Revision of Pharmacological Treatment Recommendations for Cancer Pain: Clinical Guidelines from the Japanese Society of Palliative Medicine

Background: Pain is one of the most common symptoms in cancer patients. The Japanese Society for Palliative Medicine (JSPM) first published its clinical guidelines for the management of cancer pain in 2010. Since then, more research on cancer pain management has been reported, and new drugs have become available in Japan. Thus, the JSPM has now revised the clinical guidelines using a validated methodology. Methods: This guideline was developed through a systematic review, discussion, and the Delphi method, following a formal guideline development process. Results: Thirty-five recommendations were created: 19 for the pharmacological management of cancer pain, 6 for the management of opioid-induced adverse effects, and 10 for pharmacological treatment procedures. Due to the lack of evidence that directly addressed our clinical questions, most of the recommendations had to be based on consensus among committee members and other guidelines. Discussion: It is critical to continue to build high-quality evidence in cancer pain management, and revise these guidelines accordingly.

Opioid Use in the Nondialysis Chronic Kidney Disease Population

Although pain is a common and burdensome condition in patients with chronic kidney disease (CKD), little is known about the use and safety of opioids in this patient population. Recommendations regarding opioid use in patients with CKD are based on pharmacokinetic data, extrapolation from non-CKD studies, and from clinical experience. Given the potential increased risk for opioid-related adverse events in patients with reduced kidney function, health care providers may be hesitant to prescribe opioids, resulting in inadequate pain control. This review summarizes current studies of opioid use in patients with CKD, highlights special considerations, and proposes an opioid prescribing strategy for this unique patient population. Specifically, oral hydromorphone, transdermal fentanyl, and buprenorphine should be considered as the first-line opioids for patients with CKD if opioid management is indicated. A stepwise approach such as the Screen-Quantify-Use opioids-Adjust-Reassess-Engage prescribing strategy proposed here is critical to ensure optimal pain control while minimizing the side effects and adverse events of opioids. The effects of opioids on clinically relevant outcomes in the CKD population remains to be explored in future studies.

Efficacy And Safety Of Controlled-Release Oxycodone For The Management Of Moderate-To-Severe Chronic Non-Cancer Pain In Japanese Patients: Results From An Open-Label Study

Purpose

To assess the efficacy and safety of S-8117, an oral, controlled-release formulation of oxycodone hydrochloride, in Japanese patients with chronic non-cancer pain (CNCP).

Patients and methods

In this multicenter, non-randomized, open-label, 2-part (part 1, dose-titration followed by maintenance period; part 2, long-term administration period) study at 38 centers in Japan (2013-2015), adult patients with CNCP for ≥12 weeks were administered S-8117. The primary endpoint was proportion of patients with successful maintenance of pain control in part 1 and long-term safety in part 2. Secondary endpoints included time to inadequate analgesia, rate of transition to the maintenance period, and discontinuation due to inadequate analgesia/adverse events (AEs), Brief Pain Inventory (BPI) pain severity, BPI pain interference, 36-item Short Form Health Survey (SF-36) score, and Western Ontario and McMaster Universities (WOMAC) index, Subjective Opioid Withdrawal Scale (SOWS), Clinical Opioid Withdrawal Scale (COWS), Dependency-2-A (D-2-A), and Dependency-2-B (D-2-B) questionnaires.

Results

Of 130 patients (mean age, 63.6 years; women, 62.3%) in the dose-titration period, 95 entered the maintenance period; 60 of 83 who entered the long-term administration period completed it. The proportion of patients (95% confidence interval) with successful maintenance of pain control, transition to maintenance period, and discontinuation due to inadequate analgesia/AEs was 78.9% (69.4-86.6), 73.1% (64.6-80.5), and 21.1% (13.4-30.6), respectively. Time to inadequate analgesia could not be estimated. Changes from baseline in BPI, SF-36, and WOMAC index scores suggested improvements in pain relief and quality of life. Based on the SOWS, COWS, D-2-A and D-2-B questionnaires, no patient developed clinically relevant withdrawal syndrome or was ascertained to have developed drug dependence. Overall, the incidence of treatment-emergent AEs (TEAEs) was 93.8%; most common TEAEs were constipation (49.2%), nausea (42.3%), nasopharyngitis (34.6%), and somnolence (32.3%).

Conclusion

These results demonstrate the efficacy and safety of S-8117 in Japanese patients with CNCP.

Opioid Management in Older Adults with Chronic Kidney Disease: A Review

Chronic pain, a common comorbidity of chronic kidney disease, is consistently under-recognized and difficult to treat in older adults with nondialysis chronic kidney disease. Given the decreased kidney function associated with aging and chronic kidney disease, these patients are at increased risk for drug accumulation and adverse events. Emerging research has demonstrated the efficacy of opioids in chronic kidney disease patients, but research specifically focusing on older, nondialysis chronic kidney disease patients is scarce. The primary objective of this review is to determine which oral and transdermal opioids are the safest for older, nondialysis chronic kidney disease patients. We discuss the limited existing evidence on opioid prescription in older, nondialysis chronic kidney disease patients and provide recommendations for the management of oral and transdermal opioids in this patient population. Specifically, transdermal buprenorphine, transdermal fentanyl, and oral hydromorphone are the most tolerable opioids in these patients; hydrocodone, oxycodone, and methadone are useful but require careful monitoring; and tramadol, codeine, morphine, and meperidine should be avoided due to risk of accumulation and adverse events. Because older adults with nondialysis chronic kidney disease are at increased risk for adverse events, vigilant monitoring of opioid prescription is critical. Lastly, collaboration among an interprofessional clinical team can ensure safe prescription of opioids in older adults with nondialysis chronic kidney disease.

Practical management of opioid rotation and equianalgesia

Purpose

To review the recent literature on opioid rotation (ie, switching from one opioid drug to another or changing an opioid’s administration route) in cancer patients experiencing severe pain and to develop a novel equianalgesia table for use in routine clinical practice.

