Granisetron. A review of its pharmacological properties and therapeutic use as an antiemetic

Access to Fully Substituted Dihydroindazoles Via Hexadehydro-Diels-Alder/[3 + 2] Cycloaddition

A cascade hexadehydro-Diels-Alder (HDDA)/[3 + 2] cycloaddition reaction between tetrayne and N,N'-cyclic acylhydrazone is described. This strategy allows the efficient construction of fully substituted 2,3-dihydro-1H-indazole scaffolds which have insecticidal activity against the third instar larvae of Mythimna separata.

Comprehensive Analysis of Adverse Events Induced by PARP Inhibitors Using JADER and Time to Onset

Poly (ADP-ribose) polymerase (PARP) inhibitors are effective against breast cancer susceptibility gene (BRCA) mutations. Clinical trials have reported hematologic toxicity and gastrointestinal symptoms as class effects of PARP inhibitors. However, information on adverse events (AEs) in a Japanese clinical cohort is currently lacking. In this study, we conducted a comprehensive survey of the AEs of two PARP inhibitors, olaparib and niraparib, using the Japanese Adverse Reaction Reporting (JADER) database provided by the Pharmaceuticals and Medical Devices Agency (PMDA). Moreover, we also analyzed the course and time to the onset of AEs. Signals were detected for 15 and 11 AEs for olaparib and niraparib, respectively. Most occurred within the first month of treatment with either agent. These results may indicate the importance of early response and monitoring after beginning PARP inhibitor therapy. The results of this study may be useful for managing side effects and suggesting supportive care for patients using PARP inhibitors in the future.

Dynamic in vitro intestinal barrier model coupled to chip-based liquid chromatography mass spectrometry for oral bioavailability studies

In oral bioavailability studies, evaluation of the absorption and transport of drugs and food components across the intestinal barrier is crucial. Advances in the field of organ-on-a-chip technology have resulted in a dynamic gut-on-a-chip model that better mimics the in vivo microenvironment of the intestine. Despite a few recent integration attempts, ensuring a biologically relevant microenvironment while coupling with a fully online detection system still represents a major challenge. Herein, we designed an online technique to measure drug permeability and analyse unknown product formation across an intestinal epithelial layer of Caco-2 and HT29-MTX cells cultured on a flow-through Transwell system, while ensuring the quality and relevance of the biological model. Chip-based ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was coupled to the dynamic Transwell system via a series of switching valves, thus allowing alternating measurements of the apical and basolateral sides of the in vitro model. Two trap columns were integrated for online sample pre-treatment and compatibility enhancement. Temporal analysis of the intestinal permeability was successfully demonstrated using verapamil as a model drug and ergotamine epimers as a model for natural toxins present in foods. Evidence was obtained that our newly developed dynamic system provided reliable results versus classical static in vitro models, and moreover, for the first time, epimer-specific transport is shown for ergotamine. Finally, initial experiments with the drug granisetron suggest that metabolic activity can be studied as well, thus highlighting the versatility of the bio-integrated online analysis system developed. Graphical abstract.

Gating of long-term potentiation (LTP) in the thalamocortical auditory system of rats by serotonergic (5-HT) receptors

The neuromodulator serotonin (5-hydroxytryptamine, 5-HT) plays an important role in controlling the induction threshold and maintenance of long-term potentiation (LTP) in the visual cortex and hippocampus of rodents. Serotonergic fibers also innervate the rodent primary auditory cortex (A1), but the regulation of A1 plasticity by 5-HT receptors (5-HTRs) is largely uncharted. Thus, we examined the role of several, predominant 5-HT receptor classes (5-HT_1ARs, 5-HT₂Rs, and 5-HT₃Rs) in gating in vivo LTP induction at A1 synapses of adult, urethane-anesthetized rats. Theta-burst stimulation (TBS) applied to the medial geniculate nucleus resulted in successful LTP induction of field postsynaptic potentials (fPSPs) generated by excitation of thalamocortical and intracortical A1 synapses. Local application (by reverse microdialysis in A1) of the broad-acting 5-HTR antagonist methiothepin suppressed LTP at both thalamocortical and intracortical synapses. In fact, rather than LTP, TBS elicited long-term depression during methiothepin application, an effect that was mimicked by the selective 5-HT₂R antagonist ketanserin, but not the 5-HT_1AR blocker WAY 100635. Interestingly, antagonism of 5-HT₃Rs by granisetron selectively blocked LTP at thalamocortical, but not intracortical A1 synapses. Further, in the absence of TBS, granisetron application resulted in a pronounced increase in fPSP amplitude, suggesting that 5-HT₃Rs play an important role in regulating baseline (non-potentiated) transmission at A1 synapses. Together, these results indicate that activation of 5-HT₂Rs and 5-HT₃Rs, but not 5-HT_1ARs, exerts a clear, facilitating effect on LTP induction at A1 synapses, allowing 5-HT to act as a powerful regulator of long-term plasticity induction in the fully matured A1 of mammalian species.

