tropisetron and dolasetron

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).. 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).. 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).. 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.

Topics: Antiemetics; Antineoplastic Agents; Granisetron; Humans; Indoles; Ondansetron; Quinolizines; Serotonin 5-HT3 Receptor Antagonists; Serotonin Antagonists; Treatment Outcome; Tropisetron; Vomiting

The need to control chemotherapy-induced emesis has stimulated research into anti-emetics. Emesis is not only unpleasant, but negatively impacts on global quality of life. The development of two new classes of drugs has been responsible for the major advances in anti-emesis. The 5 hydroxytryptamine3 (5HT3) antagonists in combination with dexamethasone significantly improved the control of acute post chemotherapy emesis, but delayed emesis which can last for several days was still problematic, yet its incidence was underestimated by clinicians. Both the control of acute and delayed emesis was improved when the neurokinin1 (NK1) receptor antagonists were added to 5HT3 antagonists and steroids. The complete control of delayed emesis was improved by 21% with little toxicity. The triple drug combination has become the standard of care for preventing the emesis associated with cytotoxic drugs of high emetic potential.

Topics: Administration, Oral; Antiemetics; Antineoplastic Combined Chemotherapy Protocols; Australia; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Granisetron; Humans; Indoles; Isoquinolines; Male; Neoplasms; Ondansetron; Palonosetron; Patient Satisfaction; Prognosis; Quality of Life; Quinolizines; Quinuclidines; Treatment Outcome; Tropisetron; Vomiting

Since there continues to be a high incidence of postoperative nausea and vomiting associated with many types of surgery, and the standard antiemetics often do not achieve satisfactory results, there have been attempts to use the 5-HT3 antagonists. This group of substances is relatively new, but has already been used successfully as an antiemetic during chemotherapy. To date, results are on hand for four different 5-HT3 receptor blockers: ondansetron, tropisetron, granisetron and dolasetron. Applied intravenously, all four have been effective both in prophylaxis and also as therapy for postoperative emesis. Except for ondansetron, there is so far no definitely clear knowledge about the lowest possible effective dosage. The entire group is well tolerated: only occasional and minor side effects have been reported. Even though not all the hopes originally set in the 5-HT3 group of antagonists have been fulfilled, progress has nevertheless been achieved. Especially noteworthy points are a positive cost-effectiveness relationship of these drugs and their appropriate use in case of the proper indications.

Topics: Antiemetics; Clinical Trials as Topic; Dose-Response Relationship, Drug; Granisetron; Humans; Indoles; Infusions, Intravenous; Nausea; Ondansetron; Postoperative Complications; Quinolizines; Serotonin Antagonists; Tropisetron; Vomiting

There are currently three 5-hydroxytryptamine3 (5-HT3) receptor antagonists available in Australia. In this randomized, double-blind, parallel group study the prophylactic antiemetic effect of a single dose of tropisetron 2 mg, ondansetron 4 mg or dolasetron 12.5 mg was compared after major gynaecological surgery. One hundred and eighteen patients (group T n = 42; group O n = 36; group D n = 40) were evaluated for nausea, vomiting, recovery characteristics and satisfaction for 24 hours postoperatively. A cost-effectiveness analysis was performed. Rescue antiemetic, prochlorperazine 12.5 mg i.m., was given if vomiting occurred more than 10 minutes after arrival in the recovery room. If prochlorperazine was ineffective one hour after administration, droperidol 1 mg i.v. was given. There were no significant differences between groups for the incidence of vomiting during consecutive epochs until 24 hours postoperatively or overall (57%, 75% and 72.5% for groups T, O and D respectively, P = 0.18). The incidence and number of rescue antiementic treatments for nausea or vomiting were similar. The incidence of nausea and the overall and interval nausea scores were similar except for lower "worst nausea" score in group T between 12 and 18 hours (P = 0.02). Recovery times, satisfaction and cost per patient did not differ between groups. We conclude that the risk of postoperative nausea and vomiting remained high in this setting despite 5-HT3 receptor antagonist prophylaxis and that the choice between these agents should be based on the lowest available acquisition cost.

