose oral granisetron 1 mg and dexamethasone 12 mg or single-dose oral ondansetron 16 mg and dexamethasone 12 mg was administered before chemotherapy.

MEASUREMENTS AND RESULTS

Twenty-four hours after administration patients were contacted to assess nausea, emesis, and adverse events. There were no statistical differences in frequency of nausea or emesis between groups. Seventy-six percent and 82% of patients receiving ondansetron and granisetron, respectively, experienced no emesis 24 hours after chemotherapy. Complete protection from nausea occurred in 58% and 46% of patients receiving the drugs, respectively. Adverse events were similar between groups.

CONCLUSION

Oral granisetron 1 mg and ondansetron 16 mg plus dexamethasone are safe and effective in preventing nausea and vomiting related to emetogenic chemotherapy.

Computerized system for outcomes-based antiemetic therapy in children

OBJECTIVE

To introduce a computerized data collection system used for an outcomes-based approach to antiemetic therapy in children, and to present data collected with this system in support of a new antiemetic dosing regimen.

METHODS

A validated nausea/vomiting survey was used to collect data on nausea severity (NSEV), vomiting severity (VSEV), daily activity interference (DAI), and the number of vomiting episodes. NSEV, VSEV, and DAI were rated as 0 = none to 3 = severe. All children and/or their parents were surveyed following the completion of each highly emetogenic chemotherapy regimen. This survey was computerized and transferred to a handheld data entry unit. Time and motion studies were performed to compare the time required to collect nausea/vomiting data and transfer the data to a computerized database with the hand-held system versus traditional paper (manual) surveys. The hand-held technology was used to collect survey data for children receiving a new antiemetic regimen (daily ondansetron and dexamethasone [OD]), which was then compared with data obtained with a previously employed regimen (thrice-daily ondansetron and daily methylprednisolone [OM]). Statistical analysis and a cost-effectiveness analysis (CEA) were performed to compare the two antiemetic regimens.

RESULTS

The mean time required for total data entry with the manual system was 5.2 minutes per survey versus 2.4 minutes with the hand-held technology (p = 0.0026). A total of 376 nausea/vomiting surveys in 78 children receiving the OM antiemetic regimen were compared with 153 surveys in 38 children treated with the OD regimen. The mean survey scores were as follows: NSEV (1.2 vs. 0.8), VSEV (1.0 vs. 0.7), DAI (1.0 vs. 0.7), and number of vomiting episodes (4.3 vs. 2.1) for OM and OD, respectively; all were significantly lower with the OD regimen (p < 0.05). The percentage of patients with complete control of nausea and vomiting (19.2% vs. 39.2%) and good control (55.6% vs. 65.4%) were significantly greater with the OD regimen (p < 0.05). The CEA revealed that the OD resulted in a reduction of approximately $31 per patient for good protection and a $258 reduction for complete protection from nausea and vomiting.

CONCLUSIONS

A computerized outcomes-based system aided by handheld technology allowed for more prompt and efficient collection of nausea/vomiting data. The OD antiemetic regimen was shown to be a more cost-effective alternative for children receiving severely emetogenic chemotherapy.

Control of cisplatin-induced emesis with intravenous ondansetron plus intravenous dexamethasone: a crossover study of triple 8-mg dose of ondansetron

Two hundred seventy-five patients were enrolled in one of two arms in a crossover fashion. Arm A: three 8-mg doses of ondansetron intravenous (IV) were given at 4-hour intervals plus dexamethasone 20 mg IV from the start of chemotherapy followed by dexamethasone 5 mg IV every 12 hours. Arm B: as in arm A but with three 8-mg doses of ondansetron IV were given at 24-hour intervals substituted for ondansetron IV given at 4-hour intervals. There were 237 patients in arm A and 223 patients in arm B. Complete protection from acute and delayed vomiting/nausea obtained in arm A was 94.5%/90.3% and 71.3%/57.8%, respectively; protection obtained in arm B was 92.7%/91.0% and 71.7%/60.5%, respectively. No differences were observed in control of acute emesis after the addition of dexamethasone to ondansetron, given as either a triple 8-mg dose at 4-hour intervals or a single 8-mg dose. The triple dose of ondansetron given at 24-hour intervals was also not more effective than ondansetron given at 4-hour intervals in preventing delayed emesis when dexamethasone was added. However, the former improved control of delayed nausea on day 2. Adverse events tended to be minor, with constipation and hiccup the most common.

