The analgesic efficacy of tramadol is impaired by concurrent administration of ondansetron

Prevalence, Attributes, and Risk Factors of QT-Interval-Prolonging Drugs and Potential Drug-Drug Interactions in Cancer Patients: A Prospective Study in a Tertiary Care Hospital

Introduction Cancer chemotherapy regimens include multiple classes of adjuvant drugs as supportive therapy. Because of the concurrent intake of other drugs (like antiemetics, antidepressants, analgesics, and antimicrobials), there is a heightened risk for possible QT interval prolongation. There is a dearth of evidence in the literature regarding the usage of QT-prolonging anticancer drugs and associated risk factors that have the propensity to prolong QT interval. The purpose was to explore the extent of the use of QT-interval-prolonging drugs and potential QT-prolonging drug-drug interactions (QT-DDIs) in cancer patients attending OPD in a tertiary-care hospital. Methods This was a hospital-based, cross-sectional, observational study. Risk stratification of QT-prolonging drugs for torsades de pointes (TdP) was done by the Arizona Center for Education and Research on Therapeutics (AzCERT)/CredibleMeds-lists, and potential QT-DDIs were determined with four online DDI-checker-software. Results In 1331 cancer patients, the overall prevalence of potential QT-prolonging drug utilization was 97.3%. Ondansetron, pantoprazole, domperidone, and olanzapine were the most frequent QT-prolonging drugs in cancer patients. The top six antineoplastics with potential QT-prolonging and torsadogenic actions were capecitabine, oxaliplatin, imatinib, bortezomib, 5-fluorouracil, and bendamustine. Evidence-based pragmatic QTc interval prolongation risk assessment tools are imperative for cancer patients. Conclusion This study revealed a high prevalence of QT-prolonging drugs and QT-DDIs among cancer patients who are treated with anticancer and non-anticancer drugs. As a result, it's critical to take precautions, stay vigilant, and avoid QT-prolonging in clinical situations. Evidence-based pragmatic QTc interval prolongation risk assessment tools are needed for cancer patients.

Pharmacological profile and potential drug interactions in ovarian cancer hospitalized patients

The aim of this study was to identify the main therapeutic classes prescribed to ovarian cancer patients and the potential drug interactions (PDI) during hospitalization. This descriptive retrospective work was carried out in a referral gynecological cancer hospital from the Brazilian public health system. The first 24 h inpatients’ prescriptions were evaluated to obtain the pharmacological profile data. Clinical and epidemiological characteristics were collected through the analysis of electronic medical records. A total of 236 patients were included in the study, of which 154 (65.25%) had PDI, with a mean of 1.43 ± 1.76 interactions per patient. The main therapeutic classes prescribed were analgesics and antiemetics (35%), compatible with the oncologic supportive care. All PDI identified (n = 331) were categorized by severity, using the Micromedex database, resulting in: 1.51% contraindicated, 67.67% major, 24.77% moderate, and 6.04% minor. The more prevalent PDI were ondansetron/tramadol (22.05%) and metoclopramide/tramadol (7.25%), both major. An association between PDI and polypharmacy was observed, which did not occur between age or length of stay. Ongoing prescription review by the pharmaceutical team is necessary to identify, monitor, and manage PDI-related adverse events and carry out required interventions with patients, physicians, and nurses. Taken together the data showed that even in a specialized hospital, the complexity of the pharmacotherapy can cause harm to the ovarian cancer patient. The clinical pharmacist acting in a multidisciplinary team is important for improving patient safety in oncology services.

The Effect of Ondansetron on the Analgesic Efficacy of Tramadol in Patients Undergoing Laparoscopic Cholecystectomy

Purpose

Investigating the effect of ondansetron on the efficacy of tramadol in patients undergoing laparoscopic cholecystectomy.

Methods

Sixty American Society of Anesthesiologists (ASA) I-II patients over the age of 18 who underwent laparoscopic cholecystectomy were included in this study. All patients were given 1 mg/kg tramadol intravenously (iv) during the intraoperative period. Patients were randomly assigned to receive either 4 mg ondansetron (Group O) or 2 mL saline (Group S). Postoperative tramadol consumption, pain score (NRS), intensity of nausea (NRS), presence of vomiting, consumption of rescue analgesics and antiemetics, and patient satisfaction were recorded.

Results

A total of 60 patients were enrolled in the study; five patients were excluded due to deviation from the protocol. Data from 55 patients (Group O: 28 patients, Group S: 27 patients) were evaluated in the study. No differences between the two groups were detected for postoperative consumption of tramadol, pain score (NRS), intensity of nausea (NRS), presence of vomiting, consumption of rescue analgesics and antiemetics, and patient satisfaction.

Conclusions

The results showed that coadministration of tramadol and ondansetron did not change tramadol consumption during the postoperative 24 hours after laparoscopic cholecystectomy. Clinical trial registration number is as follows: https://clinicaltrials.gov/ct2/show/NCT04745273-01/31/2021.

The Effects of Ondansetron on the Analgesic Action of Intravenous Acetaminophen after Tonsillectomy in Children: A Triple-Blind Randomized Controlled Trial

Introduction

Severe pain, nausea, and vomiting after tonsillectomy surgery are among the issues that not only affect patient satisfaction but also may result in complications and delay patient discharge. This study was conducted to assess the effect of intravenous administration of ondansetron on the analgesic action of intravenous acetaminophen after tonsillectomy in children. Materials and methods. This randomized controlled trial was conducted on 53 children between the age of 3 and 12 years old who were referred to Besat Hospital Hamadan, Iran, for tonsillectomy. Patients were randomly assigned to two groups. The intervention group (I) received intravenous acetaminophen plus 0.1 mg/kg ondansetron intravenously while the control group (C) received intravenous acetaminophen plus 2 ml of normal saline intravenously. Postoperative pain severity was assessed using the Children's Hospital Eastern Ontario Pain Scale (CHEOPS). Frequency of nausea, vomiting, and need for analgesic was assessed and recorded four times, at recovery unit, after 6, 12, and 24 hours postsurgery. Data analysis was performed at 95% confidence level using the statistical package for social sciences (SPSS) software version 21.

Results

The number of patients in groups I and C was 27 and 26 patients, respectively. Mean pain score in I and C groups was 4.48 and 2.88 at recovery unit, 2.74 and 2.04 after 6 hours, 1.67 and 0.81 after 12 hours, and 0.67 and 0.20 after 24 hours postsurgery, respectively. Frequency of nausea at recovery unit was 23.1% in I group and 0.0% in group C (p = 0.010) while the mean number of analgesic requirements in I and C groups was 1.07 and 0.56 times, respectively (p = 0.027).

Conclusions

Intravenous administration of 0.1 mg/kg ondansetron reduces the analgesic action of intravenous acetaminophen after tonsillectomy in 3 to 12-year-old children.

Organic Cation Transporter 1 an Intestinal Uptake Transporter: Fact or Fiction?

