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

Tramadol use and risk of seizure: A report of two cases and a review of recent literature

Tramadol is a common pain medication used in practice across numerous specialties. Increased incidence of tramadol abuse and overdose in recent decades has led to it being classified as a controlled drug in several countries. Tramadol appears to be an increasingly popular drug of abuse, possibly related to ease of access to it on prescription, and its potential euphoric effects. We identified two cases of seizures directly related to tramadol exposure. We then reviewed recent literature on tramadol and its adverse effects, particularly looking at its effect on seizure risk and the incidence of seizures. We found that there were scarce recent studies on the relationship between tramadol and seizure risk. Of studies found, many were carried out in animal models. Tramadol-induced seizures were studied in humans more commonly in the context of overdose, and studies involving humans tended to have small patient cohorts and suggested further study in the area. We suggest that tramadol may be useful as part of multi-modal analgesia in moderate to severe pain in specific contexts, but that greater awareness of its potential adverse effects, and particularly its potential to lower seizure threshold, is warranted. We feel that more readily available information specifically about tramadol's effects on seizure threshold may be of interest to colleagues from any specialty prescribing opioid analgesia on a regular basis, but that colleagues treating patients with seizure disorders should be particularly aware of these potential adverse effects.

Supportive pain therapy in dermatology

In conservative dermatology, significant pain frequently presents as an accompanying symptom of complex and severe diseases, severely impacting patients' quality of life. Herpes zoster and pyoderma gangrenosum are two conditions commonly associated with pain. Supportive therapy refers to measures designed to alleviate and improve disease-related symptoms, such as pain, in addition to disease-specific treatments. This review focuses on strategies for targeted pharmacological pain management, addressing contraindications, usage restrictions, dosing, dose adjustments, and potential drug interactions. While nonopioid analgesics are central to pain management, carefully selected opioids are also utilized. However, these may negatively affect patients' well-being and treatment adherence due to side effects like constipation and nausea. As a result, a supportive adjunctive therapy to address these side effects is crucial. The principles of targeted pharmacological pain therapy, consistent with current guidelines and recommendations from professional societies, are outlined in this article for use in dermatological practice.

Fibromyalgia and Inflammation: Unrevealing the Connection

Fibromyalgia represents a chronic pain pathology characterized by severe musculoskeletal pain, fatigue, disturbances in sleep, and cognitive issues. Despite its presence, the underlying mechanisms of fibromyalgia remain inadequately understood; however, recent investigations have suggested that inflammation could play a fundamental role in the pathophysiology of this condition. Several studies highlight elevated concentrations of pro-inflammatory cytokines, dysregulation of immune responses, and neuroinflammation in fibromyalgia patients. Furthermore, chronic low-grade inflammation has been proposed as a potential catalyst for the sensitization of pain pathways, which exacerbates the symptoms of fibromyalgia. Understanding the role of inflammation in this disease might open new avenues for therapeutic interventions while providing a more profound insight into the complex nature of this debilitating disorder. Although progress has been made, further research is needed to uncover the complexities involved. This review investigates the intricate relationship between inflammation and fibromyalgia, analyzing the evidence that supports the involvement of both peripheral and central inflammatory processes in the onset and persistence of the disorder.

Pharmacodynamic characteristics and influencing factors of tapentadol for chronic pain relief under dose titration

Objective

The aim of this study was to establish a pharmacodynamic model of tapentadol analgesia under dose titration conditions, to quantitatively analyze the time-effect relationship of the drug, and to identify relevant influencing factors. This model is intended to provide a pharmacodynamic reference for designing rational tapentadol dose titration schemes in clinical research.

Methods

Randomized controlled trials assessing the efficacy of tapentadol in the management of chronic pain were retrieved from public databases (PubMed and EMBASE). A time-effect relationship model of the percent change in Numerical Rating Scale (NRS) scores post-tapentadol intervention from baseline was constructed, along with a covariate model to identify factors significantly impacting the analgesic effects of tapentadol. Potential influencing factors that were clinically significant but not included in the final covariate model were examined for their impact trends on tapentadol analgesia through subgroup analysis.

Results

A total of 16 studies involving 4,508 participants were included in the analysis. Covariate analysis indicated that age significantly affected the maximum reduction in NRS scores following tapentadol treatment, with the reduction rate being 40.9% for patients aged 45 and 60.7% for those aged 65, suggesting that older patients have a higher demand for pain relief. Furthermore, studies published after 2014 and placebo-controlled trials showed a slower rate of NRS reduction, indicating a more cautious approach to tapentadol dosing titration post the U.S. opioid crisis and in placebo-controlled contexts. Additionally, subgroup analysis suggested that higher titration doses, higher baseline NRS levels, the use of extended-release tapentadol, and a smaller proportion of male participants were trends associated with better analgesic effects, although the differences were not statistically significant. Moreover, the study found that tapentadol was significantly more effective in treating lower back pain compared to non-lower back pain.

Conclusion

This research successfully developed a pharmacodynamic model for dose-titrated tapentadol administration, which can simulate the temporal changes in analgesic effects of tapentadol across different clinical scenarios. This model can guide the formulation of dosing titration protocols for tapentadol in clinical research.

Systematic Review Registration

https://inplasy.com/inplasy-2024-5-0014/.

