5-HT3 receptor antagonists vs traditional agents for the prophylaxis of postoperative nausea and vomiting

Comparison of the Effectiveness of Palonosetron and Ramosetron in Preventing Postoperative Nausea and Vomiting: Updated Systematic Review and Meta-Analysis with Trial Sequential Analysis

This updated systematic review and meta-analysis with trial sequential analysis aimed to compare the efficacy of the perioperative administration of palonosetron with that of ramosetron in preventing postoperative nausea and vomiting (PONV). A total of 17 randomized controlled trials comparing the efficacy of the perioperative administration of palonosetron to that of ramosetron for preventing PONV were included. The primary outcomes were the incidences of postoperative nausea (PON), postoperative vomiting (POV), and PONV, which were measured in early, late, and overall phases. Subgroup analysis was performed on the basis of the administration time of the 5-HT3 receptor antagonist and divided into two phases: early phase and the end of surgery. A total of 17 studies with 1823 patients were included in the final analysis. The incidence of retching (relative risk [RR] = 0.525; 95% confidence interval [CI] = 0.390 to 0.707) and late POV (RR = 0.604; 95% CI = 0.404 to 0.903) was significantly lower in the palonosetron group than in the ramosetron group. No significant differences were demonstrated in the incidence of PON, PONV, complete response, use of antiemetics, and adverse effects. Subgroup analysis showed that palonosetron was superior to ramosetron in terms of early PON, late PON, overall POV, and use of rescue antiemetics when they were administered early; in terms of retching, regardless of the timing of administration. Ramosetron was superior to palonosetron in terms of early PON when they were administered late. The prophylactic administration of palonosetron was more effective than that of ramosetron in preventing the development of retching and late POV. In this meta-analysis, no significant differences in PONV prevention between the two drugs were demonstrated. Further studies are required to validate the outcomes of our study.

Experimentally designed electrochemical sensor for therapeutic drug monitoring of Ondansetron co-administered with chemotherapeutic drugs

The experimental design extracts valuable information about the main effects and interactions from the least number of experiments. The current work constructs a solid-state sensor for selective assay of Ondansetron (OND) in pharmaceutical dosage form and plasma samples. During optimization, the Design Expert^® statistical package constructed a custom design of 15 sensors with different recipes. We fed the software with the experimentally observed performance parameters for each sensor (slope, LOQ, correlation coefficient, and selectivity coefficient for sodium ions). The computer software analyzed the results to construct a prediction model for each response. The desirability function was adjusted to optimize the Nernstian slope, minimize the LOQ and selectivity coefficients, and maximize the correlation coefficient (r). The practical responses of the optimized sensor were close to those predicted by the model (slope = 60.23 mV/decade slope, LOQ = 9.09 × 10^–6 M, r = 0.999, sodium selectivity coefficient = 1.09 × 10⁻³). The sensor successfully recovered OND spiked to tablets and human plasma samples with mean percentage recoveries of 100.01 ± 1.082 and 98.26 ± 2.227, respectively. Results were statistically comparable to those obtained by the reference chromatographic method. The validated potentiometric method can be used for fast and direct therapeutic drug monitoring of OND co-administered with chemotherapeutic drugs in plasma samples.

[Effect of palonosetron, ondansetron and dexamethasone in the prevention of postoperative nausea and vomiting in video cholecystectomy with total venous anesthesia with propofol-remifentanil - randomized clinical trial]

INTRODUCTION AND OBJECTIVES

The incidence of Postoperative Nausea and Vomiting (PONV) after video cholecystectomy is high. Progress in pharmacological PONV prophylaxis includes a new generation of 5-HT₃ antagonists. This study aims to assess the effect of the 5-HT₃ antagonist in postanesthetic antiemetic management of patients submitted to laparoscopic cholecystectomy with total intravenous anesthesia.

METHODS

Sixty individuals who underwent video cholecystectomy were randomized into three groups of 20 individuals according to the treatment administered: 0.125 mg of palonosetron (Group 1); 4 mg of ondansetron associated with 4 mg of dexamethasone (Group 2); 4 mg of dexamethasone (Group 3). General intravenous anesthesia was performed with propofol, remifentanil and rocuronium. The group to which the participant belonged was concealed from the investigator who assessed drug effect. PONV was assessed using the Rhodes Scale at 12 and 24 hours after surgery. Rescue medication was 0.655 to 1.5 mg of droperidol.

RESULTS

Group 1 presented a lower incidence of PONV and required less rescue medication in the first postoperative hour. There was no significant difference among the three groups regarding PONV incidence in the first 12 postoperative hours. Groups 1 and 2 were superior to Group 3 regarding the control of PONV from 12 to 24 hours, and after rescue medication from 12 to 24 hours. Group 1 showed significantly superior nausea control in the first 12 postoperative hours.

CONCLUSIONS

The present study showed evidence that palonosetron is superior to the drugs compared regarding a protracted antiemetic effect and less requirement of rescue drugs, mainly related to its ability to completely inhibit the uncomfortable symptom of nausea.

Effect of palonosetron, ondansetron and dexamethasone in the prevention of postoperative nausea and vomiting in video cholecystectomy with total venous anesthesia with propofol-remifentanil – randomized clinical trial

Introduction and objectives

Methods

Results

Conclusions

Clinical efficacy of 5-hydroxytryptamine 3 receptor antagonists in reducing propofol injection pain, postoperative nausea/vomiting and shivering: A meta-analysis

Objective To investigate the clinical efficacy of 5-hydroxytryptamine 3 (5-HT3) receptor antagonists in reducing propofol injection pain, postoperative nausea/ vomiting, and shivering through pooling the available published data.

Methods Prospective randomized clinical studies relevant to 5-HT3 receptor antagonists in reducing propofol injection pain published before June 2019 were identified from four electronic databases, Pubmed, the Cochrane central register of controlled trials, EMBASE and Wanfang. The incidence of propofol injection pain, postoperative nausea/vomiting, and shivering in patients after 5-HT3 receptor antagonists were compared to relevant control groups by pooling the individual data through random or fixed-effect models. The publication bias was assessed by funnel plot and Egger’s line regression test.

Results After screening, a total of 19 publications relevant to 5-HT3 receptor antagonists in reducing propofol injection pain and prevention of postoperative nausea/vomiting or shivering were included for analysis. The pooled results demonstrated that 5-HT3 receptor antagonists could significantly reduce the total propofol injection pain compared to placebo (RR=0.49, 95%CI:0.45-0.54, P<0.05). For mild propofol injection pain, there was no statistical difference between 5-HT3 receptor antagonists and control groups (RR=1.07,95%CI:0.89-1.29, P>0.05). However, for moderate (RR=0.37, 95%CI: 0.31-0.46, P<0.05) and severe (RR=0.19, 95%CI:0.14-0.27, P<0.05) propofol injection pain, the incidence in 5-HT3 receptor antagonists was significantly lower than that of control groups. The pooled results also indicated that incidence of postoperative nausea/vomiting (RR=0.28, 95%CI:0.17-0.44, P<0.05) and postoperative shivering (RR=0.33, 95%CI:0.23-0.48, P<0.05) were significantly reduced in 5-HT3 receptor antagonists group compared to control group with a statistical difference.

