Review of the preclinical pharmacology and comparative efficacy of 5-hydroxytryptamine-3 receptor antagonists for chemotherapy-induced emesis

PURPOSE: This analysis was undertaken to review published reports of the comparative efficacy and safety of 5-hydroxytryptamine-3 (5-HT3) receptor antagonists in the prophylaxis of acute chemotherapy-induced emesis. METHODS: Comparison data used are the preclinical pharmacology as well as the design and results of clinical trials. Seven comparative studies that used granisetron, ondansetron, or tropisetron in patients who received either moderately or highly emetogenic chemotherapy are reviewed. As the study designs, patient population, chemotherapy, antiemetic doses and schedule, and methods of assessment were slightly different, the results of each study are analyzed independently. Effectiveness is assessed by emetic episodes, nausea, and patient preference. RESULTS: The preclinical pharmacologic profile is different among the 5-HT3 antagonists in terms of potency, selectivity, dose response, and duration of action. The comparative clinical trials show that a single intravenous (i.v.) dose of granisetron 3 mg is as effective as multiple (8 mg x 3) or single (32 mg) i.v. doses of ondansetron for the prevention of acute nausea and emesis due to cisplatin. In the two moderately emetogenic clinical trials, granisetron 3 mg i.v. was at least as effective as ondansetron 8 mg i.v. +/- 24 mg orally and tropisetron 5 mg i.v. Patient preference was evaluated in three of the four crossover trials: granisetron was preferred in three of four, and no preference was reported in the fourth. The one trial to compare ondansetron 0.15 mg/kg x 3 versus granisetron 10 micrograms/kg x 1 or granisetron 40 micrograms/kg i.v. demonstrated equivalent control of nausea and vomiting in patients who received cisplatin-based chemotherapy. CONCLUSION: The 5-HT3 receptor antagonists compared are highly effective antiemetic agents that have now become the standard of care for preventing chemotherapy-induced emesis. Whether the described preclinical differences among these agents are also clinically significant remains to be seen. In the comparative trials analyzed, the 5-HT3 receptor antagonists demonstrated relatively equivalent clinical efficacy. Cost analysis may favor the use of one agent over another depending on the emetogenic challenge, dose of the 5-HT3 antagonists, and number of doses recommended. Patient preference may be an important factor to be considered in future antiemetic trials.     

Differential effects of specific delta and kappa opioid receptor antagonists on the bidirectional dose-dependent effect of systemic naloxone in arthritic rats, an experimental model of persistent pain

In an attempt to determine the opioid receptor class(es) which underly the two opposing effects of naloxone in models of persistent pain, we tested the action of the selective delta antagonist naltrindole, and that of the kappa antagonist MR-2266 on the bidirectional effect of systemic naloxone in arthritic rats. As a nociceptive test, we used the measure of the vocalization thresholds to paw pressure. The antagonists were administered at a dose (1 mg/kg i.v. naltrindole, 0.2 mg/kg i.v. MR-2266), without action per se but which prevents the analgesic effect of the delta agonist DTLET (3 mg/kg, i.v.) or the kappa agonist U-69,593 (1.5 mg/kg, i.v.) respectively, and does not influence the effect of morphine (1 mg/kg i.v.) or the mu agonist DAMGO (2 mg/kg, i.v.) in these animals. In arthritic rats injected with the delta antagonist, the paradoxical antinociceptive effect produced by 3 micrograms/kg i.v. naloxone was not significantly modified (maximal vocalization thresholds (% of control) were 146 +/- 9% versus 161 +/- 7% in the control group). By contrast, the hyperalgesic effect produced by 1 mg/kg i.v. naloxone was significantly reduced (maximal vocalization thresholds were 87 +/- 4% versus 69 +/- 5% in the control group). In rats injected with the kappa antagonist, the antinociceptive effect of the low dose of naloxone was almost abolished (mean vocalization thresholds were 115 +/- 3% versus 169 +/- 7%) whereas the hyperalgesic effect of naloxone 1 mg/kg i.v. was not significantly modified (mean vocalization thresholds = 70 +/- 3% and 65 +/- 3%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Using chromosomal lacIQ1 to control expression of genes on high-copy-number plasmids in Escherichia coli