Building a 5-HT3A Receptor Expression Map in the Mouse Brain

Of the many serotonin receptors, the type 3 receptors (5-HT3R) are the only ionotropic ones, playing a key role in fast synaptic transmission and cognitive and emotional brain function through controlled neuronal excitation. To better understand the various functions of 5-HT3Rs, it is very important to know their expression pattern in the central nervous system (CNS). To date, many distributional studies have shown localized 5-HT3R expression in the brain and spinal cord. However, an accurate pattern of 5-HT3R expression in the CNS remains to be elucidated. To investigate the distribution of 5-HT3R in the mouse brain in detail, we performed immunofluorescent staining using 5-HT3AR-GFP transgenic mice. We found strong 5-HT3AR expression in the olfactory bulb, cerebral cortex, hippocampus, and amygdala; and partial expression in the pons, medulla, and spinal cord. Meanwhile, the thalamus, hypothalamus, and midbrain exhibited a few 5-HT3AR-expressing cells, and no expression was detected in the cerebellum. Further, double-immunostaining using neural markers confirmed that 5-HT3AR is expressed in GABAergic interneurons containing somatostatin or calretinin. In the present study, we built a 5-HT3AR expression map in the mouse brain. Our findings make significant contributions in elucidating the novel functions of 5-HT3R in the CNS.

Palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles and other heteroarenes using chloroform as a carbon monoxide source

A palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles and other heterocycles utilizing CHCl₃ as the carbonyl source has been developed for the straightforward incorporation of an amide functional group.

A comparison of the safety and efficacy of ondansetron versus granisetron as prophylaxis against chemo/ radiotherapy-induced nausea and vomiting in bone marrow transplantation patients. A double-blinded, randomized, prospective, pilot study

Introduction. Nausea and vomiting (N&V) are well known and distressing side effects of chemoradio therapy. Conditioning protocols for patients undergo ing bone marrow transplantation (BMT) consist of highly emetogenic high-dose chemotherapy with or without total body irradiation (TBI). The 5HT3 (sero tonin receptor) antagonists heralded a marked im provement in controlling chemotherapy-induced N&V. Ondansetron and granisetron have been avail able for some time with limited information available concerning their pharmacological and pharmacoeco nomic differences and patient acceptability.

Patients and Methods. This pilot study initiated comparison of the two drugs and evaluated the antiemetic efficacy and safety of a single daily dose of ondansetron, 16 mg, plus dexamethasone, 10 mg, compared to granisetron, 3 mg, plus dexamethasone, 10 mg, in patients receiving high dose chemotherapy (±TBI), prior to BMT. The 12-month pilot study was double-blinded, randomized, and prospective. A non- homogenous cohort of 23 patients (10 receiving ondansetron and 13 granisetron) were enrolled.

Results. No significant differences in the efficacy of the two protocols were observed. In each arm about 50% of the patients had a complete response, and a similar number had a major response.

Side Effects. The most common adverse events reported during the study included diarrhea and head ache. No patients were withdrawn due to side effects.

Conclusions. Our preliminary findings suggest that both of these two antiemetic protocols are safe and similarly effective in preventing chemotherapy-induced emesis in patients receiving BMT conditioning.

Discussion. Further evaluation in a multicenter study should now be made to compare efficacy, safety, cost-effectiveness, and quality of life parame ters of these two drugs.

Chemical composition of Nigella sativa Linn: Part 2 Recent advances

The black cumin or Nigella sativa L. seeds have many acclaimed medicinal properties such as bronchodilatory, hypotensive, antibacterial, antifungal, analgesic, anti-inflammatory and immunopotentiating. This review article is an update on the previous article published on Nigella sativa L. in this journal in 1999. It covers the medicinal properties and chemical syntheses of the alkaloids isolated from the seeds of the herb.

A Robust Protocol for Pd(II)-catalyzed C-3 Arylation of (1H) Indazoles and Pyrazoles: Total Synthesis of Nigellidine Hydrobromide

C3-arylated indazole and pyrazoles are privileged structural motifs in agrochemicals and pharmaceuticals. C-3 C-H arylation of (1H) indazole and pyrazole has been a significant challenge due to the poor reactivity of the C-3 position. Herein, we report a practical Pd(II)/Phen catalyst and conditions for direct C-3 arylation of indazole and pyrazole with ArI or ArBr without using Ag additives as halide scavengers. The use of toluene, chlorobenzene, trifluoromethylbenzene and mesitylene as the solvent was found to be crucial for the selectivity and reactivity. We further demonstrate the robustness of this protocol through the first total synthesis of Nigellidine hydrobromide as well as expedient preparation of heterocycles structurally related to pesticides and drug molecules.