Conclusion: In this meta-analysis, 5-HT3 receptor antagonists effectively reduced propofol injection pain, postoperative nausea/vomiting, and shivering.

Sub-hypnotic dose of propofol as antiemetic prophylaxis attenuates intrathecal morphine-induced postoperative nausea and vomiting, and pruritus in parturient undergoing cesarean section - a randomized control trial

Background

Postoperative Nausea and Vomiting (PONV) is a dreadful and uncomfortable experience that significantly detracts patients’ quality of life after surgery. This study aimed to examine the antiemetic effect of a single sub-hypnotic dose of propofol as prophylaxis for PONV.

Method

In this prospective, double-blind, randomized control trial, 345 parturients presented for elective cesarean section at the Obstetric unit of Tamale Teaching Hospital were recruited. Each recruited parturient was randomly assigned to one of three groups; Propofol group (n = 115) represented those who received propofol 0.5 mg/kg, Metoclopramide group (n = 115) represented those who received metoclopramide 10 mg and, Control group (n = 115) represented those who received 0.9% saline. Spinal anesthesia with 0.5% hyperbaric bupivacaine 7.5–10 mg, and intrathecal morphine 0.2 mg was employed for the anesthesia.

Results

The data indicate that 108 (93.9%) parturients from the control group, 10 (8.7%) from the propofol group and 8 (7.0%) from the metoclopramide group experienced some incidence of PONV. There was no significant difference in the incidence of PONV (nausea, vomiting, and none) between the propofol and the metoclopramide groups (P = 0.99; 0.31; and 0.35 respectively). Parturients who received antiemetic agents were 105 (97.2%), 1 (10.0%) and 3 (37.5%) from the control, propofol and metoclopramide groups respectively. The data indicated that 98 (85.2%) parturients from the control, 3 (2.6%) from propofol group, and 100 (87.0%) from the metoclopramide group experienced some levels of pruritus. There was a significant difference in the incidence of pruritus (mild, moderate, and no pruritus) between the metoclopramide and propofol groups (P <  0.01; P <  0.01; and P <  0.01 respectively).

Conclusion

A sub-hypnotic dose of propofol is effective as metoclopramide in the prevention of PONV in parturient undergoing cesarean section under spinal anesthesia with intrathecal morphine. Sub-hypnotic dose of propofol significantly reduces the incidence of postoperative pruritus following intrathecal morphine use.

Trial registration

Current control trial, registered at ISRCTN trial registry: ISRCTN15475205. Date registered: 03/04/2019. Retrospectively registered.

Extended release granisetron: Review of pharmacologic considerations and clinical role in the perioperative setting

In this review, we evaluate recent literature on use of ER granisetron in clinical practice as compared with current antiemetics and describe its potential uses for perioperative PONV prophylaxis and treatment. Recent literature was evaluated on ER granisetron use compared with currently used antiemetic agents ondansetron, droperidol, metoclopramide, promethazine, and dexamethasone with a focus on procedural anti-emesis. Though promising great effect, application of extended release granisetron to clinical use may be limited by it's increased relative cost.

Palonosetron, Ondansetron, and Granisetron for antiemetic prophylaxis of postoperative nausea and vomiting - A comparative evaluation

Background:

Postoperative nausea and vomiting is commonly associated with adverse consequences and hamper the postoperative recovery in spite of the availability of many antiemetic drugs and regimens for its prevention. The study was aimed to compare the prophylactic effects of intravenously administered palonosetron, ondansetron, and granisetron on prevention of postoperative nausea and vomiting after general anesthesia.

Materials and Methods:

This prospective, double-blind study, comprised 120 adult consented patients of ASA grade I and II of either gender, was carried out after approval of Institutional Ethical Committee. Patients were randomized into three equal groups of 40 patients each in double-blind manner. Group P received inj. palonosetron (0.075 mg), group O received inj. ondansetron (4 mg), and group G received inj. granisetron (2 mg) intravenously five minutes before induction of anesthesia. The need for rescue antiemetic, episode of postoperative nausea and vomiting, and side effects were observed for 12 hours in the post-anesthesia care unit. At the end of study, results were compiled and statistical analysis was done by using ANOVA, Chi-square test, and Kruskal Wallis Test. Value of P < 0.05 was considered significant.

Results:

The incidence of nausea and vomiting was maximal during the first four hours postoperatively. The complete control of postoperative nausea and vomiting for first 12 hours was achieved in 30% patients of ondansetron group, 55% patients of granisetron group, and 90% patients of palonosetron group. Safety profile was more with palonosetron.

Conclusion:

Palonosetron was comparatively highly effective to prevent the PONV after anesthesia due to its prolonged duration of action than ondansetron and granisetron.

Reevaluation of the effectiveness of ramosetron for preventing postoperative nausea and vomiting: a systematic review and meta-analysis

BACKGROUND

Ramosetron has been shown to have a very strong effect for preventing postoperative nausea and vomiting (PONV) in previous meta-analyses. However, these previous meta-analyses included a number of studies by Fujii et al. which have now been proven to have been fabricated. In the present meta-analysis, we reevaluated the effectiveness of ramosetron in preventing PONV after excluding Fujii et al.'s randomized controlled trials.

METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Web of Science. All double-blind randomized controlled trials that tested the efficacy of ramosetron compared with a placebo or other drugs as a control in the prophylaxis of PONV were considered to be eligible. The first postoperative 24 hours were divided into early (0-6 hours) and late (6-24 hours) time periods, and we collected these data separately.

RESULTS

A total of 1372 patients were included in the final analysis. Compared with a placebo, ramosetron reduced the incidence of early postoperative nausea (PON) (relative risk [RR] [95% confidence interval] 0.59 [0.47-0.73]: number needed to treat [NNT] [95% confidence interval] 6.0 [4.3-9.7]), late PON (RR 0.65 [0.49-0.85]: NNT 7.2 [4.6-16.6]), early postoperative vomiting (POV) (RR 0.48 [0.31-0.74]: NNT 14.8 [8.3-70.4]), and late POV (RR 0.50 [0.35-0.73]: NNT 12.3 [7.1-47.6]). Compared with ondansetron, ramosetron reduces early POV (RR 0.50 [0.28-0.90]: NNT 24.1 [10.7-98.0]) and late POV (RR 0.53 [0.34-0.81]: NNT 27.2 [12.0-102.0]) but not PON.

