Comparison of the Effects of OPRM1 A118G Polymorphism Using Different Opioids: A Prospective Study

CONTEXT

μ-opioid receptor gene (OPRM1) A118G polymorphism (rs1799971) causes loss of N-glycosylation sites at the extracellular domain of μ-opioid receptors. G-allele carriers show a limited response to morphine; however, studies investigating the impact of A118G polymorphism on the efficacy of opioids other than morphine are limited.

OBJECTIVE

To compare the impact of A118G polymorphism on the efficacy of various opioids.

METHODS

This prospective cohort study enrolled 222 in-patients administered one of the following opioid therapies for cancer pain as part of an opioid introduction or rotation strategy: tapentadol extended-release tablets, methadone tablets, hydromorphone controlled-release tablets, oxycodone controlled-release tablets, or transdermal fentanyl patches. The impact of A118G polymorphism on the difference in the Brief Pain Inventory-Short Form score on days three, seven, and 14 from baseline was compared among the groups.

RESULTS

Overall, 81, 74, and 67 patients had the AA, AG, and GG genotypes, respectively, with an OPRM1 A118G G-allele variant frequency of 0.47. The reduction in the Brief Pain Inventory-Short Form score after opioid therapy initiation did not differ significantly among the patients with the three A118G genotypes treated with tapentadol (p = 0.84) or methadone (p = 0.97), whereas it was significantly smaller in G-allele carriers than that in AA homozygous patients treated with hydromorphone (p < 0.001), oxycodone (p = 0.031), or fentanyl (p < 0.001).

CONCLUSION

Tapentadol and methadone may be more suitable than hydromorphone, oxycodone, and fentanyl for G-allele carriers due to their dual mechanism of action and low susceptibility to OPRM1 A118G polymorphism.

Tapentadol helps in trigeminal neuralgia: a case report

BACKGROUND

Trigeminal neuralgia (TN) usually affects people over 50 years old. TN-related pains are short-lived, and the disease course is characterized by exacerbations and remissions. Sometimes chronic pain develops due to central sensitization. This is the first case report on the effectiveness of tapentadol in pain control in TN.

CASE DESCRIPTION

It is an instructive case history demonstrating the high effectiveness of tapentadol in a 55-year-old Caucasian male with severe [Visual Analogue Scale (VAS) 9/10] TN-related pain and a history of ineffective treatment with antiepileptic drugs. The neuralgia had occurred twice a year for the three preceding years, and typically the TN periods lasted 2-3 weeks with complete remissions between. Previously the patient had been treated with antiepileptic drugs (e.g., carbamazepine, phenytoin, clonazepam, gabapentin, and lamotrigine). However, he found all treatments to be ineffective and accompanied by unacceptable somnolence. Thus, a prolonged-release oral tapentadol was proposed at the beginning of the next relapse. After application of tapentadol, the patient reported a significant improvement. The severity of pain declined to VAS 6/10 (2nd day) and 4/10 (3rd day), and the attacks resolved entirely on the fourth day of treatment. He reported no side effects. The drug was discontinued after 14 days.

CONCLUSIONS

Despite pain chronification, tapentadol was efficient and well tolerated in TN. Further research is needed to reveal tapentadol's efficacy in neuralgias.

Tapentadol Immediate Release (IR) versus Morphine Hydrochloride for Postoperative Analgesia of Patients Undergoing Total Abdominal Hysterectomy-A Prospective Cohort Study

Background and Objectives: This study aimed to examine the efficacy of tapentadol immediate release (IR) and morphine hydrochloride in the treatment of acute postoperative pain after total abdominal hysterectomy, as well as to examine the frequency of opioid-related side effects in observed patients. Materials and Methods: The prospective observational study was conducted over five months, and it included a total number of 100 patients. The two cohorts had different types of postoperative analgesia, and the effects were observed for 24 h postoperatively, by following the pain scores on NRS (Numerical Pain Scale), contentment with analgesia, and opioid-related side effects. Results: Statistical significance was found when assessing pain 24 h after surgery while coughing, where patients in the tapentadol IR group had significantly higher mean pain scores (p < 0.01). The subjective feeling of satisfaction with postoperative analgesia was statistically significant in the tapentadol IR group (p = 0.005). Vertigo appeared significantly more in patients from the morphine group (p = 0.03). Conclusions: Tapentadol IR (immediate release) and morphine hydrochloride are both effective analgesics used in the first 24 h after total transabdominal hysterectomy. Overall satisfaction of patients with analgesia was good. The frequency of side effects was higher in the morphine group, with statistical significance regarding the vertigo.