Advances in use of the 5-HT3 receptor antagonists

Nausea and vomiting continue to rank as important side effects for cancer patients receiving chemotherapy. The class of drugs known as the 5-HT3 receptor antagonists have become widely used for chemotherapy-induced nausea and vomiting, and are considered a standard part of care for moderately- and highly-emetogenic chemotherapy in combination with corticosteroids. Ondansetron (Zofran, Glaxo Wellcome), granisetron (Kytril, SmithKline Beecham) and dolasetron (Anzemet, Hoechst Marion Roussel) are commercially available in the US. Intravenous forms of all three drugs have demonstrated efficacy in preventing acute (< or = 24 h following chemotherapy) nausea and emesis due to moderately- and highly-emetogenic chemotherapy. Oral forms of the drugs have been shown to be effective in prevention of nausea and emesis due to moderately-emetogenic chemotherapy. More recently, oral 5-HT3 receptor antagonists have demonstrated efficacy in the prevention of nausea and vomiting due to highly-emetogenic chemotherapy as well. Comparative trials between the three agents have shown no clinically important differences in outcome and they should be considered clinically equivalent. Optimal oral anti-emetic regimens for high-dose chemotherapy with bone marrow or stem cell transplantation remain to be determined and future oral studies should target this population. In general, the decision of which 5-HT3 receptor antagonist to select for formulary inclusion should be based on the dose of anti-emetic used and the acquisition cost of the agents being compared. The oral route should be used whenever possible.

Randomized double-blind comparison of single high-dose ondansetron and multiple standard-dose ondansetron in chemotherapy-naive pediatric oncology patients

This prospective, double-blind, randomized study compares the antiemetic efficacy of an equivalent dose of ondansetron administered as a single high dose or as multiple standard doses in pediatric oncology patients. Thirty-one chemotherapy-naive patients were randomized at diagnosis to receive either single high-dose ondansetron (0.6 mg/kg, maximum dose 32 mg) or multiple standard-dose ondansetron (0.15 mg/kg, maximum dose 8 mg, every 4 hr for four doses). Antiemetic efficacy was assessed by an emesis scale described as follows: 1, no nausea or emesis; 2, nauseous but able to eat; 3, nauseous and unable to eat; and 4, emesis. Sixteen patients received high-dose and 15 received standard-dose ondansetron. Patients receiving moderately or severely emetogenic chemotherapy were evenly distributed between the two treatment groups. Eighty-one percent of patients receiving high-dose and 80% receiving standard-dose ondansetron rated 1 or 2 on the emesis scale (p = 0.93). No patient experienced any clinical or laboratory toxicity. Our study suggests that single high-dose ondansetron is as efficacious as the multiple standard-dose regimen and is well tolerated. Its use will facilitate the administration of ondansetron in pediatric patients receiving chemotherapy.

Guidelines for anti-emetic therapy: acute emesis

Anti-emetic therapy has become integral to the management of patients with cancer. Goals related to complete emesis control include providing treatment that reduces hospitalisation and time in the ambulatory setting, care that is convenient for the patient and therapy that enhances patients' quality of life. A panel of clinical, health economic and basic scientists with expertise in various oncology disciplines reviewed published literature to develop evidence-based consensus guidelines for the prevention and treatment of chemotherapy-induced emesis. Currently, serotonin receptor antagonists and corticosteroids are the two categories of anti-emetics that are most effective, have the fewest side-effects and are convenient to use. These agents are recommended in combination for highly emetogenic chemotherapy regimens and as single agents or in combination for moderately to highly emetogenic chemotherapy. When possible, these agents may be given orally in single doses; current evidence does not support dose escalation for either category of anti-emetics. In special situations, such as the use of high-dose chemotherapy combination regimens, the most emetogenic component of the regimen should dictate the choice of anti-emetic. Appropriate anti-emetic use described in these guidelines represents both good medical practice and a sensible economic approach to care.

