Opioid rotation for cancer pain: rationale and clinical aspects

Conversion ratios: Why is it so challenging to construct opioid conversion tables?

Standardizing opioid management is challenging due to the absence of a ceiling dose, the unknown ideal therapeutic plasma level, and the lack of an clear relationship between dose and therapeutic response. Opioid rotation or conversion, which is switching from one opioid, route of administration, or both, to another, to improve therapeutic response and reduce toxicities, occurs in 20-40 percent of patients treated with opioids. Opioid conversion is often needed when there are adverse effects, toxicities, or inability to tolerate a certain opioid formulation. A majority of patients benefit from opioid conversion, leading to improved analgesia and less adverse effects. There are different published ways of converting opioids in the literature. This review of 20 years of literature is centered on opioid conversions and aims to discuss the complexity of converting opioids. We discuss study designs, outcomes and measures, pain phenotypes, patient characteristics, comparisons of equivalent doses between opioids, reconciling conversion ratios between opioids, routes, directional differences, half-lives and metabolites, interindividual variability, and comparison to package insert information. Palliative care specialists have not yet come to a consensus on the ideal opioid equianalgesic table; however, we discuss a recently updated table, based on retrospective evidence, that may serve as a gold standard for practical use in the palliative care population. More robust, well-designed studies are needed to validate and guide future opioid conversion data.

Opioid-induced Neurotoxicity in Patients with Cancer Pain

OPINION STATEMENT

Opioid-induced neurotoxicity (OINT) is a neuropsychiatric syndrome observed with opioid therapy. The mechanism of OINT is thought to be multifactorial, and many risk factors may facilitate its development. If symptoms of OINT are seen, the prescriber should consider hydration, discontinuation of the offending opioid drug, or switching of opioid medication, or the use of some adjuvants. Multiple factors like inter- and intraindividual differences in opioid pharmacology may influence the accuracy of dose calculations for opioid switching. Experience and clinical judgment in a specialistic palliative care setting should be used and individual patient characteristics considered when applying any conversion table.

Targeting Peripheral μ-opioid Receptors or μ-opioid Receptor-Expressing Neurons Does not Prevent Morphine-induced Mechanical Allodynia and Anti-allodynic Tolerance

The chronic use of morphine and other opioids is associated with opioid-induced hypersensitivity (OIH) and analgesic tolerance. Among the different forms of OIH and tolerance, the opioid receptors and cell types mediating opioid-induced mechanical allodynia and anti-allodynic tolerance remain unresolved. Here we demonstrated that the loss of peripheral μ-opioid receptors (MORs) or MOR-expressing neurons attenuated thermal tolerance, but did not affect the expression and maintenance of morphine-induced mechanical allodynia and anti-allodynic tolerance. To confirm this result, we made dorsal root ganglia-dorsal roots-sagittal spinal cord slice preparations and recorded low-threshold Aβ-fiber stimulation-evoked inputs and outputs in superficial dorsal horn neurons. Consistent with the behavioral results, peripheral MOR loss did not prevent the opening of Aβ mechanical allodynia pathways in the spinal dorsal horn. Therefore, the peripheral MOR signaling pathway may not be an optimal target for preventing mechanical OIH and analgesic tolerance. Future studies should focus more on central mechanisms.

Levorphanol as a Second Line Opioid in Cancer Patients Presenting to an Outpatient Supportive Care Center: An Open-label Study

CONTEXT

Levorphanol is a potent opioid agonist and NMDA receptor blocker with minimal drug interactions, and there are few reports of its use in cancer patients.

OBJECTIVES

We aimed to determine the frequency of successful opioid rotation (OR) to levorphanol and the median opioid rotation ratio (ORR) from Morphine Equivalent Daily Dose (MEDD).

METHODS

This is a prospective, single-group, interventional study. Cancer outpatients requiring an OR and receiving a MEDD of 60-300 mg were rotated to levorphanol using a ratio of 10:1 and assessed daily for 10-day. Successful OR was defined as a 2-point improvement in the Edmonton Symptom Assessment System (ESAS) pain score on day 10 or achieving the personalized pain goal between days 3-10 in patients with uncontrolled pain or resolution of opioid side effects (OSE) in those undergoing OR for OSE alone. The ORR to levorphanol was calculated using net-MEDD (MEDD before OR minus the MEDD of the breakthrough opioid used along with levorphanol after OR).

RESULTS

Forty patients underwent OR to levorphanol, and uncontrolled pain 35/40 (87.5%) was the most common indication. The median net-MEDD and levorphanol doses were 95 and 10 mg, respectively, and 33/40 (82.5%) had a successful OR with a median (IQR) ORR of 8.56 (7.5-10). Successful OR was associated with significant improvement in ESAS and OSE scale scores. There was a strong association between MEDD and levorphanol dose.