Tachykinin NK1 receptor antagonists injected into the medulla oblongata are known to abolish vomiting induced by vagal afferent stimulation. Emetic vagal afferents have been shown to synapse with neurons in the medial solitary nucleus (mNTS), which suggests that substance P is a transmitter in the synapse. To examine this possibility, the effects of GR205171, an NK1 receptor antagonist, on retching and mNTS neuronal responses to the stimulation of abdominal vagal afferents were investigated in decerebrate dogs. GR205171 (0.05-0.7 mg kg-1, i.v.) abolished retching induced by either vagal or mNTS stimulation within 5 min. Firing of mNTS neurons in response to pulse-train and sustained vagal stimulation did not change even after the abolition of retching. Similarly, GR205171 did not have any effects on mNTS evoked potentials induced by pulse-train vagal stimulation. In about 20% of mNTS neurons, the peak firing frequency was facilitated to about 150% with repetitive pulse-train vagal stimulation. This facilitation remained even after the abolition of retching. Administration of GR205171 (1 mg ml-1, 30 microliters) into the 4th ventricle abolished retching, with latencies in excess of 120 min These results suggest that substance P does not participate in synaptic transmission between emetic vagal afferents and mNTS neurons in dogs.     

Antiemetic effects of morphine on motion- and drug-induced emesis in Suncus murinus

Emetic and antiemetic effects of morphine were investigated in Suncus murinus. Subcutaneous (up to 30 mg/kg) or intracerebroventricular administration (50 micrograms) of morphine failed to cause emesis. However, pretreatment with morphine (s.c.) prevented the emesis induced by nicotine (10 mg/kg, i.p.), copper sulfate (40 mg/kg, p.o.), cisplatin (20 mg/kg, i.p.) and motion stimulus. These results suggest that morphine has only antiemetic potency and may block a common mechanism for the emetic reflex of suncus, because the antiemetic effects of the drug were exerted irrespective of the stimulus.     

Blockade of the specific lethal effects of narcotic analgesics in the mouse

The capacity of the narcotic antagonists naloxone and nalorphine and the benzodiazepine derivatives diazepam and oxazepam to increase the LD50s of the narcotic analgesics morphine and methadone administered at convulsant doses was eveluated in the mouse. Naloxone produced a dose-related increase in the LD50s of both morphine and methadone. Iiazepam and oxazepam were also effective in increasing the LD50s of the narcotics; this effect was additive with that of naloxone. However, the maximal increase in the LD50s of the narcotics produced by pretreatment with naloxone alone was not increased further by the combined pretreatment of naloxone and a benzodiazepine. The anticonvulsant trimethadione did not elevate the LD50s of methadone, nor did it potentiate the effects of naloxone. These results suggest that the benzodiazepines may reduce the lethality of narcotic analgesics administered at high doses by a mechanism other than by an anticonvulsant effect alone. Therefore, the present results support the conclusion that the capacity to increase the convulsant LD50 of the narcotic analgesics is a general property of the narcotic antagonists.     

Melatonin inhibits naloxone-induced luteinizing hormone release in ovariectomized estrogen-primed rats

The present study aimed to examine the effect of melatonin on naloxone-induced luteinizing hormone (LH) secretion in ovariectomized estrogen-primed rats. A single intracerebroventricular (i.c.v.) injection of naloxone (mu opioid receptor blocker, 15 micrograms) or an intravenous (i.v.) injection of LH-releasing hormone (LHRH, 50 ng/kg) elicited a transient and significant increase in the serum LH concentration within 10 min. While an i.c.v. injection of 100 ng melatonin by itself did not change the basal LH release, it almost completely inhibited the naloxone-induced LH release. Melatonin (10 ng) also significantly reduced the effect of naloxone. However, an i.c.v. injection of 100 ng melatonin did not affect the LHRH-induced LH release. In separate experiments, the effect of melatonin on naloxone-induced pulsatile LH secretion was studied in estrogen-treated rats. A continuous i.v. infusion of naloxone (20 mg/kg/h) induced LH pulses in rats treated i.c.v. with saline. An i.c.v. administration of 100 ng melatonin, which by itself did not affect basal LH secretion, significantly reduced the frequency, but not the amplitude, of LH pulses induced by the naloxone infusion. These results show that melatonin has a suprapituitary site of action to inhibit naloxone-induced LH release, and suggest that melatonin has an effect in inhibiting the activity of the hypothalamic LHRH pulse generator, either directly or indirectly, in female rats.     