CONCLUSIONS

Ramosetron has a significant effect for preventing PONV compared with a placebo, but less than that reported in previous analyses. Ramosetron also has statistically significant differences in preventing early and late POV compared with ondansetron, but the clinical significance may be questioned because the NNTs are large.

Polymorphism of μ-Opioid Receptor Gene (OPRM1:c.118A>G) Might Not Protect against or Enhance Morphine-Induced Nausea or Vomiting

A cohort, double blind, and randomized study was conducted to investigate the effect of a single nucleotide polymorphism of the μ-opioid receptor at nucleotide position 118 (OPRM1:c.118A>G) on the association with the most common side effects (nausea or vomiting) induced by intravenous patient control analgesia (IVPCA) with morphine, including incidence and severity analysis. A total of 129 Taiwanese women undergoing gynecology surgery received IVPCA with pure morphine for postoperative pain relief. Blood samples were collected and sequenced with high resolution melting analysis to detect three different genotypes of OPRM1 (AA, AG, and GG). All candidates 24 h postoperatively will be interviewed to record the clinical phenotype with subjective complaints and objective observations. The genotyping after laboratory analysis showed that 56 women (43.4%) were AA, 57 (44.2%) were AG, and 16 (12.4%) were GG. The distribution of genotype did not violate Hardy-Weinberg equilibrium test. There was no significant difference neither between the severity and incidence of IVPCA morphine-induced side effects and genotype nor between the association between morphine consumption versus genotype. However, there was significant difference of the relation between morphine consumption and the severity and incidence of IVPCA morphine-induced nausea and vomiting. The genetic analysis for the severity and incidence of IVPCA morphine-induced nausea or vomiting showed no association between phenotype and genotype. It might imply that OPRM1:c.118A>G does not protect against IVPCA morphine-induced nausea or vomiting.

Acute pain management in the postanesthesia care unit

Pain management in the postanesthesia care unit (PACU) is continually evolving, with several new nonopioids expanding the list of available agents. Pain in the PACU is not an inevitable outcome of surgery. With careful planning, multimodal analgesic techniques instituted preoperatively will reduce pain in the PACU. Accurate assessment of the characteristics of pain will direct rational drug choices while minimizing side effects. Better management of pain in the PACU setting will likely improve patient satisfaction and facilitate shorter PACU stays.

A network meta-analysis on the efficacy of serotonin type 3 receptor antagonists used in adults during the first 24 hours for postoperative nausea and vomiting prophylaxis

BACKGROUND

The serotonin type 3 receptor antagonists (5-HT(3) antagonists) ondansetron, granisetron, tropisetron, and dolasetron are potential prophylactic agents for patients with mild to moderate risk of postoperative nausea and vomiting (PONV). A few trials have been conducted to compare the efficacy among 2 to 3 of these 4 agents. However, the comparative efficacy of all four 5-HT(3) antagonists has not yet been quantitatively investigated.

OBJECTIVE

The goal of this study was to investigate whether the 5-HT(3) antagonists--ondansetron, granisetron, tropisetron, and dolasetron-differ in efficacy when used for the prevention of PONV.

METHODS

PubMed and the Cochrane Library were searched for randomized controlled, double-blind studies measuring efficacy in terms of PONV prophylaxis. A Bayesian meta-analysis was conducted using published studies of 5-HT(3) antagonists for PONV prophylaxis. The odds of patients with no PONV and postoperative vomiting (POV) within each study arm 24 hours after surgery were the primary indices of drug efficacy. Data were extracted and analyzed via indirect comparisons using random effects Bayesian models in WinBUGS version 1.4.3.

RESULTS

A total of 85 studies were identified, representing 15,269 patients. The results indicate that granisetron was significantly better than ondansetron (odds ratio [OR] = 1.53 [95% credible interval (CI), 1.15-2.00]) and dolasetron (OR = 1.67 [95% CI, 1.12-2.38]) in preventing PONV. Four antiemetic drugs had comparable efficacy in terms of preventing POV: granisetron showed similar efficacy compared with ondansetron (OR = 1.49 [95% CI, 0.90-2.43]), tropisetron (OR = 1.69 [95% CI, 0.92-3.13]), and dolasetron (OR = 1.32 [95% CI, 0.71-2.38]). Ondansetron exhibited comparable efficacy compared with tropisetron (OR = 1.14 [95% CI, 0.66-1.96]) and dolasetron (OR = 0.88 [95% CI, 0.51-1.47]). Tropisetron and dolasetron were also similar in efficacy (OR = 0.78 [95% CI, 0.40-1.45]). All 5-HT(3) antagonists were statistically significantly better at preventing PONV or POV than placebo.

CONCLUSIONS

With respect to PONV prophylaxis, granisetron was significantly better than ondansetron and dolasetron; ondansetron, tropisetron, and dolasetron exhibited similar efficacy. With respect to POV prophylaxis, ondansetron, granisetron, tropisetron, and dolasetron seemed to have comparable efficacy.

Different doses of palonosetron for the prevention of postoperative nausea and vomiting in children undergoing strabismus surgery

Objective: The aim of this study was to evaluate the efficacy of different doses of palonosetron for the prevention of PONV in children undergoing strabismus surgery.

Patients and Method: A total of 150 children who were classified with an American Society of Anesthesiologists physical status of I, were aged between 2 and 12 years, and were undergoing strabismus surgery under general anesthesia were enrolled in the study. A random numbers table was used to assign each child to receive palonosetron 0.5, 1.0, or 1.5 μg/kg (n = 50 in each group).All episodes of PONVat the intervals of 0–2, 2–6, 6–24, and 24–48 hours were evaluated using a numeric scoring system for PONV. A p-value of <0.05 was considered statistically significant.

Results: The percentage of children with PONV during 0–48 hours after anesthesia was 24% with palonosetron 0.5 or 1.0 μg/kg, and 20% with palonosetron 1.5 μg/kg. There was no statistically significant difference between the study groups with respect to the number of children with PONV scores of 1, 2, or 3 during 0–48 hours after anesthesia. There was no statistically significant difference between the study groups with respect to the number of children with postoperative vomiting during all time periods after anesthesia. The percentage of children aged >6 years with postoperative nausea during 0–48 hours after anesthesia was 8.6%, 18.2%, and 15.4% with palonosetron 0.5, 1.0, or 1.5 μg/kg, respectively, but there was no statistically significant difference between the study groups.

Conclusion: Palonosetron doses of 0.5, 1.0, and 1.5 μg/kg are recommended for further evaluation, as they appear to be the effective doses for the prevention of PONV following strabismus surgery in children.

Pharmacologic management of postoperative nausea and vomiting

INTRODUCTION

As advances in the safety and efficacy of surgery and anesthesia have been made, other complications such as postoperative nausea and vomiting (PONV) have become more apparent. PONV occurs after 30% of all surgeries, and incidences as high as 80% have been reported among patients at high risk.