CONCLUSION

This study provided preliminary data that cancer patients could be successfully rotated to levorphanol using an ORR of 8.5. Levorphanol was associated with improved pain and symptom control and was well- tolerated.

Conversion ratios for opioid switching: a pragmatic study

BACKGROUND

The final conversion ratios among opioids used for successful switching are unknown. The aim of this study was to determine the initial and final conversion ratios used for a successful opioid switching in cancer patients, and eventual associated factors.

METHODS

Ninety-five patients who were successfully switched were evaluated. The following data were collected: age, gender, Karnofsky performance score, primary cancer, cognitive function, the presence of neuropathic, and incident pain. Opioids, route of administration, and their doses expressed in oral morphine equivalents used before OS were recorded as well as opioids use for starting opioid switching, and at time of stabilization. Physical and psychological symptoms were routinely evaluated by Edmonton Symptom Assessment Scale.

RESULTS

No statistical changes were observed between the initial conversion ratios and those achieved at time of stabilization for all the sequences of opioid switching. When considering patients switched to methadone, there was no association between factors taken into considerations.

CONCLUSION

Opioid switching is a highly effective and safe technique, improving analgesia and reducing the opioid-related symptom burden. The final conversion ratios were not different from those used for starting opioid switching. Patients receiving higher doses of opioids should be carefully monitored for individual and unexpected responses in an experienced palliative care unit, particularly those switched to methadone. Future studies should provide data regarding the profile of patients with difficult pain to be hospitalized.

Cancer Pain Treatment Strategies in Patients with Cancer

Management of cancer pain is challenging. Despite the poor evidence, opioid therapy still remains the cornerstone for the management of cancer-related pain. Opioids should be given according to the clinical presentation in the different stages of disease. There is no drug of choice, as most opioids are effective. Thus, the choice should be based on the individual characteristics of patients. Optimization of opioid therapy may allow individual treatment according to the patient's characteristics and pain syndromes, providing timely alternatives in the different stages of disease. While most patients respond to an appropriate treatment associated with a comprehensive assessment and symptom control, a high level of experience and knowledge is necessary in determining conditions to maximize the analgesic response, eventually adding adjuvants in some specific circumstances. Alternative opioids may improve the balance between analgesia and adverse effects in the presence of a poor response to the first opioid in a large number of patients. Finally, a selected population can benefit from some interventional procedures.

Treatment of Neuropathic Pain Directly Due to Cancer: An Update

Simple Summary

This review discusses treatment approaches for providing pain relief to oncological patients affected by pain caused by nerve damage due to the tumor, also known as neuropathic cancer pain. Although being encountered often and causing a relevant burden to these patients, neuropathic cancer pain remains still difficult to diagnose and treat. Strong evidence about the best drugs to be used remain limited, as do therapeutic choices.

Abstract

Neuropathic pain can be defined as pain related to abnormal somatosensory processing in either the peripheral or central nervous system. In this review article, with neuropathic cancer pain (NCP), we refer to pain due to nervous tissue lesions caused by the tumor or its metastases. Nervous tissue damage is the cause of cancer pain in approximately 40% of those experiencing cancer pain. Recognizing a neuropathic pathophysiology in these cases may be difficult and requires specific criteria that are not homogenously applied in clinical practice. The management of this type of pain can be challenging, requiring the use of specific non-opioid adjuvant drugs. The majority of the criteria for NCP diagnosis and management have been based mainly on results from the noncancer population, risking the failure of addressing the specific needs of this population of patients. In this review, we summarize current management options available for NCP and provide some insights on new promising treatments.

[The management of multimorphic cancer pain, from diagnosis to treatment]

Cancer pain remains a major public health issue. Despite progress in pain medicine thanks to the interest shown in early and timely supportive care, more than half the patients managed for cancer are in pain. One of the key factors in high quality multidisciplinary management throughout the care pathway is to assess more than just pain: it is necessary to assess the patient as a whole. Understanding the complexity of cancer pain - or the various types of pain - through the innovative multimorphic cancer pain model, effectively opens up new perspectives for a targeted, personalised, and multimodal approach. The subsequent treatment strategies, whether drug-based with opioids, or interventional, are codified by guidelines based on scientific evidence for the healthcare professionals and, ultimately, patients.

Cancer induced bone pain: current management and future perspectives

Recent improvements in the therapeutic armamentarium of oncology by the addition of targeted and immunotherapeutic agents have led to an increase in the life expectancy of advanced-stage cancer patients. This has led to an increased number of patients presenting with bone metastasis and experiencing episodes of cancer-induced bone pain (CIBP). CIBP is a crippling, chronic, morbid state interfering significantly with the functional capacity and the quality of life (QoL). CIBP is characterized by a complex multifactorial pathophysiological mechanism involving tumor cells, bone cells, inflammatory microenvironment, and the neuronal tissue. It may not be possible to mitigate pain completely; therefore, the aim should be to reach the lowest possible level of pain that allows for an acceptable QoL to the patient. Multimodality approach of surgical, radiation, medical and behavioral techniques is thus recommended to manage CIBP. This review discusses the pathogenesis and pathophysiological mechanism accompanying bone metastasis and CIBP, currently approved therapies for the management of CIBP, and the future perspective.

