Tramadol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in acute and chronic pain states

Influence of psychological factors and pain sensitivity on the efficacy of opioid-free anesthesia: A randomized clinical trial

OBJECTIVE

This study aimed to investigate the effects of opioid-free anesthesia (OFA) in laparoscopic gastrectomy and identify the psychological factors that could influence the efficacy of OFA.

METHOD

120 patients undergoing laparoscopic gastrectomy were allocated to either the opioid-based anesthesia group (OA) (n = 60) or the OFA (n = 60) group. Remifentanil was administered to the OA group intraoperatively, whereas dexmedetomidine and lidocaine were administered to the OFA group. The interaction effect of the psychological factors on OFA was analyzed using the aligned rank transform for nonparametric factorial analyses.

RESULTS

The opioid requirement for 24 h after surgery was lower in the OFA group than in the OA group (fentanyl equivalent dose 727 vs. 650 μg, p = 0.036). The effect of OFA was influenced by the pain catastrophizing scale (p = 0.041), temporal pain summation (p = 0.046), and pressure pain tolerance (p = 0.034). This indicates that patients with pain catastrophizing or high pain sensitivity significantly benefited from OFA, whereas patients without these characteristics did not.

CONCLUSIONS

This study demonstrated that OFA with dexmedetomidine and lidocaine effectively reduced the postoperative 24-h opioid requirements following laparoscopic gastrectomy, which was modified by baseline pain catastrophizing and pain sensitivity.

CLINICAL TRIAL REGISTRY

The study protocol was approved by the Institutional Review Board of Yonsei University Health System Gangnam Severance Hospital (#3-2021-0295) and registered at ClinicalTrials.gov (NCT05076903).

Increased incidence of mixed drug toxicity deaths involving tapentadol - A forensic study

Tapentadol is a relatively new synthetic opioid analgesic prescribed for the management of moderate to severe pain. While tapentadol has been shown to be more effective than traditional opioid analgesics, it still carries the risk of addiction, abuse, and misuse. In Australia, tapentadol has become one of the top five most commonly prescribed opioid drugs, with prescriptions increasing by approximately 150,000 each year since it first became available. The rapid increase in tapentadol prescriptions has occurred in parallel to an increasing number of post-mortem tapentadol detections in South Australia (SA). While the number of deaths in SA related to tapentadol use was low in the current study, findings suggest that an increasing trend of deaths involving tapentadol will continue in parallel to a rapidly increasing number of prescriptions, mirroring trends associated with traditional opioids in SA. As a comparatively new opioid analgesic, monitoring future trends will be important to determine if additional prescribing education, intervention, or restrictions are required.

Nitric oxide and potassium channels but not opioid and cannabinoid receptors mediate tramadol-induced peripheral antinociception in rat model of paw pressure withdrawal

Tramadol, an analgesic classified as an "atypical opioid", exhibits both opioid and non-opioid mechanisms of action. This study aimed to explore these mechanisms, specifically the opioid-, cannabinoid-, nitric oxide-, and potassium channel-based mechanisms, which contribute to the peripheral antinociception effect of tramadol, in an experimental rat model. The nociceptive threshold was determined using paw pressure withdrawal. To examine the mechanisms of action, several substances were administered intraplantarly: naloxone, a non-selective opioid antagonist (50 µg/paw); AM251 (80 µg/paw) and AM630 (100 µg/paw) as the selective antagonists for types 1 and 2 cannabinoid receptors, respectively; nitric oxide synthase inhibitors L-NOArg, L-NIO, L-NPA, and L-NIL (24 µg/paw); and the enzyme inhibitors of guanylatocyclase and phosphodiesterase of cGMP, ODQ, and zaprinast. Additionally, potassium channel blockers glibenclamide, tetraethylammonium, dequalinium, and paxillin were used. The results showed that opioid and cannabinoid receptor antagonists did not reverse tramadol's effects. L-NOarg, L-NIO, and L-NPA partially reversed antinociception, while ODQ completely reversed, and zaprinast enhanced tramadol's antinociception effect. Notably, glibenclamide blocked tramadol's antinociception in a dose-dependent manner. These findings suggest that tramadol's peripheral antinociception effect is likely mediated by the nitrergic pathway and sensitive ATP potassium channels, rather than the opioid and cannabinoid pathways.

The Safe Use of Analgesics in Patients with Cirrhosis: A Narrative Review

Pain is prevalent in patients with cirrhosis. Due to potential alterations in drug metabolism, risk for adverse effects, and complications from cirrhosis, physicians are often faced with difficult choices when choosing appropriate analgesics in these patients. Overall, acetaminophen remains the preferred analgesic. Despite its potential for intrinsic liver toxicity, acetaminophen is safe when used at 2 g/d. In contrast, non-selective nonsteroidals should be avoided due to their multiple side effects, including worsening renal function, blunting diuretic response, and increasing risk of portal hypertensive and peptic ulcer bleeding. Celecoxib can be administered for short term (≤5 days) in patients with Child's A and Child's B cirrhosis (50% dose reduction). Opioids carry the risk of precipitating hepatic encephalopathy and should generally be avoided, when possible. If clinical situation demands their use, opioid use should be limited to short-acting agents for short duration. Gabapentin and pregabalin are generally safe. Duloxetine should be avoided in hepatic impairment. Topical diclofenac and lidocaine seem to be safe in patients with cirrhosis.

Opioid Prescription in Patients With Chronic Kidney Disease: A Systematic Review of Comparing Safety and Efficacy of Opioid Use in Chronic Kidney Disease Patients

Patients with diminished renal function necessitate special care. In patients with chronic kidney disease (CKD), opioid analgesics should be prescribed based on the severity of renal insufficiency; this will determine treatment options at the beginning and throughout the management of pain in CKD patients. The dosage of hydrophilic drugs and drugs with active metabolites should be adjusted according to the severity of CKD, and the process of treatment should be monitored by modifying drug dosages as necessary for background and breakthrough pain. Patients with CKD may benefit from opioid analgesics that are lipophilic, such as methadone, fentanyl, and buprenorphine, as the first line; however, fentanyl is inappropriate for patients undergoing hemodialysis. Opioid prescription in CKD patients is the subject of this systematic review, which aims to compare their safety and efficacy. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations. Using three databases (PubMed, ScienceDirect, and Google Scholar), we collected and reviewed articles, including literature reviews, randomized control trials (RCTs), and systematic reviews published between 1980 and 2022, to enable us to gather enough valuable data on this rare topic. After applying appropriate filters, a total of 109 results were obtained. They were further screened and subjected to quality assessment tools, which finally yielded 11 studies included in this systematic review. This consisted of two RCTs, two systematic reviews, and seven narrative reviews. This review focused on the safety and appropriate use of opioids in patients with CKD. The accumulation of morphine and codeine metabolites may result in neurotoxic side effects. Hydromorphone and oxycodone are considered safe to administer but require careful adjustments in dosage. Common comorbidities among patients with CKD may amplify opioid-related adverse effects.

Pain Management in Children Admitted to the Emergency Room: A Narrative Review

Pain is a biopsychosocial experience characterized by sensory, physiological, cognitive, affective, and behavioral components. Both acute and chronic pain can have short and long-term negative effects. Unfortunately, pain treatment is often inadequate. Guidelines and recommendations for a rational approach to pediatric pain frequently differ, and this may be one of the most important reasons for the poor attention frequently paid to pain treatment in children. This narrative review discusses the present knowledge in this regard. A literature review conducted on papers produced over the last 8 years showed that although in recent years, compared to the past, much progress has been made in the treatment of pain in the context of the pediatric emergency room, there is still a lot to do. There is a need to create guidelines that outline standardized and easy-to-follow pathways for pain recognition and management, which are also flexible enough to take into account differences in different contexts both in terms of drug availability and education of staff as well as of the different complexities of patients. It is essential to guarantee an approach to pain that is as uniform as possible among the pediatric population that limits, as much as possible, the inequalities related to ethnicity and language barriers.