Methods

The MEDLINE database was searched with terms “cancer pain,” “opioid rotation,” “opioid switching,” “opioid ratio,” “opioid conversion ratio,” and “opioid equianalgesia” for the major opioids (morphine, oxycodone, fentanyl, and hydromorphone) and the intravenous, subcutaneous, oral, and transdermal administration routes. Selected articles were assessed for the calculated or cited opioid dose ratio, bidirectionality, and use of the oral morphine equivalent daily dose or a direct drug-to-drug ratio.

Results

Twenty publications met our selection criteria and were analyzed in detail. We did not find any large-scale, prospective, double-blind randomized controlled trial with robust design, and most of the studies assessed relatively small numbers of patients. Bidirectionality was investigated in seven studies only.

Conclusion

The updated equianalgesic table presented here incorporates the latest data and provides information on bidirectionality. Despite the daily use of equianalgesic tables, they are not based on high-level scientific evidence. More clinical research is needed on this topic.

[Opioid switch and change of route of administration in cancer patients treated by morphine]

This paper reviewed the 2002 guidelines established by the National Federation of Cancer Centres. A group of experts nominated by the 3 French Societies involved in the treatment of cancer pain (AFSOS, SFAP, SFETD), established new guidelines ratios for morphine switching and/or changing of route of administration, in patients for whom either pain was not adequatly managed or adverse effects were unbearable. After a rapid reminder of the pharmacokinetics and metabolism properties of morphine, experts explained why the theory of opioid rotation (oxycodone, hydromorphone, fentanyl, methadone, tapentadol) using fixed equianalgesic ratios is not any more appropriate for a secure clinical practice. In the light of recent publications enhancing our knowledge on the efficacy of new drug switching ratios and for changing the route of administration of morphine, the group of experts recommended to use reconsidered switching ratios favoring security upon efficacy, to minimize overdosing and adverse effects. Consequently, after the new conversion ratio (using slow release opioids) was applied, a second titration should be done by means of normal release rescue formulations for breakthrough pain episodes. A smartphone App. OpioConvert^® will be available for rapid and secure dose conversions.

A double-blind, randomized comparative study to investigate the morphine to hydromorphone conversion ratio in Japanese cancer patients

Objective

To confirm the morphine to hydromorphone conversion ratio for hydromorphone (DS-7113b) immediate-release tablets in cancer patients who achieved pain control with oral morphine.

Methods

This was a multicenter, active-controlled, randomized, double-blind, parallel-group, comparative study (July 2013 to December 2014) at 39 Japanese sites. Seventy-one patients (aged >20 years) who had achieved pain control with morphine 60 mg/day and 90 mg/day were randomly allocated 1:1 to hydromorphone immediate-release tablets at a dose converted at a hydromorphone:morphine ratio of 1:5 or 1:8, respectively, and treated for up to 5 days. The efficacy was evaluated as the pain control ratio.

Results

The pain control ratio in the full analysis set was 83.3% (25/30) in the conversion ratio 1:5 group and 95.0% (38/40) in the conversion ratio 1:8 group, and both groups demonstrated highly successful pain control. The incidence of adverse events was 46.7% (14/30) in the conversion ratio 1:5 group and 58.5% (24/41) in the 1:8 group; the difference was not clinically relevant. Frequently observed adverse events (incidence ≥5%) were nausea, vomiting, diarrhea, somnolence and dyspnea.

Conclusions

A high pain control ratio was maintained by a switch at either conversion ratio, and no notable difference was observed in the incidence of adverse events. A switch from morphine to hydromorphone is effective at a dose converted at ratios of 1:5 and 1:8.

Efficacy and Safety of Oxycodone Injection for Relieving Cancer Pain: A Study in Japan Consisting of Two Open Trials for Intravenous and Subcutaneous Administration

Pure oxycodone injection became increasingly necessary after oral oxycodone was launched in Japan in 2003. However, trials clarifying the efficacy and safety of injection are rare. Therefore, a multicenter open study on injection was designed and carried out in 2010, resulting in the launch of injection therapy in 2012. As published domestic case reports on efficacy already show widespread prescription, this study aimed to provide useful information for cancer pain relief in Japan and other countries. Our oxycodone injection study consisted of two trials, one of intravenous (S#9131) and the other of subcutaneous (S#9132) administration. The minimum required number of enrolled patients suffering cancer pain was determined to be 70 in S#9131 and 20 in S#9132. These studies had the same dose-titration protocol as the main endpoint, i.e., pain relief rate (PRR) defined as the rate of achieving adequate pain control (APC), as in prior oral oxycodone trials in Japan. In S#9131, PRR was 81.4% (95% confidence interval: 70.3-89.7%), therefore, the null hypothesis of PRR<70% was rejected using the binominal one-sided test (p=0.0217). In S#9132, PRR was 73.7% also surpassing 70%. Safety was also assessed in the same way as in prior trials. The majority of adverse effects were moderate or mild and recovered with no sequelae. As shown above, the injection was considered to be effective and safe in cancer pain treatment. The details of these trials, particularly the dose-titration protocol for achieving APC and route switching information, are expected to enhance injection convenience for prescribers.

