Efficacy of Tapentadol ER for Managing Moderate to Severe Chronic Pain

Evaluation of Phytochemistry and Pharmacological Properties of Alnus nitida

In the current study, the anti-inflammatory and analgesic potential of Alnus nitida (leaves and fruits) was evaluated in the Sprague-Dawley rat. Traditionally, A. nitida was used for the treatment of inflammatory ailments. However, A. nitida leaves and fruits have not been yet reported regarding any potential medicinal effects. Leaves/fruits of A. nitida were extracted with methanol and fractionated to attain n-hexane, chloroform, ethyl acetate and aqueous fractions. These extracts were then evaluated for in vivo analgesic and anti-inflammatory potential. For in vivo anti-inflammatory activity, carrageenan-induced paw edema assay, Freunds’ complete adjuvant-induced edema, xylene-induced ear edema and histamine-induced paw edema models were used in rats, which showed significant (p < 0.01) reduction (70−80%) in edema in comparison of inflammatory controls. On other hand, for the analgesic assessment, hot plate assay and acetic acid-induced writhing tests were used, which showed a significant (p < 0.01) rise in latency time (40−60%) as compared with pain-induced controls. These results were comparable with standard drugs in a concentration-dependent manner and no mortality or toxicity was observed during all experiments. Then, for the identification of chemical constituents gas chromatography−mass spectrometry (GC-MS) analysis was performed, which indicated the presence of neophytadiene, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, phytol and vitamin E, justifying the use of A. nitida to treat inflammatory disorders.

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.

Tapentadol and Sleepwalking: A Case Report

OBJECTIVE

This is a case report of a patient with sleepwalking likely caused by tapentadol ER secondary to higher than the recommended dose for the treatment of pain.

METHODS

This report presents the relevant patient history, laboratory data and literature review on possible causes of this patient's sleepwalking.

RESULTS

A 39-year-old female reported sleepwalking as the dose of tapentadol increased above the recommended maximum provided in the package insert. The mechanism of action of tapentadol involving norepinephrine reuptake inhibition affecting the central nervous system, higher dosage and drug interactions with other home medications likely contributed to her sleepwalking.

CONCLUSION

This case highlights the importance of adhering to the recommended dosage of a medication and if it is clinically warranted to exceed the maximum recommended dose, the importance of diligent monitoring for any adverse effects.

Novel treatment modalities for painful diabetic neuropathy

BACKGROUND AND AIMS

Painful diabetic neuropathy significantly affects the quality of life in people with diabetic peripheral neuropathy (DPN). Existing pharmacological agents have limited efficacy and development of tolerance is a limitation.

METHODS

The present review focuses on novel pharmacological (systemic and topical) and non-pharmacological modalities for the alleviation of pain in people with DPN. We identified English language articles concerning studies with novel agents (animal or human) targeting symptomatic relief of painful diabetic neuropathy.

RESULTS

Though the pathophysiology of pain in DPN is complex, a better understanding of pain pathways (peripheral and central) have helped to identify potential targets for therapeutic success. Studies of pharmacological agents acting on various aspects of pain pathways including μ-opioid receptor agonist- norepinephrine reuptake inhibitor (MONRI), cannabinoid receptor, dual serotonin-nor-adrenergic (SNRI)-and triple dopamine reuptake inhibitor (SNDRI), purinergic receptors and sodium channel v1.7 blockers have undergone trials in humans and shown to improve pain symptoms and quality of life in people with DPN. A few other investigational agents targeting acetylcholine receptor, vanilloid channel, chemokine signaling, micro-RNA or mesenchymal stem cell based therapies (animal studies) have demonstrated promise in alleviation of pain. Topical agents like high-dose lidocaine, capsaicin, clonidine, amitriptyline and ketamine may benefit refractory neuropathic pain.

CONCLUSIONS

Novel MONRI, SNRI and cannabinoid receptor agonists have shown some promise for neuropathic pain relief in human trials, but await regulatory approvals. However, most of the novel pharmacological agents (systemic or topical) require appropriately powered placebo-controlled studies for clinical usage in painful diabetic neuropathy.

Quality of life and functional outcomes with tapentadol prolonged release in chronic musculoskeletal pain: post hoc analysis

Aims: To investigate quality of life (QOL) and functionality changes in chronic pain during tapentadol prolonged release (PR) treatment. Patients & methods: Post hoc analysis of data from three Phase III trials in patients with osteoarthritis knee pain or low back pain. QOL and functionality changes were assessed by SF-36 scores. Results: All SF-36 subdomain scores improved progressively to week 3 of tapentadol titration and were sustained during 12-week maintenance treatment. Improvements in SF-36 scores were similar between tapentadol dose groups (e.g., 200 to <300 mg vs ≥500 mg), with no greater effect from higher doses. QOL and functionality improvements were consistently greater with tapentadol PR than oxycodone controlled release. Conclusion: Tapentadol PR provides consistent, clinically relevant improvements in QOL and functionality in chronic pain.

Opioid addiction, diversion, and abuse in chronic and cancer pain

PURPOSE OF REVIEW

The primary cause of overdose death in the United States is related to pharmaceutical opioids. A few particular populations that struggle with adverse outcomes related to opioid abuse are those in palliative care, those with chronic pain, and those receiving pain treatments secondary to cancer or chemotherapy.

RECENT FINDINGS

There have been massive efforts to decrease the use of opioid abuse in patient care in a gestalt manner, but palliative care provides unique challenges in applying these reduction tactics used by other specialties.