Cryoneurolysis of alveolar nerves for chronic dental pain: A new technique and a case series

BACKGROUND

Chronic neuropathic dental pain has a poor prognosis with a low chance of significant spontaneous improvement. Local or oral therapies may be efficient, however short in terms of duration with potential side effects. Cryoneurolysis has been described to prevent acute postoperative pain or to treat some chronic pain conditions; however, application to dental orofacial pain has not been reported so far.

CASE SERIES

Following a positive diagnostic block on the corresponding alveolar nerve, neuroablation was performed using a cryoprobe on three patients suffering from persistent pain after a dental extraction and 1 after multiple tooth surgeries. The effect of treatment was assessed using a Pain Numeric Rating Scale (NRS) and determined by changes in medication dosage and quality of life at day 7 and 3 months. Two patients experienced more than 50% of pain relief at 3 months, 2 by 50%. One patient was able to wean off pregabalin medication, one decreased amitriptyline by 50%, and one decreased tapentadol by 50%. No direct complications were reported. All of them mentioned improvement in sleep and quality of life.

CONCLUSION

Cryoneurolysis on alveolar nerves is a safe and easy-to-use technique allowing prolonged neuropathic pain relief after dental surgery.

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.

Appropriate use of tapentadol: focus on the optimal tapering strategy

OBJECTIVE

Due to its opioid and non-opioid mechanism of action, tapentadol is considered an atypical opioid with improved gastrointestinal tolerability versus traditional opioids. As for all opioid analgesics it is important to understand how to discontinue a treatment when it is not needed anymore. The aim of this article was to provide an overview of opioid therapy in non-cancer pain, with a specific focus on tapering of tapentadol in patients with chronic non-cancer pain, and suggestions on how to achieve tapering.

METHODS

Studies for this narrative review were identified via PubMed using a structured search strategy, focusing on management of chronic non-cancer pain with opioids, and the efficacy, tolerability, and pharmacology of tapentadol prolonged release. Publications were limited to English-language articles published within the last ∼10 years.

RESULTS

The review discusses the use and discontinuation of opioids in general, as well clinical data on discontinuation of tapentadol specifically. We provide a flow chart, which can be used by clinicians in the context of their own clinical experience to appropriately taper tapentadol in patients with chronic non-cancer pain. The flow chart can be easily tailored to individual patient characteristics, duration of tapentadol treatment, response to progressive dosage reduction, and likelihood of withdrawal symptom occurrence.

CONCLUSIONS

While tapentadol is associated with a low frequency of opioid withdrawal symptoms after abrupt discontinuation, use of a tapering strategy is prudent. Tapering strategies developed for opioids in general can potentially be safely individualized in tapentadol-treated patients, although research on tapering strategies for tapentadol is required.

[Tapentadol versus classical WHO-III opioids for chronic back pain. Health services research study based on representative data from health insurance funds]

BACKGROUND/OBJECTIVE

In clinical trials, tapentadol prolonged release (PR) showed a more favourable gastrointestinal tolerability profile compared to other strong opioids in the treatment of pain. The present analysis compared tapentadol PR and classical WHO-III PR opioids in routine clinical practice.

METHOD

Retrospective cohort study (matched pair approach) using anonymised health insurance data of patients with chronic low back pain who were prescribed strong opioids following pretreatment with WHO-I/II analgesics. Data were analysed from the date of first prescription in 2015 over a maximum period of two years. The primary analysis parameter was the prescription of laxatives.

RESULTS

Data of 227 patients per cohort could be included in the analysis. Significantly fewer tapentadol PR than WHO-III PR patients were prescribed laxatives (20.3% vs. 37%; p < 0.0001). In addition, laxative dosages were significantly lower in the tapentadol PR cohort (26.4 vs. 82.5 defined daily doses; p < 0.0001). A significant difference in laxative prescription was also observed under long-term treatment (tapentadol PR patients 27.7% vs. WHO-III PR patients 50%; p = 0.0029).

CONCLUSION

Routine clinical practice indirectly confirmed the more favourable gastrointestinal tolerability of tapentadol PR in the treatment of chronic pain which had previously been demonstrated in clinical trials and non-interventional studies.