Topics: Antiemetics; Cost-Benefit Analysis; Double-Blind Method; Female; Humans; Indoles; Middle Aged; Ondansetron; Patient Satisfaction; Postoperative Nausea and Vomiting; Quinolizines; Serotonin Antagonists; Tropisetron

Effective antiemetic therapy is crucial for patients undergoing chemotherapy or radiotherapy for cancer. Severe nausea and vomiting associated with such cancer treatment can lead to anxiety, anorexia, dehydration, electrolyte disturbance and renal failure, and may interrupt cancer therapy, demoralise patients or even cause them to abandon treatment. In 1992, we welcomed the introduction of ondansetron, the first selective serotonin type 3- (5HT3-) receptor antagonist marketed in the UK, as an important advance in preventing chemotherapy-induced nausea and vomiting. Several selective 5HT3-receptor antagonists are now licensed. They are widely prescribed to patients receiving cancer treatment, but not always appropriately. Here we review their optimal use.

Topics: Adult; Antiemetics; Antineoplastic Combined Chemotherapy Protocols; Child; Granisetron; Humans; Indoles; Isoquinolines; Nausea; Neoplasms; Ondansetron; Palonosetron; Practice Guidelines as Topic; Quinolizines; Quinuclidines; Serotonin 5-HT3 Receptor Antagonists; Serotonin Antagonists; Tropisetron; Vomiting

Dolasetron mesilate [(2 alpha, 6 alpha, 8 alpha, 9a beta)-octahydro-3-oxo-2,6-methano-2H-quinolizin-8-yl-1H-indole-3-c arboxylate monomethane-sulfonate], is a 5-HT3 receptor antagonist, which is in development for the treatment of chemotherapy-induced emesis. The compound is rapidly reduced by carbonyl reductase to form its major pharmacologically active metabolite reduced dolasetron (red-dolasetron), which us further metabolized by cytochrome P450 (CYP450). Studies were conducted, using human liver microsomes, to characterize the CYP450 enzymes responsible for the in vitro metabolism of red-dolasetron. Red-dolasetron underwent oxidation of the indole aromatic ring at positions 5, 6, and 7, and also N-oxidation. Enzyme-selective inhibition and correlation studies showed that hydroxylation of red-dolasetron was CYP2D6-dependent, and N-oxidation was conducted by CYP3A4. The rate of formation of 6-hydroxy red-dolasetron was significantly correlated with that of 5-hydroxy red-dolasetron, which further suggested that these metabolites were formed by the same CYP450 enzyme(s). Inhibition studies also demonstrated that 6-hydroxylation was, to a lesser extent, CYP3A4-dependent. This was confirmed by correlation experiments, wherein formation of this metabolite was significantly correlated with that of N-oxide formation, in quinidine-inhibited microsomes. Results were compared with those obtained with two other indole-containing 5-HT3 receptor antagonists: tropisetron and ondansetron. Tropisetron hydroxylation was CYP2D6-dependent, whereas that of ondansetron was both CYP2D6- and CYP2E1-dependent. Results were further confirmed, when compounds were incubated with microsomes containing recombinant human liver CYP2D6, CYP3A4, and CYP2E1. Red-dolasetron was a competitive inhibitor of CYP2D6, with an IC50 value of 70 microM, which is 2 orders of magnitude above maximum plasma concentrations found in humans. The implications of these in vitro results to the in vivo metabolism of these compounds in humans and their potential pharmacokinetic consequences is discussed.

Topics: Cytochrome P-450 CYP2D6; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Humans; Hydroxylation; Indoles; Male; Mass Spectrometry; Microsomes, Liver; Mixed Function Oxygenases; Molecular Structure; Ondansetron; Oxidation-Reduction; Quinolizines; Serotonin Antagonists; Tropisetron

We estimate the influence of five 5-hydroxytryptamine receptor (5-HT3) antagonists on the activity of dihydropyrimidine dehydrogenase (DPDase), the rate-limiting enzyme in 5-fluorouracil (5FU) metabolism. The activity of DPDase from the rat liver was compared in the cytosol mixture of 5FU incubated with or without each of five 5-HT3 antagonists. DPDase activity was not altered in the presence of any 5-HT3 antagonist studied here. It may be inferred from these results that the any 5-HT3 receptor antagonist examined in this study has little or no effect on fluorouracil catabolism.