Pharmacokinetic Bioequivalence Studies of an Extended-Release Oxycodone Hydrochloride Tablet in Healthy Japanese Subjects Under Fasting and Fed Conditions Without an Opioid Antagonist

Oxycodone is a semisynthetic opioid used for the treatment of moderate to severe pain. Two separate studies were conducted to assess the pharmacokinetic bioequivalence of a newly formulated oxycodone hydrochloride extended-release tablet to a marketed oxycodone product in Japan under fasting and fed conditions. Each study was a randomized, open-label, single-dose, single-center, two-period, two-way crossover study. Healthy male Japanese subjects received the oxycodone 10-mg products under fasting and fed conditions. Blood samples were collected at specified time intervals, and plasma concentrations of oxycodone were analyzed using a validated liquid chromatography tandem mass spectrometry assay method. The pharmacokinetic parameters were determined via non-compartmental analysis. Pharmacokinetic metrics used for bioequivalence assessment were the maximum observed plasma concentration (C max) and the area under the concentration-time curve up to the last sampling time (AUC t ). A total of 24 healthy subjects were enrolled in each study. One subject withdrew after completion of the first sequence under fed conditions. The ratios of geometric least square means for C max and AUC t under fasting conditions were 1.1110 (90% confidence interval [CI] 1.0562-1.1687) and 0.9946 (90% CI 0.9670-1.0231), respectively. The ratios of geometric least square means for C max and AUCt under fed conditions were 1.1417 (90% CI 1.0959-1.1895) and 1.0135 (90% CI 0.9810-1.0470), respectively. The 90% CIs were within the predefined range (0.80-1.25). Both treatments were well tolerated when taken without an opioid antagonist in healthy Japanese subjects. Pharmacokinetic bioequivalence between test and reference formulations under fasting and fed conditions was concluded in terms of both rate and extent of absorption.

Addressing the barriers related with opioid therapy for management of chronic pain in India

India has a high prevalence of chronic disorders which may be associated with persistent pain. Despite the availability of multiple treatment options, chronic pain is largely untreated and contributes to disability and mortality. Medical consumption of opioids remains low due to various barriers that prevent access to opioids for patients and healthcare practitioners. Stringent regulatory provisions outlined in the Narcotic Drugs and Psychotropic Substances Act (1985) have been major deterrents to adequate opioid use. Although multiple amendments to the act have ensured ease of opioid access for medicinal purposes, concerns such as lack of awareness and prescribing practices and attitudes of physicians/patients still need to be addressed. This review aims to identify these barriers and suggest recommendations to overcome them.

Evidence for Neurotoxicity Due to Morphine or Hydromorphone Use in Renal Impairment: A Systematic Review

BACKGROUND

Opioids are the mainstay of pain control for patients with chronic pain. Often, opioids with reported active metabolites, such as morphine and hydromorphone, are thought to increase the risk of neurotoxicity in renal impairment.

OBJECTIVES

To identify and assess the quality of evidence for neurotoxic effects in patients with renal impairment receiving morphine or hydromorphone.

METHODS

Systematic searches were conducted of the following databases from inception to December 2015: MEDLINE, CINAHL, EMBASE, in addition to hand-searching relevant review articles' citations. Studies were included if they reported neurotoxic effects of either morphine or hydromorphone for chronic or malignant pain in patients with renal impairment. Review articles and case reports were excluded. Narrative review was undertaken. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess study quality.

RESULTS

Six original articles, three prospective and three retrospective studies were identified and assessed. No relevant randomized clinical trials were identified.

CONCLUSIONS

Although morphine and hydromorphone use may be associated with neurotoxic effects in patients with renal impairment, current evidence consists of very low-quality studies with conflicting findings. Clinicians may consider using either morphine or hydromorphone in mild-to-moderate renal impairment, while closely monitoring for neurotoxic effects, particularly when used in high doses and for extended duration.

The Adverse Events of Oxycodone in Cancer-Related Pain: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The adverse events (AEs) of oxycodone in cancer-related pain were controversial, so we conducted a meta-analysis to determine it. PubMed, Embase, CBM, CNKI, WanFang database, The Cochrane library, Web of Science, and the reference of included studies were searched to recognize pertinent studies. Relative risk (RR) with 95% confidence intervals (CIs) for all AEs were all extracted. The fixed-effects model was used to calculate pooled RRs and 95% CIs. Power calculation was performed using macro embedded in SAS software after all syntheses were completed. We identified 11 eligible trials involving 1211 patients: 604 patients included in oxycodone group and 607 patients involved in control group. Our quantitative analysis included 8 AEs, and the pooled analyses indicated that oxycodone compared with other opioids in cancer-related pain were not significantly decreased RRs of all AEs (dizziness RR = 0.94, 95% CI: 0.69-1.30, Z = 0.35, P = 0.72; nausea RR = 0.88, 95% CI: 0.72-1.07, Z = 1.26, P = 0.21; vomiting RR = 0.89, 95% CI: 0.70-1.15, Z = 0.9, P = 0.37; sleepiness RR = 0.86, 95% CI: 0.38-1.36, Z = 0.36, P = 0.72; constipation RR = 0.98, 95% CI: 0.81-1.19, Z = 0.21, P = 0.83; anorexia RR = 0.97, 95% CI = 0.58-1.62, Z = 0.11, P = 0.91; pruritus RR = 0.76, 95% CI: 0.44-1.30, Z = 1.01, P = 0.31; dysuria RR = 0.33, 95% CI: 0.07-1.62, Z = 1.36, P = 0.1)]. The subgroup analysis shown that Ox controlled-release (CR) had less sleepiness compared with MS-contin (Mc) CR (RR = 0.47, 95% CI: 0.25-0.90, P = 0.02). The power analysis suggests that all AEs have low statistical power. The present meta-analysis detected that no statistically significant difference were found among oxycodone and other opioids in all AEs, but Ox CR may had less sleepiness compared with Mc CR when subgroup analysis were conducted.

Gastrointestinal dysmotility disorders in critically ill dogs and cats

OBJECTIVE

To review the human and veterinary literature regarding gastrointestinal (GI) dysmotility disorders in respect to pathogenesis, patient risk factors, and treatment options in critically ill dogs and cats.

