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PubMed2005

Aprepitant inhibits cyclophosphamide bioactivation and thiotepa metabolism.

BACKGROUND: Patients receiving the highly emetogenic high-dose chemotherapy regimen with cyclophosphamide, thiotepa and carboplatin (CTC) may benefit from the neurokin-1 receptor antagonist aprepitant in addition to standard anti-emetic therapy. As aprepitant has been shown to be a moderate inhibitor of the cytochrome P450 (CYP) 3A4 isoenzyme, its effect on the pharmacokinetics and metabolism of cyclophosphamide and thiotepa was evaluated. Moreover, preliminary results on the clinical efficacy of aprepitant in the CTC regimen are reported. PATIENTS AND METHODS: Six patients were enrolled in a protocol that employed a 4-day course of CTC high-dose chemotherapy with cyclophosphamide (1,500 mg/m2/day), thiotepa (120 mg/m2/day) and carboplatin (AUC 5 mg min/ml/day). Two patients received the tCTC protocol, which comprises two-third of the dose of CTC. In addition to standard anti-emetic therapy, the patients received aprepitant from one day before the start of their course until 3 days after chemotherapy. Blood samples were collected on days one and three of the course and analyzed for cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide, thiotepa and its main active metabolite tepa. The influence of aprepitant on the pharmacokinetics of cyclophosphamide and thiotepa was analyzed using a population pharmacokinetic analysis including a reference population of 49 patients receiving the same chemotherapy regimen without aprepitant and sampled under the same conditions. The frequency of nausea and vomiting in the six patients receiving CTC was compared with those of the last 22 consecutive patients receiving CTC chemotherapy without aprepitant. Inhibitory activity of aprepitant on cyclophosphamide and thiotepa metabolism was also tested in human liver microsomes. RESULTS: In our patient population, the rate of autoinduction of cyclophosphamide (P=0.040) and the formation clearance of tepa (P<0.001) were reduced with 23% and 33% when aprepitant was co-administered, respectively. Exposures to the active metabolite 4-hydroxycyclophosphamide and tepa were therefore reduced (5% and 20%, respectively) in the presence of aprepitant. In human liver microsomes, the 50% inhibitory concentrations (IC50) of aprepitant for inhibition of cyclophosphamide (IC50=1.3 microg/ml) and thiotepa (IC50=0.27 microg/ml) metabolism were within the therapeutic range. Patients receiving aprepitant experienced less frequently CINV both during and after the CTC course compared with the reference population (nausea 3.7 days vs. 5.8 days, P=0.052; vomiting 0.5 days vs. 4.8 days, P<0.001). CONCLUSION: Aprepitant inhibited both cyclophosphamide and thiotepa metabolism, most probably due to inhibition of the CYP 3A4 and/or 2B6 isoenzymes. The effects of this interaction are, however, small compared to the total variability. Addition of aprepitant may provide superior protection against vomiting in patients receiving the highly emetogenic high-dose CTC chemotherapy.

Antiemetics↗
PubMed1996

A randomized, double-blind comparison of single-dose and divided multiple-dose dolasetron for cisplatin-induced emesis.

PURPOSE: Intravenous dolasetron has been shown to be an effective antiemetic agent in patients receiving high-dose cisplatin-containing chemotherapy. Previous studies have suggested that 1.8 mg/kg is an optimal dose for achieving control of emesis and nausea. The objective of this study was to compare the efficacy and safety of a single intravenous (IV) dose of dolasetron with an equal divided multiple dose. METHODS: In this randomized, double-blind, parallel-group, multicenter study, the efficacy and safety of a single 1.8-mg/kg dose of dolasetron given 30 min prior to high-dose cisplatin ( > or = 80 mg/m2) chemotherapy was compared with the same total amount of dolasetron administered in three separate doses (0.6 mg/kg each) over a 12-h interval commencing 30 min prior to beginning chemotherapy and ending 11.5 h later. Antiemetic efficacy, safety, and tolerability were compared in 55 patients with various malignancies during the 24 h following the initiation of chemotherapy. The number of emetic episodes was the primary efficacy parameter. RESULTS: A single IV dose of dolasetron was generally more effective than a multiple-dose regimen in all measures of efficacy. There was a larger proportion of complete responders in the single-dose group compared with the multiple-dose group (48% vs 23%), although this difference did not reach statistical significance. Compared with the multiple-dose group, patients who received a single dose of dolasetron had a significantly (P = 0.034) longer median time to the first emetic episode (10.1 h vs > 24 h, respectively). Overall, 53% of patients had either a complete response or a major response to dolasetron, and only 40% of the total patient population received escape antiemetic medication in the 24 h after cisplatin administration. Except for headache, adverse events were similar with both regimens and were generally of mild or moderate intensity; no serious adverse events occurred. Neither dolasetron treatment regimen was associated with any clinically important events, trends in laboratory variables, or differences in safety profile. CONCLUSIONS: single-dose dolasetron was well tolerated and effectively controlled emesis and nausea in patients who received highly emetogenic, high-dose cisplatin chemotherapy. The greater antiemetic efficacy of a single prophylactic dose of dolasetron offers both convenience and potential cost savings, compared with a multiple-dose schedule of administration.