SUMMARY

We explore behavioral interventions, provider education, alternative pain management techniques, postmarketing surveillance, and abuse-deterrent formulas as emerging methods to counteract opioid abuse in these populations.

Spinal α2 -adrenoceptors and neuropathic pain modulation; therapeutic target

Neuropathic pain can arise from disease or damage to the nervous system. The most common symptoms of neuropathic pain include spontaneous pain, allodynia, and hyperalgesia. There is still limited knowledge about the factors that initiate and maintain neuropathic pain. However, ample evidence has proved the antinociceptive role of spinal α-adrenoceptors following nerve injury. It is well-documented that noradrenergic descending pathways from supraspinal loci exert an inhibitory influence on the spinal cord nociceptive neurons, mostly through the activation of spinal α₂ -adrenoceptors. This, in turn, suppresses transmission of pain input and the hyperexcitability of spinal dorsal horn neurons. There is considerable evidence demonstrating that spinal application of α₂ -adrenoceptor agonists leads to analgesic effects in animal models of neuropathic pain. Today, despite the recent rapid development of neuroscience and drug discovery, effective drugs with clear basic mechanisms have remained a mystery. Here, we give an overview of the cellular mechanisms through which brainstem adrenergic descending inhibitory processing can alter spinal pain transmission to the higher centres, and how these pathways change in neuropathic pain conditions focusing on the role of spinal α₂ -adrenoceptors in the spinal dorsal horn. We then suggest that α₂ -adrenoceptor agonist may be useful to treat neuropathic pain. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.

Tapentadol Extended Release in the Treatment of Severe Chronic Low Back Pain and Osteoarthritis Pain

Tapentadol is a novel pain reliever with apparently synergistic dual mechanisms of action, capable of addressing both nociceptive and neuropathic components of chronic pain. As an effective analgesic with good tolerability, tapentadol may be appropriate for patients suffering from severe chronic pain associated with low back pain (LBP) or osteoarthritis (OA). Efficacy studies of tapentadol in populations of patients with severe chronic LBP or OA pain suggest that tapentadol is non-inferior to oxycodone. Its tolerability, especially with respect to gastrointestinal (GI) side effects, may be better than that of other strong opioids in clinical trials and analyses of multiple trials. Patient satisfaction with tapentadol extended release for chronic noncancer pain syndromes is good. Although tapentadol has an opioid component with abuse liability, it appears to be a difficult opioid for tampering with less appeal to abusers than other opioids. For patients with severe LBP and OA pain, tapentadol appears to hold promise as a safe, effective therapeutic option.

Opioid-Induced Constipation and Bowel Dysfunction: A Clinical Guideline

OBJECTIVE

To formulate timely evidence-based guidelines for the management of opioid-induced bowel dysfunction.

SETTING

Constipation is a major untoward effect of opioids. Increasing prescription of opioids has correlated to increased incidence of opioid-induced constipation. However, the inhibitory effects of opioids are not confined to the colon, but also affect higher segments of the gastrointestinal tract, leading to the coining of the term "opioid-induced bowel dysfunction."

METHODS

A literature search was conducted using Medline, EMBASE, and EMBASE Classic, and the Cochrane Central Register of Controlled Trials. Predefined search terms and inclusion/exclusion criteria were used to identify and categorize relevant papers. A series of statements were formulated and justified by a comment, then labeled with the degree of agreement and their level of evidence as judged by the Strength of Recommendation Taxonomy (SORT) system.

RESULTS

From a list of 10,832 potentially relevant studies, 33 citations were identified for review. Screening the reference lists of the pertinent papers identified additional publications. Current definitions, prevalence, and mechanism of opioid-induced bowel dysfunction were reviewed, and a treatment algorithm and statements regarding patient management were developed to provide guidance on clinical best practice in the management of patients with opioid-induced constipation and opioid-induced bowel dysfunction.

CONCLUSIONS

In recent years, more insight has been gained in the pathophysiology of this "entity"; new treatment approaches have been developed, but guidelines on clinical best practice are still lacking. Current knowledge is insufficient regarding management of the opioid side effects on the upper gastrointestinal tract, but recommendations can be derived from what we know at present.

Tapentadol prolonged-release for moderate-to-severe chronic osteoarthritis knee pain: a double-blind, randomized, placebo- and oxycodone controlled release-controlled study

OBJECTIVE

To assess efficacy and safety of tapentadol prolonged release (PR) for moderate-to-severe chronic osteoarthritis knee pain.

METHODS

Patients (n = 990) were randomized (1:1:1) to tapentadol PR, oxycodone controlled release (CR; reference compound for assay sensitivity), or placebo for a double-blind 3-week titration and 12-week maintenance period. Primary efficacy end-points were change from baseline in average pain intensity at week 12 of maintenance (US end-point) and over the entire maintenance period (non-US end-point) with "last observation carried forward" as imputation method for missing scores.

RESULTS

Both primary end-points were not significantly different for tapentadol PR nor for oxycodone CR vs placebo at week 12 (least squares [LS] mean difference = -0.3 [95% CI = -0.61-0.09]; p = 0.152 and 0.2 [95% CI = -0.16-0.54]; p = 0.279, respectively) and over the maintenance period (LS mean difference = -0.2 [95% CI = -0.55-0.07]; p = 0.135 and 0.1 [95% CI = -0.18-0.44]; p = 0.421, respectively). Considerably more patients receiving tapentadol PR than oxycodone CR completed the trial (58.3% vs 36.6%). This is consistent with better results with tapentadol PR on the overall health status (PGIC) compared to oxycodone CR. Indeed, respectively, 56% and 42.5% rated at least "much improved" at the end of treatment. Incidences of gastrointestinal adverse events were higher for both active treatments compared to placebo. Tapentadol PR was associated with a better gastrointestinal tolerability profile with incidences of constipation (17.9% vs 35%) and of the composite of nausea and/or vomiting (23.8% vs 46.8%) significantly lower vs oxycodone CR (p < 0.001).