ETIOLOGY

GI dysmotility is a common sequela of critical illness in people and small animals. The most common GI motility disorders in critically ill people and small animals include esophageal dysmotility, delayed gastric emptying, functional intestinal obstruction (ie, ileus), and colonic motility abnormalities. Medical conditions associated with the highest risk of GI dysmotility include mechanical ventilation, sepsis, shock, trauma, systemic inflammatory response syndrome, and multiple organ failure. The incidence and pathophysiology of GI dysmotility in critically ill small animals is incompletely understood.

DIAGNOSIS

A presumptive diagnosis of GI dysmotility is often made in high-risk patient populations following detection of persistent regurgitation, vomiting, lack of tolerance of enteral nutrition, abdominal pain, and constipation. Definitive diagnosis is established via radioscintigraphy; however, this diagnostic tool is not readily available and is difficult to perform on small animals. Other diagnostic modalities that have been evaluated include abdominal ultrasonography, radiographic contrast, and tracer studies.

THERAPY

Therapy is centered at optimizing GI perfusion, enhancement of GI motility, and early enteral nutrition. Pharmacological interventions are instituted to promote gastric emptying and effective intestinal motility and prevention of complications. Promotility agents, including ranitidine/nizatidine, metoclopramide, erythromycin, and cisapride are the mainstays of therapy in small animals.

PROGNOSIS

The development of complications related to GI dysmotility (eg, gastroesophageal reflux and aspiration) have been associated with increased mortality risk. Institution of prophylaxic therapy is recommended in high-risk patients, however, no consensus exists regarding optimal timing of initiating prophylaxic measures, preference of treatment, or duration of therapy. The prognosis for affected small animal patients remains unknown.

Ready conversion of patients with well-controlled, moderate to severe, chronic malignant tumor-related pain on other opioids to tapentadol extended release

Background and Objectives

The effectiveness and tolerability of tapentadol extended release (ER), a centrally acting analgesic with μ-opioid receptor agonist and norepinephrine (noradrenaline) reuptake inhibitor activities, have been demonstrated in patients with chronic pain, including those switching directly from prior opioid therapy. The objective of the current study was to evaluate the effectiveness and safety of conversion to oral tapentadol ER (50–250 mg twice daily) from previous around-the-clock strong opioid therapy in patients with moderate to severe, chronic malignant tumor–related cancer pain that was well-controlled.

Methods

This randomized, open-label, phase III study, which was conducted in Japan, included a 1- to 2-week screening period (on previous opioid) and an 8-week, open-label treatment period. Eligible patients, who were taking a strong opioid analgesic and had a mean pain intensity score <4 during the 3 days prior to randomization (adequate pain control on previous strong opioid), were randomized (1:1) to receive twice-daily treatment with tapentadol ER (100–500 mg/day) or morphine sustained release (SR; 20–140 mg/day; reference for assay sensitivity). Initial doses were estimated based on the conversion ratio of tapentadol ER:oxycodone:morphine:fentanyl = 10:2:3:0.03. The primary effectiveness endpoint was the proportion of patients who maintained pain control [change from baseline in mean pain intensity (11-point numerical rating scale) less than +1.5 for 3 consecutive days and no more than two doses of rescue medication per day for 3 consecutive days) during the first week of open-label treatment.

Results

In the tapentadol ER group (n = 50), 84.0 % of patients (42/50; 95 % CI, 70.89–92.83) maintained pain control during Week 1. On the Patient Global Impression of Change, 2.1 % (1/48), 2.1 % (1/48), 22.9 % (11/48), and 50.0 % (24/48) of patients in the tapentadol ER group reported that their overall condition was “very much improved,” “much improved,” “minimally improved,” and “not changed,” respectively, at Week 1 compared with 0 %, 10.7 % (3/28), 28.6 % (8/28), and 53.6 % (15/28) reporting these ratings at Week 8. The sensitivity of effectiveness analyses was validated based on results using morphine SR; 98.0 % (49/50; 95 % CI, 89.35–99.95) of patients in the morphine SR group maintained pain control after 1 week of treatment. The overall safety profile was similar to that demonstrated in previous studies; tapentadol ER was associated with a lower incidence of gastrointestinal treatment-emergent adverse events than morphine SR [38.0 % (19/50) vs. 54.0 % (27/50)], including constipation [12.0 % (6/50) vs. 20.0 % (10/50)] and vomiting [6.0 % (3/50) vs. 26.0 % (13/50)].

Conclusions

Overall, results indicate that conversion from previous strong opioids to tapentadol ER (50–250 mg twice daily) was successful and resulted in safe and effective pain control with improved gastrointestinal tolerability versus morphine SR in patients with moderate to severe cancer-related pain that was well-controlled on their previous opioid.

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-014-0204-3) contains supplementary material, which is available to authorized users.

Pharmacokinetics of oxycodone after intravenous and subcutaneous administration in Japanese patients with cancer pain

ABSTRACT In Japan, Oxycodone hydrochloride injection formulation has been approved in 2012. However, its pharmacokinetics has been poorly studied. The aim of this study is to evaluate the pharmacokinetics of oxycodone after intravenous and subcutaneous administration of oxycodone hydrochloride injection in Japanese patients with cancer pain. Noncompartmental analysis and population pharmacokinetic analysis were performed. We conducted a multicenter open-label study of oxycodone hydrochloride administered as constant infusion with the dose titrated individually according to the pain intensity in patients with cancer pain. Pharmacokinetic parameters for plasma oxycodone and its metabolites were estimated using pharmacokinetics of oxycodone was evaluated using a total of 344 plasma concentrations obtained from 89 patients. The estimated geometric mean clearance (CL) of oxycodone was 24.3 L per hour after constant intravenous infusion and 29.5 L per hour after constant subcutaneous infusion, respectively. Population pharmacokinetic analysis indicated that body surface area was the influencing factor on CL and there were no pharmacokinetic differences for CL between intravenous and subcutaneous infusion. These results provide important information for the clinical use of oxycodone injection.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Contribution of oxycodone and its metabolites to the overall analgesic effect after oxycodone administration

OBJECTIVE

Oxycodone (OC) is an opioid which exerts its analgesic effect through µ-receptors in the brain. It is metabolized through CYP450 enzymes and some of the metabolites show pharmacological activity. The aim of this investigation is to research the contribution of the metabolites of OC to its overall analgesic effect. A further aim was to elucidate the role of drug-drug interactions and CYP2D6 polymorphism.