Inhibition of naloxone-precipitated withdrawal jumping by i.c.v. and i.t. administration of saline in morphine-dependent mice

In morphine-dependent mice, s.c. and i.t. administered naloxone produced withdrawal jumping (ED50 values were i.t. = s.c.) but i.c.v. administered naloxone failed to produce dose-dependent jumping. Peak times of jumping were earliest after i.t. administration of naloxone among the three administration routes. These results suggested that the spinal site was more sensitive to naloxone than the supraspinal site. Concomitant administration of naloxone i.c.v. and i.t. did not precipitate jumping. It was found that i.c.v. and i.t. injections of saline inhibited withdrawal jumping precipitated by s.c. administered naloxone and that the i.c.v. effect was more profound than the i.t. effect. I.c.v. injection of saline also delayed the peak time of withdrawal jumping precipitated by s.c. administered naloxone. These inhibitory effects of the injection procedures may explain the difficulty of i.c.v. administered naloxone and concomitant i.c.v. + i.t. administered naloxone to precipitate jumping, and may explain the difference in the ED50 values of naloxone and the time courses of jumping.     

Intravenous dolasetron mesilate in the prevention of postoperative nausea and vomiting in females undergoing gynecological surgery

STUDY OBJECTIVE: To evaluate a range of doses of intravenous (i.v.) dolasetron mesilate, in preventing postoperative nausea and vomiting (PONV). DESIGN: Double-blind, placebo-controlled, randomized, multicenter trial. SETTING: Ten hospitals and/or surgical centers. PATIENTS: 281 women undergoing gynecologic surgery with general anesthesia. INTERVENTIONS: Patients received one of four single, i.v. doses of dolasetron mesilate (12.5 mg, 25 mg, 50 mg, and 100 mg) or placebo administered following cessation of anesthesia. MEASUREMENTS AND MAIN RESULTS: Patients were monitored for 24 hours following study drug administration. The antiemetic efficacy of each dolasetron mesilate dose was evaluated by recording the number and timing of emetic episodes, and the effects on nausea were assessed by use of visual analog scales (VAS). Safety was assessed by adverse event reports, clinical laboratory tests, electrocardiographic (ECG) measurements, and monitoring vital signs. Complete responses (patients with no emetic episodes and no escape antiemetic medication requirements in 24 hours) were achieved by 54% in the 12.5-mg, 67% in the 25-mg, and 59% in both the 50-mg and 100-mg dolasetron mesilate dose groups, and by 43% in the placebo group. Nausea VAS assessments demonstrated that dolasetron-treated patients were significantly (p = 0.048) more likely to report no nausea (VAS score < 5 mm) than those in the placebo group. Adverse events reported generally were mild in intensity, and there were no clinically significant changes in laboratory tests, vital signs, or ECG parameters. CONCLUSIONS: Dolasetron was effective and well tolerated for the prevention of PONV in female patients undergoing gynecologic surgery with general anesthesia.     

Options in the treatment of chemotherapy-induced emesis

PURPOSE: The incidence and duration of chemotherapy-induced emesis, pathophysiology of the emetic response, and antiemetic treatment of options are reviewed. OVERVIEW: Nausea and vomiting are among the most common and debilitating side effects of cancer chemotherapy. If not controlled, these side effects may interfere with the delivery of potentially life-saving treatment. Acute, delayed, and anticipatory nausea and vomiting may be prevented by appropriate antiemetic therapy. Drug selection is based on the emetogenicity of the patient's cancer treatment and potency of the antiemetic agent. Efficacy and safety of the antiemetic regimen are often improved by combining agents with different mechanisms of action. CLINICAL IMPLICATIONS: By preventing and controlling chemotherapy-induced emesis, clinicians may improve cancer patients' functional status and quality of life significantly. Improved tolerability may lead to greater patient acceptance of chemotherapy and prevent premature withdrawal from or cessation of treatment. Controlling chemotherapy-induced emesis also helps to decrease the direct and indirect costs of managing cancer.     