Topics: Animals; Antiemetics; Antimetabolites, Antineoplastic; Biotransformation; Bridged Bicyclo Compounds, Heterocyclic; Cytosol; Dihydrouracil Dehydrogenase (NADP); Fluorouracil; Granisetron; Indoles; Liver; Male; Ondansetron; Oxazines; Oxidoreductases; Quinolizines; Rats; Rats, Sprague-Dawley; Receptors, Serotonin; Receptors, Serotonin, 5-HT3; Serotonin Antagonists; Tropisetron

Recent studies have shown that non-opioid defensive analgesia in male mice is potently inhibited by the 5-HT3 receptor antagonist, ondansetron. The present series of experiments was conducted to further explore the involvement of 5-HT3 receptor mechanisms in this particular form of adaptive inhibition of pain. The drug ICS 205-930 significantly attenuated the reaction at 1.25-2.5 micrograms/kg, with smaller and larger doses being ineffective. Both MDL 72222 and MDL 73147EF produced flat dose-response curves, with significant inhibition of defensive analgesia at minimum effective doses of less than or equal to 10 and 300 micrograms/kg, respectively. Although MDL 72699, the quaternary salt of MDL 72222, also inhibited the reaction, this effect was seen at comparatively large doses (0.5-1.0 mg/kg) only. None of the compounds tested had significant intrinsic effects of tail-flick latencies, over the dose ranges tested. These findings indicate that 5-HT3 receptor mechanisms may have an important modulatory role in certain forms of "stress" analgesia. Data are discussed in relation to the consistent profile of partial inhibition produced by 5-HT3 receptor antagonists in this model.

Topics: Analgesia; Analysis of Variance; Animals; Dose-Response Relationship, Drug; Hot Temperature; Indoles; Male; Mice; Mice, Inbred DBA; Pain; Posture; Quinolizines; Receptors, Serotonin; Reference Values; Serotonin Antagonists; Stereotyped Behavior; Tropanes; Tropisetron

The discriminative stimulus induced in rats by amphetamine has previously been shown to be due to raised mesolimbic dopamine levels. As 5-HT3 receptor antagonists have been shown to inhibit hyperactivity resulting from raised mesolimbic dopamine levels, the present study examined their effects against the amphetamine discriminative stimulus. None of the 5-HT3 receptor antagonists tested (MDL 72,222EF, 0.3-10 mg/kg s.c.; MDL 73,147EF, 0.3-10 mg/kg s.c.; ICS 205-930, 0.01-10.0 mg/kg s.c.; ondansetron, 0.1-1000 micrograms/kg s.c.) antagonised the effects of amphetamine in this test. This suggests that 5-HT3 receptors cannot modulate the effects of raised mesolimbic dopamine in pathways involved in the interoceptive effects of amphetamine.

Topics: Amphetamine; Animals; Discrimination Learning; Imidazoles; Indoles; Male; Ondansetron; Quinolizines; Rats; Rats, Inbred Strains; Serotonin Antagonists; Tropanes; Tropisetron

Despite a number of significant advances over the past decade, prevention and treatment of chemotherapy-induced emesis remain formidable problems, particularly with cisplatin-containing regimens. Nearly one third of patients receiving high-dose cisplatin still experience substantial emesis despite the best available conventional antiemetics, and the toxic effects of these agents remain quite troublesome. In recent years, a new class of agents, the serotonin antagonists, has been identified. These agents hold promise for clinical utility in a wide range of areas. Selective antagonists of the serotonin (5-hydroxytryptamine) type 3 (5-HT3) receptor have proven in early clinical trials to be potent antiemetic agents in patients receiving cytotoxic chemotherapy, with efficacy comparable to or superior to that of conventional antiemetics. Toxic effects to date with the 5-HT3 receptor antagonists have been modest. The current state of knowledge with respect to these agents as antiemetics for patients receiving cytotoxic chemotherapy is summarized.

Topics: Antiemetics; Benzamides; Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Granisetron; Humans; Imidazoles; Indazoles; Indoles; Metoclopramide; Ondansetron; Quinolizines; Receptors, Serotonin; Serotonin Antagonists; Tropanes; Tropisetron; Vomiting