CONCLUSIONS

The study did not demonstrate assay sensitivity. The finding that both primary end-points for tapentadol PR were not met can, thus, not be interpreted. Tapentadol PR was better tolerated than oxycodone CR, largely due to fewer gastrointestinal side-effects.

Treatment for chronic low back pain: the focus should change to multimodal management that reflects the underlying pain mechanisms

Chronic low back pain: Chronic pain is the most common cause for people to utilize healthcare resources and has a considerable impact upon patients' lives. The most prevalent chronic pain condition is chronic low back pain (CLBP). CLBP may be nociceptive or neuropathic, or may incorporate both components. The presence of a neuropathic component is associated with more intense pain of longer duration, and a higher prevalence of co-morbidities. However, many physicians' knowledge of chronic pain mechanisms is currently limited and there are no universally accepted treatment guidelines, so the condition is not particularly well managed.

DIAGNOSIS

Diagnosis should begin with a focused medical history and physical examination, to exclude serious spinal pathology that may require evaluation by an appropriate specialist. Most patients have non-specific CLBP, which cannot be attributed to a particular cause. It is important to try and establish whether a neuropathic component is present, by combining the findings of physical and neurological examinations with the patient's history. This may prove difficult, however, even when using screening instruments. Multimodal management: The multifactorial nature of CLBP indicates that the most logical treatment approach is multimodal: i.e. integrated multidisciplinary therapy with co-ordinated somatic and psychotherapeutic elements. As both nociceptive and neuropathic components may be present, combining analgesic agents with different mechanisms of action is a rational treatment modality. Individually tailored combination therapy can improve analgesia whilst reducing the doses of constituent agents, thereby lessening the incidence of side effects.

CONCLUSIONS

This paper outlines the development of CLBP and the underlying mechanisms involved, as well as providing information on diagnosis and the use of a wide range of pharmaceutical agents in managing the condition (including NSAIDs, COX-2 inhibitors, tricyclic antidepressants, opioids and anticonvulsants), supplemented by appropriate non-pharmacological measures such as exercise programs, manual therapies, behavioral therapies, interventional pain management and traction. Surgery may be appropriate in carefully selected patients.

Tolerability of Opioid Analgesia for Chronic Pain: A Network Meta-Analysis

Aim of this study was to study the tolerability of opioid analgesia by performing a network meta-analysis (NMA) of randomized-controlled trials (RCTs) which investigated effectiveness of opioids for the management of chronic pain. Research articles reporting outcomes of RCT/s comparing 2 or more opioid analgesics for the management of chronic pain were obtained by database search. Bayesian NMAs were performed to combine direct comparisons between treatments with that of indirect simulated evidence. Study endpoints were: incidence of adverse events, incidence of constipation, trial withdrawal rate, and patient satisfaction with treatment. Outcomes were also compared with conventional meta-analyses. Thirty-two studies investigating 10 opioid drugs fulfilled the eligibility criteria. Tapentadol treatment was top-ranking owing to lower incidence of overall adverse events, constipation, and least trial withdrawal rate. Tapentadol was followed by oxycodone-naloxone combination in providing better tolerability and less trial withdrawal rate. Patient satisfaction was found to be higher with oxycodone-naloxone followed by fentanyl and tapentadol. These results were in agreement with those achieved with conventional meta-analyses. Tapentadol and oxycodone-naloxone are found to exhibit better tolerability characteristics in comparison with other opioid drugs for the management of chronic pain and are associated with low trial withdrawal rate and better patient satisfaction.

Health-related quality of life in patients receiving long-term opioid therapy: a systematic review with meta-analysis

PURPOSE

Over 25 million Americans reported having daily pain and between 5 and 8 million Americans used opioids to treat chronic pain in 2012. This is the first systematic review with meta-analysis to determine the effects of long-term opioid use on the Physical Component Summary (PCS) score and Mental Component Summary (MCS) scores of a Health-Related Quality of Life instrument in adults without opioid use disorder.

METHODS

The a priori eligibility criteria for the PubMed (MEDLINE), Scopus, and PsyINFO searches were (1) randomized controlled trial, (2) at least one opioid intervention group, (3) minimum of 4-week duration of opioid use, (4) comparative control group, and (5) adults ≥18 years that do not have dominant disease. The unit of analysis was the standardized mean difference effect size (Hedges's g). All results were pooled using random-effects models.

RESULTS

Of the 340 non-duplicate citations screened, 19 articles comprising 26 treatment comparisons and 6168 individuals (treatment n = 3160; comparators n = 3008 with duplicates removed) met the inclusion criteria for the systematic review. Thirteen treatment comparisons were available for the meta-analysis. Across all PCS analyses, small, statistically significant improvements were observed (opioid versus opioid only: g = 0.27, 95% CI 0.05-0.50, opioid versus placebo only: g = 0.18, 95% CI 0.08-0.28, and all studies combined: g = 0.22, 95% CI 0.11-0.32). There were small but not statistically significant changes on the MCS scores. Overall, high heterogeneity was present.

CONCLUSIONS

PCS scores improve with no change in MCS scores. However, long-term opioid trials are rare and only two trials included lasted longer than 1 year.

[Opioids for noncancer pain in the elderly]

BACKGROUND

Opioids are increasingly used in the elderly. Side effects differ compared to other analgesics.