A risk-benefit assessment of serotonin 5-HT3 receptor antagonists in antineoplastic therapy-induced emesis

Insight into the pathophysiology of antineoplastic therapy-induced nausea and vomiting led to the development of the serotonin 5-HT3 receptor antagonists as the most potent class of antiemetic agents. Among those which have been investigated are ondansetron, granisetron, tropisetron and dolasetron. A risk-benefit analysis of these drugs must not only account for the modest clinical differences in efficacy and tolerability, but also should include such issues as ease of use, route of administration, dosage considerations and patient preference. Pharmacokinetic and preclinical studies reveal distinctions among these antiemetics, but, overall, these distinctions do not translate in to clinically significant differences. In clinical trials, the most widely studied members of the 5-HT3 receptor antagonists are granisetron and ondansetron, which have been found to possess equivalent antiemetic efficacy. Dolasetron and tropisetron are also available, and some randomised trials have also documented their similar antiemetic activity, depending on the doses and schedules used. The equivalent efficacy of oral granisetron 2 mg versus intravenous ondansetron 32 mg has recently been demonstrated in prospective randomised clinical trials in patients receiving either highly emetogenic or moderately emetogenic antineoplastic therapy. The utilisation and efficacy of oral ondansetron and dolasetron in patients receiving moderately emetogenic antineoplastic therapy has also been documented. This review offers a brief overview of the pharmacokinetic and preclinical research on the 5-HT3 antagonists, a review of the comparative clinical trials of the major members of this class and a summary risk-benefit assessment that considers clinical applicability and cost, as well as efficacy and safety.

5-HT3 receptor antagonists: differences and similarities

Differences among 5-HT3 receptor antagonists have been reported in pharmacological studies with regard to selectivity of receptor binding, potency, duration of action and dose-response curves. However, whether these pharmacological differences can affect clinical efficacy and safety remains to be determined. A careful analysis of the literature revealed 22 comparative studies among the 5-HT3 receptor antagonists available for review. Unfortunately, several of these trials have some important shortcomings especially in the study design, the size of population studied and the type of anti-emetic treatment selected, making their conclusions often difficult to interpret. However, among these studies, seven large, double-blind clinical trials have clearly shown that the antiemetic activity and tolerability of ondansetron, granisetron, tropisetron and dolasetron is almost identical at least in the prevention of cisplatin-induced emesis. Therefore, from the efficacy and safety point of view, there is no reason to prefer one with respect to the other compound. From the economic perspective, instead, differences may exist and they are strictly related to the dose and schedule of administration chosen for each compound. The information available on the use of 5-HT3 receptor antagonists in the prevention of emesis induced by moderately emetogenic chemotherapy is at best scant. Contrasting results have been reported and only one well-conducted study has been published in full. Therefore, the possible differences among the various compounds are difficult to evaluate. More studies should be carried out in this group of patients.

Standard treatment of chemotherapy-induced emesis

Major breakthroughs in the treatment of chemotherapy-induced emesis have come through the use of selective 5-HT3 receptor antagonists in combination with corticosteroids. This combination can be considered standard for most but not all commonly used chemotherapeutic agents. Delayed-onset emesis remains a problem, particularly for patients receiving high-dose cisplatin. There is debate over the value of using selective 5-HT3 receptor antagonists beyond the first 24 h. Clinical trials have not settled this uncertainty, although it seems likely that they add only modestly to the effect of corticosteroids. For both the acute and delayed phases, dopamine receptor antagonists may add to the effectiveness of antiemetic therapy. This article outlines a strategy for initial antiemetic therapy and the rationale for the recommendations.

Innovative approaches in the treatment of emesis

Over the last 15 years, appreciation of the role of dopaminergic (D2) receptors and serotonergic (5-HT3) receptors has led to the development of a series of highly effective antiemetic agents. However, in spite of the suggestion of additional significant receptors (such as the NK-1 receptor and the opiate mu receptor), recent innovations in antiemetic treatment have concentrated on refinement of schedule, route, and dose. Single-dose regimens and oral formulations improve the convenience of antiemetic administration, while identification of the minimum effective dose has important economic implications. Involvement of experienced supportive care investigators in objective determination of utility scores for various supportive care modalities will be vital for rational inclusion of supportive care in pharmacoeconomic analysis, critical pathways, and clinical guidelines.