Hazard and health risk assessment of exposure to pharmaceutical active compounds via toxicological evaluation by zebrafish

The uncontrolled or continuous release of effluents from wastewater treatment plants leads to the omnipresence of pharmaceutical active compounds (PhACs) in the aquatic media. Today, this is a confirmed problem becoming a main subject of twin public and scientific concerns. However, still little information is available about the long-term impacts of these PhACs on aquatic organisms. In this review, efforts were made to reveal correlation between the occurrence in the environment, ecotoxicological and health risks of different PhACs via toxicological evaluation by zebrafish (Danio rerio). This animal model served as a bioindicator for any health impacts after the exposure to these contaminants and to better understand the responses in relation to human diseases. This review paper focused on the calculation of Risk Quotients (RQs) of 34 PhACs based on environmental and ecotoxicological data available in the literature and prediction from the ECOSAR V2.2 software. To the best of the authors' knowledge, this is the first report on the risk assessment of PhACs by the two different methods as mentioned above. RQs showed greater difference in potential environmental risks of the PhACs. These differences in risk values underline the importance of environmental and experimental factors in exposure conditions and the interpretation of RQ values. While the results showed high risk to Danio rerio of the majority of PhACs, risk qualification of the others varied between moderate to insignifiant. Further research is needed to assess pharmaceutical hazards when present in wastewater before discharge and monitor the effectiveness of treatment processes. The recent new advances in the morphological assessment of toxicant-exposed zebrafish larvae for the determination of test compounds effects on the developmental endpoints were also discussed. This review emphasizes the need for strict regulations on the release of PhACs into environmental media in order to minimize their toxicity to aquatic organisms.

CYP24A1 and CYP3A4 Levels, Renal, Hepatic Changes, and Incidence of Oxidative Stress in Tramadol-Alcohol Concomitant Misuse

Introduction Long-term population-based research has demonstrated a link between heavy drinking and the prevalence of kidney disorders; similarly, alcohol abuse has long been recognized as one of the main causes of liver diseases. A recent trend of concomitant use of the opioid analgesic Tramadol and alcohol among young males in sub-Saharan Africa has emerged. Aim and objectives This study's primary aim was to evaluate the incidence of concomitant use of alcohol and Tramadol among adult males, and observe the role of cytochrome p450 3A4 and CYP24A1 proteins and some oxidative stress indicators such as Malondialdehyde, lactate dehydrogenase, among study participants. The secondary aim was to evaluate the effect of alcohol and Tramadol concomitant use on Liver and kidney indices. Methods Our study population was male subjects with a history of Alcohol and Tramadol concomitant use. Liver enzymes, renal indices, oxidative stress markers, and CYP3A4 and CYP24A1 were determined from the serum of test and control participants. IBM Statistical Package for Social Sciences (SPSS) Statistics (version 21.0) was used to analyze the data obtained. Result One hundred and forty-two male subjects were included in this study. Eighty two (82) were males who admitted to abuse of Alcohol and Tramadol concomitantly for at least a year. The dose of Tramadol commonly used by Test subjects was 200 mg (43.9% of the test population), Tramadol users in the study population were largely Undergraduates (75.6% of Test participants). Gamma-glutamyl transferase and lactate dehydrogenase were significantly higher in Test subjects consuming Tramadol and alcohol combination (43.13±1.02 and 117.29±2.45, respectively) versus control (24.87±0.82; p=0.00 and 101.93±1.25; p=0.00). There was a significant decrease in serum bicarbonate levels of Test subjects (16.19±0.53) versus control (22.60±0.68; p=0.000). Cytochrome P450 24A1, was significantly lower in Test subjects (subjects consuming Tramadol and alcohol combination) (0.90±0.06; p=0.01), and significantly threefold higher in subjects with acute myeloid leukemia (AML) (5.16±0.5; p=0.00), when compared with values of non-drug/alcohol users that served as normal control (1.27±0.07). Conclusion The menace of Tramadol and alcohol concomitant abuse has taken a worrisome dimension in sub-Saharan Africa. In this study 77.4% of participants reported euphoria as reason for combining Alcohol and Tramadol, 6.5% claimed it was for faster pain relief and enhanced sexual performance or prolong penile erection was the response of 58.1% of the test participants. Findings of reduced CYP3A4 with Alcohol and Tramadol concomitant use could be associated with delayed drug inactivation and increased drug euphoric action.

A Meta-Analysis Showing the Quantitative Evidence Base of Preemptive Pregabalin for Postoperative Pain from Cancer-Related Surgery

Background and Objectives: As an adjunct to postoperative multimodal analgesic regimens, pregabalin has been reported in reducing postoperative acute pain and opioid consumption. However, there is only a small amount of evidence for preemptive pregabalin in patients undergoing cancer-related surgery. This systematic review was conducted to integrate high-quality evidence to evaluate the preemptive analgesic effects of pregabalin in cancer-related surgery. Materials and Methods: Seven electronic databases were searched in a combination of subject terms and free words. Efficacy and safety of preemptive pregabalin on postoperative pain for cancer-related surgery were evaluated by assessing resting and dynamic pain scores postoperatively, cumulative morphine equivalent consumption, time to first analgesic request, hemodynamic parameters, and the safety indicators. Results: Thirteen trials were incorporated for quantitative synthesis. The pooled results showed administration of pregabalin preoperatively is clinically significant for improving resting (weighted mean difference (WMD), -1.53 cm; 95% CI, -2.30 to -0.77) and dynamic (WMD, -1.16 cm; 95% CI, -2.22 to -0.11) pain severity scores at 2 h postoperatively and prolonging time to first analgesic request (WMD, 2.28 h; 95% CI, 0.79 to 3.77) in cancer-related surgery. Preemptive pregabalin was also statistically effective in some other pain indicators but would increase the risk of pregabalin-related side effects after surgery. Conclusions: Our findings do not support the administration of pregabalin in doses larger than 300 mg when put in cancer-related surgery. Taken together, more high-quality research particularly focused on the optimal dosages and timing of pregabalin in cancer-related surgery is needed in the future to establish stronger evidence for therapeutic effects.

Current and emerging treatment options for premature ejaculation

Premature ejaculation (PE) is a prevalent male sexual dysfunction. Current standard treatment regimens include behavioural therapies, topical anaesthetics, dapoxetine and other selective serotonin reuptake inhibitors (SSRIs). Most of the pharmacotherapeutic options target neurotransmitters (such as serotonin and oxytocin) that have a role in the ejaculation mechanism. However, these treatments are mildly effective and only provide a temporary delay in the ejaculation latency time, and PE recurs when the treatment is stopped. Thus, a treatment for PE is urgently needed and research is ongoing to find the ideal PE therapy. The efficacy and safety of topical anaesthetics and SSRIs in delaying ejaculation have been confirmed in many well-designed controlled trials. Both preclinical and clinical studies on new-generation SSRIs are ongoing. Moreover, promising results came from clinical trials in which the efficacy of on-demand PE therapies targeting neurotransmitters other than serotonin, such as α1-adrenoceptor antagonists and oxytocin antagonists, was assessed. Surgical intervention and neuromodulation have been proposed as potential treatment options for PE; however, current PE guidelines do not recommend these treatments owing to safety concerns.

Investigating antimicrobial features and drug interactions of sedoanalgesics in intensive care unit: an experimental study

Study Objective

Aim of this study was to evaluate antimicrobial effects and interaction between analgesic combinations of fentanyl citrate, dexmedetomidine hydrochloride and tramadol hydrochloride on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Candida albicans which are some of the most common nosocomial infection related microorganisms.

Design

In vitro prospective study.

Setting

University Clinical Microbiology Laboratory.

Measurements

In order to evaluate in vitro antimicrobial effects and interaction between analgesic combinations, tramadol hydrochloride, fentanyl citrate and dexmedetomidin were used against S. aureus ATCC 29213, K. pneumoniae, E. coli ATCC 25922, P. aeruginosa ATCC 27853 and C. albicans ATCC 10231 standard strains by microdilution method.