PURPOSE

In this review article, special aspects about using opioids for noncancer pain in older people and in geriatric patients are identified.

CURRENT SITUATION

So far randomized controlled trials for the indication of and comparison between various opioids have been performed in middle-aged patients and not exclusively in geriatric patients or elderly (> 75 years). Furthermore, the evidence for multimorbid elderly patients with respect to side effects is also very poor.

RECOMMENDATIONS

The indication for opioid therapy should be narrow. The patient and their caregivers must be provided patient information regarding opioid therapy. The principle "start low, go slow" is highly recommended. To reduce the risk of falls, longer acting opioids should be used and short acting opioids should be avoided. Everyday relevant negative effects on cognition are possible in opioid use and have to be observed. As recommended in the recently published German guideline for long-term use of opioids in noncancer pain a critical check after 3 months and in case of dosing over 120 mg morphine equivalents is advisable, especially for older patients. Liver and kidney function and drug interactions have to be taken into consideration like in every age group.

[Opioids in chronic noncancer pain-are opioids different? A systematic review and meta-analysis of efficacy, tolerability and safety in randomized head-to-head comparisons of opioids of at least four week's duration]

BACKGROUND

We updated a systematic review on the comparative efficacy, tolerability and safety of opioids and of their routes of application in chronic noncancer pain (CNCP).

METHODS

We screened MEDLINE, Scopus and the Cochrane Central Register of Controlled Trials (CENTRAL) up until October 2013, as well as the reference sections of original studies and systematic reviews of randomized controlled trials (RCTs) of opioids in CNCP. We included randomized head-to-head comparisons of opioids (opioid of the sponsor of the study versus standard opioid) of at least 4 week's duration. Using a random effects model, absolute risk differences (RD) were calculated for categorical data and standardized mean differences (SMD) for continuous variables. The quality of evidence was rated by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

We included 13 RCTs with 6748 participants. Median study duration was 15 weeks (range 4-56 weeks). Hydromorphone, morphine, oxymorphone and tapentadol were compared to oxycodone; fentanyl to morphine and buprenorphine to tramadol. In pooled analysis, there were no significant differences between the two groups of opioids in terms of mean pain reduction (low-quality evidence), the patient global impression to be much or very much improved outcome (low-quality evidence), physical function (very low-quality evidence), serious adverse events (moderate-quality evidence) or mortality (moderate-quality evidence). There was no significant difference between transdermal and oral application of opioids in terms of mean pain reduction, physical function, serious adverse events, mortality (all low-quality evidence) or dropout due to adverse events (very low-quality).

CONCLUSION

Pooled head-to-head comparisons of opioids (opioid of the sponsor of the study versus standard opioid) provide no rational for preferring one opioid and/or administration route over another in the therapy of patients with CNCP. The English full-text version of this article is freely available at SpringerLink (under "Supplemental").

Quantifying the Exposure of Tapentadol Extended Release in Japanese Patients with Cancer Pain and Bridging Tapentadol Pharmacokinetics Across Populations Using a Modeling Approach

BACKGROUND AND OBJECTIVES

Tapentadol extended release (ER) is approved for the management of chronic and acute pain in adults. There has been no report of tapentadol ER pharmacokinetics in subjects with cancer pain. This analysis investigated tapentadol ER pharmacokinetics in Japanese patients with cancer pain and bridged it with the pharmacokinetics in Japanese healthy subjects and Caucasian patients with cancer pain.

METHODS

Nonlinear mixed-effect pharmacokinetic modeling was conducted based on pooled tapentadol ER concentration data collected in five Phase 1 studies from 138 Japanese and Korean healthy subjects and in two Phase 3 studies from 215 Japanese and Korean subjects with cancer pain. Expected tapentadol exposure in subjects with different characteristics was assessed via simulation. Tapentadol ER exposures in Caucasian populations were compared with those in corresponding Japanese populations.

RESULTS

Tapentadol ER pharmacokinetics in Japanese cancer-pain patients were adequately described by a time-invariant, one-compartment disposition model with two input functions and first-order elimination. Weight, age, and albumin were identified as statistically significant covariates, but do not warrant dose adjustment. Comparable pharmacokinetics were shown between Japanese healthy and Caucasian healthy subjects, and between Japanese cancer-pain patients and Caucasian cancer-pain patients.

CONCLUSION

The apparent differences in the estimated individual pharmacokinetic parameters in Japanese healthy subjects and Japanese cancer-pain patients taking tapentadol ER were explained by covariates incorporated in a unified pharmacokinetic model. Population modeling was essential in this cross-population bridging analysis.

Impact of prolonged-release oxycodone/naloxone on outcomes affecting patients' daily functioning in comparison with extended-release tapentadol: a systematic review

PURPOSE

The objective of this systematic review was to assess the clinical efficacy, safety, tolerability, and health-related quality of life outcomes associated with management of moderate-to-severe chronic pain with oxycodone/naloxone and tapentadol, focusing on the effect of these treatments on patients' daily functioning.

METHODS

Literature from a wide range of sources, including Embase, MEDLINE, MEDLINE In-Process, and the Cochrane Central Register of Controlled Trials, was searched to identify randomized controlled trials investigating tapentadol or oxycodone/naloxone for the treatment of patients with chronic pain. A network meta-analysis was conducted to determine the relative efficacy and safety profiles of these treatments.