A Comprehensive Analysis of Fibromyalgia and the Role of the Endogenous Opioid System

Fibromyalgia represents a chronic pain disorder characterized by musculoskeletal pain, fatigue, and cognitive impairments. The exact mechanisms underlying fibromyalgia remain undefined; as a result, diagnosis and treatment present considerable challenges. On the other hand, the endogenous opioid system is believed to regulate pain intensity and emotional responses; hence, it might be expected to play a key role in the enhanced sensitivity experienced by fibromyalgia patients. One explanation for the emergence of disrupted pain modulation in individuals with fibromyalgia is a significant reduction in opioid receptor activity or an imbalance in the levels of endogenous opioid peptides. Further research is essential to clarify the complex details of the mechanisms underlying this abnormality. This complexity arises from the notion that an improved understanding could contribute to the development of innovative therapeutic strategies aimed at targeting the endogenous opioid system in the context of fibromyalgia. Although progress is being made, a complete understanding of these complexities remains a significant challenge. This paradigm has the potential to revolutionize the complex management of fibromyalgia, although its implementation may experience challenges. The effectiveness of this approach depends on multiple factors, but the implications could be profound. Despite the challenges involved in this transformation, the potential for improving patient care is considerable, as this condition has long been inadequately treated.

Noticeable changes in diaphoresis severity following pain management medication adjustments in a complex regional pain syndrome patient

BACKGROUND

Serotonin syndrome results from the use of serotonergic agents that elevate intrasynaptic serotonin level or excessively activate serotonin postsynaptic receptors. Common serotonergic agents used for pain management include opioids, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and tricyclic antidepressants.

PURPOSE

A 24-year old woman diagnosed with complex regional pain syndrome underwent multidrug therapy for pain management over approximately five years. During this period, changes in diaphoresis severity were noted following adjustments to pain medications. The concurrent use of multiple serotonergic agents, exacerbation of diaphoresis after the addition or dose escalation of opioids, and resolution of symptoms upon discontinuation of duloxetine (Cymbalta®, Lily S.A.) strongly suggest the development of serotonin syndrome.

CONCLUSIONS

Diagnosing serotonin syndrome without neuromuscular symptoms can be challenging. Careful monitoring of changes in symptoms and signs following medication use is essential in such cases.

Analgesic efficacy of tapentadol in chronic joint disorders in horses: plasma serotonin concentration and adrenocortical response as biomarkers of pain-induced stress

The study aimed to evaluate the analgesic efficacy of tapentadol in horses, by determining plasma serotonin concentration and adrenocortical response, as biomarkers of pain stress in chronic joint disorders. Thirty-six horses (20 females and 16 males) were divided into three groups of 12 subjects each: group A, osteoarthritis (OA), grade 3-4 lameness; group B, OA, grade 5 lameness; and group C, no OA, no lameness, were enrolled. The orthopedic examination included flexion tests, and radiological and ultrasound examinations. The degree of lameness has been estimated from 0 to 5 according to the American Association of Equine Practitioners (AAEPs). Heart and respiratory rates (HR and RR) and blood pressure were recorded. Serotonin concentration and circulating cortisol levels were determined at baseline and the end of every week for 4 weeks. Biochemical parameters were recorded at baseline and the end of treatment with tapentadol. Subjects with OA were treated with tapentadol 0.5 mg kg-1. The response to painful stimulus on flexion tests was evaluated using the modified numeric pain rating scale (modified NRS 0-7) from baseline and the cumulative pain score (CPS 0-4) after the first week of treatment with tapentadol. The lameness decreased throughout the timeline in both groups (score from 3-4 to 1 in group A and score from 5 to 1 in group B) (p < 0.05). The NRS score decreased throughout the timeline (p < 0.05), from mild pain to no pain in group A (score 1-3 to 0) and from moderate pain to no pain in group B (score from 4 to 0). Physiological variables remained within the physiological range throughout the timeline. Cumulative pain scores ranged from 0.5 to 4 in group A and 1.5 to 7 in group B (p = 0.008). Serotonin concentrations remained unchanged throughout the timeline in all groups (p = 1.000) but in the OA groups, the concentrations were lower than control (p < 0.001). Circulating cortisol levels were reduced compared to baseline in subjects treated with tapentadol (p < 0.001). Tapentadol is effective in OA pain management in horses. Serotonin and cortisol may be utilized as biomarkers in the pain stress response. Serotonin can also determine the state of wellbeing of patients.

Benzylpiperidine derivatives as new dual μ-opioid and σ1 receptor ligands with potent antinociceptive effects

Dual-acting μ-opioid receptor (MOR)/sigma-1 receptor (σ1R) ligands have displayed promise in exerting robust antinociceptive effects while reducing opioid-related side effects. To discover safer and more effective analgesics, we designed, prepared, and evaluated 30 benzylpiperidine derivatives as dual MOR and σ1R ligands. The obtained benzylpiperidine analogs were tested for MOR and σ1R binding affinity in vitro. The best compound 52 showed high affinity for both MOR [Ki (MOR) = 56.4 nM] and σ1R [Ki (σ1R) = 11.0 nM] and produced potent antinociceptive effects in the abdominal contraction test (ED50 = 4.04 mg/kg in mice), carrageenan-induced inflammatory pain model (ED50 = 6.88 mg/kg in mice), formalin test (ED50 = 13.98 mg/kg in rats) and complete Freund's adjuvant (CFA)-induced chronic pain model (ED50 = 7.62 mg/kg in mice). Moreover, 52 had less MOR-related adverse effects than oxycodone, including constipation, acute hyperlocomotion and physical dependence. The above results suggested that 52 may be a promising candidate for the development of safer analgesics.