RESEARCH DESIGN AND METHODS

The authors performed a literature search to identify published information on: blood concentrations of OC and metabolites, protein binding, blood-brain-barrier behavior and opioid receptor affinity. The authors then calculated the contribution of OC and metabolites to the overall analgesic effect.

RESULTS

OC itself is responsible for 83.02 and 94.76% of the analgesic effect during p.o. and i.v. administration, respectively. Oxymorphone (OM), which has a much higher affinity for the µ-receptor, only plays a minor role (15.77 and 4.52% for p.o. and i.v., respectively). Although the CYP2D6 genotype modulates OM pharmacokinetics, OC remains the major contributor to the overall analgesic effect.

CONCLUSION

This article's calculations demonstrate that OC itself is responsible for the analgesic effect. Although OM and noroxymorphone have much higher µ-receptor affinity than the parent drug, the metabolite concentrations at the site of action are very low. This suggests that there is a minimal analgesic effect from these metabolites.

The implications of tamper-resistant formulations for opioid rotation

Because rates of both opioid prescribing and opioid abuse have increased, drug companies have responded by considering strategies to make opioid formulations less attractive for abuse without compromising safety or efficacy for patients with legitimate pain management needs. The emergence of tamper-resistant opioid formulations is intended to deter abuse by creating obstacles to crushing or dissolving opioid tablets and capsules. At present, 2 long-acting and 1 immediate-release (IR) opioids are available in tamper-resistant formulations. Oxycodone controlled-release and oxymorphone extended-release tablets have each been reformulated with a hardened matrix that resists crushing or dissolution in liquids, making them difficult to prepare for nasal insufflation or intravenous use. Oxycodone IR has been reformulated with aversive ingredients that create nasal discomfort if the tablet is crushed and insufflated. Tamper-resistant opioid formulations are likely to be selected for patients who are identified as being at risk for abuse. However, patients vary in their response to individual opioids and may require rotation to a series of alternative opioids before finding one that is effective and sufficiently well tolerated. With only a few tamper-resistant opioid formulations currently available, switching and rotation may become difficult. As a result, patients who do not respond to a tamper-resistant opioid formulation or experience intolerable adverse events may require rotation to a formulation without tampering safeguards. Prescribers will need to be on guard for patients who may make false claims of poor response or adverse events to avoid tamper-resistant opioid formulations. Moreover, prescribers need to be aware of any tamper-resistance mechanisms that may affect efficacy or tolerability in patients with legitimate pain management needs compared with formulations without tampering safeguards.

Opioid rotation in clinical practice

INTRODUCTION

Although chronic opioid therapy is usually initiated using short-acting opioids, many patients with chronic pain are subsequently converted to long-acting and extended-release preparations. In clinical practice, optimal management requires careful individualization of dosage in order to achieve an appropriate balance of efficacy and adverse effects. After successful initiation and stabilization of opioid treatment, subsequent changes in regimen may still be required to maintain efficacy with an acceptable adverse effect profile.

METHODS

This is a qualitative review of the available literature from June 2012 or earlier on opioid rotation for the management of chronic pain in the clinical setting. The PubMed database was searched using various search terms, and additional articles were identified through manual search of the bibliographies of articles identified through the PubMed search. Papers were selected based on relevance to the topic.

RESULTS

When considering opioid rotation, clinicians must take into account not only the significant differences in potency among opioid drugs but also the considerable interpatient variability in response to opioids. The estimate of relative potency used in calculating an appropriate starting dose when switching from one opioid to another has been codified on equianalgesic dose tables. To reduce the risk of unintentional overdose, a two-step calculation has been proposed, which incorporates an initial reduction (typically 25-50%) in the equianalgesic dose followed by a second evaluation based on the severity of pain at the time of rotation along with other medical or psychosocial factors that might alter the effectiveness and tolerability of the new drug. Given the uncertainty of accurately predicting a patient's response to treatment, each initial exposure to a new opioid should be considered a discrete clinical trial to assess the degree of response. Systematic reviews of opioid rotation have documented the re-establishment of adequate pain control or reduced adverse effects in 50-80% of patients.

CONCLUSIONS

Although continued research is needed to refine equianalgesic doses further, opioid rotation is an important and necessary practice in patients with chronic cancer or noncancer pain that is refractory to the initially used opioid.

Is morphine still the best reference opioid?

SUMMARY Cancer and noncancer pain can usually be managed according to the WHO analgesic ladder and, in many countries, morphine remains the first-line opioid of choice for chronic severe pain. There have been many advances in the use of opioids for moderate-to-severe pain control in recent years. Consequently, the position of morphine as the gold standard became gradually more questioned, mostly because of serious adverse effects and the availability of different opioids and new formulations. The place of morphine as the first-line option is based on reasons of familiarity, availability or cost rather than medical advantages. In recent years, a number of systematic reviews failed to demonstrate superiority of morphine over other opioids in terms of efficacy or tolerability. Moreover, some strong opioids have shown improved tolerability or convenience. Currently, morphine might still be considered as a reference drug for equivalent dosing, but not for strategic healthcare decisions, as it has not demonstrated clinical or pharmacological superiority over other opioids. Therefore, there is a lack of evidence to sustain the role of morphine as the gold standard in the treatment of chronic severe pain.