FINDINGS

Oxycodone/naloxone was significantly better than tapentadol with respect to the Patient Assessment of Constipation Symptoms total score (risk ratio = -3.60; 95% credible interval, -5.36 to -2.11) and revealed a significantly lower risk of dizziness (risk ratio = 0.72; 95% credible interval, 0.42-0.98). Oxycodone/naloxone was directionally favored, although not significantly superior to tapentadol for headache, fatigue, dry mouth, dyspepsia, and withdrawals due to lack of efficacy. For the AE outcomes of constipation, nausea, and vomiting, as well as pain efficacy and all-cause withdrawals from studies, tapentadol was directionally favored without any statistical difference from oxycodone/naloxone. However, the two treatments were not wholly comparable for the evaluation of pain efficacy because of differences in on-study rescue medication and a higher baseline pain severity in the tapentadol studies.

IMPLICATIONS

Oxycodone/naloxone offers significant improvements in Patient Assessment of Constipation Symptoms total score and dizziness and was directionally favored for fatigue and headache compared with extended-release tapentadol, which may translate to improved patient daily functioning and health-related quality of life.

Tapentadol and nitric oxide synthase systems

Tapentadol, a new analgesic drug with a dual mechanism of action (μ-opioid receptor agonism and norepinephrine reuptake inhibition), is indicated for the treatment of moderate to severe acute and chronic pain. In this paper, the possible additional involvement of the nitric oxide synthase (NOS) system in the antinociceptive activity of tapentadol was investigated using an unspecific inhibitor of NOS, L-NOArg, a relatively specific inhibitor of neuronal NOS, 7-NI, a relatively selective inhibitor of inducible NOS, L-NIL, and a potent inhibitor of endothelial NOS, L-NIO. Tapentadol (1-10 mg/kg, intraperitoneal) increased the threshold for mechanical (Randall-Selitto test) and thermal (tail-flick test) nociceptive stimuli in a dose-dependent manner. All four NOS inhibitors, administered intraperitoneally in the dose range 0.1-10 mg/kg, potentiated the analgesic action of tapentadol at a low dose of 2 mg/kg in both models of pain. We conclude that NOS systems participate in tapentadol analgesia.

Evolving paradigms in the treatment of opioid-induced bowel dysfunction

In recent years prescription of opioids has increased significantly. Although effective in pain management, bothersome gastrointestinal adverse effects are experienced by a substantial proportion of opioid-treated patients. This can lead to difficulties with therapy and subsequently inadequate pain relief. Collectively referred to as opioid-induced bowel dysfunction, these adverse effects are the result of binding of exogenous opioids to opioid receptors in the gastrointestinal tract. This leads to disturbance of three important gastrointestinal functions: motility, coordination of sphincter function and secretion. In the clinic this manifests in a wide range of symptoms such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation, although the most known adverse effect is opioid-induced constipation. Traditional treatment with laxatives is often insufficient, but in recent years a number of novel pharmacological approaches have been introduced. In this review the pathophysiology, symptomatology and prevalence of opioid-induced bowel dysfunction is presented along with the benefits and caveats of a suggested consensus definition for opioid-induced constipation. Finally, traditional treatment is appraised and compared with the latest pharmacological developments. In conclusion, opioid antagonists restricted to the periphery show promising results, but use of different definitions and outcome measures complicate comparison. However, an international working group has recently suggested a consensus definition for opioid-induced constipation and relevant outcome measures have also been proposed. If investigators within this field adapt the suggested consensus and include symptoms related to dysfunction of the upper gut, it will ease comparison and be a step forward in future research.

Comparison of Real-world Outcomes Between Patients Treated with Tapentadol ER or Oxycodone CR

Background: The objective of this study was to compare health care utilization and costs between matched cohorts of chronic pain patients treated with the opioids tapentadol extended release (ER) or oxycodone controlled release (CR). Methods: This retrospective study used claims data from the Optum Research Database. Commercial and Medicare Advantage adult patients with ≥1 prescription fill for oxycodone CR or tapentadol ER between September 1, 2011 and September 30, 2012 were eligible. The date of the first observed oxycodone CR or tapentadol ER claim was the index date. Patients had continuous health plan enrollment for 6 months before and after the index date, ≥ 90 days supply of opioid therapy, and no index drug claims in the preindex period. Patients were propensity score matched in a 1:2 ratio (tapentadol ER : oxycodone CR). Results: The attributes of the matched cohorts (1,120 tapentadol ER and 2,240 oxycodone CR patients) appeared similar. In the 6 month post-index period, lower proportions of the tapentadol ER cohort than the oxycodone CR cohort had ≥1 inpatient stay (14.6% versus 20.5%; p<0.001) and ≥1 emergency department visit (33.4% versus 37.5%; p=0.021). The tapentadol ER compared with the oxycodone CR cohort had higher mean pharmacy costs ($4,263 versus $3,694; p <0.001), lower mean inpatient costs ($3,625 versus $6,309; p<0.001), and lower mean total healthcare costs ($16,510 versus $19,330; p=0.004). Conclusions: During follow-up, total mean healthcare costs were lower among tapentadol ER patients than oxycodone CR patients, and tapentadol ER patients were less likely to have an inpatient admission or emergency department visit.

Tapentadol for chronic musculoskeletal pain in adults

BACKGROUND

Chronic musculoskeletal pain is a prevalent condition and a major cause of disability and absence from the workplace worldwide. Opioids are frequently used to treat chronic pain, although adverse effects often restrict their long-term benefits. Tapentadol is an opioid and norepinephrine re-uptake inhibitor, which may cause a lower incidence (and severity) of adverse effects compared to other strong opioids.

OBJECTIVES

To determine the efficacy, safety and tolerability of tapentadol extended release for moderate-to-severe pain for at least three months for any musculoskeletal cause.