Intestinal transporter proteins are known to affect the pharmacokinetics and in turn the efficacy and safety of many orally administered drugs in a clinically relevant manner. This knowledge is especially well-established for intestinal ATP-binding cassette transporters such as P-gp and BCRP. In contrast to this, information about intestinal uptake carriers is much more limited although many hydrophilic or ionic drugs are not expected to undergo passive diffusion but probably require specific uptake transporters. A transporter which is controversially discussed with respect to its expression, localization and function in the human intestine is the organic cation transporter 1 (OCT1). This review article provides an up-to-date summary on the available data from expression analysis as well as functional studies in vitro, animal findings and clinical observations. The current evidence suggests that OCT1 is expressed in the human intestine in small amounts (on gene and protein levels), while its cellular localization in the apical or basolateral membrane of the enterocytes remains to be finally defined, but functional data point to a secretory function of the transporter at the basolateral membrane. Thus, OCT1 should not be considered as a classical uptake transporter in the intestine but rather as an intestinal elimination pathway for cationic compounds from the systemic circulation.

Drugs for preventing postoperative nausea and vomiting in adults after general anaesthesia: a network meta-analysis

BACKGROUND

Postoperative nausea and vomiting (PONV) is a common adverse effect of anaesthesia and surgery. Up to 80% of patients may be affected. These outcomes are a major cause of patient dissatisfaction and may lead to prolonged hospital stay and higher costs of care along with more severe complications. Many antiemetic drugs are available for prophylaxis. They have various mechanisms of action and side effects, but there is still uncertainty about which drugs are most effective with the fewest side effects.

OBJECTIVES

• To compare the efficacy and safety of different prophylactic pharmacologic interventions (antiemetic drugs) against no treatment, against placebo, or against each other (as monotherapy or combination prophylaxis) for prevention of postoperative nausea and vomiting in adults undergoing any type of surgery under general anaesthesia • To generate a clinically useful ranking of antiemetic drugs (monotherapy and combination prophylaxis) based on efficacy and safety • To identify the best dose or dose range of antiemetic drugs in terms of efficacy and safety SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, and reference lists of relevant systematic reviews. The first search was performed in November 2017 and was updated in April 2020. In the update of the search, 39 eligible studies were found that were not included in the analysis (listed as awaiting classification).

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing effectiveness or side effects of single antiemetic drugs in any dose or combination against each other or against an inactive control in adults undergoing any type of surgery under general anaesthesia. All antiemetic drugs belonged to one of the following substance classes: 5-HT₃ receptor antagonists, D₂ receptor antagonists, NK₁ receptor antagonists, corticosteroids, antihistamines, and anticholinergics. No language restrictions were applied. Abstract publications were excluded.

DATA COLLECTION AND ANALYSIS

A review team of 11 authors independently assessed trials for inclusion and risk of bias and subsequently extracted data. We performed pair-wise meta-analyses for drugs of direct interest (amisulpride, aprepitant, casopitant, dexamethasone, dimenhydrinate, dolasetron, droperidol, fosaprepitant, granisetron, haloperidol, meclizine, methylprednisolone, metoclopramide, ondansetron, palonosetron, perphenazine, promethazine, ramosetron, rolapitant, scopolamine, and tropisetron) compared to placebo (inactive control). We performed network meta-analyses (NMAs) to estimate the relative effects and ranking (with placebo as reference) of all available single drugs and combinations. Primary outcomes were vomiting within 24 hours postoperatively, serious adverse events (SAEs), and any adverse event (AE). Secondary outcomes were drug class-specific side effects (e.g. headache), mortality, early and late vomiting, nausea, and complete response. We performed subgroup network meta-analysis with dose of drugs as a moderator variable using dose ranges based on previous consensus recommendations. We assessed certainty of evidence of NMA treatment effects for all primary outcomes and drug class-specific side effects according to GRADE (CINeMA, Confidence in Network Meta-Analysis). We restricted GRADE assessment to single drugs of direct interest compared to placebo.

MAIN RESULTS

We included 585 studies (97,516 randomized participants). Most of these studies were small (median sample size of 100); they were published between 1965 and 2017 and were primarily conducted in Asia (51%), Europe (25%), and North America (16%). Mean age of the overall population was 42 years. Most participants were women (83%), had American Society of Anesthesiologists (ASA) physical status I and II (70%), received perioperative opioids (88%), and underwent gynaecologic (32%) or gastrointestinal surgery (19%) under general anaesthesia using volatile anaesthetics (88%). In this review, 44 single drugs and 51 drug combinations were compared. Most studies investigated only single drugs (72%) and included an inactive control arm (66%). The three most investigated single drugs in this review were ondansetron (246 studies), dexamethasone (120 studies), and droperidol (97 studies). Almost all studies (89%) reported at least one efficacy outcome relevant for this review. However, only 56% reported at least one relevant safety outcome. Altogether, 157 studies (27%) were assessed as having overall low risk of bias, 101 studies (17%) overall high risk of bias, and 327 studies (56%) overall unclear risk of bias. Vomiting within 24 hours postoperatively Relative effects from NMA for vomiting within 24 hours (282 RCTs, 50,812 participants, 28 single drugs, and 36 drug combinations) suggest that 29 out of 36 drug combinations and 10 out of 28 single drugs showed a clinically important benefit (defined as the upper end of the 95% confidence interval (CI) below a risk ratio (RR) of 0.8) compared to placebo. Combinations of drugs were generally more effective than single drugs in preventing vomiting. However, single NK₁ receptor antagonists showed treatment effects similar to most of the drug combinations. High-certainty evidence suggests that the following single drugs reduce vomiting (ordered by decreasing efficacy): aprepitant (RR 0.26, 95% CI 0.18 to 0.38, high certainty, rank 3/28 of single drugs); ramosetron (RR 0.44, 95% CI 0.32 to 0.59, high certainty, rank 5/28); granisetron (RR 0.45, 95% CI 0.38 to 0.54, high certainty, rank 6/28); dexamethasone (RR 0.51, 95% CI 0.44 to 0.57, high certainty, rank 8/28); and ondansetron (RR 0.55, 95% CI 0.51 to 0.60, high certainty, rank 13/28). Moderate-certainty evidence suggests that the following single drugs probably reduce vomiting: fosaprepitant (RR 0.06, 95% CI 0.02 to 0.21, moderate certainty, rank 1/28) and droperidol (RR 0.61, 95% CI 0.54 to 0.69, moderate certainty, rank 20/28). Recommended and high doses of granisetron, dexamethasone, ondansetron, and droperidol showed clinically important benefit, but low doses showed no clinically important benefit. Aprepitant was used mainly at high doses, ramosetron at recommended doses, and fosaprepitant at doses of 150 mg (with no dose recommendation available). Frequency of SAEs Twenty-eight RCTs were included in the NMA for SAEs (10,766 participants, 13 single drugs, and eight drug combinations). The certainty of evidence for SAEs when using one of the best and most reliable anti-vomiting drugs (aprepitant, ramosetron, granisetron, dexamethasone, ondansetron, and droperidol compared to placebo) ranged from very low to low. Droperidol (RR 0.88, 95% CI 0.08 to 9.71, low certainty, rank 6/13) may reduce SAEs. We are uncertain about the effects of aprepitant (RR 1.39, 95% CI 0.26 to 7.36, very low certainty, rank 11/13), ramosetron (RR 0.89, 95% CI 0.05 to 15.74, very low certainty, rank 7/13), granisetron (RR 1.21, 95% CI 0.11 to 13.15, very low certainty, rank 10/13), dexamethasone (RR 1.16, 95% CI 0.28 to 4.85, very low certainty, rank 9/13), and ondansetron (RR 1.62, 95% CI 0.32 to 8.10, very low certainty, rank 12/13). No studies reporting SAEs were available for fosaprepitant. Frequency of any AE Sixty-one RCTs were included in the NMA for any AE (19,423 participants, 15 single drugs, and 11 drug combinations). The certainty of evidence for any AE when using one of the best and most reliable anti-vomiting drugs (aprepitant, ramosetron, granisetron, dexamethasone, ondansetron, and droperidol compared to placebo) ranged from very low to moderate. Granisetron (RR 0.92, 95% CI 0.80 to 1.05, moderate certainty, rank 7/15) probably has no or little effect on any AE. Dexamethasone (RR 0.77, 95% CI 0.55 to 1.08, low certainty, rank 2/15) and droperidol (RR 0.89, 95% CI 0.81 to 0.98, low certainty, rank 6/15) may reduce any AE. Ondansetron (RR 0.95, 95% CI 0.88 to 1.01, low certainty, rank 9/15) may have little or no effect on any AE. We are uncertain about the effects of aprepitant (RR 0.87, 95% CI 0.78 to 0.97, very low certainty, rank 3/15) and ramosetron (RR 1.00, 95% CI 0.65 to 1.54, very low certainty, rank 11/15) on any AE. No studies reporting any AE were available for fosaprepitant. Class-specific side effects For class-specific side effects (headache, constipation, wound infection, extrapyramidal symptoms, sedation, arrhythmia, and QT prolongation) of relevant substances, the certainty of evidence for the best and most reliable anti-vomiting drugs mostly ranged from very low to low. Exceptions were that ondansetron probably increases headache (RR 1.16, 95% CI 1.06 to 1.28, moderate certainty, rank 18/23) and probably reduces sedation (RR 0.87, 95% CI 0.79 to 0.96, moderate certainty, rank 5/24) compared to placebo. The latter effect is limited to recommended and high doses of ondansetron. Droperidol probably reduces headache (RR 0.76, 95% CI 0.67 to 0.86, moderate certainty, rank 5/23) compared to placebo. We have high-certainty evidence that dexamethasone (RR 1.00, 95% CI 0.91 to 1.09, high certainty, rank 16/24) has no effect on sedation compared to placebo. No studies assessed substance class-specific side effects for fosaprepitant. Direction and magnitude of network effect estimates together with level of evidence certainty are graphically summarized for all pre-defined GRADE-relevant outcomes and all drugs of direct interest compared to placebo in http://doi.org/10.5281/zenodo.4066353.