Main Results

According to microdilution assays tramadol has shown the most efficient antimicrobial activity also it has been observed that 10 μg/ml concentrated dexmedetomidine has antimicrobial effects on S. aureus, K. pneumoniae and P. aeruginosa. Fentanyl has displayed evident inhibitory potency on the pathogens except for Klebsiella pneumoniae, nevertheless our predefined minimum concentration inhibited growth by 9.5 %. Fentanyl and dexmedetomidine together exhibited more antimicrobial effect on P. aeruginosa and E. coli growth. Additionally, when the three drugs examined together, microbial inhibition occurred more than expected on E. coli again and also on C. albicans growth.

Conclusions

Our results revealed the antimicrobial properties and synergy with the different combinations of fentanyl, dexmedetomidine and tramadol against the most common nosocomial infection agents in the ICU. This is the first study in the literature looking into the microbial “interactions” of opioids and sedative drugs but more research is needed in order to define clinico-laboratory correlation.

The Relationship Between Postoperative Opioid Analgesia and Sleep Apnea Severity in Patients Undergoing Hip Arthroplasty: A Randomized, Controlled, Triple-Blinded Trial

PURPOSE

Residual postoperative pain after hip arthroplasty is usually treated with oral opioids. While classic opioids are associated with respiratory depression and worsening of sleep apnea, tramadol has been reported to preserve respiratory function. However, this has not been investigated in a prospective trial using respiratory polygraphy. This randomized controlled triple-blinded trial tested the hypothesis that postoperative treatment with oral opioids such as oxycodone would increase sleep apnea severity, measured with a respiratory polygraphy, compared with oral tramadol.

PATIENTS AND METHODS

Sixty patients undergoing hip arthroplasty under spinal anesthesia with 15 mg isobaric bupivacaine 0.5% were randomized to receive postoperative pain treatment with either oral oxycodone (controlled-release 10 mg every 12 hours and immediate-release 5 mg every 4 hours as needed) or oral tramadol (controlled-release 100 mg every 8 hours and immediate-release 50 mg every 4 hours as needed). Respiratory polygraphy was performed on the first postoperative night. The primary outcome was the apnea-hypopnea index in the supine position. Secondary outcomes included the oxygen desaturation index, postoperative pain scores and intravenous morphine consumption.

RESULTS

Mean supine apnea-hypopnea index on postoperative night 1 was 11.3 events.h^-1 (95% confidence interval, 4.8-17.7) in the oxycodone group and 10.7 (4.6-16.8) events.h^-1 in the tramadol group (p=0.89). There were no significant differences between the oxycodone and tramadol groups with respect to any secondary sleep-related or pain-related outcomes.

CONCLUSION

Oral oxycodone did not increase sleep apnea severity measured using respiratory polygraphy compared with oral tramadol on the first postoperative night after hip arthroplasty.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov - NCT03454217 (date of registration: 05/03/2018).

A Comparative Evaluation of Nalbuphine and Tramadol for the Control of Post-Spinal Anaesthesia Shivering

Objectives

In this study, our primary aim was to compare the efficacy of and haemodynamic changes related to nalbuphine and tramadol when used for the control of post-spinal anaesthesia shivering, as per Wrench shivering grades. The secondary aim was to study the complications and adverse effects associated with the drugs.

Methodology

A total of 60 patients with the American Society of Anesthesiologists (ASA) physical status class I/II who were scheduled to undergo elective surgeries under spinal anaesthesia were divided into two groups of 30 each. Group N received intravenous nalbuphine 0.05 mg/kg and Group T received intravenous tramadol 1 mg/kg, two minutes after the patients started shivering after undergoing spinal anaesthesia. The anaesthesia technique was standardised for all the patients in the study. The shivering grade was measured using the Wrench shivering grade and the level of sedation was studied using the Ramsay Sedation Scale. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded. All the parameters were measured at the baseline and at one, two, five, 10, 15, and 30 minutes after administering the drug.

Results

Immediately after giving the drug, the time taken to control shivering was significantly lower in Group T: 3.633 minutes. However both the drugs controlled shivering effectively. There were no significant haemodynamic changes in both groups, probably due to the lower dosage of drugs used in our study. A different set of side effects were seen in each group. In Group N, out of 30 patients, five (16.67%) patients were sedated, four (13.33%) had hypotension, and two (6.67%) had bradycardia, whereas In Group T, out of 30 patients, five (16.67%) patients had nausea, four (13.33%) had nausea and vomiting, and two (16.67%) had dizziness following the administration of the drug. Respiratory depression or itching was not seen in any patients in either group.

Conclusion

Based on our findings, both Intravenous nalbuphine 0.05 mg/kg and intravenous tramadol 1 mg/kg are effective in treating patients with post-spinal anaesthesia shivering; however, the time taken to control shivering is lower with tramadol than nalbuphine. Both the drugs resulted in minimal haemodynamic changes and adverse effects.

Changing Pain Management Strategy from Opioid-Centric towards Improve Postoperative Cognitive Dysfunction with Dexmedetomidine

OBJECTIVE

This study was aimed to investigate the effectiveness of dexmedetomidine (DEX) on improving the level of pain and disability to find out the possible correlation between psychological factors with pain management satisfaction and physical function in patients with femoral neck fractures.

METHODS

One hundred twenty-four adult patients with stable femoral neck fractures (type I and II, Garden classification) who underwent internal fixation, were prospectively enrolled including 62 patients in the DEX group and 62 patients in the control group. The magnitude of disability using Harris Hip Score, Postoperative Cognitive Dysfunction (POCD) using Mini-Mental State Examination (MMSE score), Quality of Recovery (QoR-40), pain-related anxiety (PASS-20), pain management and pain catastrophizing scale (PCS) were recorded on the first and second day after surgery.

RESULTS

The DEX group on the first and second days after surgery exhibited higher quality of recovery scores, greater satisfaction with pain management, low disability scores, less catastrophic thinking, lower pain anxiety, greater mini mental state examination scores and less opioid intake and the differences were statistically significant compared with the control group (P<0.001). Emergence agitation and incidence of POCD were significantly less in the DEX group (P<0.001). Decreased disability was associated with less catastrophic thinking and lower pain anxiety, but not associated with more opioid intake (P<0.001). Higher QoR-40 scores had a negative correlation with more catastrophic thinking and more opioid intake (P<0.001). Greater satisfaction with pain management was correlated with less catastrophic thinking and less opioid intake (P<0.001).

CONCLUSION

Using DEX as an adjunct to anesthesia could significantly improve postoperative cognitive dysfunction and the quality of recovery and these improvements were accompanied by decrease in pain, emergence agitation, and opioid consumption by DEX administration. Since pain relief and decreased disability were not associated with prescribing greater amounts of opioid intake in the patients, improving psychological factors, including reducing catastrophic thinking or self-efficacy about pain, could be a more effective strategy to reduce pain and disability, meanwhile reducing opioid prescription in the patients. Our findings showed that DEX administration is safe sedation with anti-inflammatory, analgesic and antiemetic effects and it could help change pain management strategy from opioid-centric towards improved postoperative cognitive dysfunction.

Pectoral Nerve Blocks for Breast Augmentation Surgery: A Randomized, Double-blind, Dual-centered Controlled Trial

BACKGROUND

Pectoral nerve blocks have been proposed for analgesia during and after breast cancer surgery, but data are conflicted in aesthetic breast surgery. This trial tested the primary hypothesis that adding a preincisional pectoral nerve block is superior to systemic multimodal analgesic regimen alone for pain control after breast augmentation surgery. A second hypothesis is that rescue opioid consumption would be decreased with a long-lasting effect for both outcomes during the following days.

METHODS

Seventy-three adult female patients undergoing aesthetic breast augmentation surgery under general anesthesia were randomly allocated to receive a pectoral nerve block versus no block. Both groups received standard care with protocolized multimodal analgesia alone including systematic acetaminophen and nonsteroidal anti-inflammatory drugs. The primary outcome measure was the maximal numerical rating scale in the first 6 h after extubation. Secondary outcomes included intraoperative remifentanil consumption and from extubation to day 5: maximal numerical rating scale, postoperative cumulative opioid consumption and postoperative opioid side effects, and patient satisfaction recorded at day 5.