SEARCH METHODS

We searched electronic databases (CENTRAL, MEDLINE, EMBASE, Web of Science) to March 2014, unrestricted by language, as well as trials registers and reference lists from retrieved studies. We contacted drug manufacturers for further information.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of tapentadol in people with chronic musculoskeletal pain, compared to placebo or active control.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed risk of bias of included studies and extracted data. We performed two meta-analyses for the comparisons tapentadol extended release vs. placebo, and tapentadol extended release vs. active-control (oxycodone). We used random-effects and fixed-effect models according to the presence or not of heterogeneity, respectively. Also, we performed subgroup analyses. The primary efficacy outcome was pain control assessed by change in pain intensity scores and responder's rate (at least 50% pain relief). Primary safety outcome was withdrawal rate due to adverse effects.

MAIN RESULTS

Four parallel-design RCTs of moderate quality including 4094 patients with osteoarthritis or back pain, or both, met the inclusion criteria. Three trials were phase III studies with 12-weeks follow-up and the fourth trial was an open-label safety study of 52-weeks follow-up. All trials were oxycodone-controlled and three were also placebo-controlled. Two trials included patients with knee osteoarthritis, one evaluated patients with low back pain and one enrolled both. All studies reported last-observation-carried-forward (LOCF) as imputation method. We requested baseline-observation-carried-forward (BOCF) imputed analyses and any unpublished data from the manufacturer but the manufacturers denied the request. Two out of the four oxycodone-controlled studies and one out of the three placebo-controlled studies did not provided data on responder's rate. Two studies were considered to be of high risk of bias.In comparison to placebo, tapentadol was associated with a mean reduction of 0.56 points (95% confidence interval (CI) 0.92 to 0.20) in the 11-point numerical rating scale (NRS) at 12 weeks and with a 1.36 increase (95% CI 1.13 to 1.64) in the risk of responding to treatment (number needed to treat for an additional beneficial outcome (NNTB) 16; 95% CI 9 to 57, for 12-weeks). Moderate-to-high heterogeneity was found for the efficacy outcome estimates. Tapentadol was associated with a 2.7 fold increase (95% CI 2.05 to 3.52) in the risk of discontinuing treatment due to adverse effects number needed to treat for an additional harmful outcome (NNTH) 10; 95%CI 7 to 12, for 12 weeks).In comparison to oxycodone, pooled data showed a 0.24 points (95%CI 0.43 to 0.05) reduction in pain intensity from baseline in the 11-point NRS. The two studies that evaluated responder's rate showed a non-significant 1.46 increase (95% CI 0.92 to 2.32) in the risk of responding to treatment among tapentadol treated patients. Tapentadol was associated with a 50% risk reduction (95% CI 42% to 60%) of discontinuing treatment due to adverse effects (NNTB 6; 95% CI 5 to 7, for 12 weeks). Tapentadol was also associated with a 9% reduction (95% CI 4 to 15) in the overall risk of adverse effects (NNTH 18; 95% CI 12 to 35, for 12 weeks) and with a non-significant 43% reduction (95% CI 33 to 76) in the risk of serious adverse effects. Moderate to high heterogeneity was found for most efficacy (except for the primary outcome) and safety outcome estimates. Subgroup analysis showed a higher improvement with tapentadol among patients with knee osteoarthritis and among pooled results from studies of higher quality and shorter follow-up period, although there were no statistical significant differences in the effect size between these subgroups.

AUTHORS' CONCLUSIONS

Tapentadol extended release is associated with a reduction in pain intensity in comparison to placebo and oxycodone. However, the clinical significance of the results is uncertain due to the following reasons: modest difference between interventions in efficacy outcomes, high heterogeneity in some comparisons and outcomes, high withdrawals rates, lack of data for the primary outcome in some studies and impossibility to use BOCF as imputation method. Tapentadol is associated with a more favourable safety profile and tolerability than oxycodone.

Treatment of painful diabetic peripheral neuropathy

BACKGROUND

Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat.

OBJECTIVE

To discuss current treatment recommendations for painful diabetic peripheral neuropathy.

STUDY DESIGN

Literature review.

METHODS

Systematic review of the literature discussing treatment of painful diabetic peripheral neuropathy. Existing treatment guidelines were studied and compared.

RESULTS

Painful diabetic peripheral neuropathy occurs in about one in six people with diabetes. This condition impairs quality of life and increases healthcare costs. Treatment recommendations exist, but individual patient therapy can require a trial-and-error approach. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control. Adequate medication titration and a reasonable trial period should be allowed.

CONCLUSION

The treatment of painful diabetic peripheral neuropathy can be challenging, but effective management can improve patient's quality of life.

CLINICAL RELEVANCE

Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control.

Lasting Prolonged-Release Tapentadol for Moderate/Severe Non-Cancer Musculoskeletal Chronic Pain

Introduction

Despite opioids’ recognized role in the treatment of moderate/severe musculoskeletal chronic pain, their long-term benefits need investigation. We explored the lasting analgesic efficacy, tolerability, influence on life quality, and chronicity stage of the novel prolonged release (PR) opioid, tapentadol, in 30 outpatients.

Methods

We evaluated patients’ pain intensity and relief (Numerical Rating Scale; NRS), adverse effects, sleep quality, treatment satisfaction, health status (12-questions Health-Survey; SF-12), chronicity stage (Italian Mainz Pain-Staging System; I-MPSS) at 10, 30, 60, and 90 days after tapentadol prescription.