Transdermal granisetron: a guide to its use in preventing nausea and vomiting induced by chemotherapy

Transdermal granisetron (Sancuso®) is effective in the prevention of nausea and vomiting in patients with cancer who are receiving moderately or highly emetogenic chemotherapy for 3-5 days. Transdermal granisetron is noninferior to oral granisetron in this indication, and is generally well tolerated in this indication. Thus, transdermal granisetron provides a convenient option for the prevention of chemotherapy-induced nausea and vomiting, with the potential to improve patient compliance.

Treating nausea and vomiting in palliative care: a review

Nausea and vomiting are portrayed in the specialist palliative care literature as common and distressing symptoms affecting the majority of patients with advanced cancer and other life-limiting illnesses. However, recent surveys indicate that these symptoms may be less common and bothersome than has previously been reported. The standard palliative care approach to the assessment and treatment of nausea and vomiting is based on determining the cause and then relating this back to the "emetic pathway" before prescribing drugs such as dopamine antagonists, antihistamines, and anticholinergic agents which block neurotransmitters at different sites along the pathway. However, the evidence base for the effectiveness of this approach is meager, and may be in part because relevance of the neuropharmacology of the emetic pathway to palliative care patients is limited. Many palliative care patients are over the age of 65 years, making these agents difficult to use. Greater awareness of drug interactions and QT(c) prolongation are emerging concerns for all age groups. The selective serotonin receptor antagonists are the safest antiemetics, but are not used first-line in many countries because there is very little scientific rationale or clinical evidence to support their use outside the licensed indications. Cannabinoids may have an increasing role. Advances in interventional gastroenterology are increasing the options for nonpharmacological management. Despite these emerging issues, the approach to nausea and vomiting developed within palliative medicine over the past 40 years remains relevant. It advocates careful clinical evaluation of the symptom and the person suffering it, and an understanding of the clinical pharmacology of medicines that are available for palliating them.

Antiemetics in cancer chemotherapy

Progress has been made in the prevention of chemotherapy-induced nausea and vomiting but it remains a major problem.

Treatment of nausea and vomiting in terminally ill cancer patients

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

Quantification of granisetron in human plasma by liquid chromatography coupled to electrospray tandem mass spectrometry

A simple, sensitive and rapid high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the assay of granisetron in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reversed-phase C18 column and analyzed by MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 313/138 for granisetron and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 0.1-20 ng/mL for granisetron in human plasma. The lower limit of quantification was 100 pg/mL with a relative standard deviation of less than 5%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.0 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.

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.

Prevention and Management of Chemotherapy-Induced Nausea and Vomiting, Part 2

Credit

This lesson is good for 0.3 CE units, with a passing grade of 70%.

Goal

The goal of this program is to inform the participant about cost-effective 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 chemotherapy-induced 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 when 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.

Distribution of [3H]GR65630 binding in human brain postmortem

We investigated the distribution of serotonin (5-HT) receptors of type 3 (5-HT3) in human brain areas, by means of the the specific binding of [3H]GR65630. The brains were obtained during autoptic sessions from 6 subjects. Human brain membranes and the binding of [3H]GR65630 were carried out according to standardized methods. The highest density (Bmax +/- SD, fmol/mg protein) of [3H]GR65630 binding sites was found in area postrema (13.1+/-9.7), followed at a statistically lower level, by nucleus tractus solitarius (6.7+/-3.4), nervus vagus (5.5+/-2.1), striatum (4.8+/-2.4) with a progressive decrease in amygdala, olivar nuclei, hippocampus, olfactory bulbus and prefrontal cortex, and then by the other cortical areas and the cerebellum, where no binding was detected. These observations extend previous findings on the distribution of 5-HT3 receptors and confirm interspecies variations that might explain the heterogeneous properties of 5-HT3 receptors in different animals.

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.