Tapentadol: navigating the complexities of abuse, patient safety & regulatory measures

AIM

To evaluate tapentadol abuse cases by analyzing real-world data and identifying under-reporting countries from Southeast Asian Region (SEAR) to enhance vigilance.

METHOD

A retrospective, observational study from 2013 to March 2024 using VigiBase was conducted.

RESULT

Tapentadol-related abuse falls within the System Organ Class (SOC) categories of psychiatric disorder, nervous system disorder and injury, poisoning, and procedural complications. These are further categorized into Preferred Terms (PT) such as anxiety, delirium, Central Nervous System toxicity, depressive disorder, drug abuse, dependence/withdrawal syndrome, and overdose using the Medical Dictionary for Regulatory Activities (MedDRA) system. Among the 11 countries in the SEAR, India is the only country to report cases of tapentadol-related abuse, no Individual Case Safety Reports (ICSRs) related to tapentadol abuse have been submitted from other SEAR nations. Out of 127 ICSRs concerning tapentadol-related adverse events reported in India, 20 cases involved abuse. Focusing on the ICSRs submitted in India, the reported adverse reactions included anger(n = 1,10%), anxiety (n = 2, 10%), delirium (n = 1, 5%), drug abuse (n = 4, 20%), drug dependence/withdrawal syndrome (n = 7, 35%), intentional overdose (n = 2, 10%), depressive disorder (n = 1, 5%), euphoric mood (n = 1, 5%), and product misuse (n = 1, 5%) indicating a concerning pattern of substance abuse.

CONCLUSION

Stringent regulatory actions are needed to curb this practice in India, such as rescheduling tapentadol from Schedule H (Prescription drugs) to Schedule X(Narcotic drugs) in India could offer more regulatory oversight and measures to reduce risks related to abuse, addiction, and dependence while enhancing patient safety in pain management practices. Additionally, tapentadol should be closely monitored in other SEAR countries due to its potential for dependence. This study also emphasizes the importance of encouraging SEAR countries to report more Adverse Drug Reactions (ADRs), which would facilitate the implementation of more rigorous regulatory measures.

Tramadol Effects on Brain Activity During Cognitive and Emotional Empathy for Pain: A Randomized Controlled Study

Pain is perceived not only by personal experience but also vicariously. Pain empathy is the ability to share and understand other's intentions and emotions in their painful conditions, which can be divided into cognitive and emotional empathy. It remains unclear how centrally acting analgesics would modulate brain activity related to pain empathy and which component of pain empathy would be altered by analgesics. In this study, we examined the effects of the analgesic tramadol on the brain activity for pain empathy in healthy adults. We used 2 tasks to assess brain activity for pain empathy. In experiment 1, we used a well-established picture-based pain empathy task involving passive observation of other's pain. In experiment 2, we developed a novel pain empathy task to assess brain activity during cognitive and emotional empathy for pain separately in a single task. We conducted a double-blind, placebo-controlled within-subject crossover study with functional magnetic resonance imaging for 33 participants in experiment 1 and 31 participants in experiment 2, respectively. In experiment 1, we found that tramadol decreased activation in the supramarginal gyrus during observation of other's pain compared with placebo. Supramarginal gyrus activation correlated negatively with the thermal pain threshold. In experiment 2, we found that tramadol decreased activation in angular gyrus in cognitive empathy for pain compared with placebo but did not change brain activity in emotional empathy for pain. PERSPECTIVE: Centrally acting analgesics such as tramadol may have not only analgesic effects on self-experienced pain but also on the complex neural processing of pain empathy.

Pharmacological Pain Treatment in Older Persons

Pharmacological pain treatment in older persons is presented by a multi-disciplinary group of European pain experts. Drugs recommended for acute or chronic nociceptive pain, also for neuropathic pain and the routes of administration of choice are the same as those prescribed for younger persons but comorbidities and polypharmacy in older persons increase the risk of adverse effects and drug interactions. Not all drugs are available or authorised in all European countries. For mild-to-moderate pain, non-opioids including paracetamol and non-steroidal anti-inflammatory drugs are first-line treatments, followed by nefopam and metamizole. Codeine, dihydrocodeine and tramadol are prescribed for moderate to severe pain and 'strong' opioids, including morphine, hydromorphone, oxycodone, fentanyl, buprenorphine, methadone and tapentadol, for severe pain. Chronic neuropathic pain treatment relies on coanalgesics, including anti-epileptics (gabapentinoids) and anti-depressants with additional option of topical lidocaine and capsaicine. The choice of analgesic(s) and the route of administration should be guided by the pain characteristics, as well as by the patient's comorbidities, organ function and medications. Several directions have been highlighted to optimise pharmacological pain management in older individuals: (1) before starting pain treatment adequately detect and assess pain and always perform a full geriatric assessment, (2) consider kidney function systematically to adjust the doses of analgesics and avoid the risks of overdose, (3) start with the lowest dose of an analgesic and increase it gradually under the control of the effect, (4) involve the older persons and family in their treatment, (5) reevaluate pain regularly during treatment and (6) combine pharmacological treatment with non-pharmacological approaches.