Levonantradol, a new antiemetic with a high rate of side-effects for the prevention of nausea and vomiting in patients receiving cancer chemotherapy

Levonantradol, a new antiemetic compound pharmacologically related to the cannabinoids, was given to 17 patients who had experienced severe and protracted nausea and vomiting during previous courses of cancer chemotherapy, and to six patients receiving a first course of strongly emetic cytostatic treatment. Eight patients were partially protected from acute gastrointestinal disturbances. Of the 23 patients, 21 exhibited some toxicity, with six patients exhibiting major affective side-effects and 13 patients complaining of pain at the injection site. Levonantradol is an active antiemetic compound. Due to the rate of side-effects observed in our study however, we would not recommend use of this agent as an antiemetic drug.     

Adhesiveness of the free surface of a human endometrial monolayer for trophoblast as related to actin cytoskeleton

We have previously shown that angiotensin II(3-7) [Ang II(3-7)] stimulates behavioural activity of rats similar to angiotensin II (Ang II). The involvement of AT1 angiotensin receptors in stimulating the behavioural activity of rats, using their selective ligand losartan (DUP 753), was examined. Ang II(3-7), given intracerebroventricularly (i.c.v.) at a dose of 1 nmol, significantly enhanced recall of a passive avoidance behaviour, object recognition, learning of conditioned avoidance responses (CARs) and apomorphine (1 mg kg-1, i.p.) stereotypy. Losartan (1 microgram, i.c.v.) did not alter any of the behaviours except for that measuring anxiety which was diminished both, in peptide treated and in control rats. On the other hand, losartan abolished Ang II(3-7) facilitation of recall of the passive avoidance, object recognition and the increase in apomorphine stereotypy. Losartan did not influence the increased rate of CARs acquisition after the peptide. None of the treatments significantly changed locomotor activity estimated in an open field. These data point to some involvement of AT1 angiotensin receptors in the behavioural activity of Ang II(3-7).     

Amantadine: aggressive effect; effect on apomorphine-induced aggressivity in the rat

In rats characterized by aggressive behaviour induced by apomorphine, only amantadine in doses of 10 mg/kg i.v. and 50 mg/kg i.p. induces a very slight aggressive effect, but in doses of 30 and 50 mg/kg i.p. it inhibits the aggressive behaviour induced by 1 mg/kg apomorphine. The effect is dose-related and it is more pronounced when amantadine (50 mg/kg i.p.) is injected 30 min rather than 1 h before apomorphine.     

Early neuropsychological impairment in HIV-seropositive intravenous drug users: evidence from the Italian Multicentre Neuropsychological HIV Study

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.     

Inter-RNA interaction of phage phi29 pRNA to form a hexameric complex for viral DNA transportation

The order of potency of tachykinin (TK) receptor agonists suggests that TK NK-1 receptors mediate their inhibitory effect on water intake induced by intracerebroventricular (i.c.v.) injection of angiotensin II (AngII) in rats. The present study was aimed at further evaluating which TK receptor subtype mediates the effect, using selective antagonists for the TK receptor subtypes. Pulse i.c.v. injection of the TK agonist neuropeptide gamma (NP gamma), 31-250 ng/rat, markedly inhibited AngII-induced water intake. The i.c.v. injection of the NK-1 receptor antagonist SR14033, 0.5 microgram/rat, significantly reduced, while 1 microgram/rat completely abolished the inhibitory effect of NP gamma, 125 ng/rat. The selective NK-2 receptor antagonist SR48968 and the selective NK-3 receptor antagonist R820 were devoid of any effect up to the i.c.v. dose of 2 micrograms/rat. On the other hand, i.c.v. injection of SR140333, 1 microgram/rat, did not increase drinking induced by i.c.v. injection of AngII, 0.1-10 ng/rat, and did not increase drinking in water sated or water deprived rats. The results of the present study confirm that central TKergic mechanisms inhibit AngII-induced drinking in rats, and provide further evidence that TK NK-1 receptors mediate the effect. Failure of i.c.v. injected SR 140333 to increase AngII-induced drinking, as well as water intake in sated or deprived rats suggests that brain NK-1 receptor mechanisms apparently do not exert a tonic control on AngII-induced drinking and, in general, on water intake in rats. From a pharmacological point of view, the inhibitory effect of TKs on the dipsogenic action of AngII can represent a functional test for activity at central NK-1 receptors in rats.     