Granisetron (Kytril) plus dexamethasone for antiemetic control in bone marrow transplant patients receiving highly emetogenic chemotherapy with or without total body irradiation

This prospective trial evaluated the efficacy and toxicity of granisetron for antiemetic control in patients receiving high-dose cyclophosphamide (CY)-containing regimens with/without TBI for bone marrow (BM) or peripheral blood stem cell (PBSC) transplantation or PBSC mobilization. Granisetron 1 mg i.v. plus dexamethasone 10 mg i. v. were administered daily 30 min before chemotherapy or radiation for a median of 5 days. Response was defined as the number of emetic episodes per 24 h: complete response, 0 and no emetic rescue; major response, 1-2; minor response, 3-5; failure, >5. One hundred patients were enrolled. Ninety-eight received CY-containing regimens and 26 of these additionally received TBI (12 Gy divided over 4 days). Response was complete on 216 (47%) of a total 456 patient days, major on 222 (49%), minor on 14 (3%), and failure on 4 (1%). Mean number of emetic episodes per patient per day and breakthrough medication required per patient per day was 0.24 (range 0-8) and 0. 40 (range 0-8), respectively. Adverse effects were minimal, with headache (20%) reported most frequently. Based on these results, granisetron plus dexamethasone is an effective and well-tolerated antiemetic regimen in BMT/PBSCT recipients conditioned with high-dose chemotherapy with/without TBI. Bone Marrow Transplantation (2000) 25, 1279-1283.

Comparative review of 5-HT3 receptor antagonists in the treatment of acute chemotherapy-induced nausea and vomiting

Since their introduction, 5-HT3 receptor antagonists have become the agents of choice in the prevention of acute chemotherapy-induced nausea and vomiting and are generally superior to high-dose metoclopramide regimens. The availability of four different agents (ondansetron, granisetron, dolasetron, and tropisetron) within this class has prompted investigations into potential differences between the drugs, which appear to be few. More importantly, the results of recently conducted randomized comparative trials in patients receiving moderately or highly emetogenic chemotherapy have demonstrated similar efficacy. Although study designs and patient populations differed, seven large comparative trials in patients receiving highly emetogenic chemotherapy reported no significant differences in complete or complete plus major response rates among the agents. Similar results were generally reported in trials evaluating patients receiving moderately emetogenic chemotherapy. The safety and tolerability of these agents also appear to be similar. The most common adverse events include headache, gastrointestinal effects, lightheadedness, and sedation. All agents are available in both intravenous and oral dosage forms and may be administered as a single dose.

Open-label comparison of the antiemetic efficacy of single intravenous doses of dolasetron mesylate in pediatric cancer patients receiving moderately to highly emetogenic chemotherapy

BACKGROUND

Nausea and vomiting are among the most unpleasant adverse side effects of cancer therapy.

PROCEDURE

An open-label dose-escalation study was conducted to assess the appropriate intravenous dose of dolasetron for pediatric patients undergoing chemotherapy. Patients received dolasetron in single intravenous doses of 0.6 (n = 10), 1.2 (n = 12), 1.8 (n = 12), or 2.4 (n = 12) mg/kg 30 min before receiving emetogenic chemotherapy. Pharmacokinetic parameters were evaluated at each dose level and efficacy was evaluated over the first 24 hr following the administration of dolasetron.

RESULTS

A complete response was achieved in 10% of patients given 0.6 mg/kg, 25% of patients given 1. 2 mg/kg, 67% of patients given 1.8 mg/kg, and 33% of patients given 2.4 mg/kg. Peak plasma concentrations (Cmax) were observed between 0. 33 and 0.75 hr following dolasetron infusion. Cmax and area under plasma concentration-time (AUC) increased with larger doses of dolasetron, while terminal disposition half-life (t1/2) and apparent clearance (Clapp) were not significantly changed with respect to dose. For 1.8-mg/kg dolasetron, the t1/2 was 4.98 hr and the maximum plasma concentration (tmax) 0.47 hr. Adverse events were mild to moderate. No serious events occurred. Conclusions. This study suggests that a single intravenous dose of 1.8 mg/kg is the optimum single intravenous dose for controlling chemotherapy-induced emesis in pediatric patients.

Safety, tolerability, antiemetic efficacy, and pharmacokinetics of oral dolasetron mesylate in pediatric cancer patients receiving moderately to highly emetogenic chemotherapy

PURPOSE

The safety, antiemetic efficacy, and pharmacokinetics of single oral doses of dolasetron, a new highly selective 5-HT3 receptor antagonist, were evaluated in children with cancer undergoing treatment with moderately to highly emetogenic chemotherapy.

PATIENTS AND METHODS

A total of 32 children, ages 3 to 18 years, were enrolled in a nonrandomized, multicenter, open-label, dose-escalation study. Three oral dose levels (0.6, 1.2, or 1.8 mg/kg) were studied. Safety, efficacy, and pharmacokinetic parameters were assessed over 24 hours at each dosage level.