Tapentadol: A Comprehensive Review of Its Role in Pain Management

Pain is a prevalent issue among patients, requiring effective management to prevent the transition of acute pain into chronic pain and to mitigate significant clinical and socioeconomic impacts, such as increased morbidity, mortality, prolonged recovery, unplanned readmissions, and diminished quality of life. Despite advancements in pain management guidelines, achieving consistent pain relief remains challenging due to individual differences in pain thresholds, the nature of surgical procedures, patient age, and existing comorbidities. Tapentadol, an opioid that acts as both a μ-opioid receptor agonist and a noradrenaline reuptake inhibitor, presents a promising option for pain management. Approved by the FDA in 2008 for immediate release and in 2011 for extended release, tapentadol effectively addresses both nociceptive and neuropathic pain, offering a more favorable efficacy-safety profile compared to traditional opioids such as tramadol. Additionally, tapentadol is gaining recognition as a preferred option for managing significant pain in cancer patients due to its effectiveness and reduced side effects. This review evaluates tapentadol's clinical and pharmacological attributes, systematically analyzing literature on its efficacy, safety, pharmacokinetics, and comparative effectiveness, suggesting that tapentadol is a viable option for effective pain management with potential for broader clinical applications.

Comparative Bioavailability of a Novel Fixed-dose Combination Etoricoxib and Tramadol

Multimodal analgesia is defined as using several drugs or techniques simultaneously to target different pain pathways or receptors to avoid pain propagation. This study evaluated the pharmacokinetic profile and comparative bioavailability of etoricoxib 90 mg and tramadol 50 mg dosing alone (reference drugs) or in a novel fixed-dose combination (test drug) under fasting conditions in Mexican healthy volunteers. This was a randomized, open-label, 3-way, crossover, single-dose, prospective, and longitudinal study with a 14-day washout period. Eligible subjects were healthy Mexican adult volunteers. The drugs were dosing orally, according to the randomization sequence, after 10 hours of fasting and 4 hours before breakfast with 250 mL of water at room temperature. Serial blood samples were collected before and after dosing, both drugs were quantified using high-performance liquid chromatography coupled with tandem mass spectrometry. Forty-two subjects were enrolled and 38 completed the study (28 men and 14 women, mean age 25.2 years, mean weight 66.6 kg). Test products were considered to have comparative bioavailability if confidence intervals of natural log-transformed for (maximum plasma drug concentration (Cmax), (area under the plasma drug concentration-time curve form 0 up to last sampling time (AUC0-t), and (area under the plasma drug concentration-time curve from 0 up to infinity (AUC0-∞) data were within the range of 80%-125%. Non-serious adverse events were observed. The results demonstrate that the pharmacokinetic profile and bioavailability of the etoricoxib/tramadol fixed-dose combination are comparable to those of the reference products.

Intranasal Tapentadol Versus Intravenous Paracetamol for Postoperative Analgesia in Lower Limb Orthopaedic Surgeries Under Spinal Anaesthesia: A Single Blind RCT

OBJECTIVE

We aimed to compare the analgesic effectiveness of intranasal tapentadol nasal spray 44.5 mg and intravenous (IV) paracetamol 1 gm during the postoperative period in patients undergoing lower limb orthopedic surgeries under spinal anesthesia.

METHODS

This prospective, randomized, single-blind clinical trial was carried out in a tertiary care teaching hospital. Patients aged between 18 and 60 years of physical status ASA grade 1-3 were included in the study. Postoperative pain scores were measured using the visual analog scale (VAS) in centimeters (cm) every 12 hours in 37 patients per group. The patients were administered either intranasal tapentadol or IV paracetamol every 6 hours for 72 hours, beginning 3 hours after surgery.

RESULTS

There was a significant group by intervention effect favoring intranasal tapentadol, suggesting a greater reduction in VAS pain scores after the intervention at 72 hours (estimate: -1.58 cm; SE:0.2; P<0.001). Group by time effect for all the measured time frames, except for 36 hours, favored intranasal tapentadol with estimated values for greater reduction in VAS pain scores ranging from -0.8 cm to -1.6 cm.

DISCUSSION

The results of the present study suggests that intranasal tapentadol results in a greater reduction of postoperative pain compared with IV paracetamol in lower limb orthopedic surgeries. The ease of administration of tapentadol may make it a preferred option over IV paracetamol in such surgeries.

Unraveling the Hippocampal Molecular and Cellular Alterations behind Tramadol and Tapentadol Neurobehavioral Toxicity

Tramadol and tapentadol are chemically related opioids prescribed for the analgesia of moderate to severe pain. Although safer than classical opioids, they are associated with neurotoxicity and behavioral dysfunction, which arise as a concern, considering their central action and growing misuse and abuse. The hippocampal formation is known to participate in memory and learning processes and has been documented to contribute to opioid dependence. Accordingly, the present study assessed molecular and cellular alterations in the hippocampal formation of Wistar rats intraperitoneally administered with 50 mg/kg tramadol or tapentadol for eight alternate days. Alterations were found in serum hydrogen peroxide, cysteine, homocysteine, and dopamine concentrations upon exposure to one or both opioids, as well as in hippocampal 8-hydroxydeoxyguanosine and gene expression levels of a panel of neurotoxicity, neuroinflammation, and neuromodulation biomarkers, assessed through quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemical analysis of hippocampal formation sections showed increased glial fibrillary acidic protein (GFAP) and decreased cluster of differentiation 11b (CD11b) protein expression, suggesting opioid-induced astrogliosis and microgliosis. Collectively, the results emphasize the hippocampal neuromodulator effects of tramadol and tapentadol, with potential behavioral implications, underlining the need to prescribe and use both opioids cautiously.