Oral ondansetron 8 mg twice daily is as effective as 8 mg three times daily in the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy. S3A-376 Study Group

The efficacy and safety of ondansetron 8 mg BID compared with 8 mg TID for 3 days in the prevention of nausea and vomiting in 402 patients on cyclophosphamide (> or = 500 mg/m2)-based chemotherapy were evaluated in a multicenter, randomized, double-blind, stratified study. The percentage of patients with no emetic episodes over the 3-day study period was 61% in the ondansetron BID group compared with 58% in the ondansetron TID group. Among patients with at least one emetic episode, the mean time to emesis was 14 hr and 17 min in the ondansetron BID group compared with 12 hr and 48 min in the ondansetron TID group. Patients' daily appetite ratings and nausea scores were not significantly different between groups. Clinical laboratory and adverse event profiles were similar between groups. This study is the first large-scale, double-blind trial to demonstrate that ondansetron 8 mg BID for 3 days, a dosing regimen that may enhance patient convenience and compliance, is as effective as ondansetron 8 mg TID for 3 days in the prevention of nausea and vomiting associated with cyclophosphamide-based chemotherapy.

Ethical issues regarding study designs used in serotonin-antagonist drug development

The time has come to develop new methods for the evaluation of antiemetic compounds. The well-established tenet that combination antiemetic therapy is superior to that achieved with any single agent for severely emetogenic cisplatin-containing chemotherapy does not warrant reevaluation with future cancer patients whenever a new antiemetic enters Phase II and III evaluation. New trials should instead focus on the more important issues of whether the new agent in combination offers comparable or superior efficacy to that achievable with the current standard antiemetic regimen for both acute and delayed nausea and vomiting. While proof of efficacy is crucial in drug trials, adequacy of patient care needs to be the first and foremost priority in any trial.

An increased loading dose of ondansetron: a north european, double-blind randomised study in children, comparing 5 mg/m2 with 10 mg/m2

A North European, randomised, double-blind study, comparing a loading-dose of ondansetron of 5 mg/m2 with 10 mg/m2, administered intravenously before highly emetogenic chemotherapy, was carried out in 187 chemotherapy-naïve children. In the first 24 h, both groups received further ondansetron intravenously at a dose of 5 mg/m2 8-hourly. Thereafter, ondansetron was given at an oral dose of 4 or 8 mg depending on the surface area of the child, three times a day and continued for at least 3 days after the last day of chemotherapy. There was no difference in the control of emesis between the two groups. Ondansetron provided good control of emesis and nausea on day 1 with 71-72% of patients experiencing two or fewer emetic episodes (complete or major responders) and 90-86% of patients reporting nausea as none or mild. There was also no difference in the efficacy of the treatment arms in the control of emesis and nausea on subsequent days of the study period. Both anti-emetic regimens were well-tolerated.

Comparative studies of various antiemetic regimens

Since 1981, when high-dose intravenous metoclopramide was demonstrated to be efficacious, slow but constant improvement in the prevention of chemotherapy-induced emesis has been achieved. Today, a combination of a serotonin receptor 3 (5-HT3) antagonist plus dexamethasone can be considered the most efficacious treatment for the prevention of emesis induced by cisplatin and by moderately emetogenic chemotherapy. Which 5-HT3receptor antagonist should be used? Preclinical differences among 5-HT3receptor antagonists have been reported with regard to selectivity of receptor binding, potency, dose response, and duration of action. Twelve comparative studies among 5-HT3receptor antagonists have been carried out. Unfortunately, all these trials have some important shortcomings (patient population not large enough to show small but clinically important differences; not blinded studies; no association with steroids to maximize treatment efficacy) and, therefore, no definitive conclusions can be drawn. Very recently three large, well-conducted double-blind comparative studies have been published. All three showed that 5-HT3receptor antagonists have almost identical antiemetic efficacy and tolerability. Therefore, the choice among the 5-HT3receptor antagonists should be based only on the acquisition cost of the prescribed dose in each country for each compound.