RESULTS

The most effective dose was 1.8 mg/kg; 60% of the patients achieved a complete or major response (< or =2 emetic episodes in 24 hours). A complete response was achieved in 3 of 9 patients (33%) who received 0.6 mg/kg, 4 of 13 (31%) patients who received 1.2 mg/kg, and 5 of 10 (50%) patients who received 1.8 mg/kg of dolasetron. Overall, dolasetron was well tolerated. Adverse events were mild and similar to those reported in adults. Peak plasma concentrations (Cmax) of dolasetron's active reduced metabolite, MDL 74,156, were dose proportional and occurred, on the average, within 1 hour of oral administration. The half-life (t1/2) in plasma was approximately 6 hours for all dose levels, and the mean clearance (CLapp) was unrelated to dose.

CONCLUSIONS

Oral dolasetron is safe and effective in reducing chemotherapy-induced nausea and vomiting, particularly at the 1.8-mg/kg dose level. These results support further evaluation of oral dolasetron in larger randomized clinical trials in the pediatric cancer population.

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.

Nitrogen-containing heteroalicycles with serotonin receptor binding affinity: development of gastroprokinetic and antiemetic agents

To obtain gastroprokinetic agents with more potent and selective activity than metoclopramide and cisapride, a series of N-(4-benzyl-2-morpholinylmethyl)benzamides were designed and prepared. Their synthesis and structure-activity relationships were described. As a result, mosapride was selected as a promising candidate for potent gastroprokinetic activity with selective 5-HT4 receptor agonistic activity. As an extension to this project, the novel benzamide and the carboxamide derivatives having 1-benzyl-4-methylhexahydro-1,4-diazepine ring in the amine moiety were prepared and evaluated for 5-HT3 receptor antagonistic activity. DAT-582 was identified as an antiemetic agent in cancer chemotherapy. The asymmetric synthesis of DAT-582 and the SAR studies were briefly reviewed. In further modifications of the N-(1-benzyl-4-methylhexahydro-1,4-diazepin-6-yl)benzamides, the novel nicotinamides with 1-ethyl-4-methylhexahydro-1,4-diazepin ring were found to have potent 5-HT3 and dopamine D2 and D3 receptor antagonistic activities and to show weak central nervous system depression and extrapyramidal syndrome. After extensive SARs, AS-8112 was selected as a broad antiemetic agent.

Phenylimidazolidin-2-one derivatives as selective 5-HT3 receptor antagonists and refinement of the pharmacophore model for 5-HT3 receptor binding

A possible bioisosterism between the benzamido and the phenylimidazolidin-2-one moieties has been suggested on the basis of the similarity between the molecular electrostatic potential (MEP) of metoclopramide, a D2 receptor antagonist with weak 5-HT3 receptor antagonist properties, and zetidoline, a D2 receptor antagonist. Starting from this premise, a series of phenylimidazolidin-2-one derivatives bearing a basic azabicycloalkyl or an imidazolylalkyl moiety were synthesized and evaluated for 5-HT3 receptor radioligand binding affinity ([3H]-GR 43,694). In vitro 5-HT3 receptor antagonist activity was tested in the guinea pig ileum assay (GPI). A number of high-affinity ligands were shown to be potent 5-HT3 receptor antagonists in vivo as determined by inhibition of the Bezold--Jarisch reflex in the anesthetized rat. In general, the imidazolylalkyl derivatives were found to be more active than azabicycloalkyls. 1-(3,5-Dichlorophenyl)-3-[(5-methyl-1H-imidazol-4-yl)methyl]imidazoli din-2-one (58), in particular, displayed very high affinity for the 5-HT3 receptor (Ki of 0.038 nM) with a Kb of 5.62 nM in the GPI assay, being more potent than the reference compounds (ondansetron, tropisetron, granisetron, and BRL 46,470) tested. 58 showed an ID50 comparable to that of ondansetron (2.2 micrograms/kg i.v.) in the Bezold--Jarisch reflex. A molecular modeling study based on this structurally novel series of compounds allowed the refinement of previously reported 5-HT3 receptor antagonist pharmacophore models.

Intravenous dolasetron mesilate ameliorates postoperative nausea and vomiting

PURPOSE

To compare the efficacy, safety, and tolerability of dolasetron mesilate with placebo for the treatment of postoperative nausea and vomiting (PONV).

METHODS

In a randomized, multicentre, double-blind, placebo-controlled study 337 adult patients undergoing surgery with general anaesthesia received one of four single, doses of dolasetron mesilate iv (12.5, 25, 50, or 100 mg) or placebo. Study medication was administered postoperatively when the patient reported nausea lasting 10 min or when one emetic episode occurred within two hours of the patient's arrival in the recovery room. Efficacy was assessed by the investigators over the 24-hr study period by recording the number and timing of emetic episodes, the severity of nausea, the timing of administration of escape antiemetic medications, and patients' and investigators' satisfaction with antiemetic therapy.