Novel Opioids in the Setting of Acute Postoperative Pain: A Narrative Review

Although traditional opioids such as morphine and oxycodone are commonly used in the management of acute postoperative pain, novel opioids may play a role as alternatives that provide potent pain relief while minimizing adverse effects. In this review, we discuss the mechanisms of action, findings from preclinical studies and clinical trials, and potential advantages of several novel opioids. The more established include oliceridine (biased ligand activity to activate analgesia and downregulate opioid-related adverse events), tapentadol (mu-opioid agonist and norepinephrine reuptake inhibitor), and cebranopadol (mu-opioid agonist with nociceptin opioid peptide activity)-all of which have demonstrated success in the clinical setting when compared to traditional opioids. On the other hand, dinalbuphine sebacate (DNS; semi-synthetic mu partial antagonist and kappa agonist), dual enkephalinase inhibitors (STR-324, PL37, and PL265), and endomorphin-1 analog (CYT-1010) have shown good efficacy in preclinical studies with future plans for clinical trials. Rather than relying solely on mu-opioid receptor agonism to relieve pain and risk opioid-related adverse events (ORAEs), novel opioids make use of alternative mechanisms of action to treat pain while maintaining a safer side-effect profile, such as lower incidence of nausea, vomiting, sedation, and respiratory depression as well as reduced abuse potential.

Tapentadol dependence through intravenous injection ('shooting') of crushed tablets associated with cutaneous pseudoallergic reactions

Tapentadol is a synthetic opioid analgesic with a low risk of abuse and diversion. The rising trend of abuse of tapentadol is largely attributable to its intrinsic pharmacological profile and easy availability due to poor regulatory control. We report a case of intravenous injection of crushed tapentadol tablets that presented with cutaneous adverse drug reactions. Cutaneous adverse reactions are common in injection drug abuse, and clinical examination is a must to inspect the injection sites. Stringent regulatory measures are required to restrict the increasing abuse of tapentadol in India.

The transit of oral premedication beyond the stomach in patients undergoing laparoscopic sleeve gastrectomy: a retrospective observational multicentre study

BACKGROUND

Antiemetic and analgesic oral premedications are frequently prescribed preoperatively to enhance recovery after laparoscopic sleeve gastrectomy. However, it is unknown whether these medications transit beyond the stomach or if they remain in the sleeve resection specimen, thereby negating their pharmacological effects.

METHODS

A retrospective cohort study was performed on patients undergoing laparoscopic sleeve gastrectomy and receiving oral premedication (slow-release tapentadol and netupitant/palonosetron) as part of enhanced recovery after bariatric surgery program. Patients were stratified into the Transit group (premedication absent in the resection specimen) and Failure-to-Transit group (premedication present in the resection specimen). Age, sex, body mass index, and presence of diabetes were compared amongst the groups. The premedication lead time (time between premedications' administration and gastric specimen resection), and the premedication presence or absence in the specimen was evaluated.

RESULTS

One hundred consecutive patients were included in the analysis. Ninety-nine patients (99%) were morbidly obese, and 17 patients (17%) had Type 2 diabetes mellitus. One hundred patients (100%) received tapentadol and 89 patients (89%) received netupitant/palonosetron. One or more tablets were discovered in the resected specimens of 38 patients (38%). No statistically significant differences were observed between the groups regarding age, sex, diabetes, or body mass index. The median (Q1‒Q3) premedication lead time was 80 min (57.8‒140.0) in the Failure-to-Transit group and 119.5 min (85.0‒171.3) in the Transit group; P = 0.006. The lead time required to expect complete absorption in 80% of patients was 232 min (95%CI:180‒310).

CONCLUSIONS

Preoperative oral analgesia and antiemetics did not transit beyond the stomach in 38% of patients undergoing laparoscopic sleeve gastrectomy. When given orally in combination, tapentadol and netupitant/palonosetron should be administered at least 4 h before surgery to ensure transition beyond the stomach. Future enhanced recovery after bariatric surgery guidelines may benefit from the standardization of premedication lead times to facilitate increased absorption.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry; number ACTRN12623000187640; retrospective registered on 22/02/2023.

Tapentadol for the management of cancer pain in adults: an update

PURPOSE OF REVIEW

Tapentadol is the first of a new class of analgesics, having synergistic µ-opioid receptor agonist and noradrenaline reuptake inhibitory actions. It has been widely researched in many areas of pain, often in noninferiority studies against potent opioids. This review describes all randomized and recent nonrandomized studies of tapentadol in adults with cancer pain.

RECENT FINDINGS

Tapentadol has been shown to be at least as effective as morphine and oxycodone in five randomized (two of which were multicenter and double-blind) and a range of nonrandomized trials, although caution is needed when interpreting these results. It is effective in both opioid-naive patients and those already taking opioids. By having a lower µ-opioid receptor binding affinity, it has fewer opioid-related toxicities such as constipation and nausea. A recent randomized trial comparing tapentadol to tapentadol plus duloxetine in patients with chemotherapy-induced peripheral neuropathy shows similar improvement in both groups in a range of pain relieving and quality of life measures, with similar adverse effects.

SUMMARY

Tapentadol has been shown in a range of studies to be an effective analgesic and thus should be considered as an alternative to morphine and oxycodone, especially when opioid toxicities are an issue.