Results

At follow-ups, the investigated outcomes showed an overall statistically significant (Wilcoxon signed-rank test) improvement and remained stable over time, as did the health status and chronicity stage. Adverse effects were limited, transitory, and tolerable.

Conclusions

Twelve weeks of PR tapentadol in outpatients with moderate/severe chronic musculoskeletal pain showed satisfactory analgesic efficacy and tolerability, and had a positive influence on life quality and chronicity stage. The results are robust enough to warrant a subsequent study with a larger sample and a longer observation period.

Pharmacological treatment of chronic non-cancer pain in pediatric patients

Chronic pain in children and young adults occurs frequently and contributes to early disability as well as personal and familial distress. A biopsychosocial approach to evaluation and treatment is recommended. Within this approach, there is a role for pharmacologic intervention. A variety of medications are used for chronic pain conditions in pediatric patients. Medication classes include anticonvulsants, muscle relaxants, antidepressants, opioids, local anesthetics, and anti-inflammatory drugs. Data is sparse, and most medications are used without condition-specific approval by national regulatory agencies such as the Food and Drug Administration in the US and the European Medicines Agency. In the absence of evidence on which to base practice, optimal drug therapy decisions rest on understanding proposed mechanisms of pain conditions, extrapolation from adult data-when such exists, and empirical and experiential knowledge. Drug delivery systems have evolved, and practitioners have to decide amongst not only medication classes, but also routes of delivery. Opioids are not recommended for use by non-pain specialists for the treatment of pediatric chronic pain, and even then the issues are more complex than can be addressed here. This article reviews the major medications used for pediatric chronic pain conditions.

Management of severe chronic pain with tapentadol prolonged release - long-term data from pain specialists

BACKGROUND AND OBJECTIVE

Clinical trials have documented the efficacy and good tolerability of tapentadol prolonged released (PR) for severe chronic pain. This study investigated routine long-term administration by pain specialists.

METHODS

The effectiveness analysis included prospective data collected over a 3 month period (cohort I, n = 1457, mean age 61.2 ± 13 years) and over a 12 month period (cohort II, n = 588, 60.1 ± 13.2 years) regarding previous and concomitant analgesic treatment, tapentadol dosage, pain intensity, sleep and quality of life parameters, and tolerability.

RESULTS

Most patients (>77%) had suffered from severe chronic pain for ≥2 years with low back pain the main pain diagnosis (82%); 91% had already received analgesic long-term treatment prior to initiation of tapentadol therapy (42% of those received strong opioids). After 3 month tapentadol treatment, cohort I had experienced a mean pain reduction of 2.4 points (from 6.8 ± 1.6 at baseline) and improvements of 2.1 points in quality of sleep (from 5.8 ± 2.5) and quality of life (from 6.5 ± 2; all p ≤ 0.001). The 12 month tapentadol treatment (cohort II) reduced the mean pain intensity by 3.2 points from 6.7 ± 1.6 at baseline (NRS-11; p ≤ 0.001); 57% of the patients experienced clinically relevant pain relief of ≥50%. At end of observation, 92% attained either their intended pain reduction and/or an additional individual treatment target, both predefined at start of tapentadol therapy. This was accompanied by a significant reduction in pain-related impairments in daily activities and an improvement in quality of life (all p ≤ 0.001). Most frequent side-effects were nausea (6.3% of patients) and dizziness (3.8%) for cohort I, and nausea (1.5%) and constipation (1.2%) for cohort II.

CONCLUSION

Tapentadol PR is effective and well tolerated and can be considered an alternative to classical strong opioids in long-term chronic pain therapy.

LIMITATIONS

The study lacks a control group; assessment under routine practice conditions, however, reflects daily practice clinical management conditions.

Uliginosin B, a natural phloroglucinol derivative, presents a multimediated antinociceptive effect in mice

Objective

Investigate the involvement of monoaminergic and glutamatergic systems on the antinociceptive and ataxic effects of uliginosin B, which we have already demonstrated to be a promising molecular scaffold to develop new analgesic drugs.

Methods

Uliginosin B was obtained from hexane extract of aerial parts of Hypericum polyanthemum by chromatographic methods. Uliginosin B antinociceptive and motor coordination effects were evaluated in mice by using hot-plate (15 and 90 mg/kg, i.p.) and rotarod (90 mg/kg, i.p.) tests, respectively. The mechanism of action was investigated through pretreatments with prazosin 1 mg/kg intraperitoneal (α1 receptor antagonist), yohimbine 5 mg/kg intraperitoneal (α2 receptor antagonist), pCPA 300 mg/kg intraperitoneal (serotonin synthesis inhibitor) and MK-801 0.25 mg/kg intraperitoneal (N-methyl-D-aspartic acid receptor antagonist).

Key findings

The antinociceptive effect of uliginosin B (15 and 90 mg/kg, i.p.) was reduced significantly by pCPA and MK-801. Prazosin and yohimbine improved the antinociceptive effect of the highest dose (90 mg/kg, i.p.) of uliginosin B only. The ataxic effect of uliginosin B (90 mg/kg, i.p.) was completely prevented by pretreatment with pCPA or MK-801, but it was unaffected by pretreatment with prazosin or yohimbine.

Conclusion

These data confirm the contribution of monoaminergic neurotransmission as well as provide the first evidence of glutamatergic neurotransmission contribution to the uliginosin B effects.

Effectiveness and Safety of Tapentadol Prolonged Release (PR) Versus a Combination of Tapentadol PR and Pregabalin for the Management of Severe, Chronic Low Back Pain With a Neuropathic Component: A Randomized, Double-blind, Phase 3b Study

OBJECTIVE

To evaluate the effectiveness and tolerability of tapentadol PR monotherapy versus tapentadol PR/pregabalin combination therapy for severe, chronic low back pain with a neuropathic component.