Aged↗
PubMed1998

Pharmacokinetic interaction between ondansetron and cyclophosphamide during high-dose chemotherapy for breast cancer.

PURPOSE: Both ondansetron and cyclophosphamide are thought to be metabolized by hepatic microsomal processes. The purpose of this study was to evaluate the potential pharmacokinetic interactions between ondansetron and high-dose alkylating agent chemotherapy. METHODS: A total of 54 breast cancer patients receiving high-dose cyclophosphamide, cisplatin and carmustine were treated prospectively in four sequential cohorts. Cohorts I and II received continuous infusions of both ondansetron and prochlorperazine, and cohorts III and IV received a continuous infusion of ondansetron alone at the same doses. All patients received lorazepam every 4 h. A group of 75 matched historical controls had received a continuous infusion of prochlorperazine with lorazepam. Pharmacokinetic monitoring of each drug used in the high-dose chemotherapy regimen was conducted. RESULTS: Median AUCs of cyclophosphamide in patients receiving ondansetron (73.6 mg/ml x min) were lower than those of the control patients (88.3 mg/ml x min, n = 75, P = 0.0004), but the median cisplatin AUC was approximately 10% higher and no difference in the disposition of carmustine was demonstrated. Patients treated with ondansetron displayed a higher frequency of headaches than the controls. The frequency of achieving complete emetic control was greater in the ondansetron + prochlorperazine groups compared to the ondansetron alone groups and was greater in both these groups than in the prochlorperazine alone group on the first day of therapy only. CONCLUSION: Ondansetron altered the systemic exposure to cyclophosphamide when these agents were administered concomitantly. Ondansetron did not substantially improve overall emetic control when used alone but may improve control in combination with prochlorperazine. Future randomized studies are needed to delineate the effect of ondansetron on the disposition of the active cyclophosphamide metabolites so that clinical implications can be addressed.

Antiemetics↗
PubMed2002

Antiemetic guidelines: creating a more practical treatment approach.

Antiemetic guidelines from a variety of professional organizations have been available for several years. It is unclear just how often these guidelines have been used, however; data indicate that some practitioners still do not treat their patients according to the recommendations. Some of those involved in the creation of the original guidelines convened to try to create a simpler, more practical approach to the use of antiemetics in preventing chemotherapy-induced nausea and vomiting. The group's intention was to clarify available guidelines and produce a practical document, based on evidence, that could be used in everyday practice. The group created four consensus statements that would serve as a basis for their recommendations. One primary strategy used was to have chemotherapy-induced nausea and vomiting viewed as a single process that can occur throughout a treatment cycle, and not so much as an acute and a delayed process, as is usual in clinical trials. Patients' management should be considered over a 4- to 5-day period, rather than primarily dealing with the day of treatment only. The group created three tables: emetic risk of chemotherapy; treatment options based on emetic category; and antiemetic dosing recommendations. Use of these tables should make appropriate antiemetic selection more straightforward and easier for the practitioner in an everyday setting. Although this document alone may not solve all the challenges with appropriate antiemetic management, it will hopefully prove to be a step in the right direction.

Antiemetics↗
PubMed2003

Granisetron in the control of nausea and vomiting associated with bone marrow transplantation: a review of its efficacy and tolerability.