Neuropathic pain: Mechanisms and therapeutic strategies

The physiopathology and neurotransmission of pain are of an owe inspiring complexity. Our ability to satisfactorily suppress neuropathic or other forms of chronic pain is limited. The number of pharmacodynamically distinct and clinically available medications is low and the successes achieved modest. Pain Medicine practitioners are confronted with the ethical dichotomy imposed by Hippocrates: On one hand the mandate of primum non nocere, on the other hand, the promise of heavenly joys if successful divinum est opus sedare dolorem. We briefly summarize the concepts associated with nociceptive pain from nociceptive input (afferents from periphery), modulatory output [descending noradrenergic (NE) and serotoninergic (5-HT) fibers] to local control. The local control is comprised of the "inflammatory soup" at the site of pain origin and synaptic relay stations, with an ATP-rich environment promoting inflammation and nociception while an adenosine-rich environment having the opposite effect. Subsequently, we address the transition from nociceptor pain to neuropathic pain (independent of nociceptor activation) and the process of sensitization and pain chronification (transient pain progressing into persistent pain). Having sketched a model of pain perception and processing we attempt to identify the sites and modes of action of clinically available drugs used in chronic pain treatment, focusing on adjuvant (co-analgesic) medication.

Treatment of Pain in Ferrets

Ferrets often require pain management as part of comprehensive veterinary care. Recognition and objective quantification of pain, such as the ferret grimace scale, are the first steps of an analgesic plan. As in other species, a multimodal approach to pain management is preferred, which includes combining analgesic drugs of multiple classes and/or techniques to affect different areas of the pain pathway. This article reviews the current published literature on analgesic medications in domestic ferrets, including specific drugs, doses, dosing intervals, and routes of administration.

Synergistic action between a synthetic cannabinoid compound and tramadol in neuropathic pain rats

In the present study the interaction of cannabinoid, PhAR-DBH-Me [(R, Z)-18-((1S,4S)-5-methyl-2,5-diazabicyclo[2.2.1]heptan-2-yl)-18-oxooctadec-9-en-7-ylphenyl-acetate] and tramadol in two neuropathy models, as well as their possible toxic effects, was analyzed. The anti-allodynic effect of PhAR-DBH-Me, tramadol, or their combination, were evaluated in neuropathic rats. Furthermore, the effective dose 35 (as the 35 % of the anti allodynic effect) was calculated from the maximum effect of each drug. Moreover, the isobolographic analysis was performed to determine the type of interaction between the drugs. A plasma acute toxicity study was carried out to assess the hepatic, renal, and heart functions after an individual or combined administration of the drugs, as well as histology using the hematoxylin-eosin or Masson-trichome method. PhAR-DBH-Me, tramadol, and their combination produced an antiallodynic effect on spinal nerve ligation (SNL) and cisplatin-induced neuropathic pain in rats. Moreover, PhAR-DBH-Me and tramadol combination showed a synergistic interaction in neuropathic pain rats induced by SNL but not for cisplatin-induced neuropathy. On the other hand, changes in renal and hepatic functions were not observed. Likewise, analysis of liver, kidney and heart histology showed no alterations compared with controls. Results show that the combination of PhAR-DBH-Me and tramadol attenuates the allodynia in SNL rats; the acute toxicology analysis suggests that this combination could be considered safe in administered doses.

Effect of preoperative tramadol, ibuprofen, ibuprofen/acetaminophen on the anaesthetic efficacy of inferior alveolar nerve block in patients with symptomatic irreversible pulpitis

The purpose of this double-blind clinical trial was to compare the effect of preoperative tramadol 50 mg, tramadol 100 mg, ibuprofen 600 mg, ibuprofen 600 mg/acetaminophen 1000 mg or placebo 60 min before the administration of inferior alveolar nerve blocks (IANB) of mandibular teeth in patients experiencing symptomatic irreversible pulpitis (SIP). Two hundred and fifty emergency patients diagnosed with SIP were randomly divided into five groups and received medications. Endodontic access was begun 15 min after completion of the IANB, and all patients had profound lip numbness. The Heft-Parker visual analogue scale was used to evaluate pain. Premedication with tramadol 100 mg significantly increased the success rate to 62% than the other groups (p < 0.05). The success rates of ibuprofen, ibuprofen/acetaminophen and tramadol 50 mg groups were not significantly different (p > 0.05). Premedication with tramadol 100 mg enhanced the anaesthetic success of IANB in mandibular molars with SIP.

Complex Regional Pain Syndrome: Practical Diagnostic and Treatment Guidelines, 5th Edition

There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated multifactorial disease remains low (with some notable exceptions; e.g., the recent work on the dorsal root ganglion stimulation). The semi-systematic (though in some cases narrative) approach to review is necessary so that we might treat our patients while waiting for "better research." This semi-systematic review was conducted by experts in the field, (deliberately) some of whom are promising young researchers supplemented by the experience of "elder statesman" researchers, who all mention the system they have used to examine the literature. What we found is generally low- to medium-quality research with small numbers of subjects; however, there are some recent exceptions to this. The primary reason for this paucity of research is the fact that this is a rare disease, and it is very difficult to acquire a sufficient sample size for statistical significance using traditional statistical approaches. Several larger trials have failed, probably due to using the broad general diagnostic criteria (the "Budapest" criteria) in a multifactorial/multi-mechanism disease. Responsive subsets can often be identified in these larger trials, but not sufficient to achieve statistically significant results in the general diagnostic grouping. This being the case the authors have necessarily included data from less compelling protocols, including trials such as case series and even in some instances case reports/empirical information. In the humanitarian spirit of treating our often desperate patients with this rare syndrome, without great evidence, we must take what data we can find (as in this work) and tailor a treatment regime for each patient.