RESULTS

The maximal numerical rating scale score in the first 6 h was lower in the pectoral nerve block group compared with the control group (3.9 ± 2.5 vs. 5.2 ± 2.2; difference: -1.2 [95% CI, -2.3 to -0.1]; P = 0.036). The pectoral nerve block group had a lower maximal numerical rating scale between days 1 and 5 (2.2 ± 1.9 vs. 3.2 ± 1.7; P = 0.032). The cumulative amount of overall opioids consumption (oral morphine equivalent) was lower for the pectoral nerve block group from hour 6 to day 1 (0.0 [0.0 to 21.0] vs. 21.0 [0.0 to 31.5] mg, P = 0.006) and from days 1 to 5 (0.0 [0.0 to 21.0] vs. 21.0 [0.0 to 51] mg, P = 0.002).

CONCLUSIONS

Pectoral nerve block in conjunction with multimodal analgesia provides effective perioperative pain relief after aesthetic breast surgery and is associated with reduced opioid consumption over the first 5 postoperative days.

EDITOR’S PERSPECTIVE

Narcotic Use for Acute Postoperative Pain Management in Mohs Micrographic Surgery Patients With End Stage Renal Disease: A Review of the Literature

BACKGROUND

Uncontrolled acute postoperative pain presents a significant management challenge when opioids are used in patients with end-stage renal disease (ESRD). Currently, there is a lack of quality pharmacokinetic and pharmacodynamic data regarding opioid medication use in ESRD patients to optimize safe and effective management.

OBJECTIVE

To review the published literature on pharmacologic evidence for and against the use of opioid medications for acute postoperative pain following Mohs micrographic surgery in ESRD patients.

METHODS

A search of PubMed was conducted to identify articles on the pharmacokinetic and pharmacodynamic properties of opioid pain medications in ESRD patients through March 1, 2020.

RESULTS

Seventy-five articles were reviewed. Limited data exist on opioids safe for use in ESRD and are mostly confined to small case series. Studies suggest tramadol and hydromorphone could be considered when indicated. Methadone may be a safe option, but should be reserved for treatment coordinated by a trained pain subspecialist.

CONCLUSION

Randomized clinical trials are lacking. Studies that are available are not sufficient to perform a quantitative methodologic approach. Evidence supports the judicious use of postoperative opioid medications in ESRD patients at the lowest possible dose to achieve clinically meaningful improvement in pain and function.

Tapentadol Versus Tramadol: A Narrative and Comparative Review of Their Pharmacological, Efficacy and Safety Profiles in Adult Patients

We conducted a narrative review of the literature to compare the pharmacological, efficacy and safety profiles of tapentadol and tramadol, and to assess the clinical interest of tapentadol in adult patients. Tapentadol and tramadol share a mixed mechanism of action, including both mu-agonist and monoaminergic properties. Tapentadol is approximately two to three times more potent than tramadol and two to three times less potent than morphine. It has no identified analgesically active metabolite and is not significantly metabolised by cytochrome P450 enzymes, thus overcoming some limitations of tramadol, including the potential for pharmacokinetic drug-drug interactions and interindividual variability due to genetic polymorphisms of cytochrome P450 enzymes. The toxicity profiles of tramadol and tapentadol are similar; however tapentadol is likely to result in less exposure to serotoninergic adverse effects (nausea, vomiting, hypoglycaemia) but cause more opioid adverse effects (constipation, respiratory depression, abuse) than tramadol. The safety of tapentadol in real-world conditions remains poorly documented, particularly in at-risk patient subgroups and also in the ability to assess the risk associated with its residual serotonergic activity (serotonin syndrome, seizures). Because of an earlier market introduction, more real-world safety data are available for tramadol, including data from at-risk patient subgroups. The level of evidence on the efficacy of both tramadol and tapentadol for the treatment of chronic pain is globally low. The trials published to date show overall that tapentadol does not provide a clinically significant analgesic improvement compared to existing treatments, for which the safety profile is much better known. In conclusion, tapentadol is not a first-line opioid but represents an additional analgesic in the therapeutic choices, which some patients may benefit from after careful examination of their clinical situation, co-morbidities and co-medications.

Perimortem Distribution of U-47700, Tramadol and their Main Metabolites in pigs Following Intravenous Administration

In spite of a decreasing number of new releases, New Synthetic Opioids (NSO) are gaining increasing importance in postmortem (PM) forensic toxicology. For the interpretation of analytical results, toxicokinetic (TK) data, e.g. on tissue distribution, are helpful. Concerning NSO, such data are usually not available due to the lack of controlled human studies. Hence, a controlled TK study using pigs was carried out and the tissue distribution of U-47700 and tramadol as reference was examined. Twelve pigs received an intravenous dose of 100 µg/kg body weight (BW) U-47700 or 1000 µg/kg BW tramadol, respectively. Eight hours after administration, the animals were put to death with T61. Relevant organs, body fluids and tissues were sampled. After homogenization and solid-phase extraction, quantification was performed applying standard addition and liquid chromatography-tandem mass spectrometry. At the time of death, the two parent compounds were determined in all analyzed specimens. Regarding U-47700, concentrations were highest in duodenum content, bile fluid and adipose tissue (AT). Concerning tramadol, next to bile fluid and duodenum content, highest concentrations were determined in the lung. Regarding the metabolites, N-desmethyl-U-47700 and O-desmethyltramadol (ODT) were detected in all analyzed specimens except for AT (ODT). Higher metabolite concentrations were found in specimens involved in metabolism. N-desmethyl-U-47700 showed much higher concentrations in routinely analyzed organs (lung, liver, kidney) than U-47700. To conclude, besides the routinely analyzed specimens in PM toxicology, AT, bile fluid and duodenum content could serve as alternative matrices for blood, urine or standard specimens such as kidney or liver. In case of U-47700, quantification of the main metabolite N-desmethyl-U-47700 is highly recommendable.

Randomized Double-Blinded Comparative Study of Intravenous Nalbuphine and Tramadol for the Treatment of Postspinal Anesthesia Shivering

Context:

Shivering is one of the most commonly recognized complications of the central neuraxial blockade. For optimal perioperative care, control of postspinal anesthesia shivering is essential.

Aims:

The present study designed to compare the clinical efficacy, hemodynamic parameters, and side effects of nalbuphine and tramadol for control of postspinal anesthesia shivering.

Settings and Design:

This was a prospective, randomized, double-blind study.

Materials and Methods:

This study was conducted on 90 American Society of Anesthesiologists Physical Status I and II patients of either gender, aged between 18 and 60 years, who subsequently developed shivering grade 3 or 4, scheduled for different surgical procedures under spinal anesthesia. The patients were randomized into two groups of 45 patients each to receive either nalbuphine 0.06 mg.kg⁻¹ (Group N) or tramadol 1 mg.kg⁻¹ (Group T). Grade of shivering, onset of shivering, time interval for cessation of shivering, response rate at 5 and 30 min, rescue dose, hemodynamic parameters, and side effects were observed at scheduled intervals.

Statistical Analysis Used:

Independent t-test and Chi-square/Fisher's exact test were used to analyze the data.

Results:

The time taken for cessation of shivering was significantly less with nalbuphine in comparison with tramadol (P < 0.05). It was observed that the response time at 5 and 30 min and rescue dose requirement for control of shivering were not much difference (P > 0.05).

Conclusions:

Both nalbuphine and tramadol are effective; however, the time taken for cessation of shivering is significantly less with nalbuphine when compared to tramadol. Furthermore, tramadol causes significantly more nausea and vomiting; however, nalbuphine causes significantly more sedation.