AREAS COVERED

This review provides a brief overview of the etiology and mechanisms of emesis and of known risk factors for PONV. It also covers pharmacologic therapies, appropriate management strategies, prophylactic strategies, multimodal therapy and rescue treatment.

EXPERT OPINION

The main triggers for PONV are general anesthesia with inhalational anesthetics and opioids. When given to susceptible patients, e.g., females, the risk may be as high as 80%. In such patients, opioid-free regional anesthesia would be the most logical approach. However, if general anesthesia is needed, we prefer total intravenous anesthesia as it eliminates the use of inhalational anesthetics and reduces the risk for PONV. Importantly, efficacy of antiemetic interventions is independent as long as interventions have different mechanisms. Thus, for practical purposes, we prefer to titrate the use of antiemetics according to the validated Apfel simplified risk score. If a patient has 0, 1, 2, 3 or 4 of the four risk factors, we apply a similar number of antiemetic strategies.

Palonosetron: A novel approach to control postoperative nausea and vomiting in day care surgery

Background:

Postoperative nausea and vomiting (PONV) is one of the complications which hamper the successful implementation of day care surgical procedure in spite of the availability of so many antiemetic drugs and regimens for its prevention. The aim was to compare the prophylactic effects of intravenously (IV) administered ondansetron and palonosetron on PONV prevention in patients undergoing laparoscopic gynecological surgery under general anesthesia.

Methods:

A prospective double-blind study comprised of 60 ASAI/II female patients between the age group of 25 and 40 years was carried out in the Departments of Anesthesiology and Obstetrics and Gynecology of our institute. Patients were randomly divided into two groups of 30 patients each in a double-blind manner. Group I received 8 mg of inj. ondansetron IV while group II received inj. palonosetron 0.075 mg IV 5 minutes before the induction of anesthesia. The need for rescue antiemetics, episodes of PONV and other side effects were observed for 6 hours in the postanesthesia care unit and thereafter complaints were received on phone after the discharge. At the end of study, results were compiled and statistical data was subjected to statistical analysis using Student two-tailed ‘t’ and χ² test and value of P<0.05 was considered significant.

Results:

The demographical profile of the patients was comparable. Twenty and 13.33% of the patients in group I had nausea and vomiting episodes postoperatively as compared to 6.67% and 3.33%, respectively, in group II which was statistically significant (P<0.05). Twenty percent of the patients in group I experienced significant post-op headache as compared to 6.67% in group II. The mean rescue dose of antiemetic was significantly higher (10.6 mg) in the group I as compared to group II (6.4 mg) (P=0.036). The rest of parameters were comparable and statistically nonsignificant.

Conclusions:

Palonosetron is a comparatively better drug to prevent the PONV in patients undergoing day care surgical procedures as compared to ondansetron as it has got a prolonged duration of action and favorable side-effects profile.

Efficacy of perphenazine to prevent postoperative nausea and vomiting: a quantitative systematic review

BACKGROUND AND OBJECTIVE

despite the introduction of newer antiemetics in the prevention of postoperative nausea and vomiting (PONV), perphenazine is recommended in current guidelines, as the concept of multimodal management of PONV in high-risk patients requires more than two drugs to be combined. The aim of this quantitative systematic review was to assess the efficacy and safety of perphenazine in the prophylaxis of PONV in adults and children.

METHODS

randomised controlled trials investigating the efficacy of perphenazine in the prevention of PONV in comparison with any other drug or placebo were systematically searched in MEDLINE, EMBASE, CINAHL and the Cochrane Library. Dichotomous data on the efficacy and adverse effects were combined and relative risks (RRs) as well as corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

eleven trials published between 1965 and 1999 including a total of 2081 participants fulfilled the inclusion criteria and were further analysed. In children, perphenazine 0.07 mg kg was effective in preventing vomiting (RR, 0.31; 95% CI, 0.18-0.54), whereas in adults, a dose of about 5 mg was effective for the prevention of PONV (RR, 0.50; 95% CI, 0.37-0.67). When compared with established newer drugs, for example, ondansetron, dexamethasone or droperidol, no significant differences were observed in the pooled analysis with limited data. Reporting of adverse events was poor. Transient sedation was reported in three eligible trials (RR, 0.9; 95% CI, 0.40-2.05).

CONCLUSION

there is evidence that perphenazine is effective in the prevention of PONV in children and adults without serious adverse effects compared with placebo.

Neurokinin-1 and novel serotonin antagonists for postoperative and postdischarge nausea and vomiting

PURPOSE OF REVIEW

This review will address novel options for the prevention and treatment of postoperative and postdischarge nausea and vomiting (PONV and PDNV) after ambulatory anesthesia. In particular, this paper will review the characteristics of neurokinin-1 receptor antagonists (NK1-RAs) and the new serotonin receptor antagonist (5HT3-RA) palonosetron. Finally, we will discuss strategies for prophylaxis and treatment of PONV and PDNV that address the unique concerns in ambulatory surgery patients.

RECENT FINDINGS

First, although PONV has previously been recognized to be a problem for inpatients, new research suggests that the incidence of PDNV after ambulatory surgery may be as high as 35%. Second, NK1-RAs, including aprepitant, the first approved member of this family, are significantly more efficacious than any other antiemetic for the prevention of vomiting. They are however not more effective than other interventions for the control of nausea. Third, the next generation of 5HT3-RAs, such as palonosetron, does not affect the QT interval and has a half-life of 40 h that should be advantageous for the prevention of PDNV.

SUMMARY

Because of the high incidence of PDNV, a predictive model for PDNV would be helpful to determine appropriate antiemetic interventions for each individual patient. Drugs that may be particularly favorable are the novel NK1-RA aprepitant and the next generation 5HT3-RA palonosetron.

Effect of Prophylactic Ondansetron on Postoperative Nausea and Vomiting in Patients on Preoperative Steroids Undergoing Craniotomy for Supratentorial Tumors

The exact incidence of postoperative nausea and vomiting (PONV) in patients on steroids undergoing neurosurgical procedures is not known. This prospective randomized double-blind study was planned to know the efficacy of prophylactic ondansetron in the prevention of PONV in patients on steroids as compared with placebo. Seventy adult patients of either sex who had received preoperative steroids (dexamethasone) for at least 24 hours and were scheduled to undergo craniotomy for supratentorial tumors were included. Patients were randomly allocated using a randomization chart to 1 of the 2 groups to receive either ondansetron 4 mg (group O) or 0.9% saline (group S) intravenously at the time of dural closure. Numeric Rating Scale score for nausea and pain intensity was recorded preoperatively and till 24 hours postoperatively. The 6-hour postoperative nausea score was significantly lower in group O [median, 0; interquartile range (IQR), 0 to 20] than in group S (median, 20; IQR, 0 to 20) (P<0.05). The incidence of vomiting was lower in group O (23%) than in group S (46%) (P<0.05). The total number of emetic episodes, the number of doses of rescue antiemetics given in the first 6 postoperative hours, and the total number of rescue antiemetics given were significantly lower in group O than in group S (P<0.05). Intravenous administration of 4 mg of ondansetron at the time of dural closure was effective in reducing the incidence of PONV and the rescue antiemetics requirement in patients on preoperative steroids undergoing craniotomy for supratentorial tumors.