The Treatment of Painful Diabetic Neuropathy

Painful diabetic peripheral neuropathy (painful-DPN) is a highly prevalent and disabling condition, affecting up to one-third of patients with diabetes. This condition can have a profound impact resulting in a poor quality of life, disruption of employment, impaired sleep, and poor mental health with an excess of depression and anxiety. The management of painful-DPN poses a great challenge. Unfortunately, currently there are no Food and Drug Administration (USA) approved disease-modifying treatments for diabetic peripheral neuropathy (DPN) as trials of putative pathogenetic treatments have failed at phase 3 clinical trial stage. Therefore, the focus of managing painful- DPN other than improving glycaemic control and cardiovascular risk factor modification is treating symptoms. The recommended treatments based on expert international consensus for painful- DPN have remained essentially unchanged for the last decade. Both the serotonin re-uptake inhibitor (SNRI) duloxetine and α2δ ligand pregabalin have the most robust evidence for treating painful-DPN. The weak opioids (e.g. tapentadol and tramadol, both of which have an SNRI effect), tricyclic antidepressants such as amitriptyline and α2δ ligand gabapentin are also widely recommended and prescribed agents. Opioids (except tramadol and tapentadol), should be prescribed with caution in view of the lack of definitive data surrounding efficacy, concerns surrounding addiction and adverse events. Recently, emerging therapies have gained local licenses, including the α2δ ligand mirogabalin (Japan) and the high dose 8% capsaicin patch (FDA and Europe). The management of refractory painful-DPN is difficult; specialist pain services may offer off-label therapies (e.g. botulinum toxin, intravenous lidocaine and spinal cord stimulation), although there is limited clinical trial evidence supporting their use. Additionally, despite combination therapy being commonly used clinically, there is little evidence supporting this practise. There is a need for further clinical trials to assess novel therapeutic agents, optimal combination therapy and existing agents to determine which are the most effective for the treatment of painful-DPN. This article reviews the evidence for the treatment of painful-DPN, including emerging treatment strategies such as novel compounds and stratification of patients according to individual characteristics (e.g. pain phenotype, neuroimaging and genotype) to improve treatment responses.

Efficacy and tolerability of tapentadol for the treatment of chronic low back pain in elderly patients

BACKGROUND

Chronic low back pain (CLBP) is a highly prevalent and disabling condition in the elderly, and yet it is undertreated and understudied in this patient population. Tapentadol is a central analgesic with an improved tolerability profile that may be particularly beneficial to the elderly CLBP.

METHODS

We performed an observational retrospective study to comparatively assess the efficacy and tolerability of tapentadol in young and elderly patients with severe CLBP. Sixtyfive young patients (< 65 years) and 87 elderly patients (≥ 65 years) were titrated on tapentadol extended release to their optimal dose (25-250 mg bid) over 1 month and, then, maintained at that dose for 3 months. The primary endpoint were changes from baseline in 24-h pain intensity on a 0-10 Numerical Rating Scale (NRS) at month-4 of treatment (titration plus maintenance periods). Patients were assessed for several efficacy and tolerability outcomes using a battery of scales and tests for neuropathic pain intensity, quality of life and sleep, and cognitive and gastrointestinal functions.

RESULTS

At pretreatment, young and elderly patients had similar pain intensities with younger patients presenting with more intense depressive and neuropathic pain symptoms, and lesser comorbidities and durations of pain (P < 0.05). Thirty-eight patients discontinued treatment because of adverse events occurring mostly during titration. Treatment with tapentadol was associated with comparable and clinically meaningful pain reductions in 24-h NRS from baseline to treatment month-4 both in young and elderly patients (- 5.3 ± 1.4 and - 4.8 ± 2.1; P < 0.01); a 50% pain relief was achieved in 66% and 58% of young and elderly patients. The percentage of patients with a neuropathic component decreased similarly in young and elderly patients (from 38 to 0% and from 19 to 3%; P < 0.01). Quality of life and sleep improved. The performances in global cognition and sustained attention tasks remained stable or improved across all age group.

CONCLUSIONS

These findings indicate that tapentadol extended release maintains efficacy and good tolerability in CLBP patients with advancing age.