RESULTS

The study sample was predominately women, and the surgical procedures were primarily gynaecological. All dolasetron mesilate doses produced higher complete response rates than placebo (P < 0.05). Only approximately one-third of dolasetron patients required escape antiemetic medication compared with more than 50% of patients in the placebo group. Both patient and physician satisfaction with dolasetron treatment was high. The most common adverse event was mild or moderate headache for both placebo-treated patients and dolasetron-treated patients. Clinical laboratory results were unremarkable.

CONCLUSION

Single doses of dolasetron mesilate iv, given after the first episode of PONV, were both effective and safe in this adult patient population.

A double-blind, randomized study of two different dosage regimens of intravenous dolasetron in patients receiving high-dose cisplatin chemotherapy

This study compared the antiemetic efficacy and safety of two different intravenous (i.v.) dolasetron dosing regimens in patients receiving their first course of high-dose (> or = 80 mg/m2) cisplatin. Of 30 patients enrolled, 14 received a single i.v. dolasetron dose (0.6 mg/kg) before cisplatin and 16 received a multiple i.v. dose regimen (0.6 mg/kg x 3) given before and after cisplatin. Complete plus major responses were achieved by 71% (10/14) of patients who received single-dose dolasetron and by 50% (8/16) of those who received the multiple-dose regimen. Forty-three percent (6/14) of patients who received the single dose had a complete response compared with 25% (4/16) who received multiple doses. Multiple doses resulted in less nausea at 24 hr following cisplatin; however, differences were not statistically significant. Both regimens were well tolerated, with mild headache (33%) and diarrhea (13%) the most common adverse events. This study demonstrated that a single 0.6-mg/kg dose of dolasetron given before chemotherapy provides equivalent antiemetic efficacy to three 0.6-mg/kg doses given before and after high-dose cisplatin chemotherapy; thus, there was no additional antiemetic benefit by using the multiple-dose regimen.

Antiemetic efficacy of two different single intravenous doses of dolasetron in patients receiving high-dose cisplatin-containing chemotherapy

This randomized, double-blind, parallel-group, multicenter study compared the antiemetic effectiveness, safety, and tolerability of two different intravenous (i.v.) doses of dolasetron mesylate (0.6 and 1.8 mg/kg) in cancer patients receiving their first course of high-dose cisplatin-containing chemotherapy (> or = 75 mg/m2). Efficacy was assessed by recording the timing, number, and severity of emetic episodes in the 24 h following high-dose cisplatin. Safety was evaluated by monitoring adverse events, vital signs, clinical laboratory parameters, and electrocardiograms. Of the 62 patients enrolled in the study, 29 received 0.6 mg/kg of dolasetron mesylate and 33 received 1.8 mg/kg. Patients who received dolasetron mesylate 1.8 mg/kg consistently experienced a greater degree of antiemetic control than those who received 0.6 mg/kg. Complete responses were achieved by 55% of patients who received 1.8 mg/kg compared with 31% for the 0.6-mg/kg group. The 1.8-mg/kg group achieved a significantly (p = 0.039) higher complete/ major response rate than the 0.6-mg/kg group (77% vs 55%, respectively) and a significantly (p = 0.004) longer time to the first emetic episode (> 24 h vs 13.5 h, respectively). More than 80% of patients were either satisfied or very satisfied with dolasetron treatment. The most common adverse events were mild to moderate in intensity, consistent with other studies, and included headache (24.1% of patients) and diarrhea (4.8%). These results demonstrated that a single 1.8-mg/kg i.v. dose of dolasetron mesylate provided effective antiemetic activity in a majority of patients given high-dose cisplatin for the first time and should be evaluated further in clinical trials.

Autoradiographic distribution of [3H]-(S)-zacopride-labelled 5-HT3 receptors in human brain

Autoradiographic binding studies using the 5-HT3 (5-hydroxytryptamine3) receptor radioligand, [3H]-(S)-zacopride (0.5 nM), identified a heterogeneous distribution of specific binding sites (defined by granisetron, 1 microM) throughout the human brain. Highest radiolabelled 5-HT3 receptor densities were detected in discrete nuclei within the brainstem (nucleus tractus solitarius, area postrema, spinal trigeminal nerve nucleus; 50-200 fmol/mg tissue equivalent) with more modest levels of expression in the forebrain (e.g. hippocampus, nucleus accumbens, putamen, caudate; 4-17 fmol/mg tissue equivalent). Within the hippocampal formation, radiolabelled 5-HT3 receptors were differentially distributed with highest levels in the granule cell layer of the dentate gyrus. Saturation studies with [3H]-(S)-zacopride (0.05-16 nM; non-specific binding defined by granisetron, 10 microM) binding to homogenates of human putamen indicated that [3H]-(S)-zacopride (0.05-16 nM; non-specific binding defined by granisetron, 10 microM) binding to homogenates of human putamen indicated that [3H]-(S)-zacopride labelled an apparently homogenous population of binding sites (Bmax = 72 + 7 fmol mg-1 protein, pKd = 8.69 +/- 0.09, Hill coefficient = 0.99 +/- 0.06, mean +/- SEM, n = 4). The pharmacological profile of [3H]-(S)-zacopride binding to homogenates of putamen indicated the selective labelling of the human variant of the 5-HT3 receptor. The marked differences, however, in the pharmacology (e.g. low affinity for D-tubocurarine) and relative distribution (e.g. presence of 5-HT3 receptors in the human extrapyramidal system) of 5-HT3 receptors in the human forebrain when compared with other species further necessitates caution in predicting clinical responses based on data generated in animal models of disease.