AUTHORS' CONCLUSIONS

We found high-certainty evidence that five single drugs (aprepitant, ramosetron, granisetron, dexamethasone, and ondansetron) reduce vomiting, and moderate-certainty evidence that two other single drugs (fosaprepitant and droperidol) probably reduce vomiting, compared to placebo. Four of the six substance classes (5-HT₃ receptor antagonists, D₂ receptor antagonists, NK₁ receptor antagonists, and corticosteroids) were thus represented by at least one drug with important benefit for prevention of vomiting. Combinations of drugs were generally more effective than the corresponding single drugs in preventing vomiting. NK₁ receptor antagonists were the most effective drug class and had comparable efficacy to most of the drug combinations. 5-HT₃ receptor antagonists were the best studied substance class. For most of the single drugs of direct interest, we found only very low to low certainty evidence for safety outcomes such as occurrence of SAEs, any AE, and substance class-specific side effects. Recommended and high doses of granisetron, dexamethasone, ondansetron, and droperidol were more effective than low doses for prevention of vomiting. Dose dependency of side effects was rarely found due to the limited number of studies, except for the less sedating effect of recommended and high doses of ondansetron. The results of the review are transferable mainly to patients at higher risk of nausea and vomiting (i.e. healthy women undergoing inhalational anaesthesia and receiving perioperative opioids). Overall study quality was limited, but certainty assessments of effect estimates consider this limitation. No further efficacy studies are needed as there is evidence of moderate to high certainty for seven single drugs with relevant benefit for prevention of vomiting. However, additional studies are needed to investigate potential side effects of these drugs and to examine higher-risk patient populations (e.g. individuals with diabetes and heart disease).

Ketamine Versus Tramadol As an Adjunct To PCA Morphine for Postoperative Analgesia After Major Upper Abdominal Surgery: a Prospective, Comparative, Randomized Trial

Background and aims

Patient-controlled analgesia (PCA) with morphine is commonly used to provide analgesia following major surgery, but is not sufficient as a monotherapy strategy. This study aimed to compare the adjunctive analgesic effect of ketamine versus tramadol on postoperative analgesia provided via PCA-morphine in patients undergoing major upper abdominal surgeries.

Methods

Forty-two patients undergoing elective major upper abdominal surgery under general anesthesia were allocated to receive either ketamine (load dose of 0.5 mg kg⁻¹ followed by a continuous infusion of 0.12 mg kg⁻¹ h⁻¹ up to 48 postoperative hours; ketamine group, n = 21) or tramadol (load dose of 1 mg kg⁻¹ followed by a continuous infusion of 0.2 mg kg⁻¹ h⁻¹ up to 48 postoperative hours; tramadol group, n = 21) in addition to their standard postoperative analgesia with PCA-morphine. Postoperative data included morphine consumption, visual analog scale (VAS) scores, and side effects during the first 48 postoperative hours after PCA-morphine initiation.

Results

There were no significant differences in patient demographic and intraoperative data between the two groups. Tramadol group had significantly less total morphine consumption during the first 48 postoperative hours (28.905 [16.504] vs 54.524 [20.846] mg [p < 0.001]) and presented significantly lower VAS scores at rest and mobilization (p < 0.05) than the ketamine group. No statistical difference was recorded between the two groups (p > 0.05) regarding postoperative cough, sedation, hallucinations, pruritus, urine retention, and postoperative nausea and vomiting. However, patients in the ketamine group reported dry mouth more frequently than patients in the tramadol group (p = 0.032).

Conclusions

Postoperative administration of tramadol was superior to ketamine due to significantly reduced opioid consumption and better pain scores in patients receiving PCA-morphine after major upper abdominal surgery.

Ramosetron Does Not Reduce the Analgesic Efficacy of Tramadol after Gynecological Laparoscopic Surgery

Background

The effect of ramosetron on the analgesic action of tramadol is not well known when ramosetron is added to intravenous-tramadol patient-controlled analgesia (PCA) and infused continuously. The aim of this randomized noninferiority study was to evaluate the effects of ramosetron on the analgesic action of tramadol when it is administered simultaneously in women undergoing laparoscopic gynecology who are receiving tramadol via IV PCA.

Method

This study used a prospective, randomized, controlled, noninferiority clinical trial design and compared the analgesic effect of tramadol plus ramosetron with that of tramadol only. A total of 110 postoperative patients, who were using IV PCA tramadol, were randomly assigned either to a group receiving ramosetron (group R, n=49) or to a group that received the same volume of normal saline continuously (group N, n=51). Observation time points for cumulative tramadol consumption were the first hour, and every 4 h up to 12 h and then 24 h after surgery. Pain intensity at rest and during movement, coughing, and nausea scores, the analgesic and antiemetic doses used, side effects, and patient satisfaction were evaluated 1 and 24 h after surgery.