Tapentadol vs oxycodone for postoperative pain treatment the first 7 days after total knee arthroplasty: a randomized clinical trial

ABSTRACT

Pain after total knee arthroplasty is a prevalent condition. This study compared the effectiveness of tapentadol extended-release (ER) 50 mg × 2, oxycodone controlled-release (CR) 10 mg × 2, and placebo, as added to a multimodal analgesic regime both in-hospital and at home the first week after total knee arthroplasty. The study was randomized and blinded for investigators, staff, outcome assessors, and patients. Follow-up included pain intensity on mobilization, pain at rest, worst pain in the previous 24 hours, and adverse effects measured on 0 to 10 numerical rating scales. A total of 134 patients in 3 study groups received their allocated intervention and were included in the analysis. The primary outcome pain on mobilization the 7 first postoperative days reported as area under the curve was 528.1 (SD 267.5, interquartile range (IQR) 356.6-665.4) for placebo, 427.2 (SD 203.9, IQR 303.6-544.3) for tapentadol ER, and 507.9 (SD 243.7, IQR 292.4-686.8) for oxycodone CR (P = 0.12). With the exception of constipation being less prevalent in the tapentadol ER group (P = 0.02), we found no significant differences between treatment groups for the secondary outcomes. Tapentadol ER as an add-on to multimodal analgesia did not significantly improve pain relief when compared to oxycodone CR or placebo. Constipation was lowest in the tapentadol ER group.

Safety of tapentadol compared with other opioids in chronic pain treatment: network meta-analysis of randomized controlled and withdrawal trials

OBJECTIVE

To assess the relative safety of oral tapentadol PR and other opioid analgesics for moderate or severe chronic pain in adults, we conducted a systematic review and network meta-analysis (NMA).

METHODS

A systematic review was conducted to identify randomized controlled trials (RCTs) and randomized withdrawal trials of tapentadol with other WHO stage II and III opioid analgesics in patients with moderate or severe chronic pain. Searches were conducted in MEDLINE, EMBASE, PubMed, Cochrane databases and trial registries. Feasibility assessment evaluated the trials' suitability for NMA. Outcomes assessed were overall AEs, overall serious adverse events, constipation, nausea, dizziness, somnolence, headache, and discontinuation due to AEs. Randomized withdrawal trials were analyzed separately to other RCTs.

RESULTS

Searches conducted in April 2019 identified 16,604 records. Following screening and feasibility assessment, 29 RCTs and 19 randomized withdrawal trials were identified and included in the NMA. Consistent with existing research, evidence from RCTs suggested that tapentadol is associated with relatively lower odds of adverse events occurring than most active comparators. The withdrawal trial data were less clear, with higher uncertainty around the results, and results that appear to contradict the RCT evidence. There are a number of trial design factors that may be affecting these results.

CONCLUSIONS

RCT evidence suggests that tapentadol can be a useful treatment option for patients suffering from chronic pain and in need of an opioid analgesic. Opioids should be prescribed by a qualified physician only after other analgesics have been considered, taking side effects and misuse risk into account.

Long-Term Effectiveness and Tolerability of Pain Treatment with Tapentadol Prolonged Release

BACKGROUND

The central analgesic tapentadol prolonged release (PR) has proven effective and generally well tolerated in a broad range of chronic pain conditions. Long-term data of its use are still scarce.

OBJECTIVES

To evaluate long-term effectiveness, tolerability, and safety of tapentadol PR in patients with severe chronic osteoarthritis (OA) knee pain or low back pain (LBP) who responded to tapentadol in 1 of 4 preceding 12-week phase 3b clinical trials.

STUDY DESIGN

Open-label, uncontrolled, observational extension study of up to 72 weeks.

SETTING

Fourteen centers in Spain. Protocol approval by the reference ethics committee for all the participating centers.

METHODS

Eligible patients started the extension trial on the tapentadol PR dosage optimized for them in the preceding trial; dose adjustments were permitted throughout the extension. Treatment effectiveness outcomes included changes in pain intensity, sleep, state of health, quality of life, patient and clinician global impression of change, and patients' satisfaction with treatment. Patients with OA knee pain also answered the Western Ontario and McMaster Universities OA index, and patients with LBP with a possible neuropathic pain component completed neuropathic pain-related questionnaires.

RESULTS

Eighty-three patients were enrolled: 40 with OA knee pain, 43 with LBP. The full analysis set consisted of 81 patients. Mean pain intensity remained relatively stable over the 72-week extension period with mean increases from baseline of 0.44 (95% confidence interval [CI], -0.1,1.0; Numeric Rating Scale) for all patients, 0.2 (95% CI, -0.5, 0.9) for patients with OA, and 0.68 (95% CI, -0.2, 1.6) for patients with LBP. State of health and quality of life baseline ratings were maintained; overall impression of change was "improved." Most patients (88.9%) reported at least good treatment satisfaction at the end of treatment. Mean daily tapentadol PR doses slightly increased from 313.3 ± 139.5 mg at baseline to 315.7 ± 140.1 mg at end of study. Uptitration was required for 8.4% of the patients, 4.8% had a dose reduction during the trial. Adverse events considered probably/likely or certainly related to tapentadol PR treatment by the investigator were documented for 18.1% of all patients, most commonly constipation (7.2%). Seven patients (8.4%) experienced adverse events leading to premature discontinuation.