Efficacy and tolerability of oral ondansetron versus prochlorperazine in the prevention of emesis associated with cyclophosphamide-based chemotherapy and maintenance of health-related quality of life

This study compared the efficacy and tolerability of oral ondansetron (8 mg twice daily [BID] for up to 3 days) with those of phenothiazine prochlorperazine (10 mg BID for up to 3 days) in 133 cancer patients receiving cyclophosphamide-based chemotherapy. In addition, the study evaluated the impact of these treatments on patients' health-related quality of life, measured with both the Functional Living Index-Cancer and the Functional Living Index-Emesis questionnaires. The first dose of study drug was administered 30 minutes before initiation of chemotherapy. Patients received a rescue antiemetic at their request or if the investigator deemed it necessary. There was a statistically significant difference in the number of patients with no emetic episodes over the 3-day study period: 60% in the ondansetron group compared with 21% in the prochlorperazine group. Twenty-five percent of ondansetron-treated patients compared with 68% of prochlorperazine-treated patients experienced three or more emetic episodes, rescue medication use, or withdrawal from the study due to emesis or adverse events. Among patients with at least one emetic episode, the mean time to emesis was significantly longer (13 hours and 37 minutes) in the ondansetron group compared with the prochlorperazine group (9 hours and 30 minutes). Nausea and appetite scores did not differ significantly between groups. The score on the vomiting subscale of the Functional Living Index-Emesis was significantly more favorable in the ondansetron group compared with the prochlorperazine group, indicating better maintenance of health-related quality of life in ondansetron-treated patients. Both treatments were well tolerated. The most common potentially drug-related adverse event was headache, which occurred in significantly more (16%) ondansetron-treated patients compared with prochlorperazine-treated patients (3%). The results of this study demonstrate that oral ondansetron 8 mg BID for up to 3 days is more effective than prochlorperazine 10 mg BID for up to 3 days in the prevention of emesis associated with moderately emetogenic chemotherapy.

Differences in nausea, vomiting, and retching between younger and older outpatients receiving cancer chemotherapy

The purpose of this study was to determine whether there were differences in the side effects of nausea, vomiting, and retching (N, V, and R) between younger ( < 65 years, n = 102) and older ( > or = 65 years, n = 25) persons receiving outpatient chemotherapy. A longitudinal 4-month study was used for the 127 participants recruited from 18 settings. Participants completed two questionnaires (Inventory of N, V, and R and Behavior Checklist) over the course of the study. The pattern between the younger and older patients' N, V, and R subscale scores was consistent in that the younger patients' scores were consistently (except on one occasion) higher than the older patients' scores, but this difference was statistically insignificant. This study furthers our understanding of N, V, and R and has several clinical implications.

Efficacy and tolerability of oral ondansetron versus prochlorperazine in the prevention of emesis associated with cyclophosphamide-based chemotherapy and maintenance of health-related quality of life

This study compared the efficacy and tolerability of oral ondansetron (8 mg twice daily [BID] for up to 3 days) with those of phenothiazine prochlorperazine (10 mg BID for up to 3 days) in 133 cancer patients receiving cyclophosphamide-based chemotherapy. In addition, the study evaluated the impact of these treatments on patients' health-related quality of life, measured with both the Functional Living Index--Cancer and the Functional Living Index--Emesis questionnaires. The first dose of study drug was administered 30 minutes before initiation of chemotherapy. Patients received a rescue antiemetic at their request or if the investigator deemed it necessary. There was a statistically significant difference in the number of patients with no emetic episodes over the 3-day study period: 60% in the ondansetron group compared with 21% in the prochlorperazine group. Twenty-five percent of ondansetron-treated patients compared with 68% of prochlorperazine-treated patients experienced three or more emetic episodes, rescue medication use, or withdrawal from the study due to adverse events or lack of efficacy of the study drug. Among patients with at least one emetic episode, the mean time to emesis was significantly longer (13 hours and 37 minutes) in the ondansetron group compared with the prochlorperazine group (9 hours and 30 minutes). Nausea and appetite scores did not differ significantly between groups. The score on the vomiting subscale of the Functional Living Index--Emesis was significantly more favorable in the ondansetron group compared with the prochlorperazine group, indicating better maintenance of health-related quality of life in ondansetron-treated patients. Both treatments were well tolerated. The most common potentially drug-related adverse event was headache, which occurred in significantly more (16%) ondansetron-treated patients compared with prochlorperazine-treated patients (3%). The results of this study demonstrate that oral ondansetron 8 mg BID for up to 3 days is more effective than prochlorperazine 10 mg BID for up to 3 days in the prevention of emesis associated with moderately emetogenic chemotherapy.