Bystander effects of ionizing radiation can be modulated by signaling amines

Actual risk and risk management of exposure to ionizing radiation are among the most controversial areas in environmental health protection. Recent developments in radiobiology especially characterization of bystander effects have called into question established dogmas and are thought to cast doubt on the scientific basis of the risk assessment framework, leading to uncertainty for regulators and concern among affected populations. In this paper we test the hypothesis that small signaling molecules widely used throughout the animal kingdom for signaling stress or environmental change, such as 5-Hydroxytryptamine (5-HT, serotonin), l-DOPA, glycine or nicotine are involved in bystander signaling processes following ionizing radiation exposure. We report data which suggest that nano to micromolar concentrations of these agents can modulate bystander-induced cell death. Depletion of 5-HT present in tissue culture medium, occurred following irradiation of cells. This suggested that 5-HT might be bound by membrane receptors after irradiation. Expression of 5-HT type 3 receptors which are Ca(2+) ion channels was confirmed in the cells using immunocytochemistry and receptor expression could be increased using radiation or 5-HT exposure. Zofran and Kitryl, inhibitors of 5-HT type 3 receptors, and reserpine a generic serotonin antagonist block the bystander effect induced by radiation or by serotonin. The results may be important for the mechanistic understanding of how low doses of radiation interact with cells to produce biological effects.

Intravenous droperidol: a review of its use in the management of postoperative nausea and vomiting

Droperidol (Dehydrobenzperidol, Dehidrobenzoperidol, Dridol, Droleptan, Inapsine) is a dopamine D(2) receptor antagonist that has been widely used in adults and children for the prevention and treatment of postoperative nausea and vomiting (PONV) over several decades and, more recently, for the prevention of opioid-induced PONV during patient-controlled analgesia (PCA) in adults. In well controlled clinical trials of patients undergoing surgery, the efficacy of single-dose intravenous (IV) droperidol in preventing PONV was similar to that of ondansetron and dexamethasone. Droperidol significantly reduced opioid-induced PONV in adults during PCA and had a morphine-sparing effect. Droperidol is generally well tolerated and the incidence of adverse effects is similar to that observed with placebo and the serotonin 5-HT(3) receptor antagonists (setrons). Guidelines recommend that, in adults, droperidol monotherapy be considered for those at moderate risk of PONV, and droperidol in combination with a setron and/or dexamethasone be considered for patients at moderate or high risk of PONV. In children with moderate or high risk of PONV, droperidol is recommended for first-line use in some countries, and second-line use in others.

Pharmacology, pharmacogenetics, and clinical efficacy of 5-hydroxytryptamine type 3 receptor antagonists for postoperative nausea and vomiting

PURPOSE OF REVIEW

The use of selective 5-hydroxytryptamine type 3 receptor antagonists has improved the management of postoperative nausea and vomiting, but has not completely eliminated it. In this article, we discuss the pharmacology of 5-hydroxytryptamine type 3 receptor antagonists and the impact of pharmacogenetics on postoperative nausea and vomiting.

RECENT FINDINGS

Dolasetron, granisetron, ondansetron, palonosetron, and tropisetron have similar mechanisms of action but different pharmacokinetic and pharmacodynamic properties. Genetic polymorphism in the cytochrome P450 mono-oxygenase system, drug efflux transporter adenosine triphosphate-binding cassette subfamily B member 1 and 5-hydroxytryptamine type 3 receptor subunits also contribute to the interindividual variation in response to different 5-hydroxytryptamine type 3 receptor antagonists. These differences account for differences in the duration of action and clinical efficacy of these agents.

SUMMARY

Pharmacogenetics testing in patients may help differentiate responders to 5-hydroxytryptamine type 3 receptor antagonists from non-responders and allow the anesthesiologist to individualize antiemetic therapy. The cost-effectiveness of such screening in postoperative nausea and vomiting management has, however, not been evaluated. Given the multifactorial nature of postoperative nausea and vomiting, a multimodal approach to reduce or eliminate risk factors will be most successful in its management.

Determination of tropisetron in human plasma by high performance liquid chromatographic method with UV detection and its application to a bioequivalence study

A simple and sensitive high performance liquid chromatography method with UV detection was described for the determination of tropisetron in human plasma. The prepared sample solution was injected onto BDS-C(8) reversed column using a mixture of ammonium acetate (100 mM, PH adjusted to 4.3 with glacial acetic acid) and acetonitrile (80:20, v/v) as mobile phase. The wavelength of UV detector was set at 285 nm. No interference from any endogenous substances was observed during the elution of tropisetron and internal standard (ondansetron hydrochloride). The lower limit of quantification was evaluated to be 1 ng/mL. The method was used in a randomized crossover bioequivalence study of two different tropisetron preparations in 20 healthy volunteers.

The Efficacy of 5-HT3 Receptor Antagonists for the Prevention of Postoperative Nausea and Vomiting After Craniotomy: A Meta-Analysis

The purpose of this meta-analysis was to assess the efficacy of prophylactic administration of 5-HT3 receptor antagonists for postoperative nausea and vomiting in neurosurgical patients at 24 and 48+ hours. After a systematic search, 7 published randomized placebo controlled trials involving 448 craniotomy patients (222 treatment, 226 control) were included in the meta-analysis. Study drugs included ondansetron, granisetron, and tropisetron. The cumulative incidence of emesis was significantly reduced in the treatment group at 24 hours [relative risk (RR)=0.50, 95% confidence interval (CI): 0.38-0.66] and 48+ hours (RR=0.52, 95% CI: 0.36-0.75). There were no differences between the treatment and control groups in the cumulative incidence of nausea at 24 hours (RR=0.76, 95% CI: 0.54-1.06) and 48+ hours (RR=0.81, 95% CI: 0.62-1.06). The cumulative incidence of both nausea and vomiting continued to increase after 24 hours in both groups. Despite the ability of 5-HT3 receptor antagonists to reduce emetic episodes, future investigations should seek to address the control of postoperative nausea and to reduce further postoperative emesis in this population.

How can we best prevent or treat postoperative nausea and vomiting?