LIMITATIONS

An open-label design, stable concomitant analgesics (World Health Organization step I), and dose adjustments were allowed during the study. All patients had benefitted from tapentadol PR in preceding trials.

CONCLUSIONS

Sustained pain relief and quality of life for up to 72 treatment weeks under relatively stable dosing, as well as the good safety profile, indicate the usefulness of tapentadol PR for patients who suffer from severe chronic OA knee pain and LBP with limited risk for tolerance development.

Modulation of sensitization processes in the management of pain and the importance of descending pathways: a role for tapentadol?

Objective: This paper presents and discusses recent evidence on the pathophysiological mechanisms of pain. The role of tapentadol - an opioid characterized by an innovative mechanism of action (i.e. µ-opioid receptor [MOR] agonism and inhibition of noradrenaline [NA] reuptake [NRI]) - in the modulation of pain, and the most recent pharmacological evidence on this molecule (e.g. the µ-load concept) are also presented and commented upon.Methods: Narrative review.Results: Solid evidence has highlighted the importance of central sensitization in the transition from acute to chronic pain. In particular, the noradrenergic system holds a major role in limiting central sensitization and the progression to chronic pain. Therefore, pharmacological modulation of the noradrenergic system appears to be a well-grounded strategy for the control of chronic pain. Tapentadol is characterized by a to-date-unique mechanism of action, since it acts both as a MOR agonist and as an inhibitor of NA reuptake. The synergistic interaction of these two mechanisms allows a strong analgesic effect by acting on both ascending and descending pathways. Of note, the reduced µ-load of tapentadol limits the risk of opioid-related adverse events, such as gastrointestinal disturbances. Moreover, the NA component becomes predominant, at least, in some types of pain, with consequent specific clinical efficacy in the treatment of neuropathic and chronic pain.Conclusions: According to these characteristics, tapentadol appears suitable in the treatment of severe uncontrolled chronic pain characterized by both a nociceptive and a neuropathic component, such as osteoarthritis or back pain.

[Retrospective Examination of Usefulness and Adverse Effects of Tapentadol in Patients with Cancer Pain during Anticancer Treatment]

We retrospectively examined 106 cases of tapentadol use in Japan in August 2014 for cancer pain at our hospital.The advantage of the opioid medication tapentadol is that its introduction is suitable in patients undergoing anti-cancer treatment because of the low incidence of gastrointestinal symptoms, with glucuronidation involved in the metabolism, and lack of interactions with other drugs.However, depending on the dosage form and presence of swallowing disorders, the administration should be considered carefully.

Outcomes Associated with Treatment of Chronic Pain with Tapentadol Compared with Morphine and Oxycodone: A UK Primary Care Observational Study

Introduction

This study compared adverse outcomes and resource use for patients with a diagnosis of pain treated with tapentadol prolonged-release (PR) versus those treated with morphine controlled-release (CR) and oxycodone CR.

Methods

Data were sourced from the Clinical Practice Research Datalink (CPRD), a database derived from UK primary care. Patients prescribed tapentadol PR between May 2011 and December 2016 were selected and matched to two groups of controls treated with either morphine CR or oxycodone CR on gender, age, pain duration, pain site, pain aetiology, Charlson index and prior analgesia. Times to first adverse event (constipation or nausea/vomiting) were compared within a Cox proportional hazards model. Rates of primary care contacts, accident and emergency contacts and, for a subset of patients linked to Hospital Episode Statistics (HES), inpatient admissions and outpatient contacts were compared using incidence rate ratios (IRRs) derived from Poisson regression.

Results

A total of 1907 patients prescribed tapentadol PR were identified and 1791 (93.9%) had a pain diagnosis. Of these 1246 (65.3%) were matched to morphine controls and 829 (43.4%) to oxycodone controls. Compared to controls, gastrointestinal adverse events with tapentadol PR treatment were reduced; aHR = 0.532 (0.402–0.703; p < 0.001) versus morphine CR and 0.517 (0.363–0.735; p < 0.001) versus oxycodone CR. Compared with morphine CR, primary care contacts [IRR = 0.831 (0.802–0.861)], accident and emergency attendance [0.739 (0.572–0.951)], outpatient contacts [0.917 (0.851–0.989)] and inpatients contacts [0.789 (0.664–0.938)] were reduced. For oxycodone, the respective figures were 0.735 (0.703–0.768), 0.971 (0.699–1.352), 0.877 (0.799–0.962) and 0.748 (0.601–0.932).