Acute postoperative pain management in the older patient

Acute pain management in the older adult is both challenging and rewarding. This review addresses the difficulty with assessment of pain in the older adult, variations in the pain experience of older adults, physiological differences between the young and old, changes in pharmacokinetics and pharmacodynamics with age, and useful pharmacological treatments for acute pain in older adults. It then presents a few representative cases of pain management in older adults. The goal of this review is to provide relevant information that can be used to manage acute postoperative pain in the older adult.

Efficacy of opioid rotation to continuous parenteral hydromorphone in advanced cancer patients failing on other opioids

Purpose

The effectiveness of an opioid rotation to parenteral hydromorphone in advanced cancer patients has never been investigated. Therefore, the purpose of this study was to investigate the analgesic efficacy and side effects of parenteral hydromorphone on serious cancer-related pain.

Methods

We included 104 consecutive advanced cancer patients who were extensively pretreated with opioids. They were rotated to parenteral hydromorphone because they failed to achieve adequate pain relief on other opioids. Pain intensity and side effects were daily assessed. The moment of adequate pain control was defined as the first of at least 2 consecutive days when the mean pain intensity at rest was ≤4 (on a 0–10 numeric rating scale) and side effects were tolerable.

Results

The reasons for rotation to parenteral hydromorphone were inadequate pain control with/without expected delivery problems due to high opioid dosages (n = 61) and intolerable side effects with persistent pain (n = 43). Adequate pain control was achieved in 86 patients (83%) within a mean of 5 days. Eight of 86 patients still had side effects, but these were scored as acceptable. The mean pain intensity at rest decreased from 5.4 [standard deviation (sd) = 2.1] to 2.4 (sd = 1.5; p < 0.001). The median failure-free treatment period was 57 days and covered a substantial part of the median survival of 78 days in the responding patients.

Conclusions

In advanced cancer patients with serious unstable cancer-related pain refractory to other opioids, continuous parenteral administration of hydromorphone often results in long-lasting adequate pain control and should be considered even after extensive pretreatment with opioids.

European Palliative Care Research Collaborative pain guidelines: opioid switching to improve analgesia or reduce side effects. A systematic review

According to a Cochrane review on opioid switching, sound evidence on the practice of substituting one strong opioid with another to improve pain control and reduce adverse effects was lacking in 2004. A systematic search strategy was developed to include studies after 2004, with adult cancer patients switching between strong opioids and reporting estimates of effect on pain and adverse effects. The search retrieved 288 publications (71 duplicates); 187 abstracts and 19 full papers were excluded. Eleven papers met the inclusion criteria; none were randomized controlled trials/meta-analyses. Studies comprised 280 patients (group size 10-32). A variety of opioids and switching strategies were studied. Pain intensity was significantly reduced in the majority of studies. Serious adverse effects were improved. Due to serious design limitations, the level of evidence was low (D). Randomized trials, with standardization of cohort classification, use of outcomes and analysis are warranted to establish the practice of opioid switching.

A systematic review of the use of opioid medication for those with moderate to severe cancer pain and renal impairment: a European Palliative Care Research Collaborative opioid guidelines project

BACKGROUND

Opioid use in patients with renal impairment can lead to increased adverse effects. Opioids differ in their effect in renal impairment in both efficacy and tolerability. This systematic literature review forms the basis of guidelines for opioid use in renal impairment and cancer pain as part of the European Palliative Care Research Collaborative's opioid guidelines project.

OBJECTIVE

The objective of this study was to identify and assess the quality of evidence for the safe and effective use of opioids for the relief of cancer pain in patients with renal impairment and to produce guidelines.

SEARCH STRATEGY

The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MedLine, EMBASE and CINAHL were systematically searched in addition to hand searching of relevant journals.

SELECTION CRITERIA

Studies were included if they reported a clinical outcome relevant to the use of selected opioids in cancer-related pain and renal impairment. The selected opioids were morphine, diamorphine, codeine, dextropropoxyphene, dihydrocodeine, oxycodone, hydromorphone, buprenorphine, tramadol, alfentanil, fentanyl, sufentanil, remifentanil, pethidine and methadone. No direct comparator was required for inclusion. Studies assessing the long-term efficacy of opioids during dialysis were excluded.

DATA COLLECTION AND ANALYSIS

This is a narrative systematic review and no meta-analysis was performed. The Grading of RECOMMENDATIONS Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of the studies and to formulate guidelines.

MAIN RESULTS

Fifteen original articles were identified. Eight prospective and seven retrospective clinical studies were identified but no randomized controlled trials. No results were found for diamorphine, codeine, dihydrocodeine, buprenorphine, tramadol, dextropropoxyphene, methadone or remifentanil.

CONCLUSIONS

All of the studies identified have a significant risk of bias inherent in the study methodology and there is additional significant risk of publication bias. Overall evidence is of very low quality. The direct clinical evidence in cancer-related pain and renal impairment is insufficient to allow formulation of guidelines but is suggestive of significant differences in risk between opioids.

RECOMMENDATIONS

RECOMMENDATIONS regarding opioid use in renal impairment and cancer pain are made on the basis of pharmacokinetic data, extrapolation from non-cancer pain studies and from clinical experience. The risk of opioid use in renal impairment is stratified according to the activity of opioid metabolites, potential for accumulation and reports of successful or harmful use. Fentanyl, alfentanil and methadone are identified, with caveats, as the least likely to cause harm when used appropriately. Morphine may be associated with toxicity in patients with renal impairment. Unwanted side effects with morphine may be satisfactorily dealt with by either increasing the dosing interval or reducing the 24 hour dose or by switching to an alternative opioid.

A systematic review of combination step III opioid therapy in cancer pain: an EPCRC opioid guideline project

BACKGROUND

The use of combinations of opioids is a common clinical practice; however, this is not advocated by the World Health Organization (WHO) analgesic ladder. As opioid combination therapy becomes used increasingly, a review of the evidence on this practice was conducted.

AIMS

To carry out a systematic review of the use of strong opioids in combination in cancer pain.