Results

Groups R and N received, respectively, 88 ± 55 vs. 79 ± 42 mg tramadol (P=0.511) after 1 h, 211 ± 122 vs. 198 ± 109 mg cumulative tramadol (P=0.610) after 4 h, 244 ± 150 vs. 231 ± 134 mg cumulative tramadol (P= 0.793) after 8 h, 250 ± 156 vs. 247 ± 153 mg cumulative tramadol (P=0.972) after 12 h, and 294 ± 190 vs. 284 ± 178 mg cumulative tramadol (P=0.791) after 24 h, postsurgery. Tramadol plus ramosetron was shown to be not significantly inferior to tramadol alone in alleviating the postoperative pain.

Conclusions

The analgesic effect of tramadol combined with ramosetron was found to be noninferior to tramadol alone for postoperative PCA after laparoscopic gynecologic surgery.

Efficacy of Tramadol for Pain Management in Patients Receiving Strong Cytochrome P450 2D6 Inhibitors

STUDY OBJECTIVE

Tramadol is metabolized by cytochrome P450 (CYP) 2D6 to form an active metabolite that exhibits its analgesic effect. Medications that inhibit this enzyme are used often in practice, yet the clinical impact of this interaction on the analgesic effects of tramadol has yet to be fully described. The objective was to determine whether a clinically relevant decrease in pain control is observed in patients taking scheduled tramadol concomitantly with a strong CYP2D6 inhibitor.

DESIGN

Retrospective cohort study.

SETTING

Large health care system.

PATIENTS

One hundred fifty-two adult inpatients who received scheduled tramadol for at least 24 hours with (76 patients) or without (76 patients) a strong CYP2D6 inhibitor between January 1, 2012, and February 28, 2017, were included in the analysis. Patients hospitalized for opioid use disorder or those receiving substandard dosing of tramadol were excluded.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was mean breakthrough opiate consumption in the presence and absence of CYP2D6 inhibitors. Secondary outcomes included mean pain scores, length of hospital stay, tramadol discontinuation rates, and prespecified subgroup analyses based on patient sex, race, and specific CYP2D6 inhibitor administered. Patients receiving concurrent CYP2D6 inhibitors required significantly more breakthrough morphine milligram equivalents per day compared with patients receiving scheduled tramadol without CYP2D6 inhibitors (geometric mean ± SD 18.2 ± 6.3 vs 5.7 ± 6.7 mg morphine milligram equivalents, p<0.001). No significant differences existed between cohorts for mean pain score, length of hospital stay, or tramadol discontinuation rate.

CONCLUSION

This study demonstrated a clinically relevant decrease in the efficacy of tramadol when used for pain control in patients receiving a strong CYP2D6 inhibitor. These results should encourage clinicians to review medication lists for this interaction and adjust regimens accordingly to ensure adequate pain control.

Managing Postoperative Analgesic Failure: Tramadol Versus Morphine for Refractory Pain in the Post-Operative Recovery Unit

Objective

This study aimed to discover whether co-analgesia with tramadol or additional morphine was more effective for patients who still had severe pain despite being given 10 mg intravenous morphine in the post-anesthesia care unit (PACU).

Methods

All eligible patients were consented and recruited to the trial pre-operatively, but only a small subgroup – whose pain was not successfully controlled (pain score 6/10 or more) after receiving 10 mg of morphine in the PACU—were then randomized to enter the trial and receive, in a double blinded fashion, the analgesic study drug; which consisted of either a further 10 mg of morphine, or 100 mg of tramadol, titrated intravenously to control their pain. The groups were compared as to: the time to readiness for discharge, the patient’s pain scores over time, and the presence of side effects.

Results

There was no statistically significant difference in any of the outcomes measured. The time to readiness for discharge from PACU was 119 minutes in the morphine group and 120 minutes in the tramadol group. However in approximately half the cases who entered the trial (i.e., where pain had not been controlled with the pre-enrollment baseline 10 mg of morphine in PACU) neither a further 10 mg of morphine nor 100 mg of tramadol effectively relieved the patient’s pain.

Conclusions

We found no difference between additional morphine and co-analgesia with tramadol in this study. Patients who don’t respond to reasonable doses of opioids in PACU are very likely to be unresponsive to further opioids, and other non-opioid analgesic techniques (such as regional anesthesia) should be considered early in this group of patients.

Local Infiltration of Tramadol versus Bupivacaine for Post Cesarean Section Pain Control: A Double-Blind Randomized Study

BACKGROUND

Postoperative pain control after cesarean section (C/S) is important because inadequate postoperative pain control can result in a prolonged hospital stay. In this study, we compared postoperative somatic wound pain control between patients receiving tramadol and bupivacaine, infiltrated at the wound site.

METHODS

In this randomized clinical trial, 98 patients, eligible for elective C/S under general anesthesia, were randomly allocated to 2 groups. Before wound closure, 20 cc of 0.025% bupivacaine and 2 mg/kg of tramadol, diluted to 20 cc, were infiltrated at the wound site in groups A and B, respectively. After surgery, the pain score was measured using the visual analogue scale (VAS). Additionally, 24-hour total morphine consumption, nausea and vomiting, and respiratory depression were compared after 2, 4, 8, 16, and 24 hours between the 2 groups. The data were analyzed using SPSS with the Student independent t test, χ² test, Fisher exact test, and repeated measure test.

RESULTS

Postoperatively, there was no significant difference between these 2 groups in their VAS scores until 16 hours (P>0.05). However, at the 16^th and 24^th hours, the mean VAS scores were 3.20±2.24 and 2.51±2.55 in the bupivacaine group and 2.51±0.99 and 1.40±0.88 in the tramadol group, respectively (P<0.05). There was no difference in nausea and vomiting during the 24-hour period between the 2 groups. Also, no respiratory depression was detected in the both groups.

CONCLUSION

Local infiltration of tramadol (2 mg/kg) at the incision site of C/S was effective in somatic wound pain relief without significant complications.

TRIAL REGISTRATION NUMBER

IRCT2013070111662N2.

Comparative Pharmacology and Guide to the Use of the Serotonin 5-HT3 Receptor Antagonists for Postoperative Nausea and Vomiting

Since the introduction of the serotonin 5-hydroxy tryptamine 3 (5-HT₃) receptor antagonists in the early 1990s, the incidence of postoperative nausea and vomiting (PONV) and post-discharge nausea and vomiting (PDNV) has decreased, yet continues to be a problem for the surgical patient. The clinical application of the 5-HT₃ receptor antagonists has helped define the approach and role of these antiemetics in the prevention and treatment of PONV and PDNV. Pharmacological and clinical differences exist among these medications resulting in corresponding differences in effectiveness, safety, optimal dosage, time of administration, and use as combination and rescue antiemetic therapy. The clinical application of the 5-HT₃ receptor antagonist antiemetics has improved the prevention and treatment of PONV and PDNV. The most recent consensus guidelines for PONV published in 2014 outline the use of these antiemetics. The 5-HT₃ receptor antagonists play an important role to help prevent PONV and PDNV in perioperative care pathways such as Enhanced Recovery After Surgery (ERAS). Comparisons and guidelines for use of the 5-HT₃ receptor antagonists in relation to the risk for PONV and PDNV are reviewed.