The efficacy of RS-25259, a long-acting selective 5-HT3 receptor antagonist, for preventing postoperative nausea and vomiting after hysterectomy procedures

We evaluated the safety and efficacy of RS-25259, a potent and long-acting selective 5-HT3 receptor antagonist, for the prevention of postoperative nausea and vomiting (PONV) in women undergoing hysterectomy procedures. In this randomized, double-blind, placebo controlled, dose-ranging study, 218 healthy, consenting women were assigned to one of the six treatment groups: placebo or RS-25259 0.1, 0.3, 1.0, 3.0, or 30 microg/kg. All patients underwent a standardized general anesthetic technique. The study medication was administered i.v. 20-30 min before the end of surgery. During the initial 24-h period after surgery, the incidence of vomiting, the need for rescue antiemetics, the time to the first episode of emesis, and administration of rescue antiemetic medication, as well as a nausea visual analog scale and verbal categorical scale scores were recorded. In addition, recovery times from the end of anesthesia and the incidences of perioperative side effects were noted. Only 30 microg/kg RS-25259 significantly decreased the incidence of vomiting and the requirement for rescue antiemetics. The largest dose of RS-25259 also delayed the time to the first emetic episode and reduced the number of treatment failures. However, no differences were found in the severity of postoperative nausea (versus saline), and postoperative headaches were more common after the administration of RS-25259 0.3-30 microg/kg i.v. In conclusion, RS-25259 30 microg/kg i.v. was effective in reducing the incidence of PONV after major gynecologic surgery, but the occurrence of headaches with the larger doses of RS-25259 is a concern. Implications: RS-25259, a long-acting 5-HT3 antagonist, was effective in reducing postoperative vomiting only at the largest dose studied (30 microg/kg). However, RS-25259 had no antinausea activity, and the larger doses were associated with an increased incidence of headaches in the postoperative period.     

Monocyte chemotactic protein 1 regulates oral tolerance induction by inhibition of T helper cell 1-related cytokines

Intracerebroventricular (i.c.v.) choline (50-150 microg) increased blood pressure and decreased heart rate in spinal cord transected, hypotensive rats. Choline administered intraperitoneally (60 mg/kg), also, increased blood pressure, but to a lesser extent. The pressor response to i.c.v. choline was associated with an increase in plasma vasopressin. Mecamylamine pretreatment (50 microg; i.c.v.) blocked the pressor, bradycardic and vasopressin responses to choline (150 microg). Atropine pretreatment (10 microg; i.c.v.) abolished the bradycardia but failed to alter pressor and vasopressin responses. Hemicholinium-3 [HC-3 (20 microg; i.c.v.)] pretreatment attenuated both bradycardia and pressor responses to choline. The vasopressin V1 receptor antagonist, (beta-mercapto-beta,beta-cyclopenta-methylenepropionyl1, O-Me-Tyr2, Arg8)-vasopressin (10 microg/kg) administered intravenously 5 min after choline abolished the pressor response and attenuated the bradycardia-induced by choline. These data show that choline restores hypotension effectively by activating central nicotinic receptors via presynaptic mechanisms, in spinal shock. Choline-induced bradycardia is mediated by central nicotinic and muscarinic receptors. Increase in plasma vasopressin is involved in cardiovascular effects of choline.     

The effect of nociceptin, an endogenous ligand for the ORL1 receptor, on rat colonic contraction and transit

To assess the role of ORL1 (opioid receptor-like 1) receptor in the bowel movement, we investigated the effect of nociceptin on colonic contraction and transit in rats. Nociceptin (0.1-100 nM) concentration-dependently caused an immediate tonic contraction followed by rhythmic waves of contractions in the isolated colon. The response to nociceptin (10 nM) was not affected by the classical opioid receptor antagonists, naloxone, naltrindole and nor-binaltorphimine. Suppression of effect of inhibitory neurotransmitters using pituitary adenylate cyclase activating polypeptide(6-38) (PACAP-(6-38); 3 microM), vasoactive intestinal polypeptide(10-28) (VIP-(10-28); 3 microM) and N(omega)-nitro-L-arginine methyl ester (L-NAME; 100 microM) did not influence the nociceptin-induced contractions. In anesthetized rats, intravenous administration of nociceptin (1 microg/kg) or morphine (1 mg/kg) caused phasic contractions in the proximal colon. Pretreatment with naloxone (300 microg/kg, i.v.) abolished the contractions induced by morphine, but not by nociceptin. The rate of large intestinal transit was dose-dependently accelerated by nociceptin (0.03-3 microg/kg, s.c.), but was retarded by morphine (1.7-5 mg/kg, s.c.). These results indicate that stimulation of ORL1 receptor accelerates the colonic contraction and transit independently from opioid receptors.     