In pursuit of preventing or rapidly rescuing patients from postoperative nausea and vomiting, new clinical studies provide revised postoperative nausea and vomiting risk prediction tools, risk stratification formulae, comparative trials to identify the most appropriate cost-effective anti-emetics, and several trials recommending the addition of steroids in anti-emetic prophylactic multimodal approaches. Common variables that identify high-risk postoperative nausea and vomiting patients include female sex, a history of postoperative nausea and vomiting or motion sickness, young age, volatile anesthetic agents, nitrous oxide, and the administration of opioids. The most successful approach to the prevention of postoperative nausea and vomiting is multimodal, with combination anti-emetics, dexamethasone, aggressive hydration, the avoidance of opioids, and aggressive pain control.

Meta-analysis of the safety of 5-HT3 antagonists with dexamethasone or droperidol for prevention of PONV

BACKGROUND

Antiemetic guidelines recommend a combination of serotonin (5-HT3) with a second agent such as droperidol or dexamethasone. Physicians have been reluctant to employ these guidelines due to concerns over the black-box warning of droperidol and safety concerns with a steroid.

OBJECTIVE

To assess the safety profiles of 5-HT3 receptor antagonist (5-HT3RA) monotherapy and combination therapy with a steroid or droperidol for prophylaxis of postoperative nausea and vomiting (PONV).

METHODS

A MEDLINE search of English-language reports of randomized controlled trials (RCTs) was conducted (1966-September 2005) using the key terms 5-HT3, granisetron, ondansetron, dolasetron, tropisetron, PONV, postoperative, vomiting, emesis, and nausea. RCTs with treatment arms comparing 5-HT3RA monotherapy (granisetron, ondansetron, dolasetron, or tropisetron) with dexamethasone or droperidol or 5-HT3RA combinations and providing incidence data on adverse events were identified and reviewed. Within-study odds ratios with 95% confidence intervals were calculated to determine the incidence rates of all adverse events in RCTs using 5-HT3RA monotherapy and combination therapies. Overall effect sizes for frequently reported adverse events were estimated by pooling ORs using fixed- and random-effect models.

RESULTS

Pooled ORs (OR(pooled)) for adverse events with 5-HT3RA/dexamethasone versus 5-HT3RA for PONV prophylaxis were not significant for any reported adverse events or the overall incidence of adverse events; 5-HT3RA/droperidol versus 5-HT3RA was significant only for decreased headache incidence (fixed model: OR(pooled) 0.35; 95% CI 0.18 to 0.69). The OR(pooled) for 5-HT3RA/dexamethasone versus dexamethasone was not significant for any reported adverse events except headaches (fixed model OR(pooled) 1.75; 95% CI 1.01 to 3.03), none of which was serious. OR(pooled) for 5-HT3RA/droperidol versus droperidol was not significant for any reported adverse events. Avascular necrosis, occult infection, and delayed wound healing were not observed with either combination therapy. Cardiac abnormalities were observed with 5-HT3RA/droperidol therapy.

CONCLUSIONS

This meta-analysis indicates that either therapy has a safety profile similar to that of dexamethasone, droperidol, or 5-HT3RA.

Prevention and treatment of postoperative nausea and vomiting

PURPOSE

The physiology, risk factors, and prevention and treatment of postoperative nausea and vomiting (PONV) are discussed.

SUMMARY

Factors to consider when determining a patient's risk for PONV include sex, history of PONV, history of motion sickness, smoking status, duration of anesthesia, use of opioids, and type of surgery. Receptors that, when activated, can cause nausea or vomiting or both include dopamine type 2, serotonin type 3, histamine type 1, and muscarinic cholinergic type 1 receptors. Patients at moderate to high risk for PONV benefit from the administration of a prophylactic antiemetic agent that blocks one or more of these receptors. Effective agents include transdermal scopolamine, prochlorperazine, promethazine, droperidol, ondansetron, dolasetron, granisetron, and dexamethasone. In high-risk patients, combining two or more antiemetics with different mechanisms of action has been shown to be more effective than using a single agent. In addition to administering a prophylactic antiemetic, it is important to reduce the patient's risk by considering regional anesthesia, considering inducing and maintaining general anesthesia with propofol, ensuring good intravenous hydration, avoiding hypotension, and providing effective analgesia. If PONV occurs in the immediate postoperative period, it is best treated with an antiemetic agent from a pharmacologic class different from that of the prophylactic agent.

CONCLUSION

Prophylactic antiemetic therapy for PONV is effective, but combinations of agents may be necessary for high-risk patients. Nonpharmacologic strategies are also important.

Selective serotonin 5-HT3 receptor antagonists for postoperative nausea and vomiting: are they all the same?

Selective serotonin 5-HT(3) receptor antagonists have proven safe and effective for the management of postoperative nausea and vomiting. Dolasetron, granisetron, ondansetron and tropisetron selectively and competitively bind to 5-HT(3) receptors, blocking serotonin binding at vagal afferents in the gut and in the regions of the CNS involved in emesis, including the chemoreceptor trigger zone and the nucleus tractus solitarii. Despite their shared mechanism of action, 5-HT(3) receptor antagonists have different chemical structures and exhibit differences in receptor binding affinity, dose response and duration of effect. Furthermore, although dolasetron, granisetron, ondansetron and tropisetron are all extensively metabolised by the cytochrome P450 (CYP) system, different components of this system predominate in the metabolism of each of these agents. Hence, although these agents are considered equally effective in the overall population, their pharmacokinetic and pharmacodynamic differences may explain the variability in individual responses to these drugs. This review discusses the pharmacological profiles of dolasetron, granisetron, ondansetron and tropisetron, and the clinical implications of differences in their profiles.

Strategies for postoperative nausea and vomiting

Significant improvement towards a better control of postoperative nausea and vomiting have been achieved in recent years. Today, we understand better who is likely to vomit or to be nauseous after surgery. Significant amounts of the huge literature on anti-emetic interventions have been systematically reviewed, critically appraised and quantitatively synthesized. Thus, we know what anti-emetic interventions work, and how well they work, and we know their adverse effect profile. We also know which interventions have no worthwhile efficacy. A rational approach to postoperative nausea and vomiting includes three steps: identification of patients at risk, keeping the baseline risk low, and prophylactic administration of anti-emetics in those patients who are most likely to need them. For patients who are identified as high-risk patients, all measurements should be simultaneously initiated (multimodal anti-emesis).

RETRACTED: Randomized, double-blind comparison of subhypnotic-dose propofol alone and combined with dexamethasone for emesis in parturients undergoing cesarean delivery

BACKGROUND

Nausea, retching, and vomiting are common in parturients undergoing cesarean delivery performed under regional anesthesia. Subhypnotic-dose propofol 1.0 mg/kg per hour has been used to reduce the incidence of these emetic symptoms. Dexamethasone has been shown to reduce chemotherapy-induced emesis when added to an antiemetic regimen.

OBJECTIVE

The aim of this study was to examine the difference in efficacy and tolerability between subhypnoticdose propofol 1.0 mg/kg per hour alone and combined with dexamethasone 8 mg for reducing postdelivery emetic episodes in parturients undergoing cesarean delivery.