A Comparative Assessment of Postoperative Analgesic Efficacy of Lornoxicam versus Tramadol after Open Reduction and Internal Fixation of Mandibular Fractures

Pain after any surgical procedure is inevitable but can be controlled by administration of analgesics in most cases. Postoperative pain after surgical treatment of mandibular fractures can be treated by nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics. The purpose of this study is to critically compare the postoperative analgesic efficacy of small doses of intravenous TRAMADOL (opioid analgesic) versus LORNOXICAM (NSAID) in patients with mandibular trauma undergoing open reduction and internal fixation (ORIF) and to assess the presence of any adverse effects due to NSAID or opioid use. Forty adult ASA grade I-II patients with mandibular trauma, scheduled for ORIF under general anesthesia in the Department of Oral and Maxillofacial Surgery, College of Dental Sciences, Davangere, were selected for the study. The patients were randomly assigned into a tramadol group (Group T) and a lornoxicam group (Group L) and were administered intravenous tramadol 50 mg and intravenous lornoxicam 8 mg, respectively, at specific postoperative intervals. Pain intensity was quantitatively assessed at the 2nd, 4th, 6th, 12th, and 24th postoperative hours using a visual analog scale of 10 cm. Adverse effects of the analgesics were also recorded and compared. Both the drugs resulted in a significant decrease in pain intensity from 2nd to 24th postoperative hours, but better pain control was observed in Group L at 24th postoperative hour. Only two patients experienced nausea and vomiting in Group T and one patient experienced gastric acidity in Group L. The comparative results clearly demonstrate that pain control by intravenous lornoxicam is significantly better than by intravenous tramadol at 24th postoperative hour after ORIF of mandibular trauma. Side effects produced by both the drugs were minor and had no apparent effect on the study results.

The analgesic agent tapentadol inhibits calcitonin gene-related peptide release from isolated rat brainstem via a serotonergic mechanism

AIMS

In this study we tested the hypothesis that tapentadol inhibits GGRP release from the rat brainstem through a mechanism mediated by the inhibition of NA reuptake; as a second alternative hypothesis, we investigated whether tapentadol inhibits GGRP release via the inhibition of 5-HT reuptake.

METHODS

Rat brainstems were explanted and incubated in short-term experiments. CGRP released in the incubation medium was taken as a marker of CGRP release from the central terminals of trigeminal neurons within the brainstem. CGRP levels were measured by radioimmunoassay under basal conditions or in the presence of tapentadol; NA, 5-HT, clonidine, yohimbine and ondansetron were used as pharmacological tools to investigate the action mechanism of tapentadol.

RESULTS

The α2-antagonist yohimbine failed to counteract the effects of tapentadol. Moreover, neither NA nor the α2-agonist clonidine per se inhibited K(+)-stimulated CGRP release, thereby indicating that the effects of tapentadol are nor mediated through the block of NA reuptake. Further experiments showed that 5-HT and tramadol, which inhibits both NA and 5-HT reuptake, significantly reduced K(+)-stimulated CGRP release. Moreover, the 5-HT3 antagonist ondansetron was able to counteract the effects of tapentadol in this system.

SIGNIFICANCE

This study provided pharmacological evidence that tapentadol inhibits stimulated CGRP release from the rat brainstem in vitro through a mechanism involving an increase in 5-HT levels in the system and the subsequent activation of 5-HT3 receptors.

Anaesthetic effects of tiletamine-zolazepam-xylazine-tramadol combination in cats undergoing surgical sterilization

This study was conducted to evaluate the anaesthetic and physiological effects of tiletamine-zolazepam-xylazine-tramadol (TZXT) combination in cats undergoing surgical sterilization. A total of 20, 13.3 ± 2.5 months old, with a body weight of 2.4 ± 0.2 kg, male cats were used in the experiment. Cats were randomly assigned into the anaesthesia group (group A) or to the surgery group (group S). The tiletamine-zolazepam-xylazine-tramadol combination was administered with an intended dose of 2.4 mg·kg-1 tiletamine-zolazepam (TZ), 0.36 mg·kg-1 xylazine (X), and 0.8 mg·kg-1 tramadol (T) into the lateral femoral muscle. Physiological indicators including rectal temperature (RT), heart rate (HR), respiration rate (RR), haemoglobin saturation by oxygen (SpO2), mean arterial pressure (MAP), systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) were collected after baseline values (time 0). Cats were immediately given the intramuscular injection drug combination. Physiological indicators were recorded before injection of this combination and at time 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 min after administration of the tiletamine-zolazepam-xylazine-tramadol combination. In group S, castrations were performed using a closed procedure. Vomiting, excitement, apnoea, and abnormal behaviour were not observed in any cat during anaesthesia. All changes in indicators were within cardiorespiratory acceptable limits in both groups. The tiletamine-zolazepam-xylazine-tramadol combination produced satisfactory anaesthesia in cats and it will be useful not only in induction of anaesthesia but also for surgery of short duration.

Role of CYP2D6 Polymorphisms in the Outcome of Postoperative Pain Treatment

OBJECTIVE

To investigate the role of CYP2D6 phenotype in the outcome of postoperative (PO) pain (POP) treatment.

DESIGN

Longitudinal cohort study. Open-label trial with post hoc analysis.

SETTING

General Hospital Surgery and Recovery Units.

PATIENTS

Ninety unrelated Caucasians submitted to abdominal/thoracic surgery.

INTERVENTIONS

Standard multimodal POP treatment including opioids (tramadol) and nonsteroidal anti-inflammatory drugs (ketoprofen) at different dosages and infusion rates according to the predicted mild, moderate, or severe POP.

OUTCOME MEASURES

Pain (Numeric Rating Scale-NRS) and sedation (Ramsay Sedation Scale-RSS) up to 24 hours after surgery. By genotyping 16 CYP2D6 alleles, the four CYP2D6 phenotypes poor metabolizer (PM), intermediate metabolizers (IM), extensive metabolizers (EM) and ultrarapid metabolizers (UM) were predicted.

RESULTS

As compared with the CYP2D6-EM phenotype, in the early PO time (30 min) a higher RSS mean score in IM was observed (P = 0.035). A suggestion towards higher mean score in PM (P = 0.091) and a minor mean score in UM (P = 0.091) was also detected. No difference in the outcome of pain across the CYP2D6 phenotypes was observed.

CONCLUSIONS

In respect to the normal CYP2D6 phenotype, our results suggested that slowly metabolizers (IMs and PMs) might have a major sedation, whereas more rapid metabolizers (UM) a minor sedation, in the early time after surgery. A minor role of CYP2D6 phenotype in PO analgesia may be suggested.