Cancer patients undergoing bone marrow transplantation (BMT) experience severe nausea and vomiting associated with high-dose chemotherapy agents; these emetic symptoms are compounded by total body irradiation used in many conditioning regimens. This paper reviews clinical experience with the 5-HT(3) receptor antagonist granisetron, both as a single agent and in combination with other anti-emetics, in patients undergoing BMT and peripheral blood stem cell transplantation (PBSCT). Clinical studies demonstrate the efficacy (47-61% with no vomiting and no worse than mild nausea) and tolerability of granisetron. Its long half-life and duration of action may be responsible for its effective 24 h control of nausea and vomiting in BMT patients.

Administration, Oral↗
PubMed2004

Antiemetic therapy for multiple-day chemotherapy and high-dose chemotherapy with stem cell transplant: review and consensus statement.

The objective of this paper is to evaluate the efficacy of modern antiemetic therapy for chemotherapy-induced nausea and vomiting for patients receiving multiple-day or high-dose chemotherapy. Published phase II and phase III studies as well as their personal experiences were evaluated by the authors to develop this consensus statement. The largest published experience with multiple-day chemotherapy is with 5-day cisplatin combination chemotherapy. The introduction of 5-HT3 antagonists greatly improved emetic control. However, day 4-5 nausea as well as delayed nausea and vomiting remains a clinical problem despite the inclusion of dexamethasone. A 5-HT3 antagonist plus dexamethasone is the preferred current option for patients receiving high-dose chemotherapy with stem cell transplant. However, the results do not appear as successful as for highly emetic standard-dose chemotherapy.

Antiemetics↗
PubMed2006

Randomized, double-blind trial comparing the antiemetic effect of tropisetron plus metopimazine with tropisetron plus placebo in patients receiving multiple cycles of multiple-day cisplatin-based chemotherapy.

PURPOSE: To compare the antiemetic efficacy and tolerability of tropisetron plus metopimazine with tropisetron plus placebo during 4 cycles of multiple-day, cisplatin-based chemotherapy. MATERIALS AND METHODS: 82 chemotherapy-naive patients with germ cell cancer scheduled to 4 cycles of multiple-day cisplatin-based chemotherapy (20 or 40 mg/m(2)/day for 5 days) given every 3 weeks were included. A double-blind parallel trial design was used and patients randomized to tropisetron plus metopimazine or tropisetron plus placebo. Tropisetron was administered as a single 5 mg intravenous dose on days 1-5 and a single 5 mg oral dose on day 6, and metopimazine as 30 mg orally t.i.d. on day 1, and q.i.d on days 2-6. RESULTS: Patients were evaluable for efficacy during a total of 195 cycles. Small, but certain advantages were obtained with the combination. In cycle 1, complete protection from emetic episodes on day 1, days 1-5, days 6-9 and days 1-9 was achieved in 85.7%, 42.9%, 86.2% and 40.5% with tropisetron plus metopimazine and in 90.0%, 22.5%, 64.3% and 17.5% with tropisetron plus placebo, respectively. This difference achieved statistical significance in the overall period, days 1-9 (P = 0.029). During the entire period (days 1-9), significantly less nausea was seen in patients receiving tropisetron plus metopimazine (P = 0.027), whereas other nausea parameters did not reach statistical significance. The cumulative emetic protection rate after 4 cycles was 0.51 with tropisetron plus metopimazine and 0.25 with tropisetron plus placebo (P = 0.037). Side effects were generally few and mild with both treatments and no significant differences were seen. CONCLUSION: Tropisetron plus metopimazine is superior to tropisetron during 4 cycles of multiple-day cisplatin-based chemotherapy, but both treatments are ineffective in a number of patients. The effect of the combination seems comparable to that of ondansetron plus dexamethasone. Newer drugs such as the neurokinin(1) receptor antagonist, aprepitant, should be investigated to optimize antiemetic therapy in patients receiving multiple-day chemotherapy.

Adolescent↗
PubMed1997

Oral dolasetron mesilate (MDL 73,147EF) for the control of emesis during fractionated total-body irradiation and high-dose cyclophosphamide in patients undergoing allogeneic bone marrow transplantation.