An open randomised cross-over study on granisetron versus ondansetron in the prevention of acute emesis induced by moderate dose cisplatin-containing regimens

The aim of the study was to compare granisetron (GRA) with ondansetron (OND) in the prevention of acute emesis in consecutive chemotherapy-naive patients admitted to our department to receive a cytotoxic treatment containing cisplatinum (CP) at a dose > or = 50 mg/m2. Eligible patients were randomised at their first cycle to receive either OND or GRA with cross-over of the anti-emetic treatment on the second cycle. The cytotoxic treatments included five different multidrug regimens containing CP (median dose 60 mg/m2, range 50-70 mg/m2) administered on day 1 and repeated every 21-28 days. OND was administered at the dose of 8 mg x 3 i.v. on day 1 and 8 mg x 2 orally on day 2. GRA was always administered at the dose of 3 mg i.v. on day 1. 124 patients entered the study. 58 patients received OND at their first cycle and 66 received GRA. Complete protection of acute emesis with OND and GRA was observed, with the first and second cycles combined as follows: nausea 53 and 60%, vomiting 68 and 71%, respectively (no statistically significant difference). The cross-over analysis comprising 101 patients confirmed no difference between the two anti-emetic treatments. 21 patients (19%) on OND and 14 patients (12%) on GRA suffered headaches (P = 0.15). 25 (25%) patients preferred OND, 45 (45%) preferred GRA, while 31 (30%) expressed no preference (P = 0.003). However, these differences also depended on the sequence of anti-emetics in the cross-over. In conclusion, in this study, a single dose of GRA is demonstrated to be as effective as multiple doses of OND in the prevention of acute emesis.

Antiemetic Therapy in the Outpatient Oncology Setting

Nausea and vomiting (N/V) are well-recognized and potentially serious complications of cancer chemotherapy that can significantly impact therapeutic outcomes and overall quality of life. As the management of cancer patients moves to the outpatient setting, therapeutic strategies for N/V control must be adapted accordingly. The purpose of this article is to provide an overview of the pathophysiology and basic principles of N/V management and the available antiemetic agents, with an emphasis on applications in outpatient oncology. Development of antiemetic guidelines promotes selection of appropriate antiemetics to maximize N/V control, while minimizing associated cost. Use of oral antiemetics when possible also significantly reduces the cost of N/V management, without compromising therapeutic efficacy. In addition to designing an appropriate treatment regimen, measures for the early evaluation of N/V outcomes must also be instituted. Pharmacists can have an important role in ensuring optimal control of N/V in cancer patients.

Comparative efficacy of a single oral dose of ondansetron and of buspirone against cisplatin-induced emesis in cancer patients

Buspirone, an agonist of the 5-HT1A subtype of serotonin receptors, has shown antiemetic activity in animal models. However, in cancer patients treated with cisplatin, ondansetron, given either i.v. (one 8-mg dose 30 min after cisplatin) or orally (one 16-mg dose at the end of cisplatin infusion) was superior (P < 0.001) to buspirone (60 mg p.o. at the end of cisplatin and 60 mg p.o., 30 min later), in all parameters of antiemetic efficacy. These results are in favour of 5-HT3 receptors, but against the participation of 5-HT1A receptors in acute emesis associated with cisplatin chemotherapy.

5-HT3 receptors: pharmacologic and therapeutic aspects

The serotonin 5-HT3 receptor is unique among the seven serotonin receptor "families" that have been recognized so far. It functions not as a G-protein coupled but as a direct ion channel gated receptor. Because of the varied neural functions linked to this receptor, intensive research interest has developed in recent years about its basic and clinical pharmacology, which are summarized in this review. Some new agonists and many new antagonists have been developed. These agents have a useful role as selective pharmacologic research probes, and some of them can be used therapeutically as potent and selective anti-nausea and antiemetic drugs, particularly in patients undergoing cancer chemotherapy treatment or general anesthesia procedures. Potential applications of these agents include the treatment of some behavioral disorders in mental disease, drug addiction, and certain types of pain syndromes.