METHODS

Eligible patients had painDETECT "unclear" or "positive" ratings and average pain intensity ≥ 6 (11-point NRS-3 [average 3-day pain intensity]) at baseline. Patients were titrated to tapentadol PR 300 mg/day over 3 weeks. Patients with ≥ 1-point decrease in pain intensity and average pain intensity ≥ 4 were randomized to tapentadol PR (500 mg/day) or tapentadol PR (300 mg/day)/pregabalin (300 mg/day) during an 8-week comparative period.

RESULTS

In the per-protocol population (n = 288), the effectiveness of tapentadol PR was clinically and statistically comparable to tapentadol PR/pregabalin based on the change in pain intensity from randomization to final evaluation (LOCF; LSMD [95% CI], -0.066 [-0.57, 0.43]; P < 0.0001 for noninferiority). Neuropathic pain and quality-of-life measures improved significantly in both groups. Tolerability was good in both groups, in line with prior trials in the high dose range of 500 mg/day for tapentadol PR monotherapy, and favorable compared with historical combination trials of strong opioids and anticonvulsants for combination therapy. The incidence of the composite of dizziness and/or somnolence was significantly lower with tapentadol PR (16.9%) than tapentadol PR/pregabalin (27.0%; P = 0.0302).

CONCLUSIONS

Tapentadol PR 500 mg is associated with comparable improvements in pain intensity and quality-of-life measures to tapentadol PR 300 mg/pregabalin 300 mg, with improved central nervous system tolerability, suggesting that tapentadol PR monotherapy may offer a favorable treatment option for severe low back pain with a neuropathic component.

Spinal-supraspinal and intrinsic μ-opioid receptor agonist-norepinephrine reuptake inhibitor (MOR-NRI) synergy of tapentadol in diabetic heat hyperalgesia in mice

Tapentadol is a μ-opioid receptor (MOR) agonist and norepinephrine reuptake inhibitor (NRI) with established efficacy in neuropathic pain in patients and intrinsic synergistic interaction of both mechanisms as demonstrated in rodents. In diabetic mice, we analyzed the central antihyperalgesic activity, the occurrence of site-site interaction, as well as the spinal contribution of opioid and noradrenergic mechanisms in a hotplate test. Tapentadol (0.1-3.16 µg/animal) showed full efficacy after intrathecal as well as after intracerebroventricular administration (ED50 0.42 µg/animal i.t., 0.18 µg/animal i.c.v.). Combined administration of equianalgesic doses revealed spinal-supraspinal synergy (ED50 0.053 µg/animal i.t. + i.c.v.). Morphine (0.001-10 µg/animal) also showed central efficacy and synergy (ED50 0.547 µg/animal i.t., 0.004 µg/animal i.c.v., 0.014 µg/animal i.t. + i.c.v.). Supraspinal potencies of tapentadol and morphine correlated with the 50-fold difference in their MOR affinities. In contrast, spinal potencies of both drugs were similar and correlated with their relative systemic potencies (ED50 0.27 mg/kg i.p. tapentadol, 1.1 mg/kg i.p. morphine). Spinal administration of the opioid antagonist naloxone or the α2-adrenoceptor antagonist yohimbine before systemic administration of equianalgesic doses of tapentadol (1 mg/kg i.p.) or morphine (3.16 mg/kg i.p.) revealed pronounced influence on opioidergic and noradrenergic pathways for both compounds. Tapentadol was more sensitive toward both antagonists than was morphine, with median effective dose values of 0.75 and 1.72 ng/animal i.t. naloxone and 1.56 and 2.04 ng/animal i.t. yohimbine, respectively. It is suggested that the antihyperalgesic action of systemically administered tapentadol is based on opioid spinal-supraspinal synergy, as well as intrinsic spinally mediated MOR-NRI synergy.

Opioid switching from and to tapentadol extended release in cancer patients: conversion ratio with other opioids

OBJECTIVES

The aim of this exploratory study was to assess the conversion ratios between tapentadol and other opioids in patients requiring an opioid switching.

METHODS

A prospective study was carried out in a convenience sample of consecutive patients admitted to an acute palliative care unit and a home care unit for a period of 1 year. Patients who were switched from/to tapentadol were selected. The initial ratio between tapentadol and other opioids, expressed as oral morphine equivalents was 1:3.3. The subsequent doses were flexible and were changed to fit the patients' needs. Pain intensity and distress score were recorded until opioid doses were stable. In all, 37 patients were examined; 24 and 13 patients were switched from and to tapentadol, respectively.

RESULTS

The most frequent sequences were tapentadol-morphine (18 patients) in one direction, and morphine-tapentadol (8 patients) in the other direction. In the sequence tapentadol-morphine and morphine-tapentadol, the mean final tapentadol-morphine ratios were 3.9:1 (SD 2.3), and 1:4.5 (SD 3.2), respectively, which did not differ significantly from the initial established conversion ratio. A minority of patients were switched from/to tapentadol to/from other opioids. Globally, the initial ratio did not change after switching took place.

CONCLUSION

Data suggest that a conversion ratio between tapentadol and other opioids, expressed in oral morphine equivalents could be 1:3.3 in both direction, particularly in patients who are switched in conditions of equianalgesia. The limited number of patients prevents a definitive conclusion to be drawn, and data should be interpreted with caution, given the exploratory nature of the study and the question of the low number of patients should be addressed in future studies.