The purpose of the present study was to evaluate the efficacy and safety of oral dolasetron mesilate in the prevention of nausea and vomiting that might otherwise be induced by total-body irradiation (TBI) and high-dose cyclophosphamide. In an open non-comparative study 20 patients who received TBI for 3 days and high-dose cyclophosphamide chemotherapy for 2 days as part of their preparation for bone marrow transplantation were given oral dolasetron mesilate at dosages ranging from 50 to 200 mg 1 h before each fraction of radiotherapy and cyclophosphamide administration. Initial rescue therapy consisted of intravenous dolasetron mesilate. If nausea and vomiting remained uncontrolled, standard antiemetics were to be used. Of the 20 patients, 13 had only two emetic episodes or fewer in the 3-day TBI period. On days 1 and 2 of cyclophosphamide administration, 11 and 6 patients had fewer than two emetic episodes. From day 1 to day 3, 15 patients experienced no nausea or only mild nausea, and on the days of chemotherapy 8 and 7 patients had mild nausea or none at all. Rescue with i.v. dolasetron mesilate was needed by 3 and 6 patients during the TBI and the chemotherapy periods respectively. In 2 patients additional antiemetics were used on days 2-3 and 4-5. Mild to moderate headache was reported in 6 patients. No unexpected abnormalities were observed in haematology, biochemistry or urinalysis, and vital signs were unaffected throughout the study period. The data suggest that oral dolasetron mesilate is effective and safe for the prevention of nausea and vomiting during TBI and cyclophosphamide chemotherapy prior to bone marrow transplantation. Future controlled studies should evaluate combination antiemetic therapy with dolasetron mesilate for this indication.

Administration, Oral↗
PubMed1997

Fatigue in patients with cancer: results with National Cancer Institute of Canada Clinical Trials Group studies employing the EORTC QLQ-C30.

The purpose of this study was to examine the factors which affect the level of fatigue among patients participating in clinical trials in which this symptom had been assessed with the EORTC QLQ-C30. Data were assembled from 2390 patients in ten clinical trials in which the QLQ-C30 had been used to assess baseline and on-study quality of life. The relationship between the level of fatigue reported by the patients on the fatigue scale of this questionnaire and patient and disease characteristics was assessed in univariate and multivariate cross-sectional analyses. In addition, changes in fatigue scores were compared in a longitudinal analysis among patients on two arms of an anti-emetic trial whose emesis control was markedly different. Baseline fatigue levels differed substantially among patients taking part in the different trials. Factors associated with greater fatigue severity on univariate analysis included: female gender, presence of metastatic disease, and poorer performance status. In addition, on multivariate analyses the oldest patients were found to have less fatigue, as were patients with breast cancer, while patients with ovarian and lung cancer experienced greater fatigue. Patients on the arm of the anti-emetic trial in which emesis was better controlled showed significantly less increase in fatigue after receiving chemotherapy. The fatigue scale of the QLQ-C30 appears to provide a useful approach to assessing this important symptom. The relationships found between fatigue and patient and disease characteristics need further exploration as does the degree to which the QLQ-C30 fully captures this dimension of quality of life.

Adult↗
PubMed1998

Assessment of the emetogenic potential of intrathecal chemotherapy and response to prophylactic treatment with ondansetron.