Current and Future Therapeutic Options in Pain Management: Multi-mechanistic Opioids Involving Both MOR and NOP Receptor Activation

Opioids are widely used in chronic pain management, despite major concerns about their risk of adverse events, particularly abuse, misuse, and respiratory depression from overdose. Multi-mechanistic opioids, such as tapentadol and buprenorphine, have been widely studied as a valid alternative to traditional opioids for their safer profile. Special interest was focused on the role of the nociceptin opioid peptide (NOP) receptor in terms of analgesia and improved tolerability. Nociceptin opioid peptide receptor agonists were shown to reinforce the antinociceptive effect of mu opioid receptor (MOR) agonists and modulate some of their adverse effects. Therefore, multi-mechanistic opioids involving both MOR and NOP receptor activation became a major field of pharmaceutical and clinical investigations. Buprenorphine was re-discovered in a new perspective, as an atypical analgesic and as a substitution therapy for opioid use disorders; and buprenorphine derivatives have been tested in animal models of nociceptive and neuropathic pain. Similarly, cebranopadol, a full MOR/NOP receptor agonist, has been clinically evaluated for its potent analgesic efficacy and better tolerability profile, compared with traditional opioids. This review overviews pharmacological mechanisms of the NOP receptor system, including its role in pain management and in the development of opioid tolerance. Clinical data on buprenorphine suggest its role as a safer alternative to traditional opioids, particularly in patients with non-cancer pain; while data on cebranopadol still require phase III study results to approve its introduction on the market. Other bifunctional MOR/NOP receptor ligands, such as BU08028, BU10038, and AT-121, are currently under pharmacological investigations and could represent promising analgesic agents for the future.

CYP2D6 phenotypes and opioid metabolism: the path to personalized analgesia

INTRODUCTION

Opioids play a fundamental role in chronic pain, especially considering when 1 of 5 Europeans adults, even more in older females, suffer from it. However, half of them do not reach an adequate pain relief. Could pharmacogenomics help to choose the most appropriate analgesic drug?

AREAS COVERED

The objective of the present narrative review was to assess the influence of cytochrome P450 2D6 (CYP2D6) phenotypes on pain relief, analgesic tolerability, and potential opioid misuse. Until December 2021, a literature search was conducted through the MEDLINE, PubMed database, including papers from the last 10 years. CYP2D6 plays a major role in metabolism that directly impacts on opioid (tramadol, codeine, or oxycodone) concentration with differences between sexes, with a female trend toward poorer pain control. In fact, CYP2D6 gene variants are the most actionable to be translated into clinical practice according to regulatory drug agencies and international guidelines.

EXPERT OPINION

CYP2D6 genotype can influence opioids' pharmacokinetics, effectiveness, side effects, and average opioid dose. This knowledge needs to be incorporated in pain management. Environmental factors, psychological together with genetic factors, under a sex perspective, must be considered when you are selecting the most personalized pain therapy for your patients.

Evaluation of opioid consumption trends for pain in Taiwan and comparison with neighboring Asian countries

Opioids are effective analgesics for pain relief, however, inappropriate use may cause risks. The aims of the study were to evaluate trends of opioid consumption for pain management in Taiwan and compare them among neighboring Asian countries. Opioid consumption data, including fentanyl, morphine, oxycodone, hydromorphone, codeine, and pethidine, were collected from the Controlled Drugs Management Information System of Taiwan Food and Drug Administration from 2008 to 2018. Data of different continents and neighboring Asian countries were retrieved from the WHO website. The major findings include: (1) In Taiwan, the total annual opioid consumption has gradually increased from 2008 to 2018, with fentanyl being the most frequently consumed opioid analgesic, followed by morphine. Codeine and pethidine consumption dropped significantly over the years. (2) In neighboring Asian countries, the opioid consumption in order from highest to lowest consumption were South Korea, Japan, Taiwan, Singapore, Hong Kong (China), and China. We concluded that, from 2008 to 2018, the total opioid consumption trend for pain management in Taiwan has slowly increased, with fentanyl and morphine being the most commonly used opioids. When compared with neighboring Asian countries, level of opioid consumption in Taiwan was between Japan and Singapore. The research results may provide a reference for healthcare professionals worldwide.

Tapentadol shows lower intrinsic efficacy at µ receptor than morphine and oxycodone

Tapentadol is a centrally acting analgesic with a dual mechanism of action. It acts as an agonist at the µ receptor and inhibitor of noradrenaline reuptake. Clinical trials suggest similar analgesic efficacy of tapentadol, oxycodone, and morphine in acute and chronic pain. Given the limited information about the molecular actions of tapentadol at the µ receptor, we investigated the intrinsic efficacy of tapentadol and compared it with other opioids. β-chlornaltrexamine (β-CNA, 100 nM, 20 min) was used to deplete spare receptors in AtT20 cells stably transfected with human µ receptor wild-type (WT). Opioid-mediated changes in membrane potential were measured in real-time using a membrane potential-sensitive fluorescent dye. Using Black and Leff's operational model, intrinsic efficacy relative to DAMGO was calculated for each opioid. Tapentadol (0.05 ± 0.01) activated the GIRK channel with lesser intrinsic efficacy than morphine (0.17 ± 0.02) and oxycodone (0.16 ± 0.02). We further assessed the signaling of tapentadol in the common µ receptor variants (N40D and A6V) which are associated with altered receptor signaling. We found no difference in the response of tapentadol between these receptor variants.