METHODS

The following databases were searched electronically: Embase (1980-2010 week 2), Medline (1950-2010 week 1) and the Cochrane Database of Systematic Reviews (fourth quarter 2009). Only strong opioids as defined by the WHO ladder and full opioid agonists were examined. Only studies conducted in human, adult patients with chronic cancer pain were eligible. Studies must have contained data on efficacy and/or side effects in the key point. Appraisal was conducted using predetermined criteria set by the EAPC guideline development group. All potential papers were reviewed independently by both authors.

RESULTS

In total 596 articles were retrieved resulting in only two eligible studies, which were rated as grade C and grade D evidence. These examined morphine in combination with oxycodone or fentanyl/methadone.

CONCLUSION

Only a weak recommendation can be used to support combination opioid therapy. This recommendation is also based on the caveat that the desirable effects of combination opioid therapy is outweighed by any disadvantages that this would confer. Prospective randomized trials are needed to clarify the benefits and safety of combination opioid therapy.

Conversion ratios for opioid switching in the treatment of cancer pain: a systematic review

In this paper we describe the results of a systematic search of the literature on conversion ratios during opioid switching. This is part of a project of the European Palliative Care Research Collaboration to update the European Association for Palliative Care recommendations for the use of opioid analgesics in the treatment of cancer pain. Studies were eligible for inclusion if they involved adult patients with chronic cancer pain, contained data on opioid conversion ratios, were prospective and were written in English. Thirty-one studies were identified and included. The majority of the studies had methodological flaws and were not designed to explore or demonstrate equianalgesic dose data. However, the data allow some recommendations to be made that could be helpful to clinicians for whom there are few reliable experimental data on which to base dosing guidelines. Switching to transdermal fentanyl (TDfe) or buprenorphine (TDbu) is an option for patients with stable, controlled pain. Reliable and consistent studies show a ratio of 100 : 1 between oral morphine (ORmo) and TDfe. A ratio of 75 : 1 between ORmo and TDbu may be appropriate, but the supporting evidence here is much less robust. Data are relatively consistent to support a conversion ratio between ORmo and oral hydromorphone (ORhy) of 5 : 1. Despite some limitations, there is evidence to support the use of an approximate conversion ratio of ORmo:oral oxycodone (ORox) of 1.5 : 1. The conversion between ORox and ORhy is estimated to be 1 : 4. When switching from different opioids to methadone the conversion ratio is highly variable, ranging from 5 : 1 to 10 : 1 and much higher in some studies. The derived ratios are influenced by several factors, including the reasons for switching and previous opioid doses. An individual treatment decision and strict monitoring is recommended for patients considered at risk.

Role of oxycodone and oxycodone/naloxone in cancer pain management

Oxycodone is a valued opioid analgesic, which may be administered either as the first strong opioid or when other strong opioids are ineffective. In case of insufficient analgesia and/or intense adverse effects such as sedation, hallucinations and nausea/vomiting a switch from another opioid to oxycodone might be beneficial. Oxycodone is administered to opioid-naive patients with severe pain and to patients who were unsuccessfully treated with weak opioids, namely tramadol, codeine and dihydrocodeine. Oxycodone effective analgesia may be attributed to its affinity to μ and possibly κ opioid receptors, rapid penetration through the blood-brain barrier and higher concentrations in brain than in plasma. Oxycodone displays high bioavailability after oral administration and may be better than morphine in patients with renal impairment due to the decreased production of active metabolites. Recently an oral controlled-release oxycodone formulation was introduced in Poland. Another new product that was launched recently is a combination of prolonged-release oxycodone with prolonged-release naloxone (oxycodone/naloxone tablets). The aim of this review is to outline the pharmacodynamic and pharmacokinetic properties, drug interactions, dosing rules, adverse effects, equianalgesic dose ratio with other opioids and clinical studies of oxycodone in patients with cancer pain. The potential role of oxycodone/naloxone in chronic pain management and its impact on the bowel function is also discussed.

Different effects of morphine and oxycodone in experimentally evoked hyperalgesia: a human translational study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Previous studies using short-lasting experimental pain stimulations in healthy volunteers have shown differences in opioid effects regarding visceral pain stimulations. However, these differences can be more pronounced in patients due to a sensitized pain system. Therefore, the aim of the present study was to mimic the clinical situation by investigating opioid effects on experimental pain in healthy volunteers after experimentally evoked hyperalgesia. WHAT THIS STUDY ADDS? * We now know that morphine and oxycodone exerts different effects in the sensitized pain system as we found a greater analgesic effect of oxycodone in response to skin, muscle and oesophageal pain stimulation. This supports clinicians' experiences that oxycodone can be superior to morphine in the treatment of some pain conditions. The evoked hyperalgesia bridged findings from studies in healthy volunteers to patients, and new fundamental knowledge on different analgesic effects in hyperalgesia was found. AIM Similar analgesics may have different analgesic potencies especially in patients in whom the pain system is sensitized. The aim was to investigate different opioid effects on experimental pain after the sensitized pain system was mimicked evoking hyperalgesia in healthy volunteers. METHODS Twenty-four healthy volunteers were randomized to treatment with morphine (30 mg orally) and oxycodone (15 mg orally) or placebo in a double-blind crossover study. Hyperalgesia was induced by oesophageal perfusion with acid and capsaicin. Several exploratory endpoints were studied using skin heat, muscle pressure and oesophageal mechanical, heat and electrical stimulation. Effects on pain from deeper structures were considered most important. RESULTS Different analgesic potencies were found. Oxycodone had a greater analgesic effect than morphine attenuating pain from: (i) heat stimulation of skin (P= 0.016); difference between the means of 0.39 degrees C, 95% CI 0.22, 2.09. (ii) muscle pressure (P < 0.001); difference between the means of 11.93kPa, 95% CI 5.4, 18.5. (iii) oesophageal heat stimulation (P < 0.001); difference between the means of 38.54 cm(2), 95% CI 15.37, 61.71 and (iv) oesophageal electrical stimulation (P= 0.016); difference between the means of 6.69mA, 95% CI 1.23, 12.13. CONCLUSION After sensitization of the pain system different analgesic potencies of morphine and oxycodone were found in response to skin, muscle and oesophageal pain stimulation, in which oxycodone had a greater effect. As similar differential analgesic potencies of the two opioids have been found in patients with chronic pain, the experimental hyperalgesia model bridged findings from studies in healthy volunteers to patients.