Dynamic Distribution and Postmortem Redistribution of Tramadol in Poisoned Rats

In the past dozen years, the cases of tramadol intoxication have become frequent in many countries. Most previous studies focused on tramadol's pharmacology, such as pharmacokinetics, pharmacodynamics and pharmacogenetics. However, the dynamic distribution and postmortem redistribution (PMR) of tramadol remain unclear. Our study aimed to investigate these two issues systematically in various specimens of 216 poisoned male rats. A validated gas chromatography-mass spectrometry method was used in this study to measure the concentrations of tramadol. In the first part, 66 tramadol poisoned rats were sacrificed at 11 different time points and their organs were collected separately for the study of tramadol's dynamic distribution, which made it feasible to investigate its PMR later on. The results of this part showed that tramadol's concentrations varied according to the organ and time, and peaked 2 h after intragastric administration in the specimens of liver, kidney, spleen, lung, brain and heart-blood (except stomach and heart). Based on the results of the first part, the concentration of tramadol peaked 2 h in most tissues. Therefore, this time point was used for the study of tramadol's PMR. In the second part, the remaining 150 rats were sacrificed 2 h after intragastric administration of tramadol, and the carcasses were stored under three different conditions (-20, 4 and 20°C). The autopsy was carried out at eight different time points and their organs were collected separately. The results of this part showed that under storage temperatures of -20 and 4°C, the concentrations of tramadol in individual organs showed no significant changes at different time points whereas under a storage temperature of 20°C, the concentrations in certain organs (liver, kidney, spleen, lung, brain and heart-blood) increased significantly at the last few time points. PMR of tramadol was therefore confirmed. The process of PMR of tramadol could be slowed or stopped at lower storage temperatures (-20 or 4°C), which is significant in cases of suspected tramadol poisoning.

The role of perioperative intravenous low-dose dexamethasone in rapid recovery after total knee arthroplasty: a meta-analysis

PURPOSE

The purpose of this meta-analysis was to evaluate the overall safety and effectiveness of perioperative intravenous dexamethasone to facilitate postoperative rehabilitation in patients after total knee arthroplasty (TKA).

METHODS

A comprehensive literature search was performed using the Embase, PubMed, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases for relevant randomized controlled trials (RCTs) from inception to 2020. Methodological quality of the trials was assessed using the Cochrane Risk of Bias Tool, and the relevant data were extracted using a predefined data extraction form.

RESULTS

Ten RCTs with 1100 knees were included. Our study showed a significant reduction in pain using a postoperative pain visual analog scale (VAS) at 24 hours and 48 hours, total opioid consumption at 24 hours and 48 hours, postoperative nausea and vomiting (PONV), active range of motion (ROM) limitation, and passive ROM limitation at 72 hours in dexamethasone-treated groups compared with controls.

CONCLUSION

Intravenous low-dose dexamethasone is potentially useful in the perioperative setting for reducing postsurgical immediate ROM limitations, pain, opioid consumption, and PONV. There are no data that directly attribute an increase in postoperative complications to intravenous dexamethasone. More high-quality studies are necessary to draw these conclusions.

The In Vivo Antinociceptive and Antiinflammatory Effects of Verbascum exuberans Hub.-Mor

Objectives

Safe and effective drugs are still lacking for many pain therapies. In recent years, growing interest has been devoted thus on herbal drugs as an option to identify new pain killers. Based on this, extensive researches are carried out on Verbascum L. genus due to its therapeutic potency on pain and inflammation therapy. In this study, among Verbascum species, the antinociceptive effect of Verbascum exuberans Hub.-Mor., and its contributions to nitrergic, serotonergic, or opioidergic pathways as well as its antiinflammatory acitivity were investigated.

Materials and Methods

Tail clip, tail flick, and hot plate tests were used to determine the central (spinal and supraspinal) antinociceptive effect, while an acetic acid-induced writhing test was used to measure the peripheral antinociceptive effect of the extract (250 and 500 mg/kg). The extract (250 mg/kg) was then combined with nω-nitro-L-arginine methyl ester, cyproheptadine, and naloxone to evaluate its involvement in nitrergic, serotonergic, or opioidergic pathways, respectively. Carrageenan-induced hind paw edema model was used to determine the antiinflammatory effect of the extract (250 mg/kg).

Results

The extract shows central spinal but not central supraspinal antinociceptive effect, and presents peripheral antinociceptive effect. The antinociceptive actions of the extract is largely regulated via targeting the nitrergic pathway, while the opioidergic pathway is partly involved. Further, the extract shows antiinflammatory effect due to the significant inhibitions on the time dependent edema progression and the cytokine (tumor necrosis factor-alfa and interleukin-1beta) productions.

Conclusion

V. exuberans could be stated as a new source with a high beneficial potential in alleviating pain and inflammation.

Role of Oral Tramadol 50 mg in Reducing Pain During Colposcopy-Directed Cervical Biopsy: A Randomized Controlled Trial

OBJECTIVE

The aim of the study was to assess safety and efficacy of 50-mg tramadol in reducing patient-perceived pain during colposcopy.

MATERIAL AND METHODS

We conducted a randomized double-blind placebo-controlled trial in the colposcopy unit of a tertiary referral hospital, Cairo, Egypt, from April 2018 to October 2018. Our primary outcome was pain during colposcopy-guided ectocervical punch biopsy. Our secondary outcomes were pain during speculum insertion, acetic acid application, Lugol iodine application, endocervical curettage (ECC), endocervical brushing, 10-minute postprocedure, and additional analgesia requirement. Pain was assessed using 10-cm visual analog scale.

RESULTS

One hundred fifty women were randomized into 2 groups: tramadol group (n = 75) received oral 50-mg tramadol tablets, and control group (n = 75) received placebo tablets. Both groups showed no significant difference in anticipated pain score (p = .56), pain scores during speculum insertion (p = .70), application of acetic acid (p = .40), and Lugol iodine (p = .79). However, the mean pain scores were significantly lower in tramadol group compared with placebo at ectocervical biopsy (p = .001), ECC (p = .001), endocervical brushing (p = .001), and 10 minutes after colposcopy (p = .001). Need for additional analgesia was significantly lower in tramadol group (p = .03).

CONCLUSIONS

Oral tramadol 50 mg significantly reduces pain perception during colposcopy-guided ectocervical biopsy, ECC, endocervical brushing, and 10 minutes after colposcopy with tolerable adverse effects.

Increasing tramadol utilisation under strict regulatory control of opioid prescribing - A cross-sectional study in Taiwan from 2002 through 2016

BACKGROUND/PURPOSE

Prescribing of opioids to patients with non-cancer pain is strictly regulated in Taiwan, but tramadol is not included in the regulation on chronic opioid prescribing. This study aims to identify the utilization trend of prescribing tramadol and other opioid analgesics and investigate the influence of government regulation on opioid prescribing in Taiwan.

METHODS

This cross-sectional study used the Taiwan National Health Insurance claims database and the cancer registry from 2001 through 2016. The annual number of adult opioid users, opioid utilization (Defined Daily Doses [DDDs]/1000 registrants) and the number of supply days were enumerated for each calendar year and stratified by cancer or non-cancer patients. Descriptive statistics were used to report the trends in utilization for each calendar year.

RESULTS

The regulation strictly limited persistent use of opioids for patients with non-cancer pain, of which only a small proportion of fentanyl (20%) and morphine (<2%) users were prescribed with an annual number of supply days greater than 28 days. The annual utilization of morphine (6.4-53.5 vs. 1.1 to 9.6 DDD/1000 registrants) and fentanyl (8.3-37.0 vs. 0.16 to 1.8 DDD/1000 registrants) to patients with cancer was consistently higher than patients without cancer. In contrast to morphine and fentanyl, the utilization of tramadol prescribed to patients without cancer increased 92.2-fold (3.7-341.2 DDD/1000 registrants) from 2002 to 2016.

CONCLUSION

The regulation in Taiwan limited the prescribing of selective opioids for patients with non-cancer pain and the substitution of tramadol for other opioids may have safety implications.

Centrally administered CYP2D inhibitors increase oral tramadol analgesia in rats

Cytochrome P450 2D (CYP2D) mediates the activation and inactivation of several classes of psychoactive drugs, including opioids, which can alter drug response. Tramadol is a synthetic opioid with analgesic activity of its own as well as being metabolically activated by CYP2D to O-desmethyltramadol (ODMST) an opioid receptor agonist. We investigated the impact of brain CYP2D metabolism on central tramadol and ODSMT levels, and resulting analgesic response after oral tramadol administration in rats. CYP2D inhibitors propranolol and propafenone were administered intracerebroventricularly prior to oral tramadol administration and analgesia was measured by tail-flick latency. Drug levels of tramadol and its metabolites, ODSMT and N-desmethyltramadol, were assessed in plasma and in brain by microdialysis using LC-ESI-MS/MS. Inhibiting brain CYP2D with propafenone pretreatment increased analgesia after oral tramadol administration (ANOVA p = 0.02), resulting in a 1.5-fold increase in area under the analgesia-time curve (AUC_0-60, p < 0.01). This effect was associated with changes in the brain levels of tramadol and its metabolites consistent with brain CYP2D inhibition. In conclusion, under oral tramadol dosing pretreatment with a central administration of the CYP2D inhibitor propafenone increased analgesia (without altering plasma drug or metabolite levels), indicating that tramadol itself (and activity of CYP2D within the brain) contributed to analgesia.