Pharmacokinetics of single intravenous and oral doses of dolasetron mesylate in healthy elderly volunteers

Dolasetron mesylate (MDL 73,147EF, Anzemet; Hoechst Marion Roussel, Laval, Canada) is a 5-HT3 receptor antagonist undergoing clinical evaluation for use as an antiemetic agent. The pharmacokinetics of dolasetron and its reduced metabolite (MDL 74,156) were studied after administration of single intravenous and oral doses of dolasetron mesylate 2.4 mg/kg in 18 healthy elderly subjects. Expressed as the dolasetron base, this dose was 1.8 mg/kg. Dolasetron was rapidly metabolized to the reduced metabolite, which appeared in plasma within 10 minutes after intravenous or oral administration. The mean half-life (t1/2) of dolasetron was 0.24 hours after intravenous administration and 0.50 hours after oral administration. The pharmacokinetic parameters of the reduced metabolite were similar after intravenous and oral administration. The apparent absolute bioavailability of the reduced metabolite was 89%, and it had an elimination t1/2 of approximately 7 hours and an apparent volume of distribution (Vd beta) of 4.69 L/kg. Dolasetron was not detected in urine. Metabolites were excreted in urine almost completely within 24 hours of administration. The primary metabolite detected in urine was the (+)-enantiomer of the reduced metabolite, which accounted for 25.35% (+/- 7.79%) and 18.88% (+/- 7.65%) of the intravenous and oral doses, respectively. Hydroxylated metabolites accounted for 5% or less of the total dose via either route. The pharmacokinetics of the reduced metabolite after single intravenous or oral doses in elderly volunteers were consistent with pharmacokinetics observed in both young healthy men and cancer patients receiving high-dose cisplatin chemotherapy. Dosage adjustments of dolasetron mesylate on the basis of age do not appear to be necessary.

Direct plasma liquid chromatographic-tandem mass spectrometric analysis of granisetron and its 7-hydroxy metabolite utilizing internal surface reversed-phase guard columns and automated column switching devices

An alternative on-line automated sample enrichment technique useful for the direct determination of various drugs and their metabolites in plasma is described for rapid development of highly sensitive and selective liquid chromatographic methods using mass spectrometric detection. The method involves direct injection of plasma onto an internal surface reversed-phase (ISRP) guard column, washing the proteins from the column to waste with aqueous acetonitrile, and backflushing the analytes onto a reversed-phase octyl silica column using switching valves. The analytes were detected using a tandem mass spectrometer operated in selected reaction monitoring (SRM) mode using atmospheric pressure chemical ionization (APCI). Use of two ISRP guard columns in parallel configuration allowed alternate injections of plasma samples on these columns for sample enrichment and shortened the column equilibration and LC-MS-MS analysis times, thereby increasing the sample throughput. The total run time, including both sample enrichment and chromatography, was about 6 min. Using this technique, an analytical method was developed for the quantitation of granisetron and its active 7-hydroxy metabolite in dog plasma. Granisetron is a selective 5-HT3 receptor antagonist used in the prevention and treatment of cytostatic induced nausea and vomiting. Recovery of the analytes was quantitative and the method displayed excellent linearity over the concentration ranges tested. Results from a three day validation study for both compounds demonstrated excellent precision (1.3-8.7%) and accuracy (93-105%) across the calibration range of 0.1 to 50 ng/ml using an 80 microliters plasma sample. The automated method described here was simple, reliable and economical. This on-line approach using ISRP columns and column switching with LC-MS-MS is applicable for the quantification of other pharmaceuticals in pharmacokinetic studies in animals and humans which require high sensitivity.

Granisetron: the second serotonin-receptor antagonist

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical efficacy, and adverse effects of granisetron, focusing on critical analysis of published clinical trials and comparison with other antiemetic agents, including ondansetron.