Recent advances in the use of opioids for cancer pain

Opioids are the mainstay of treatment for moderate to severe cancer pain. In recent years there have been many advances in the use of opioids for cancer pain. Availability and consumption of opioids have increased and opioids other than morphine (including methadone, fentanyl, oxycodone) have become more widely used. Inter-individual variation in response to opioids has been identified as a significant challenge in the management of cancer pain. Many studies have been published demonstrating the benefits of opioid switching as a clinical maneuver to improve tolerability. Constipation has been recognized as a significant burden in cancer patients on opioids. Peripherally restricted opioid antagonists have been developed for the prevention and management of opioid induced constipation. The phenomenon of breakthrough pain has been characterized and novel modes of opioid administration (transmucosal, intranasal, sublingual) have been explored to facilitate improved management of breakthrough cancer pain. Advances have also been made in the realm of molecular biology. Pharmacogenetic studies have explored associations between clinical response to opioids and genetic variation at a DNA level. To date these studies have been small but future research may facilitate prospective prediction of response to individual drugs.

Oxycodone controlled-release as first-choice therapy for moderate-to-severe cancer pain in Italian patients: results of an open-label, multicentre, observational study

BACKGROUND AND OBJECTIVES

Cancer pain affects patients at all stages of the disease and there are clear guidelines for its management. Morphine is considered the first-choice strong opioid in the treatment of moderate-to-severe pain; however, numerous studies have shown that oxycodone controlled-release (CR) has a similar efficacy and safety profile. The purpose of this study was to evaluate the efficacy and tolerability of oxycodone CR as a first-line strong opioid for the treatment of moderate-to-severe pain in Italian cancer patients.

METHODS

This was a prospective, open-label, multicentre, observational trial carried out at 15 locations across Italy. Patients with a referral for cancer-related pain of > or =5 on a 10-point numerical rating scale were enrolled. Patients were treated with oral oxycodone CR and monitored for 21 days. Dosage was individualized for each patient and up-titrated until effective pain control was achieved. Pain, adverse events and quality-of-life scores were assessed throughout the study.

RESULTS

390 patients (174 females and 216 males) with a mean age of 66 +/- 11 years were evaluated. The average daily dose ranged from 22.84 on day 1 to 40 mg/day on day 21. Pain intensity (assessed on a 10-point numerical rating scale) decreased significantly within 1 day of treatment commencement (p = 0.00001) and continued to decrease throughout the study period (from a mean 7.22 at baseline to a mean 2.11 points on day 21). Adverse events were mild to moderate in intensity and consisted of common opioid-related events. Ten patients (2.6%) discontinued the study because of adverse events and four (1%) because of uncontrolled pain. All aspects of activities of daily life assessed were improved by study end.

CONCLUSIONS

Oxycodone CR is efficacious and well tolerated as a first-line strong opioid for the treatment of moderate-to-severe cancer-related pain in Italian patients.

A randomized, double-blind comparison of OROS(R) hydromorphone and controlled-release morphine for the control of chronic cancer pain

BACKGROUND

Long-acting opioid formulations are advocated for maintaining pain control in chronic cancer pain. OROS(R) hydromorphone is a sustained-release formulation of hydromorphone that requires dosing once daily to maintain therapeutic concentrations. The objective of this study was to demonstrate the clinical equivalence of immediate-release and sustained-release formulations of hydromorphone and morphine for chronic cancer pain.

METHODS

200 patients with cancer pain (requiring </= 540 mg/d of oral morphine) participated in this double-blind, parallel-group trial. Patients were randomized to receive hydromorphone or morphine (immediate-release for 2-9 days, sustained-release for 10-15 days). Efficacy was assessed with the Brief Pain Inventory (BPI), investigator and patient global evaluations, Eastern Cooperative Oncology Group performance status, and the Mini-Mental State Examination. The primary endpoint was the 'worst pain in the past 24 hours' item of the BPI, in both the immediate-release and sustained-release study phases, with treatments deemed equivalent if the 95% confidence intervals (CI) of the between-group differences at endpoint were between -1.5 and 1.5. No equivalence limits were defined for secondary endpoints.

RESULTS

Least-squares mean differences (95% CI) between groups were 0.2 (-0.4, 0.9) in the immediate-release phase and -0.8 (-1.6, -0.01) in the sustained-release phase (intent-to-treat population), indicating that the immediate-release formulations met the pre-specified equivalence criteria, but that the lower limit of the 95% CI (-1.6) was outside the boundary (-1.5) for the sustained-release formulations. BPI 'pain now PM' was significantly lower with OROS(R) hydromorphone compared with controlled-release morphine (least-squares mean difference [95% CI], -0.77 [-1.49, -0.05]; p = 0.0372). Scores for other secondary efficacy variables were similar between the two sustained-release treatments. At endpoint, > 70% of investigators and patients rated both treatments as good to excellent. The safety profiles of hydromorphone and morphine were similar and typical of opioid analgesics.

CONCLUSION

Equivalence was demonstrated for immediate-release formulations of hydromorphone and morphine, but not for the sustained-release formulations of OROS(R) hydromorphone and controlled-release morphine. The direction of the mean difference between the treatments (-0.8) and the out-of-range lower limit of the 95% CI (-1.6) were in favor of OROS(R) hydromorphone.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT0041054.