Safe Use of Opioids in Chronic Kidney Disease and Hemodialysis Patients: Tips and Tricks for Non-Pain Specialists

In patients suffering from moderate-to-severe chronic kidney disease (CKD) or end-stage renal disease (ESRD), subjected to hemodialysis (HD), pain is very common, but often underestimated. Opioids are still the mainstay of severe chronic pain management; however, their prescription in CKD and HD patients is still significantly low and pain is often under-treated. Altered pharmacokinetics and the lack of clinical trials on the use of opioids in patients with renal impairment increase physicians' concerns in this specific population. This narrative review focused on the correct and safe use of opioids in patients with CKD and HD. Morphine and codeine are not recommended, because the accumulation of their metabolites may cause neurotoxic symptoms. Oxycodone and hydromorphone can be safely used, but adequate dosage adjustments are required in CKD. In dialyzed patients, these opioids should be considered as second-line agents and patients should be carefully monitored. According to different studies, buprenorphine and fentanyl could be considered first-line opioids in the management of pain in CKD; however, fentanyl is not appropriate in patients undergoing HD. Tapentadol does not need dosage adjustment in mild-to-moderate renal impairment conditions; however, no data are available on its use in ESRD. Opioid-related side effects may be exacerbated by common comorbidities in CKD patients. Opioid-induced constipation can be managed with peripherally-acting-μ-opioid-receptor-antagonists (PAMORA). Unlike the other PAMORA, naldemedine does not require any dose adjustment in CKD and HD patients. Accurate pain diagnosis, opioid titration and tailoring are mandatory to minimize the risks and to improve the outcome of the analgesic therapy.

The relationship between the level of μ-opioid receptor (μORs) and postoperative analgesic use in patients undergoing septoplasty: a prospective randomized controlled trial

Background

In this study, the μ-Opioid receptor activity was assessed pre-operatively for its association with postoperative pain level and second analgesic requirement in patients undergoing septoplasty.

Methods

In our prospective study, 120 adult patients underwent septoplasty from June 2015 to January 2019 were randomly divided into 2 pre-operative groups. The first group (n = 60) was patients given tramadol (1–2 mg/kg) for post-operative analgesia, and the second group (control group) (n = 60) was initially prescribed only fentanyl (1 μg/ kg-i.v.) in the induction. Acetaminophen with codeine analgesic 325/30 mg (p.o.) was used as an rescue painkiller in the post-operative period. The μ-Opioid receptor activity was investigated in pre-operative blood samples and compared to post-operative pain level and time required for second round of analgesic administration. The visual analogue score (VAS) was used to evaluate the post-operative pain degree (0 no pain; 10 worst pain). The patients’ post-operative VAS scores were evaluated upon arrival to recovery room, and at the 1st, 3rd, 7th, 10th, and 24th hour post-operative period.

Results

Demographic data and peri-operative variables were similar in both study group (p < 0.05).There was no significant difference between the receptor levels in both groups and the mean receptor level was 200.94 ± 15.34 pg/mL (max:489.92 ± 22.36 pg/mL, min: 94.56 ± 11.23 pg/mL).In patients who used tramadol as the levels of μ-Opioid receptors increased, VAS scores of patients and second analgesic use decreased in post-operative period.The VAS scores in patients with higher receptor levels were lower in the recovery room (p < 0.05), 1st (p < 0.05) and 3rd hours (p < 0.05).The VAS scores were lower in the tramadol group compared to the control group (p < 0.05).Number of secondary analgesic requirement was significantly lower in patients of the tramadol group with higher receptor levels compared to the ones with lower receptor (p < 0.05) for arrival at the recovery room and 1st hour. Patients in the tramadol group needed a second pain killer much later than patients in the control group.

Conclusions

Our study demonstrates that patients with higher μOR levels have a higher efficacy of opioid analgesic agents and an lesser need for additional analgesic agents.

Trial registration

This trial was registered retrospectively (The ACTRN: ACTRN12619001652167, registration date: 26/11/2019).

Repeated Administration of Clinical Doses of Tramadol and Tapentadol Causes Hepato- and Nephrotoxic Effects in Wistar Rats

Tramadol and tapentadol are fully synthetic and extensively used analgesic opioids, presenting enhanced therapeutic and safety profiles as compared with their peers. However, reports of adverse reactions, intoxications and fatalities have been increasing. Information regarding the molecular, biochemical, and histological alterations underlying their toxicological potential is missing, particularly for tapentadol, owing to its more recent market authorization. Considering the paramount importance of liver and kidney for the metabolism and excretion of both opioids, these organs are especially susceptible to toxicological damage. In the present study, we aimed to characterize the putative hepatic and renal deleterious effects of repeated exposure to therapeutic doses of tramadol and tapentadol, using an in vivo animal model. Male Wistar rats were randomly divided into six experimental groups, composed of six animals each, which received daily single intraperitoneal injections of 10, 25 or 50 mg/kg tramadol or tapentadol (a low, standard analgesic dose, an intermediate dose and the maximum recommended daily dose, respectively). An additional control group was injected with normal saline. Following 14 consecutive days of administration, serum, urine and liver and kidney tissue samples were processed for biochemical, metabolic and histological analysis. Repeated administration of therapeutic doses of both opioids led to: (i) increased lipid and protein oxidation in liver and kidney, as well as to decreased total liver antioxidant capacity; (ii) decreased serum albumin, urea, butyrylcholinesterase and complement C3 and C4 levels, denoting liver synthesis impairment; (iii) elevated serum activity of liver enzymes, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and γ-glutamyl transpeptidase, as well as lipid profile alterations, also reflecting hepatobiliary commitment; (iv) derangement of iron metabolism, as shown through increases in serum iron, ferritin, haptoglobin and heme oxygenase-1 levels. In turn, elevated serum cystatin C, decreased urine creatinine output and increased urine microalbumin levels were detected upon exposure to tapentadol only, while increased serum amylase and urine N-acetyl-β-D-glucosaminidase activities were observed for both opioids. Collectively, these results are compatible with kidney injury. Changes were also found in the expression levels of liver- and kidney-specific toxicity biomarker genes, upon exposure to tramadol and tapentadol, correlating well with alterations in lipid profile, iron metabolism and glomerular and tubular function. Histopathological analysis evidenced sinusoidal dilatation, microsteatosis, mononuclear cell infiltrates, glomerular and tubular disorganization, and increased Bowman's spaces. Although some findings are more pronounced upon tapentadol exposure, our study shows that, when compared with acute exposure, prolonged administration of both opioids smooths the differences between their toxicological effects, and that these occur at lower doses within the therapeutic range.

Toxicology of tramadol following chronic exposure based on metabolomics of the cerebrum in mice

Tramadol is an opioid used as an analgesic for treating moderate or severe pain. The long-term use of tramadol can induce several adverse effects. The toxicological mechanism of tramadol abuse is unclear. Metabolomics is a very useful method for investigating the toxicology of drug abuse. We investigated the impact of chronic tramadol administration on the cerebrum of mice, focusing on the metabolites after tramadol administration. The mice received 20 or 50 mg/kg body weight tramadol dissolved in physiological saline daily for 5 weeks via oral gavage. Compared with the control group, the low dose tramadol group showed seven potential biomarkers, including gamma-hydroxybutyric acid, succinate semialdehyde, and methylmalonic acid, which were either up- or down-regulated. Compared with the control group, the high dose tramadol group showed ten potential biomarkers, including gamma-hydroxybutyric acid, glutamine, and O-phosphorylethanolamine, which were either up- or down-regulated. The up-regulated gamma-hydroxybutyric acid and the down-regulated succinate semialdehyde revealed that the neurotransmitter system was disrupted after tramadol abuse. Compared with the low dose tramadol group, there were twenty-nine potential biomarkers in the high dose tramadol group, mainly related to the pentose phosphate pathway and glycerophospholipid metabolism. In conclusion, metabolomics in the tramadol abuse group demonstrated that long-term tramadol abuse can result in oxidative damage, inflammation, and disruption of the GABA neurotransmitter system, which will help to elucidate the toxicology of tramadol abuse.