METHODS

In a randomized, double-blind trial, parturients received IV placebo (saline) or dexamethasone 8 mg followed by a continuous infusion of propofol at subhypnotic dose (1.0 mg/kg per hour) immediately after clamping of the umbilical cord. Intraoperative, postdelivery emetic episodes and safety assessments were performed by an investigator.

RESULTS

One hundred twenty parturients (mean [SD] age, 29 [5] years; age range, 21-38 years; mean [SD] height, 158 [7] cm; height range, 145-172 cm; mean [SD] body weight, 72 [8] kg; weight range, 54-90 kg) were enrolled in the study, 60 in each treatment group. The treatment groups were comparable with respect to maternal demographics and operative management. The rate of emetic symptoms (nausea, retching, and vomiting) in an intraoperative, postdelivery period was lower in patients who received the combination regimen than in those who received subhypnotic-dose propofol 1.0 mg/kg per hour alone (5% [3/60] vs 20% [12/60], respectively; P = 0.012). No clinically important adverse events attributable to the study drug were observed in either group.

CONCLUSION

In the parturients undergoing cesarean delivery performed under spinal anesthesia in this study, the combination of subhypnotic-dose propofol 1.0 mg/kg per hour and dexamethasone 8 mg was more effective than propofol alone for reducing the incidence of postdelivery emetic symptoms.

Disturbing post-operative symptoms are not reduced by prophylactic antiemetic treatment in patients at high risk of post-operative nausea and vomiting

BACKGROUND

To give prophylactics or timely treatment for post-operative nausea and vomiting (PONV) is the question. We compared the intensity and number of disturbing post-operative symptoms (i.e. pain, PONV, headache, fatigue, etc.) after prophylactic antiemetic treatment in a group of patients with >30% risk for post-operative vomiting.

METHODS

Four hundred and ninety-five patients, from three hospitals, planned for gynaecological surgery were randomized double blind. They were given granisetron 3 mg, droperidol 1.25 mg or no prophylactic antiemetic. Post-operative symptoms were followed for 24 h using a questionnaire. Symptoms were analyzed both according to their intensity and in a dichotomous fashion.

RESULTS

The intensity of different symptoms differed depending on whether droperidol, granisetron or no antiemetic had been given (P = 0.005) but the overall incidence of moderate to very severe symptoms was similar in all groups. No group fared better in general. The total number of symptoms was higher in the groups given prophylactic treatment (P < 0.05). The relative risk reduction for PONV with granisetron or droperidol prophylaxis was 27%[95% confidence interval (CI) 8-43] and 22% (2-38), respectively. The NNT (number needed to treat) for granisetron (0-24 h) was 7 and for droperidol 8. The NNH (number needed to harm) (0-24 h) for headache and visual disturbances was 6 and 13 (NS) for granisteron and, 50 (NS) and 6 for droperidol.

CONCLUSION

The intensity of symptoms or the total number of disturbing symptoms did not decrease after prophylactic antiemetic treatment in a group of patients, but the profile of disturbing symptoms changed. The relevance of post-operative symptoms in terms of patients' well-being needs to be addressed.

Intermediate dose metoclopramide is not more effective than standard dose metoclopramide for patients who present to the emergency department with nausea and vomiting: A pilot study

OBJECTIVE

To determine whether intermediate dose metoclopramide is more effective than standard dose metoclopramide for patients who present to the ED with nausea and vomiting.

METHODS

This prospective, single-blind, randomized trial was conducted in the ED of two community teaching hospitals in a convenience sample of adult patients who presented to ED with nausea and vomiting. Patients were randomized to receive either 10 mg metoclopramide IV or 0.4 mg/kg IV (up to a maximum dose of 32 mg). The outcomes measured were: change in nausea score (measured on a 11-point verbal rating scale), requirement for other anti-emetic drug administration, and presence of side-effects.

RESULTS

Fifty-eight patients were eligible for analysis (34 in 10 mg group and 24 in 0.4 mg/kg group). Median reduction in nausea score in 10 mg group was four (range 0-10, 95% CI 3-5) compared with five for 0.4 mg/kg group (range -1-10, 95% CI 4-6). This difference was not statistically significant (P = 0.629). Five patients in the 10 mg group required rescue anti-emetic, compared with three in the 0.4 mg/kg group (P = 1.00). There were no side-effects in the 10 mg group and two in the 0.4 mg/kg group.

CONCLUSION

This study suggests that there is no difference in effectiveness between 10 mg and 0.4 mg/kg of metoclopramide in the ED population with nausea and vomiting.

[Vomiting after gynecologic laparoscopy and under general anesthesia is associated with changes in excretion of serotonin metabolites]

INTRODUCTION

The efficacy of 5-HT(3)-receptor antagonists suggests a role of serotonin in the pathogenesis of postoperative nausea and vomiting (PONV). However, studies investigating the relationship between the turnover of serotonin and PONV were contradictory. Therefore we carried out a pilot study in order to find out whether results can be obtained that would justify further studies on a larger scale.

METHODS

A total of 22 patients scheduled for elective gynaecological laparoscopy were enrolled. A balanced anaesthesia using sufentanil, etomidate, cisatracurium, isoflurane and nitrous oxide was administered and 5-hydroxyindoleaceticacid (5-HIAA) concentrations in the urine were measured within the 24 h after surgery.

RESULTS

Only the patients that vomited postoperatively had a significant change in the concentrations of 5-HIAA over the time course investigated. However, comparison of urinary 5-HIAA concentrations of the group comprising patients that vomited with those that had no PONV did not reveal a significant difference.

CONCLUSIONS

Results of this study support further investigation of the relationship between serotonin and PONV and suggest that there may in fact be an association between PONV and increased serotonin turnover.

Synthesis and pharmacological characterization of a new benzoxazole derivative as a potent 5-HT3 receptor agonist

N-(2-Benzoxazol-2-yl-ethyl)-guanidine hydrochloride (10) was synthesized and pharmacologically tested. This compound showed high affinity for the 5-HT(3) receptor (K(i)=0.77 nM) and potently triggered the von Bezold-Jarisch reflex (BJR) in rats with an ED(50)=0.52 microg/kg iv and intrinsic activity next to 1 (i.a.=0.94). This stimulant effect was abolished by pretreatment with the 5-HT(3) receptor antagonist granisetron and was subject to a rapid and pronounced tachyphylaxis, due to desensitization of the peripheric cardiac 5-HT(3) receptor. Consequently, 10 acts as an in vivo 5-HT(3) antagonist inhibiting the BJR responses evoked by submaximal doses of 5-HT with an ID(50)=5.8 microg/kg iv.