The effect of ondansetron on the efficacy of postoperative tramadol: a systematic review and meta-analysis of a drug interaction

Several studies have investigated the presence of a drug interaction between tramadol and ondansetron that reduced the efficacy of tramadol postoperatively. Most of these studies were small and the results inconsistent, so we performed a systematic review and meta-analysis of randomised controlled trials comparing the cumulative dose of tramadol administered by patient-controlled analgesia within the first 24 h after surgery between subjects receiving tramadol alone and those who received tramadol with ondansetron. Six studies, with a total of 340 participants, met the selection criteria and were included in the meta-analysis. There was an increased tramadol requirement in patients receiving ondansetron. The standardised mean difference in tramadol requirements, expressed in terms of standard deviations (95% CI), was 1.03 (0.54-1.53) (p < 0.001) at 4 h, 0.66 (0.06-1.25) (p = 0.03) at 8 h, 0.86 (0.41-1.31) (p < 0.001) at 12 h and 0.45 (0.01-0.90) (p = 0.046) at 24 h postoperatively, where the mean pooled standard deviations were 79.5, 157.7, 238.1 and 289.4 mg at 4, 8, 12 and 24 h, respectively. There was a significant linear time effect over the 24 h, indicating that the effect of ondansetron on tramadol consumption diminished with time. The results support the presence of a drug interaction between tramadol and ondansetron in the early postoperative period that potentially decreases the effectiveness of tramadol.

[Effect of transcutaneous electrical stimulation of Zusanli (ST 36) and Liangqiu (ST 34) combined with general anesthesia on pain and gastrointestinal symptoms in patients undergoing gynecological laparoscopic operation]

OBJECTIVE

To observe the effects of transcutaneous acupoint electrical stimulation (TAES) combined with general anesthesia (acupuncture analgesia combined with general anesthesia) on postoperative pain, nausea and vomiting and exhausted defecation symptoms in patients undergoing gynecological laparoscopic operation.

METHODS

Sixty patients with gynecological laparoscopic operation were randomly divided into TAES group and control group, with 30 cases in each group. Patients of the control group received simple general anesthesia and those of the TAES group were treated with general anesthesia and TAES of bilateral Zusanli (ST 36) and Liangqiu (ST 34) . Visual Analogue Scale (VAS) was used for measuring the patients' pain reaction at 8 h, 24 h and 72 h after surgery. Symptoms of patients' nausea and vomiting, post-operation exhaust and defecation time were recorded after operation.

RESULTS

The VAS scores at time-points of 8 h, 24 h and 72 h and nausea level in the TAES group were significantly lower than those of the control group (P < 0.01, P < 0.05). The vomiting severity of the TAES group was also relatively lower in comparison with the control group, but without significant difference between the two groups (P > 0.05). The post-operation exhaust and defecation time of patients in the TAES group apparently appeared earlier than those of patients in the control group (P < 0.01).

CONCLUSION

TAES combined with general anesthesia is effective in reducing post-operative pain and nausea, and improving gastrointestinal function in patients undergoing laparoscopic operation.

Comparison of patient-controlled analgesia versus continuous infusion of tramadol in post-cesarean section pain management

AIM

To evaluate and compare analgesic efficacy, drug consumption and patient satisfaction with the i.v. patient-controlled and continuous infusion modes of administration of tramadol.

METHODS

A total of 40 pregnant women in American Society of Anesthesiologists physical status classification system risk classes I-II scheduled for cesarean section were randomized into two groups to receive treatment in single-blind fashion. Patients in both groups received tramadol as an i.v. infusion 15 min before the end of surgery under general anesthesia for cesarean section. In the post-anesthesia care unit, the 20 patients allocated to group I were given i.v. tramadol in patient-controlled anesthesia (PCA), while the 20 other patients assigned to group II received it as a continuous infusion. Pain visual analog scores (VAS), mean arterial pressure (MAP), heart rate, total tramadol consumption, sedation scores, side-effects (nausea/vomiting) and patient satisfaction were evaluated seven times in the course of the first postoperative 24 h. The Mann-Whitney U-test and Friedman's anova were used for the statistical treatment of data.

RESULTS

VAS, sedation scores and nausea/vomiting scores were similar in both groups (P > 0.05). The 24-h tramadol consumption was significantly lower in group I (420.15 ± 66.58 mg) than in group II (494.00 ± 29.45 mg), while patient satisfaction was significantly higher in group I (P < 0.05).

CONCLUSION

While tramadol administration by either of the methods used may ensure efficient early postoperative anesthesia in cesarean section patients, i.v. PCA may be preferred because of the lower drug consumption and higher patient satisfaction associated with it.

Effects of tramadol with tiletamine/zolazepam-xylazine as anaesthesia in cats

This study was conducted to investigate the effect of the combination of tiletamine/zolazepam-xylazine-tramadol (TZXT) in cats and to compare its efficacy as an anaesthetic technique with tiletamine/zolazepam-xylazine (TZX). Fourteen healthy thirteen-month-old cats of both sexes were immobilized by TZXT or TZX on two different occasions. The cats’ scores for immobilization, analgesia and baseline physiological indicators, heart rate, respiratory rate and rectal temperature, were recorded before and 5, 10, 15, 20, 30, 40, 50, 60, 80, 100 and 120 min after administration of TZXT or TZX. Animals in both groups became laterally recumbent within 3 min and physiological indicators changed after administration. These changes were within biologically acceptable limits; these measurements did not differ between the treatments. Induction and recovery quality in animals was better with TZXT than with TZX. Sedation, analgesia, muscle relaxation and posture scores was higher in TZXT group. During recovery, cats in TZXT group were more conscious than cats in TZX group. This study showed that in cats, addition of tramadol (T) to TZX improved the quality of anaesthetic induction and increased the analgesic effect without adversely affecting the physiological indicators. Thus tiletamine/zolazepam-xylazine-tramadol shows to be more suitable for cat anaesthesia.

Anaesthesia and cardiopulmonary effects of tiletamine-zolazepam/xylazine/tramadol and its effects on nitric oxide, plasma endothelin, 6-keto-PGF1α and thromboxanes B2 in miniature pigs

This study focused on anaesthesia and cardiopulmonary effects of tiletamine-zolazepam/xylazine/tramadol in miniature pigs and its effects on endothelium-derived vasoactive factors. A total of 14 eight-month-old Chinese experimental miniature pigs were used in this study. Tiletamine-zolazepam (3.5 mg·kg-1), xylazine (1.32 mg·kg-1) and tramadol (1.8 mg·kg-1) were administered i.m.; blood pressure and heart rate were recorded. At the same time, blood was collected through precaval vein, and nitric oxide, endothelin, 6-keto-PGF1α and thromboxanes B2 were determined by colorimetry and radioimmunoassay. The mean times to dorsal recumbency, duration of immobilization, standing and walking were 2.26 ± 0.72, 87.57 ± 9.61, 25.63 ± 12.55 and 36.70 ± 14.53 min, respectively. Blood pressure was significantly changed at 10 and 80 min (P < 0.01), and the heart rate ranged from 89 to 134 bpm without episodes of severe bradycardia or tachycardia. Significantly positive correlation was observed between endothelin, thromboxanes B2 and blood pressure as well as the heart rate (P < 0.05). There was negative correlation between PGI2 and blood pressure as well as heart rate (P < 0.05). The results showed that endothelin, 6-keto-PGF1α and thromboxanes B2 participated in the changing of cardiopulmonary parameters which were caused by tiletamine-zolazepam-xylazine-tramadol anaesthesia in miniature pigs, and the 6-keto-PGF1α, ET and TXB2 concentrations in plasma participated in the changing of blood pressures during anaesthesia. Therefore, we can recommend tiletamine-zolazepam/xylazine/tramadol for anaesthesia in pigs, and this study also contributes to the evaluation of the effect of endothelium-derived vasoactive factors during anaesthesia.