ADME and toxicity considerations for tramadol: from basic research to clinical implications

INTRODUCTION

Tramadol is widely being used in chronic pain management for improving patients' life quality and reducing trauma. Although it is listed in several medicinal guidelines, its use is controversial because of the conflicting results obtained in pharmacokinetic/pharmacodynamic studies. This multi-receptor drug acts as µ₁ opioid receptor agonist, monoamine reuptake inhibitor, and inhibitor of ligand-gated ion channels and some special protein-coupled receptors.

AREAS COVERED

This review provides a comprehensive view on the pharmacokinetic, pharmacodynamic, and toxicity of tramadol with a deep look on its side effects, biochemical and pathological changes, and possible drug interactions. In addition, the main ways of tramadol poisoning management describe according to in vivo and clinical trial studies.

EXPERT OPINION

Given the broad spectrum of targets, increasing the cases of overdoses and toxicity, and probable drugs interaction, it is necessary to take another look at the pharmacology of tramadol. Regarding the adverse effects of tramadol on different tissues, especially the nervous system and liver tissue, more attentions to tramadol metabolites, their interaction with other drugs, and active agents seem critical. Seizure as the most cited effect of tramadol and its destructive effects on tissues would alleviate by co-administration with drugs with antioxidant properties.

Tramadol/Diclofenac Fixed-Dose Combination: A Review of Its Use in Severe Acute Pain

Pain is a health issue affecting all populations, regardless of age, gender, economic status, race, or geography. Acute pain is the most common type of pain, with a complex aetiology. Inadequately managed acute pain adversely affects quality of life and imposes significant economic burden. The majority of the available pain-relieving drugs have monomodal mechanisms of analgesia, which necessitates combining drugs with non-redundant mechanisms of action in order to provide adequate pain relief and reduce the side effects from higher doses of individual drugs. In this regard, combining an oral opioid (such as codeine or tramadol) and a non-opioid (such as paracetamol or non-steroidal anti-inflammatory drug) offers a plausible option. Tramadol/diclofenac fixed-dose combination (FDC) is one such analgesic combination which has demonstrated promising clinical activity via its multimodal mechanisms of action. This review seeks to provide an up-to-date narrative on the current scientific literature regarding the pharmacological properties, clinical efficacy, and tolerability of tramadol/diclofenac FDC in the treatment of acute severe pain. A comprehensive, qualitative review of the literature was conducted using a structured search strategy in Medline/PubMed and additional Internet-based sources to identify relevant studies. Based on the available scientific literature, evidence of the efficacy and safety of tramadol/diclofenac FDC for treatment of patients with acute severe pain, including musculoskeletal pain, postoperative pain, and acute flare-up of osteoarthritis or rheumatoid arthritis, appears to be substantial. Although additional comparative studies would be required to definitively position tramadol/diclofenac FDC with respect to other analgesic combinations, the available data suggest that tramadol/diclofenac FDC is a valuable treatment option for patients with acute severe pain.

Intravenous dexmedetomidine versus tramadol for treatment of shivering after spinal anesthesia: a meta-analysis of randomized controlled trials

Background

Shivering is a frequent complication after spinal anesthesia. Increasing studies have compared the effect of intravenous dexmedetomidine and intravenous tramadol on shivering after spinal anesthesia, hence we performed a meta-analysis of randomized controlled trials to compare dexmedetomidine with tramadol on the treatment of post-spinal anesthesia shivering.

Methods

PubMed, Embase, Cochrane library, Web of Science and Google Scholar were searched to find the eligible studies comparing the effect of dexmedetomidine and tramadol on the treatment of shivering after spinal anesthesia. Mean difference (MD) or risk ratio (RR) along with 95% confidence interval (CI) was used to analyze the outcomes. I² test was conducted to assess the heterogeneity of the included trials. We utilized Review Manager 5.3 to perform statistical analyses.

Results

Thirteen randomized controlled trials including 864 subjects were included. Dexmedetomidine had higher effective rate of shivering control (RR =1.03; 95%CI [1.01, 1.06], P = 0.01, I² = 14%), shorter time to cease shivering (MD = -2.14; 95%CI [− 2.79, − 1.49], P < 0.00001, I² = 98%), lower recurrent rate of shivering (RR = 0.45; 95%CI [0.27, 0.73], P = 0.001, I² = 0%), lower incidences of nausea (RR = 0.10; 95%CI [0.05, 0.19], P < 0.00001, I² = 48%), and vomiting (RR = 0.13; 95%CI [0.06, 0.30], P < 0.00001, I² = 0%), higher incidence of sedation (RR = 2.48; 95%CI [1.32, 4.65], P = 0.005, I² = 82%), hypotension (RR = 2.50; 95%CI [1.24, 5.03], P = 0.01, I² = 0%) and bradycardia (RR = 4.78; 95%CI [1.76, 13.00], P = 0.002, I² = 0%), compared with tramadol.

Conclusions

Dexmedetomidine is superior to tramadol for shivering treatment, due to higher effective rate of shivering control, earlier onset of action and lesser recurrence of shivering with higher incidence of sedation and lower incidences of nausea and vomiting. However, dexmedetomidine is also associated with higher incidences of hypotension and bradycardia than tramadol.

Capillary Electrophoresis Methods for the Determination of Tramadol: A Review

Tramadol is a widely used opioid analgesic frequently prescribed for treatment of moderate to severe, acute and chronic pain. It has a complex mechanism of action, acting both as a central opiate agonist and as a norepinephrine and serotonin reuptake inhibitor. It is a chiral substance, having two chiral centers in its structure and it is used in therapy as a racemic mixture of two of its enantiomers, (S,S)-tramadol and (R,R)-tramadol. In the last 25 years, several analytical procedures have been published in the literature for the achiral and chiral determination of tramadol from pharmaceutical formulations and biological matrices. Among these methods, capillary electrophoresis techniques have proved to be an efficient, reliable and cost-effective solution. The purpose of the present review is to provide a systematic survey to present and discuss the electrodriven methods available in the literature for the achiral and chiral analysis of tramadol.

Impact of orally administered tramadol combined with self-selected music on adult outpatients with burns undergoing dressing change: A randomized controlled trial

OBJECTIVE

To investigate the effects of music and/or tramadol on pain and anxiety in burn outpatients undergoing dressing changes.

DESIGN

Randomized controlled trial.

SETTING

Burns and Plastic Reconstruction Unit.

PARTICIPANTS

Patients (N=180) with burns on up to 10%-30% of the total body surface area (TBSA).

INTERVENTIONS

The patients were randomly allocated to 4 equal-sized groups as follows: (1) tramadol group (TG), patients received 100mg of tramadol orally 20min before the dressing change; (2) music group (MG), patients listened to self-selected music during the dressing change; (3) music-plus-tramadol group (MTG), patients received tramadol and listened to self-selected music; and (4) control group (CG), patients received a routine dressing change only. All patients underwent the interventions once per day for 2days.

MAIN OUTCOME MEASURES

McGill Pain Questionnaire Short Form (MPQ-SF) (primary outcome), McGill Pain Persian version of Burn Specific Pain Anxiety Scale (BSPAS) (primary outcome), and heart rate (HR) and overall patient satisfaction (secondary outcomes).

RESULTS

The results showed that music-plus-tramadol group (MTG) had better outcomes with respect to pain and anxiety management during dressing changes.

CONCLUSIONS

In comparison with music or tramadol alone, the integration of music and tramadol offers a secure and favorable treatment choice to relieve pain and anxiety, ultimately improving the satisfaction levels of burn outpatients during dressing changes.