The purpose of this study was to document the emetogenic potential of intrathecal chemotherapy (IC) in children and to evaluate the efficacy of ondansetron in reducing nausea and vomiting with this chemotherapy treatment. Patients less than 18 years of age with acute lymphoblastic leukemia were eligible to participate in a survey project measuring the emetogenic potential of various chemotherapy treatments. Patients surveyed for 1 or more IC treatments were included in this report. The IC consisted of methotrexate, hydrocortisone and cytarabine, dosed according to patient age. A nausea/vomiting survey instrument was completed by each patient and/or parent following IC treatment. The instrument rated nausea, vomiting and daily activity interference (DAI) on a 4-point scale of 0 = none, 1 = mild, 2 = moderate and 3 = severe, and collected data on the number of vomiting and/or retching episodes in addition to the child's appetite following the chemotherapy treatment. When ondansetron was employed, it was administered in an i.v. infusion at a dose of 0.15 mg/kg before and after chemotherapy or as an oral dose of 4 mg or 8 mg before chemotherapy. Courses of IC without antiemetics were analyzed to determine the emetogenic potential of IC. For patients receiving IC both with and without ondansetron, courses were compared with each patient used as their own control to determine the influence of ondansetron upon survey responses. Statistical analysis consisted of nonparametric Friedman 2-way ANOVA for ordinal variables and a paired t-test for continuous variables. The binomial test was employed to analyze for differences between ondansetron and no antiemetic in the number of patients with complete control of both nausea and vomiting or vomiting alone. A total of 63 children with a mean age of 7.6 +/- 4.2 years were each studied on one or more occasions. Thirty-seven children were surveyed for 87 IC treatments without antiemetics (group I), and 17 children from this group were surveyed for 48 IC courses with i.v. ondansetron (group IA). An additional 18 children were subsequently surveyed for 39 IC courses with i.v. ondansetron (group II). Fifteen patients (7 of whom were members of group I) were surveyed following 33 IC courses with oral ondansetron (group III). The survey scores for group I patients were: nausea severity 1.3 +/- 1.1, vomiting severity 1.2 +/- 1.1, DAI 1.2 +/- 1.0 and mean number of emetic episodes 4.7 +/- 8.4. The mean appetite score was 1.5 +/- 1.1. For patients in group IA, nausea severity (0.8 +/- 0.9), vomiting severity (0.5 +/- 0.8), DAI (0.7 +/- 0.8), and the number of emetic episodes (1.4 +/- 2.8) were all significantly lower than with prior IC treatments without ondansetron. For complete protection, children receiving i.v. ondansetron had greater complete protection rates from both nausea and vomiting or vomiting alone than did patients receiving no antiemetic. Survey responses were also lower for patients receiving oral ondansetron, but insufficient control data did not allow for statistical analysis. IC results in mild to moderate nausea and vomiting in children. The emetogenic potential of IC is significantly reduced by i.v. ondansetron.

Antiemetics↗
PubMed2000

Antiemetic efficacy of combination therapy with granisetron plus prednisolone plus the dopamine D2 antagonist metopimazine during multiple cycles of moderately emetogenic chemotherapy in patients refractory to previous antiemetic therapy.

Effective antiemetic treatment of patients who have previously experienced chemotherapy-induced nausea and vomiting is difficult. The aim of this study was to evaluate the antiemetic efficacy of a single intravenous dose of granisetron plus a 3-day oral treatment with prednisolone 25 mg once a day plus metopimazine 30 mg four times a day in patients refractory to previous antiemetic treatment with granisetron or with prednisolone plus metopimazine. The study population was made up of 25 consecutive women with stage I or II breast cancer, who were treated with multiple cycles of adjuvant cyclophosphamide, fluorouracil plus methotrexate or cyclophosphamide, epirubicin plus fluorouracil given i.v. every 3 weeks. Patients received the three-drug combination of antiemetics during a total of 113 cycles of chemotherapy. No emetic episodes were reported in 88.9% cycles on day 1, in 94.7% cycles on days 2 through 5 and in 85.8% cycles on days 1 through 5 after chemotherapy. No nausea was reported in 43.4% cycles on day 1, in 49.6% cycles on days 2 through 5 and in 34.5% cycles on days 1 through 5. Nineteen patients (76.0%) completed the scheduled nine cycles of chemotherapy, 1 being withdrawn because of > or =5 emetic episodes and 5, because they were not satisfied with the antiemetic treatment. The treatment was well tolerated. In conclusion, granisetron plus prednisolone plus metopimazine is a highly effective antiemetic treatment in patients receiving moderately emetogenic chemotherapy refractory to antiemetic therapy with granisetron or prednisolone plus metopimazine.

Adult↗
PubMed1981

Taste aversions conditioned with intravenous copper sulfate: attenuation by ablation of the area postrema.