A comparison of cyclizine, ondansetron and placebo as prophylaxis against postoperative nausea and vomiting in children

Nausea and vomiting is a relevant and common problem with unfavourable sequelae in children undergoing some plastic surgery procedures. There is a lack of anti-emetic trials performed in children, with only a few investigating the roles of the older anti-emetic agents such as cyclizine compared with newer ones such as ondansetron. This randomised, controlled, double-blind study examined the effectiveness of a single dose of ondansetron (0.1 mg x kg-1), cyclizine (20 mg) and placebo (normal saline) in the prevention of postoperative nausea and vomiting in 150 children (mean age 3.6 years) undergoing plastic genitourinary procedures. Rates of previous postoperative nausea and vomiting and motion sickness were comparable across the groups. Postoperative vomiting was significantly reduced with ondansetron prophylaxis (p = 0.006) but there was no detectable anti-emetic effect with cyclizine. Furthermore, cyclizine caused pain on injection (p < 0.001).

Management of postoperative nausea and vomiting in children

In spite of improvements in anesthesia techniques, the 'big little problem' of postoperative nausea and vomiting (PONV) still exists. PONV can prolong recovery room stay and hospitalization, and is one of the most common causes of hospital readmission after day surgery. While there is little evidence to support prophylactic administration of antiemetics in patients at low risk of PONV, the higher risk population could benefit from the use of adequate antiemetic drugs. A wide variety of pharmacological approaches have been reported to be effective, as well as some nonpharmacological approaches. Antiemetic drugs available to treat or prevent PONV include phenothiazines, antihistamines, anticholinergics, benzamides, butyrophenones and 5-HT(3) antagonists. Since available drugs still present undesired adverse effects and are not completely able to control PONV, clinical investigations are ongoing for more effective and better tolerated agents; indeed, the ideal antiemetic drug might be cost-effective for routine use.

Current pharmacotherapy for the treatment of severe burns

The pharmacotherapy of burn care has evolved from the first topical antibiotics instituted > 30 years ago. These have helped greatly to reduce the incidence of burn wound sepsis, but a better understanding of the principles of burn care has resulted in earlier burn wound excision and complete coverage with autograft, cadaver skin, synthetic dressings, and amnion. This has markedly reduced septic complications and ameliorated the hypermetabolic response to burn injury. The hypermetabolic response, which is mediated by hugely increased levels of circulating catecholamines, prostaglandins, glucagon and cortisol, causes profound skeletal muscle catabolism, immune deficiency, peripheral lipolysis, reduced bone mineralisation, reduced linear growth, and increased energy expenditure. Supportive therapy and pharmacological manipulation, acutely and during rehabilitation, with growth hormone, insulin and related proteins, oxandrolone and propranolol can ameliorate the hypermetabolic response, improving survival and long-term outcome. Despite judicious use of topical and systemic antibiotics, opportunistic nosocomial bacterial resistance threatens to annul the improved survival of patients with severe burns. Patterns of emerging resistance encountered in burn units need to be considered, in light of a decreasing antibiotic armamentarium. A holistic approach to pharmacotherapy of severely burned patients including current practice in antimicrobial control, analgesia, sedation, and anxiety management is required. Current therapy of frequently encountered problems, such as post-burn pruritus, prophylaxis of deep venous thrombosis and peptic ulceration, and pharmacological manipulation of inhalation injury in the burned patient is described. Current pharmacotherapy to ameliorate psychosocial problems associated with burns such as acute stress disorder, depression and post traumatic stress disorder are discussed. Better analgesics, newer antibiotics and immune stimulating drugs are required to reduce mortality and morbidity in large burns.

The efficacy and cost-effectiveness of prophylactic 5-hydroxytryptamine3 receptor antagonists: tropisetron, ondansetron and dolasetron

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.

RETRACTED ARTICLE: Combination Antiemetic Regimens for Prevention of Postoperative Nausea and Vomiting : Focus on High-Risk Patients

None of the available antiemetics is entirely effective, perhaps because most of them act through the blockade of one receptor. There is a possibility that a combination of antiemetics with different sites of activity would be more effective than one drug alone for prophylaxis against postoperative nausea and vomiting (PONV).The clinical use of combined traditional antiemetics, including antihistamines (e.g. diphenhydramine), butyrophenones (e.g. droperidol) and benzamides (e.g. metoclopramide), for the prevention of PONV is limited because of the possibility of additive central nervous system toxicity, such as delayed emergence, drowsiness and extrapyramidal reactions. The efficacy of a combination of a serotonin 5-HT₃ receptor antagonist (ondansetron, granisetron or tropisetron) and dexamethasone is superior to that of 5-HT₃ receptor antagonists alone for the prevention of PONV, suggesting that dexamethasone enhances the antiemetic efficacy of 5-HT₃ receptor antagonists. The combination of a 5-HT₃ receptor antagonist with a traditional antiemetic (droperidol, metoclopramide or promethazine) acting at a different emetogenic receptor is more effective in reducing the incidence of PONV than each antiemetic alone acting at one receptor site. The risk of undesirable adverse effects does not increase with the combination of a 5-HT₃ receptor antagonist and a traditional antiemetic at the doses commonly used for PONV, because of the absence of drug interactions. The combination of a 5-HT₃ receptor antagonist (ondansetron) with other agents (propofol and CP-122721) reduces the incidence of PONV to a greater degree than monotherapy. However, no data are available for the combination of 5-HT₃ receptor antagonists and small doses of propofol for the prevention of PONV.Further studies are needed to evaluate the efficacy and safety of combination antiemetic regimens for PONV. Knowledge regarding combinations of these antiemetic drugs may be necessary to completely prevent PONV.

Nausea and Vomiting

Nausea and vomiting are rather stereotyped symptoms. The challenge is that nausea and vomiting have many different causes and, in some patients, management may be rather complex. The clue is to determine the causal factor early. It helps to separate acute vomiting (<48 hours onset) from chronic vomiting. In acute vomiting, the causal factor or factors are most often evident. Symptomatic treatment with parenteral central-type antiemetics is the preferred treatment. Histamine-1 receptor antagonists, phenothiazines, butyrophenones, and corticosteroids are suitable drugs. For specific types of acute vomiting, for example, chemotherapy-related vomiting, the 5-HT3 receptor antagonists are costlier but effective drugs with minimal side effects. Sometimes, oral and parenteral administration of the above-mentioned drugs may be combined. The origin of chronic vomiting is often obscure, requires specialized investigation, and the causative factor may be uncorrectable. Symptomatic treatment requires a value judgement. If delayed gastric emptying is a contributing factor, prokinetic agents (metoclopramide, erythromycin, cisapride in special cases, if authorized) may prove useful. Otherwise, symptomatic treatment with central antiemetics is the only recourse. Some patients with unexplained vomiting present with psychological disturbances that act as magnifying or contributing factors and may be helped by psychotherapeutics.