Comparing the Pharmacokinetics of 2 Novel Intravenous Tramadol Dosing Regimens to Oral Tramadol: A Randomized 3-Arm Crossover Study

Tramadol is a dual-mechanism (opiate and monoamine reuptake inhibition) analgesic. Intravenous (IV) tramadol has been widely prescribed outside the United States. However, there have not been studies comparing the pharmacokinetics (PK) of IV dosing regimens to that of oral tramadol. In this phase 1, open-label, single investigational center, 3-treatment, 3-period, multidose crossover study, we compared 2 novel IV dosing regimens (IV tramadol 75 mg and IV tramadol 50 mg) to oral tramadol 100 mg given every 6 hours (the highest approved oral dosage in the United States) Compared to the oral regimen, IV tramadol 50 mg administered at hours 0, 2, and 4 and every 4 hours thereafter reached initial tramadol peak serum concentration (C_max ) more rapidly, while resulting in similar overall steady-state C_max and area under the plasma concentration-time curve. IV tramadol 75 mg administered at hours 0, 3, and 6 and every 6 hours thereafter had higher C_max and greater fluctuation in peak to trough tramadol concentration. The primary metabolite M1 (a potent μ agonist) had lower area under the plasma concentration-time curve and C_max for both IV regimens than for the oral regimen. IV tramadol at both doses was well tolerated, with adverse event profiles consistent with the known pharmacological effects of tramadol. IV tramadol 50 mg is now in phase 3 development in patients with postsurgical pain.

Population Pharmacokinetic/Pharmacodynamic Modeling of O-Desmethyltramadol in Young and Elderly Healthy Volunteers

BACKGROUND

Age-related changes in the concentration-effect relationship of (+)-O-desmethyl-tramadol [(+)-ODM], tramadol's active metabolite, are not documented in the elderly.

OBJECTIVE

The objective of this study was to characterize, in elderly and young subjects, the (+)-ODM pharmacokinetic and pharmacodynamic relationship to examine the effect of age after single-dose administration of tramadol 200 mg extended-release tablets.

METHODS

A population analysis of a double-blind, randomized, placebo-controlled, two-period cross-over study including 13 elderly (aged ≥75 years) subjects with mild renal insufficiency and 16 young (aged 18-40 years) subjects was conducted. For 48 h post-dose, blood samples were collected and pain tolerance thresholds measured using an electrically stimulated pain model. A pharmacokinetic/pharmacodynamic model incorporating a one-compartment pharmacokinetic model for (+)-ODM parameterized with first-order formation rate, clearance (CL/f_m), volume of distribution (V/f_m) and a sigmoid maximum effect (E_max) model incorporating baseline (E₀) and placebo effect was used.

RESULTS

Maximum plasma concentrations of (+)-ODM occurred later and plasma concentrations declined more slowly in the elderly than in young subjects. In the elderly, V/f_m was 76% larger and CL/f_m 16% slower. Baseline (E₀) and sensitivity (C₅₀) for pain tolerance were similar between young and elderly subjects. However, the E_max parameter was 2.5 times higher in the elderly and maximum possible treatment-related effect was 169 (135-221) in the young and 194 (149-252) in the elderly; that is, 15% higher in the elderly.

CONCLUSIONS

This exploratory analysis suggests that age-related differences exist in the distribution and elimination of (+)-ODM, including a 76% larger distribution outside the central compartment and 16% slower clearance of (+)-ODM. These pharmacokinetic changes are associated with a 15% higher maximum possible treatment-related effect and carry the potential for greater efficacy but also the potential for increased side effects at the same dose in elderly subjects. Clinicaltrials.gov identifier: NCT02329561.

A claims analysis of the utilization of tramadol for acute pain in patients prescribed buprenorphine/naloxone for opioid use disorder

OBJECTIVE

To determine the prevalence of tramadol prescribing among commercially insured adults receiving medication-assisted therapy (MAT) with buprenorphine/naloxone.

DESIGN

The authors conducted a cross-sectional descriptive study to evaluate the use of tramadol among patients prescribed buprenorphine/suboxone for MAT.

SETTING

This study utilized data from 2010 to 2013 Optum® Clinformatics® Data Mart. This cohort is an administrative health claims database from a large national insurer. These data included pharmacy and medical care utilization and information describing patient enrollment.

PATIENTS/PARTICIPANTS

Patients were 12-64 years of age and had complete and available medical, pharmacy, and administrative records in the Optum Clinformatics Data Mart during the study period.

MAIN OUTCOME MEASURES

Patients who received at least one paid claim for buprenorphine/naloxone from 2010 to 2013 and also received at least one overlapping pharmacy dispensing for tramadol were identified for analysis. The authors determined if the concurrent buprenorphine/naloxone and tramadol dispensings were from the same or a different prescriber.

RESULTS

In this analysis of 18,734 US commercially insured patients receiving MAT with buprenorphine/naloxone, the authors identified 1,198 (6.4 percent) patients who received at least one overlapping dispensing for tramadol during a 4-year period spanning 2010-2013. Among these patients, 266 (1.42 percent) were co-prescribed buprenorphine/naloxone and tramadol from the same provider.

CONCLUSIONS

These results suggest that the use of tramadol among patients receiving buprenorphine/naloxone is not uncommon. Further study is warranted to further determine the benefits and risks associated with the use of tramadol for pain management among patients prescribed buprenorphine/naloxone.

Revisiting Tramadol: A Multi-Modal Agent for Pain Management

Tramadol-an atypical opioid analgesic-has a unique pharmacokinetic and pharmacodynamic profile, with opioidergic, noradrenergic, and serotonergic actions. Tramadol has long been used as a well-tolerated alternative to other drugs in moderate pain because of its opioidergic and monoaminergic activities. However, cumulative evidence has been gathered over the last few years that supports other likely mechanisms and uses of tramadol in pain management. Tramadol has modulatory effects on several mediators involved in pain signaling, such as voltage-gated sodium ion channels, transient receptor potential V1 channels, glutamate receptors, α₂-adrenoceptors, adenosine receptors, and mechanisms involving substance P, calcitonin gene-related peptide, prostaglandin E₂, and proinflammatory cytokines. Tramadol also modifies the crosstalk between neuronal and non-neuronal cells in peripheral and central sites. Through these molecular effects, tramadol could modulate peripheral and central neuronal hyperexcitability. Given the broad spectrum of molecular targets, tramadol as a unimodal analgesic relieves a broad range of pain types, such as postoperative, low back, and neuropathic pain and that associated with labor, osteoarthritis, fibromyalgia, and cancer. Moreover, tramadol has anxiolytic, antidepressant, and anti-shivering activities that could improve pain management outcomes. The aim of this review was to address these issues in the context of maladaptive physiological and psychological processes that are associated with different pain types.

Tramadol: a valuable treatment for pain in Ghana and Nigeria

OBJECTIVE

Pain management is unsatisfactory worldwide, particularly in developing countries where access to opioids is restricted and cost is an issue. It is a major concern in West Africa and we therefore undertook a survey of pain experts to obtain a better understanding of the problems in the region.

METHODS

Medical practitioners involved in pain management, identified via professional networks, were interviewed to share their experience in treating moderate-to-severe pain in West Africa. The questionnaire was based on an existing version modified to meet African conditions. Additionally, informal focus group meetings with palliative care physicians and pharmacists were conducted.

RESULTS

A total of 11 questionnaires were returned. All respondents were physicians who reported availability of opioids in their clinics, but access to morphine was challenging and not possible in some rural settings. Obligatory maintenance of detailed records was considered a burden. The main concern raised was the risk of misuse/addiction. Seven of 11 respondents reported that they would use tramadol as an alternative to strong opioids if required and, interestingly, 9 of 11 considered it to be an essential medicine. Based on personal experience, the respondents noted that some properties of tramadol make it a key pain treatment option in West Africa (strong/fast-acting, better tolerated than NSAIDs, less addictive than other opioids and relatively inexpensive).

CONCLUSIONS

Most stakeholders who completed the survey indicated that tramadol was essential to provide optimal pain management in the absence of access to strong opioids.