Borison and Wang identified the area postrema as the locus of chemoreceptors that mediate emetic reflexes elicited by blood-borne toxins. In the present experiments we have extended a systematic investigation of the afferent pathways mediating taste aversions by examining the effects of area postrema lesions on the aversions that follow either intravenous or intragastric administration of copper sulfate. Intrajugular cannulas were implanted in rats after ablation of the area postrema (Group AP-L) and in operated controls (Group AP-C). Every third day rats were offered a saccharin solution and immediately afterward were injected intravenously with 0.05 ml isotonic CuSO4. A group of pseudo-conditioned rats (Group SAC-C) was injected with CuSO4 approximately 24 h after ingestion of saccharin. Compared to controls animals, rats with area postrema damage acquired significantly weaker aversions to saccharin when it was paired repeatedly with intravenous CuSO4. After three conditioning trials, the rats in Group AP-L that were most resistant to acquisition of a taste aversion (Group AP-L) were again offered saccharin, but ingestion in this case was followed immediately by intragastric injection of CuSO4. After a single conditioning trial rats in Group AP-L demonstrated a robust aversion. The results are discussed in terms of the parallels in afferent systems between emetic physiology and some instances of taste aversion conditioning.

Afferent Pathways↗
PubMed1989

Inhibition of cisplatin-induced emesis in the pigeon by a non-psychotropic synthetic cannabinoid.

The (+) enantiomer of the synthetic cannabinoid, 7-hydroxy-delta-6-tetrahydrocannabinol, dimethylheptyl homolog (HU-211), possesses significant antimetic efficacy in the pigeon. However, unlike all anti-emetic cannabinoids tested in the past, it is devoid of psychotropic (cannabimimetic) activity. The anti-emetic activity of HU-211 was determined in pigeons given 10 mg/kg i.v. cisplatin, a widely used antitumour agent, which is also a potent emetogenic agent at this dose. This activity was compared with that of delta-1-tetrahydrocannabinol (delta-1-THC). HU-211 pretreatment elicited a dose-related inhibition of cisplatin vomiting, with the optimal dose of HU-211 (2.5 mg/kg) inhibiting emesis by nearly 90%. Delta-1-THC in doses up to 5 mg/kg caused only an insignificant reduction in vomiting. The activity was increased in the presence of cupric chloride (0.8 mg/kg). The optimal dose of delta-1-THC (5.0 mg/kg) with CuCl2 very significantly diminished the total amount of vomitus expelled (up to 90%). However, it failed to inhibit emesis in 50% of all animals tested, did not significantly affect the time of onset of emesis and was highly psychotropic. The optimal dose of HU-211 (2.5 mg/kg) with CuCl2 inhibited emesis by 97%, significantly delayed the time on onset of emesis in the very few animals that did vomit and was completely non-psychotropic. The curve for the antiemetic effect of HU-211 was U-shaped over a narrow dose range. The present report demonstrates that complete separation of psychotropic and antiemetic activities is possible in the cannabinoid series.

Animals↗
PubMed1995

The role of alpha-adrenergic mechanisms within the area postrema in dopamine-induced emesis.

Intracerebroventricular injection of dopamine (0.5-4.0 mg) produced dose-dependent and short-lasting emesis (1-8 min) in cats, which was abolished after ablation of the area postrema. Relatively selective alpha 2-adrenoceptor antagonists (yohimbine and idazoxan) and a mixed alpha 1- and alpha 2-adrenoceptor antagonist (tolazoline), but not a non-selective alpha 1-adrenoceptor antagonist (prazosin), injected intracerebroventricularly inhibited the emesis induced by intracerebroventricular dopamine. However, dopamine receptor antagonists (chlorpromazine, droperidol, spiperone, domperidone, triflupromazine, sulpiride and metoclopramide), an antimuscarinic drug (atropine), a ganglionic blocking agent (mecamylamine), an opioid receptor antagonist (naloxone) and a 5-HT receptor antagonist (methysergide), all injected intracerebroventricularly, had no significant effect on emesis evoked by intracerebroventricular dopamine. The emetic response to intracerebroventricular dopamine was attenuated in cats pretreated with intracerebroventricular reserpine, 6-hydroxydopamine, alpha-methyl-p-tyrosine and hemicholinium-3. It is postulated that dopamine-induced emesis is mediated through the release of noradrenaline acting at alpha 2-adrenoceptors and that it depends on the integrity of monoaminergic and possibly cholinergic structures within the area postrema. It appears, therefore, that the emetic effect of intracerebroventricular dopamine is mediated by adrenergic rather than dopaminergic mechanisms in the area postrema, at least in the cat.