Dexamethasone effect on postoperative pain and tramadol requirement after thyroidectomy

Tramadol is a central-acting analgesic associated with nausea and vomiting. Clinical studies have demonstrated that glucocorticoids have analgesic and antiemetic effects when administered perioperatively. The aim of this study is to test the hypothesis that coadministration of tramadol and dexamethasone decreases both postoperative pain and tramadol requirement by patient-controlled analgesia (PCA). Forty female patients undergoing thyroidectomy under general anesthesia were enrolled in a double-blind randomized controlled study and allocated to receive dexamethasone 4 mg i.v. (dexamethasone group, n = 20) or saline (control group, n = 20). At 0, 1, 2, 4 and 22 h of PCA, tramadol consumption and pain were evaluated. Although pain (numerical rating scale 0-10) was significantly lower in the dexamethasone group compared to the control group (2.9 ± 1.4 vs. 3.8 ± 1.2, p = 0.02) at the beginning of PCA, tramadol demand was not significantly different. Although the results herein show a possible beneficial effect of a preoperative single low dose of dexamethasone on postoperative pain, the hypothesis that this corticosteroid decreases tramadol requirement is not supported.

Estimation of the minimum effective dose of tramadol for postoperative analgesia in infants using the continual reassessment method

Tramadol is a potent analgesic. However, the analgesia efficacy of tramadol, particularly its minimum effective dose (MED), is not clear. The aim of this study is to find MED of tramadol for postoperative analgesia in infants. The continual reassessment method (CRM) was performed to find MED. Infants undergoing surgeries were included in the 3 phases of this series. In each phase, 24 participants were allocated a different tramadol dose. Pain intensity was measured by face, legs, activity, cry, consolability (FLACC) measurement at 3-hour intervals. Tramadol was considered ineffective if the FLACC score was higher than 4 in 10 at anytime. In phase 1, seven dose levels were used within the range 0.1-0.4 mg·kg(-1)·h(-1). Phase 1 was insufficient to identify the MED, and we increased the dose to 0.4-0.8 mg·kg(-1)·h(-1) in phase 2. Phase 2 was insufficient to identify the MED. In phase 3, local anesthetic wound infiltration was introduced, and the tramadol dose levels tested were the same as in phase 1. The successful analgesia probability of tramadol 0.4 mg·kg(-1)·h(-1) was 82.1% (95% CI, 0.742-0.925) in phase 1. In phase 2, it was 84.7% (95% CI, 0.789-0.991) with the dose 0.8 mg·kg(-1)·h(-1). Phase 1 and phase 2 were insufficient to identify the MED. In phase 3, the successful analgesia probability for dose 0.35 mg·kg(-1)·h(-1) was 96.7% (95% CI, 0.853-0.997).We have demonstrated that tramadol provides insufficient analgesia for surgeries considered to cause moderate-to-severe postoperative pain in infants if used as the sole analgesic, and that local anesthetic wound infiltration enhances the efficacy of tramadol.

A survey of post-craniotomy analgesia in British neurosurgical centres: time for perceptions and prescribing to change?

Patients undergoing craniotomy may experience moderate to severe pain postoperatively. An audit of analgesia of post-craniotomy patients at King's College Hospital demonstrated variable analgesic prescribing practices and suboptimal analgesia in some patients. Prior to introducing a formal post-operative analgesic regime, a survey of the adult neurosurgical units within the United Kingdom was undertaken to ascertain whether there was a general consensus regarding post-craniotomy pain management. Questions were asked as to whether there was a standardized analgesic regime/protocol; which first, second, third, and fourth-line analgesics were used; whether non-steroidal anti-inflammatory drugs were used; what the preferred anti-emetic was; and whether pain was routinely assessed. We also undertook a survey of neurosurgeons, neuroanaesthetists, intensivists, and neurosurgery high dependency nurses within our institution to ascertain what their perceptions were of post-craniotomy pain. All 31 adult neurosurgical units were surveyed. Twenty three percent (7 units) had a standardized analgesic regime/protocol and 65% routinely assessed pain post-operatively (20 units). Seventy percent of units used codeine phosphate or dihydrocodeine (22 units) as the first line opioid the other 30% using morphine (9 units). Forty two percent (13 units) used tramadol; patient controlled analgesia was used in 3 units. Regular paracetamol was prescribed in all but five (16%) units. Fifty two percent of units (16) used NSAIDs; of those that used NSAIDs 19% (3/16) prescribed them regularly. One unit used clonidine infusions. Anti-emetics were prescribed as required in all but two units. Cyclizine was the first-line anti-emetic in 45% of the units, ondansetron in 29% and metoclopramide in 16%. There is currently no consensus on pain management after craniotomy in neurosurgical centres in the UK. Until there are sufficiently powered randomized controlled studies to address the main safety and efficacy issues progress in this area will remain slow.

Intravenous and subcutaneous tramadol for inguinal herniorrhaphy: comparative study

BACKGROUND AND OBJECTIVES

Inguinal herniorrhaphy is one of the most common surgeries in men. Neuroaxis block is the anesthetic technique used more often and in the majority of the cases the patient is ready to be discharged from the hospital a few hours after the procedure, as long as satisfactory analgesia is present and nausea and vomiting are absent. Tramadol is an analgesic drug that can be used in postoperative analgesia, but it has important side effects, such as nausea and vomiting whose incidence can range from 0% to 50%. The objective of the present study was to compare the incidence of nausea and vomiting and the quality of postoperative analgesia of subcutaneous and intravenous tramadol in patients undergoing inguinal herniorrhaphy.

METHODS

This is a prospective study with 30 patients undergoing inguinal herniorrhaphy. Patients were divided into two groups: Group C (n = 15) received 1.5 mg.kg⁻¹ of subcutaneous Tramadol, and Group V (n = 15) received 1.5 mg.kg⁻¹ of intravenous Tramadol. All patients underwent continuous epidural anesthesia with 0.5% levobupivacaine. Anthropometric data, quality of analgesia, and the development of postoperative nausea and vomiting in the first eight hours were recorded.

RESULTS

Statistically significant differences were not observed between both groups for anthropometric data, quality of analgesia, and the development of nausea and vomiting.

CONCLUSIONS

The present study demonstrates the absence of statistically significant differences regarding the incidence of nausea and vomiting and quality of analgesia when using intravenous and subcutaneous Tramadol.