Association of Spinal Cord Stimulator Implantation With Persistent Opioid Use in Patients With Postlaminectomy Syndrome

IMPORTANCE

The results of studies evaluating spinal cord stimulation (SCS) for postlaminectomy syndrome (PLS) have yielded mixed results. This has led to an increased emphasis on objective outcome measures such as opioid prescribing.

OBJECTIVE

To determine the association between SCS and long-term opioid therapy (LOT) for PLS.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, adults with PLS were identified using the TriNetx Diamond Network and separated based on whether they underwent SCS. Patients were stratified according to baseline opioid use (opioid-naive or receiving LOT) and subsequent opioid therapy over the 12-month period ranging from 3 to 15 months post-SCS implantation or post-PLS index date. Statistical analysis was performed from June to December 2021.

EXPOSURE

SCS.

MAIN OUTCOMES AND MEASURES

The main outcome was cessation of opioid use among patients receiving LOT or abstinence from opioids among opioid-naive patients. Opioid-naive patients were defined as those receiving at most 2 opioid prescriptions per year, and patients on LOT were those receiving at least 6 opioid prescriptions per year.

RESULTS

Among 552 937 eligible patients treated between December 2015 and May 2021, 26 179 with PLS received an SCS implant. The median (IQR) patient age was 60 (51-69) years; 305 802 patients (55.3%) were female. Among those reporting racial identify (37.0% [204 758 patients]), 9.3% (18 971 patients) were African American, 0.3% (648 patients) were Asian, and 90.4% (185 139 patients) were White. Compared with those who did not receive an SCS, individuals who received an SCS were more likely to be using opioids preimplantation (mean [SD] prescriptions: 4.3 [8.5] vs 4.1 [9.3]; P < .001) but less likely to be using opioids after SCS implantation (mean [SD] prescriptions: 3.8 [8.2] vs 4.0 [9.4]; P = .006). In the 12-month study period, similar proportions in the SCS and no-SCS groups receiving baseline LOT remained on LOT (70.3% [n = 74 585] vs 69.2% [n = 3882], respectively; P = .10). In opioid-naive patients, SCS was associated with a small decreased likelihood of patients subsequently receiving LOT (7.6% vs 7.0%; difference, -0.6% [95% CI, -1.0% to -0.2%]; P = .003). In multivariable analysis, SCS was associated with an increased likelihood of not being on opioids in both opioid-naive (adjusted odds ratio [OR], 0.90 [95% CI, 0.85-0.96]; P < .001) and LOT patients (adjusted OR, 0.93 [95% CI, 0.88-0.99]; P = .02). White patients were significantly more likely to be diagnosed with PLS (ie, underwent surgery) (90.4% vs 85.2%; difference, 5.2% [95% CI, 5.1%-5.4%]; P < .001) and receive an SCS (93.7% vs 90.3%; difference, 3.4% [95% CI, 2.9% to 4.0%]; P < .001) than patients of other racial identities.

CONCLUSIONS AND RELEVANCE

These findings suggest that under real-life conditions, SCS was associated with small, clinically questionable associations with opioid discontinuation and not starting opioids in the context of PLS.

Perioperative Pain Management in Bariatric Anesthesia

Weight loss (bariatric) surgery is the most commonly performed elective surgical procedure in patients with morbid obesity. In this review, we provide an evidence-based update on perioperative pain management in bariatric anesthesia. We mention some newer preoperative aspects—medical optimization, physical preparation, patient education, and psychosocial factors—that can all improve pain management. In the intraoperative period, with bariatric surgery being almost universally performed laparoscopically, we emphasize the use of non-opioid adjuvant infusions (ketamine, lidocaine, and dexmedetomidine) and suggest some novel regional anesthesia techniques to reduce pain, opioid requirements, and side effects. We discuss some postoperative strategies that additionally focus on patient safety and identify patients at risk of persistent pain and opioid use after bariatric surgery. This review suggests that the use of a structured, step-wise, severity-based, opioid-sparing multimodal analgesic protocol within an enhanced recovery after surgery (ERAS) framework can improve postoperative pain management. Overall, by incorporating all these aspects throughout the perioperative journey ensures improved patient safety and outcomes from pain management in bariatric anesthesia.

Pharmacotherapy of Painful Diabetic Neuropathy: A Clinical Update

The rising prevalence of diabetes mellitus (DM) leads on to an increase in chronic diabetic complications. Diabetic peripheral neuropathies (DPNs) are common chronic complications of diabetes. Distal symmetric polyneuropathy is the most prevalent form. Most patients with DPN will remain pain-free; however, painful DPN (PDPN) occurs in 6-34% of all DM patients and is associated with reduced health-related-quality-of-life and substantial economic burden. Symptomatic treatment of PDPN and diabetic autonomic neuropathy is the key treatment goals. Using certain patient related characteristics, subjects with PDPN can be stratified and assigned targeted therapies to produce better pain outcomes. The aim of this review is to discuss the various pathogenetic mechanisms of DPN with special reference to the mechanisms leading to PDPN and the various pharmacological and non-pharmacological therapies available for its management. Recommended pharmacological therapies include anticonvulsants, antidepressants, opioid analgesics, and topical medications.