Adrenergic alpha-Antagonists↗
PubMed1990

Role of angiotensin II and vasopressin in cisplatin-induced emesis.

Cisplatin-containing chemotherapy regimens are known to produce intense nausea and vomiting. Angiotensin II (AII) and vasopressin (AVP) have been shown to have emetic properties. The role of these two peptides on cisplatin-induced vomiting was investigated in beagle dogs. Cisplatin (2 mg/kg, IV over 5 min) produced consistent emesis in all dogs after a mean latency time of 144 +/- 4 min. Serum Angiotensin Converting Enzyme (ACE) and plasma AII levels did not significantly change 3 hr after cisplatin administration (at the time of nausea and emesis) in control animals. AVP levels rose from 0.3 pg/ml to 7.5 pg/ml 3 hrs after cisplatin. Complete inhibition of ACE with enalapril (given at 3 mg/kg p.o., 3 hrs prior to cisplatin) reduced AII levels by 70%, but failed to significantly modify the increase in AVP levels (7.2 +/- 2.2 pg/ml), the latency time to emesis (149 +/- 2 min) and the number of emetic episodes induced by cisplatin. These results suggest that AII does not mediate cisplatin-induced emesis, nor does it mediate the increase in AVP observed at the time of emesis. We propose that AVP may be a good marker for nausea and emesis, and that increases in AVP may be neurally-mediated. The large increase in circulating AVP may represent a desirable water conservation response in anticipation of fluid losses induced by vomiting.

Angiotensin II↗
PubMed1986

5-Hydroxytryptamine M-receptor antagonism to prevent cisplatin-induced emesis.

The administration to the ferret of cisplatin, 10mg/kg (i.v.), caused an intense emetic response that was prevented by ICS 205-930 (0.1 and 1.0 mg/kg i.v.) and metoclopramide (4.0 mg/kg i.v.). Smaller doses of ICS 205-930 (0.01 mg/kg i.v.) and metoclopramide (2.0 mg/kg i.v.) attenuated the emetic response to cisplatin. It is concluded that the potent action of ICS 205-930 against cisplatin-induced emesis is the consequence of a 5-hydroxytryptamine M-receptor antagonism which may also contribute to the antiemetic action of metoclopramide.

Animals↗
PubMed1979

Coeliactomy: differential toxiphobia conditioning with apomorphine and copper sulfate.

Thirsty coeliac ganglionectomized and sham operated rats consumed more of a novel fluid after a series of presentations, each followed by saline injection, than when apomorphine was injected or copper sulfate intragastrically intubated. Sham rats drank significantly more of this novel solution than ganglionectomized rats following treatments with a very low dose of the peripherally-acting emetic copper sulfate that locally irritates the gastric mucosa. However, sham and ganglionectomized rats drank comparable amounts of the novel fluid following treatments with saline and the two groups drank comparable amounts following treatments with the centrally-acting emetic apomorphine. The results suggest that coeliac ganglionectomy eliminates some, but not all, of the afferent nerves transmitting information concerning visceral toxicosis (produced with intragastric copper sulfate) to the brain.

Animals↗
PubMed1980

Selective permeation of the blood-brain barrier as a cause of the anomalous properties of 'atypical'neuroleptics.

Metoclopramide is a widely used anti-emetic drug with potent dopamine-blocking effects on brain structures involved in emesis and prolactin secretion but it is apparently devoid of therapeutic effect in schizophrenia, thus calling into question the supposed role of dopamine blockade in the action of antischizophrenic drugs. This investigation compared the depression of hypothalamic self-stimulation produced by metoclopramide and by a 'typical' neuroleptic, spiroperidol (spiperone), when injected by different routes. Metoclopramide was found to9 be nearly 30 times more potent when administered directly into the brain via the cerebral ventricles than when injected intraperitoneally; on the other hand the potency of spiroperidol was virtually unaffected by the route of administration. The blood-brain barrier is known to be absent from brain sites controlling emesis and prolactin secretion; thus the potency of metoclopramide as an anti-emetic and in releasing prolactin, and its relative ineffectiveness as an antipsychotic can be accounted for by a failure to enter the brain freely except at privileged sites. Thus its anomalous properties are not necessarily inconsistent with the dopamine theory of schizophrenia.

Animals↗