Effects of different doses of apomorphine on GAD activity in rat substantia nigra

The effects of different doses of the dopamine (DA) receptor agonist apomorphine on the activity of the gamma-aminobutyric acid (GABA)-synthesizing enzyme glutamic acid decarboxylase (GAD, EC 4.1.1.15) were investigated in rat substantia nigra in comparison with haloperidol and sulpiride, two DA receptor blocking agents. Results obtained show that low doses (10,35 microgram/kg, s.c.) of apomorphine induce a decrease in nigral GAD activity whilst an opposite effect is observed with the highest dose (1000 microgram/kg, s.c.). No significant change is observed following injection of the intermediate doses (100 and 500 microgram/kg, s.c.). Moreover, sulpiride at the dose used (2 mg/kg, i.p.) induces an increase in GAD activity whilst no effect follows systemic injection of the same dose of haloperidol. The results are discussed in light of recent neurochemical and behavioral data.     

Experimental studies on the antitussive properties of the new xanthine derivative 1H-purine-2,6-dione, 3,7-dihydro-3-methyl-7[(5-methyl-1,2,4-oxadiazol-3-yl) methyl]. 3rd communication: examinations on opioid mechanisms and physical drug dependence

CH-13584 (formerly: KHL-8425, 1H-purine-2,6-dione, 3,7-dihydro-3-methyl-7[(5-methyl-1,2,4-oxadiazol-3-yl)methyl], CAS 115779-20-9) showed antitussive effect on the citric acid spray-induced cough model. The antitussive effect of p.o. CH-13584 was antagonised by i.m. or intracerebroventricular (i.c.v.) naloxone, i.m. nor-binaltorphimine or s.c. beta-funaltrexamine. Intracerebroventricular administration of CH-13584 induced long-lasting antitussive effect which was antagonised by coadministration of i.c.v. naloxone. CH-13584 did not bind to opioid mu, delta, kappa receptor in vitro or inhibit the [3H]diprenorphine binding in vivo. Two-week treatment with CH-13584 up to the dose of 100 mg/kg p.o. did not produce autonomic and behavioural signs of withdrawal induced either by drug withdrawal or by naloxone injection, while morphine and codeine induced characteristic opioid-type physical dependence in rats.     

Treatment of postoperative nausea and vomiting with single intravenous doses of dolasetron mesylate: a multicenter trial. Dolasetron Mesylate PONV Treatment Study Group

This study was conducted to determine the efficacy and safety of four intravenous (I.V.) doses of dolasetron, an investigational 5-HT3 receptor antagonist, for the treatment of postoperative nausea and/or vomiting (PONV) after outpatient surgery under general anesthesia. This multicenter, randomized, double-blind trial compared the antiemetic efficacy of 12.5, 25, 50, or 100 mg I.V. dolasetron with placebo over 24 h using complete response (no emetic episodes and no rescue medication), time to first emetic episode or rescue medication, and patient nausea and satisfaction with antiemetic therapy as rated by visual analog scale (VAS). Of 1557 patients enrolled, 620 patients were eligible for treatment. Complete response rates for all dolasetron doses--12.5 mg (35%), 25 mg (28%), 50 mg (29%), and 100 mg (29%)--were significantly more effective than placebo (11%, P < 0.05). There was a significant gender interaction for complete response (P < 0.01). Of the patients in the 25-mg and 100-mg dose groups, 12% and 13%, respectively, experienced no nausea (VAS score < 5 mm) versus 5% in the placebo group (P < 0.05). There were no clinically relevant changes in vital signs or laboratory values and no trends with dose for adverse events. Dolasetron is effective for treating PONV and has an adverse event profile similar to that of placebo. The 12.5-mg dose was as effective as larger doses for complete response. IMPLICATIONS: Nausea and vomiting are common problems for postsurgical patients. In this study of 620 patients undergoing surgery, a 12.5-mg dose of intravenous dolasetron, a new serotonin-receptor blocker, was significantly more effective than placebo in treating established postoperative nausea and vomiting. Dolasetron 12.5 mg was as safe as placebo.