[Postoperative nausea and vomiting and opioid-induced nausea and vomiting: guidelines for prevention and treatment]

Postoperative nausea and vomiting (PONV) causes patient discomfort, lowers patient satisfaction, and increases care requirements. Opioid-induced nausea and vomiting (OINV) may also occur if opioids are used to treat postoperative pain. These guidelines aim to provide recommendations for the prevention and treatment of both problems. A working group was established in accordance with the charter of the Sociedad Española de Anestesiología y Reanimación. The group undertook the critical appraisal of articles relevant to the management of PONV and OINV in adults and children early and late in the perioperative period. Discussions led to recommendations, summarized as follows: 1) Risk for PONV should be assessed in all patients undergoing surgery; 2 easy-to-use scales are useful for risk assessment: the Apfel scale for adults and the Eberhart scale for children. 2) Measures to reduce baseline risk should be used for adults at moderate or high risk and all children. 3) Pharmacologic prophylaxis with 1 drug is useful for patients at low risk (Apfel or Eberhart 1) who are to receive general anesthesia; patients with higher levels of risk should receive prophylaxis with 2 or more drugs and baseline risk should be reduced (multimodal approach). 4) Dexamethasone, droperidol, and ondansetron (or other setrons) have similar levels of efficacy; drug choice should be made based on individual patient factors. 5) The drug prescribed for treating PONV should preferably be different from the one used for prophylaxis; ondansetron is the most effective drug for treating PONV. 6) Risk for PONV should be assessed before discharge after outpatient surgery or on the ward for hospitalized patients; there is no evidence that late preventive strategies are effective. 7) The drug of choice for preventing OINV is droperidol.

Effect of the addition of tramadol to a combination of tiletamine-zolazepam and xylazine for anaesthesia of miniature pigs

This study investigated the effects of a combination of tiletamine-zolazepam and xylazine plus tramadol (TZXT) and compared the efficacy of this combination with that of tiletaminezolazepam and xylazine (TZX) for providing anaesthesia in Chinese experimental miniature pigs. Fourteen healthy, eight-month-old miniature pigs of both sexes were immobilised with TZXT or TZX on two different occasions. The pigs' immobilisation and analgesia scores and baseline physiological parameters (heart rate, respiratory rate, non-invasive systolic, diastolic and mean arterial blood pressures, arterial haemoglobin oxygen saturation and rectal temperature) were determined before and five, 10, 30, 45, 60, 80 and 100 minutes after the administration of TZXT or TZX. Pigs in both groups became laterally recumbent within three minutes. Some physiological parameters were changed after administration of the drug combinations, but they remained within biologically acceptable limits and were not significantly different between the two treatments. The use of TZXT resulted in better induction time and quality of recovery compared with TZX, with higher scores for sedation, analgesia, muscle relaxation, posture and auditory response. The animals were much calmer during recovery after TZXT immobilisation.

Aprepitant: drug-drug interactions in perspective

The implications of chemotherapeutic drug-drug interactions can be serious and thus need to be addressed. This review concerns the potential interactions of the antiemetic aprepitant, a neurokinin-1 receptor antagonist indicated for use (in Europe) in highly emetogenic chemotherapy and moderately emetogenic chemotherapy (MEC) in combination with a 5-hydroxytryptamine-3 (5-HT3) receptor antagonist and corticosteroids and (in the United States) in combination with other antiemetic agents, for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy including high-dose cisplatin. When considering use of aprepitant for prevention of chemotherapy-induced nausea and vomiting, its potential drug-drug interaction profile as a moderate inhibitor of cytochrome P-450 isoenzyme 3A4 (CYP3A4) has been a source of concern for some physicians and other health care professionals. We explore in this paper how real those concerns are. Our conclusion is that either no interaction or no clinically relevant interaction exists with chemotherapeutic agents (intravenous cyclophosphamide, docetaxel, intravenous vinorelbine) or 5-HT3 antagonists (granisetron, ondansetron, palonosetron). For relevant interactions, appropriate measures, such as corticosteroid dose modifications and extended International Normalized Ratio monitoring of patients on warfarin therapy, can be taken to effectively manage them. Therefore, the concern of negative interactions remains largely theoretical but needs to be verified with new agents extensively metabolized through the 3A4 pathway.

Pharmacokinetics, safety and tolerance of single- and multiple-dose of a novel compound tramadol hydrochloride injection (35 mg tramadol hydrochloride, 45 mgl promethazine hydrochloride) in Chinese healthy subjects

The pharmacokinetics of Tramadol and Promethazine after a single dose of 40, 80 and 120 mg intramuscular injecting CTHI was evaluated in healthy volunteers. Physical exam, vital signs, clinical laboratory tests and electrocardiogram measurements were monitored to assess the safety and tolerance of the drug. The plasma levels of Tramadol and Promethazine in serial samples were measured by a validated HPLC-MS method. No subject showed any drug-related clinically significant changes on physical examination, vital signs or laboratory tests.

Ropivacaine spinal anesthesia is not antagonized by ondansetron pretreatment

BACKGROUND

We investigated a possible effect of ondansetron on the duration of sensory and motor block produced by ropivacaine.

METHODS

Fifty male patients undergoing transurethral surgery received either 8 mg oral ondansetron the evening before surgery plus IV 8 mg ondansetron 15 min before subarachnoid anesthesia or placebo. All patients received 2.2 mL of 0.75% plain ropivacaine intrathecally. Sensory and motor block were assessed 30 min after the intrathecal injection and every 30 min thereafter until recovery from the motor block.

RESULTS

Thirty minutes after spinal injection of ropivacaine, we first measured, in both groups, the time to maximum block for both sensory and motor modalities. The maximum level of the sensory block, defined as decreased sensation, was T8 in the control and T6 in the ondansetron group, and absence of sensation was defined as T11 and T9 for the control and the ondansetron groups, respectively. Regarding block duration, 180 min after spinal injection, sensory block was detected in 11 of 22 and 16 of 24 patients and motor block in 1 of 22 and 0 of 24 in the control and ondansetron groups, respectively. Sensory and motor block did not differ between groups at any measured time point.

CONCLUSIONS

Ondansetron had no effect on the subarachnoid sensory or motor block produced by ropivacaine.

Pharmacogenetics of analgesics: toward the individualization of prescription

The use of analgesics is based on the empiric administration of a given drug with clinical monitoring for efficacy and toxicity. However, individual responses to drugs are influenced by a combination of pharmacokinetic and pharmacodynamic factors that can sometimes be regulated by genetic factors. Whereas polymorphic drug-metabolizing enzymes and drug transporters may affect the pharmacokinetics of drugs, polymorphic drug targets and disease-related pathways may influence the pharmacodynamic action of drugs. After a usual dose, variations in drug toxicity and inefficacy can be observed depending on the polymorphism, the analgesic considered and the presence or absence of active metabolites. For opioids, the most studied being morphine, mutations in the ABCB1 gene, coding for P-glycoprotein (P-gp), and in the µ-opioid receptor reduce morphine potency. Cytochrome P450 (CYP) 2D6 mutations influence the analgesic effect of codeine and tramadol, and polymorphism of CYP2C9 is potentially linked to an increase in nonsteroidal anti-inflammatory drug-induced adverse events. Furthermore, drug interactions can mimic genetic deficiency and contribute to the variability in response to analgesics. This review summarizes the available data on the pharmacokinetic and pharmacodynamic consequences of known polymorphisms of drug-metabolizing enzymes, drug transporters, drug targets and other nonopioid biological systems on central and peripheral analgesics.