DATA SOURCES

MEDLINE (1966-1995) and CANCERLIT (1991-1995) searches of English-language literature using the terms "granisetron" and "granisetron (rn)" were performed.

STUDY SELECTION AND DATA EXTRACTION

All articles were considered for possible inclusion in this review. Abstracts of clinical trials were included only when they were judged to add critical information not otherwise available in the medical literature. For studies published more than once, the most recent publication was cited.

DATA SYNTHESIS

Nausea and vomiting are rated by patients as the most distressing chemotherapy-related adverse effects and may produce potentially life-threatening complications. The discovery of the role of serotonin in nausea and vomiting and the development of selective serotonin3-receptor (5-HT3) antagonists has significantly diminished the incidence and consequences of chemotherapy-related nausea and vomiting. Granisetron is the second 5-HT3-receptor antagonist to be marketed in the US. Granisetron has been compared with other antiemetic agents, including ondansetron, against highly and moderately emetogenic chemotherapy. The results of these trials have shown granisetron to be superior to conventional antiemetics and as effective as ondansetron in the prevention of chemotherapy-induced nausea and vomiting. The optimal dose of granisetron has yet to be determined. Formulary decisions should be based on a cost comparison among the 5-HT3-receptor antagonists at individual institutions.

CONCLUSIONS

Granisetron is a safe, effective antiemetic agent for the management of nausea and vomiting caused by cancer chemotherapy.

Constipation and diarrhea: the neglected symptoms

OBJECTIVE

To review the symptom experience of constipation and diarrhea related to cancer and its treatment.

DATA SOURCES

Published articles and book chapters relating to constipation and diarrhea in patients with cancer.

CONCLUSIONS

Constipation and diarrhea often represent a major concern and source of discomfort for the cancer patients. Research is needed to establish prevention and treatment protocols for patients at risk for constipation or diarrhea.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses are in an excellent position to recognize individuals who are at high risk for constipation and diarrhea. Preventive strategies and treatment protocols are of utmost importance.

A double-blind, placebo-controlled, dose-ranging safety evaluation of single-dose intravenous dolasetron in healthy male volunteers

The safety and tolerability of dolasetron mesylate, a potent and selective 5-HT3 receptor antagonist, were evaluated after single intravenous doses in healthy male volunteers. In this double-blind, placebo-controlled, randomized, phase I study, 80 subjects received either placebo or dolasetron in escalating doses (0.6 to 5.0 mg/k). Subjects were monitored for adverse events, vital sign and laboratory alterations, and changes in electrocardiographic (ECG) intervals and electroencephalographic (EEG) patterns. Overall, the percentage of subjects reporting adverse events was similar in those receiving dolasetron (44/64; 68.8%) or placebo (10/16; 62.5%); most adverse events were mild in severity. Subjects receiving dolasetron reported a higher incidence of central nervous system (headache and dizziness/lightheadedness), gastrointestinal (increased appetite and nausea), and visual adverse events and taste alterations. No clinically significant changes in laboratory variables were observed. Transient and asymptomatic ECG changes (small mean increases in PR interval and QRS complex duration versus baseline) were noted in several subjects at 1 to 2 hours after infusion at doses > or = 3.0 mg/kg. Transient, mild blood pressure decreases were observed in five subjects, including one on placebo. Dolastron mesylate was well tolerated in single intravenous doses up to 5.0 mg/kg in healthy male volunteers. Clinical studies of the drug are ongoing for antiemetic indications.

Possible cardiac side effects of granisetron, an antiemetic agent, in patients with bone and soft-tissue sarcomas receiving cytotoxic chemotherapy

The cardiac effect of granisetron, a selective 5-hydroxytryptamine3 receptor antagonist, on 12 patients with bone and soft-tissue sarcomas treated by cytotoxic chemotherapy consisting of multiple courses was examined. Of the 12 patients, 4 showed significant electrocardiographical changes, including sinus bradycardia, integral change of P-waves, junctional escape beat, and atrioventricular (AV) block with Wenckebach phenomenon, indicating stimulatory regulation of the vagus nerve. These changes were observed in each patient after several courses of chemotherapy but not in the first course. There was no correlation between the electrocardiographical changes and the chemotherapeutic agents used or the type of tumor present. A patient with osteosarcoma showed persistent bradycardia in three courses, all protocols of which contained high-dose methotrexate. From these findings we conclude that the cardiac responses may be due to stimulated activity of the vagal efferent nerve, which is regulated reflexly by afferent nerve activity suppressed by granisetron. On the other hand, the antiemetic efficacy of granisetron was satisfactory. These results suggest that careful observation of the heart is necessary when granisetron is used, especially for chemotherapy consisting of repeated multiple courses.