Conclusion

Tapentadol PR was associated with significantly fewer adverse gastrointestinal events than morphine CR and oxycodone CR in patients with a diagnosis of pain. There was also significantly reduced primary and secondary care resource use. As with all observational studies, potential bias due to residual confounding and confounding by indication should be considered.

Funding

Grünenthal Ltd.

Electronic supplementary material

The online version of this article (10.1007/s12325-019-00932-7) contains supplementary material, which is available to authorized users.

[Opioids for Cancer Pain and its Use under Particular Conditions: A Narrative Review]

INTRODUCTION

All health professionals should be aware of the importance of evaluating pain - fifth vital sign- in cancer patients. Peripheral and central acting analgesics are widely used to treat moderate to severe pain, particularly cancer pain. Many guidelines have addressed this issue. However, real life patients' have other problems and comorbidities that may raise doubts when prescribing.

MATERIAL AND METHODS

Authors made a literature search, trying to clarify same specific situations: loss of oral route, renal impairment (hemodialysis), hepatic impairment, frequent opiod interactions and the availability of short-acting formulations.

RESULTS

The following medicines were included in this analysis: the natural opiates (morphine and codeine), their synthetic and semisynthetic derivatives (hydromorphone, oxycodone, and fentanyl), the partial agonist buprenorphine and finally tramadol and tapentadol. Transdermal systems are only available for buprenorphine and fentanyl. In hepatic impairment, fentanyl is safe, but with the exception of codeine and tramadol; other opioids should be used with caution. In renal failure: fentanyl, hydromorphone, and tapentadol are safe. Morphine should be avoided; other opioids should be used with caution. In hemodialysis, buprenorphine, fentanyl, hydromorphone and tramadol (at doses up to 200 mg/day) may be used.

DISCUSSION

Failure to recognize the impact of various situations described throughout this work, including the bioavailability due to loss of oral route, due to pharmacokinetics and pharmacodynamics of the various drugs, either in the context of the impaired metabolism or excretion, or in due to pharmacological interactions, conditions a serious risk of subtreatment of pain and consequent impact in terms of quality of life.

CONCLUSION

Opioid prescription is safe and effective, even in moderate to severe comorbidities such as renal and hepatic impairment and in patients with no oral route available. In this case, as when considering pharmacological interactions, an individualized therapeutic plan is the best solution and the patient should be assessed regularly. Unadjusted doses may relate to bad pain control and a higher prevalence of adverse events.

Tapentadol in an Experimental Animal Model of Acute Orofacial Pain

OBJECTIVE

Tapentadol exhibits a synergistic dual effect effect (MOR / NRI) -agonist effect on noradrena-line reuptake inhibition (NRI). Tapentadol is effective on pain with neuropathic characteristics, therefore we decided to use it in an experimental model of acute orofacial pain.

METHODS

The Orofacial Stimulation Test, developed by Ugo Basile, measures hypersensitivity to thermal or mechanical stimulation of the trigeminal area. In the experiment, rats had to voluntarily contact a thermal or mechanical stimulator with their unshaved vibrissal pad in order to access a food reward. Twenty adult laboratory rats (average weight 345 grams) were tested. Intraperitoneal tapentadol was used in doses of 1 mg/kg and 2 mg/kg.

RESULTS

The results of the pilot study indicate that intraperitoneal administration of tapentadol (2 mg/kg) increased mechanical anti-nociception in rats.

[Combination Therapy of Oxycodone and Tapentadol Was Effective for Intractable Pain Caused by Breast Cancer Bone Metastasis - A Case Report]

A 52-year-old woman had been prescribed oral medication of acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), and oxycodone for intractable pain associated with thoracic metastasis of breast cancer. However, the pain control was poor. Although pregabalin and gabapentin were used as supplementary analgesics, they could not be continued because of their side effects. Based on the noradrenalin reincorporation-inhibiting action of tapentadol, a combination therapy of tapentadol and oxycodone was introduced and satisfactory pain control was achieved. No side effects from the combined opioids were observed. This finding indicates the potential of administrating a combination therapy of m-opioid receptor agonists(such as morphine, oxycodone, and fentanyl)with tapentadol, which has a noradrenaline reincorporation-inhibiting action, as an effective remedy for alleviating intractable pain complicated with neuropathic pain.