Morphine produces potent antinociception, sedation, and hypothermia in humanized mice expressing human mu-opioid receptor splice variants

Morphine is a strong painkiller acting through mu-opioid receptor (MOR). Full-length 7-transmembrane (TM) variants of MOR share similar amino acid sequences of TM domains in rodents and humans; however, interspecies differences in N- and C-terminal amino acid sequences of MOR splice variants dramatically affect the downstream signaling. Thus, it is essential to develop a mouse model that expresses human MOR splice variants for opioid pharmacological studies. We generated 2 lines of fully humanized MOR mice (hMOR; mMOR mice), line #1 and #2. The novel murine model having human OPRM1 genes and human-specific variants was examined by reverse-transcription polymerase chain reaction and the MinION nanopore sequencing. The differences in the regional distribution of MOR between wild-type and humanized MOR mice brains were detected by RNAscope and radioligand binding assay. hMOR; mMOR mice were characterized in vivo using a tail-flick, charcoal meal, open field, tail suspension, naloxone precipitation tests, and rectal temperature measurement. The data indicated that wild-type and humanized MOR mice exhibited different pharmacology of morphine, including antinociception, tolerance, sedation, and withdrawal syndromes, suggesting the presence of species difference between mouse and human MORs. Therefore, hMOR; mMOR mice could serve as a novel mouse model for pharmacogenetic studies of opioids.

Neuromodulation With Burst and Tonic Stimulation Decreases Opioid Consumption: A Post Hoc Analysis of the Success Using Neuromodulation With BURST (SUNBURST) Randomized Controlled Trial

OBJECTIVE

The SUNBURST study was a prospective, multicenter, randomized crossover trial of a single device delivering burst and tonic spinal cord stimulation (SCS) for chronic trunk and/or limb pain. We performed a post hoc analysis of opioid consumption at baseline and after device implantation.

MATERIALS AND METHODS

After implantation, 100 patients were randomized to one mode (tonic or burst) for 12 weeks, and the other mode for the subsequent 12 weeks. After the crossover period (24 weeks), patients chose their preferred mode and were assessed for one year. We analyzed 69 patients who took opioid medication at baseline. The primary endpoint was opioid consumption in morphine milligram equivalents (MMEs) at baseline and 12 months postimplantation. Subgroup analysis included opioid consumption based on Center for Disease Control markers (<50, 50-90, 90-120, >120 MME/day) and stimulation mode preference.

RESULTS

Opioid consumption at 12 months was lower compared to baseline (53.94 vs. 79.19 MME, MD -25.25, 95% CI -43.77 to 6.73, p = 0.008). By 12 months, 11 of 69 patients (15.9%) discontinued all opioid (p = 0.001). Based on CDC dose markers, the proportion of patients taking >120 MME/day decreased by 61.7% at 12 months postintervention compared to baseline (p = 0.043). Forty-five of 69 patients (65.2%) preferred burst SCS while 15 of 69 patients (21.7%) preferred tonic SCS (p < 0.001).

CONCLUSION

A device delivering tonic and burst SCS was associated with decreased opioid consumption after 12 months in patients with chronic trunk and/or limb pain. The proportion of patients reporting the highest opioid intake (>120 MME/day) decreased to a lower CDC dose category by 61.7%, carrying important implications for those at highest risk for opioid-related substance use disorder, overdose, and death.

Effectiveness of Intramuscular Electrical Stimulation on Postsurgical Nociceptive Pain for Patients Undergoing Open Pancreaticoduodenectomy: A Randomized Clinical Trial

BACKGROUND

After pylorus-preserving pancreaticoduodenectomy (PPPD), incision and suture of the abdominal muscles cause inflammatory changes and elicit somatic pain that deteriorates the quality of life. There have been no previous reports on needle electrical twitch obtaining intramuscular stimulation (NETOIMS) in abdominal open operation; this study aimed to apply NETOIMS for postoperative somatic pain in patients undergoing PPPD as a new treatment modality for pain control.

METHODS

Between June 2018 and January 2019, 44 patients who underwent PPPD were randomly assigned to a control group and the NETOIMS group. The NETOIMS group received NETOIMS in the transverse abdominis muscle under ultrasound guidance right after operation under general anesthesia. The pain score (visual analog scale), peak cough flow (PCF), and gait speed were repetitively measured from 1 day before operation to 2 weeks after discharge as scheduled. Data were analyzed by the linear mixed model and repeated-measures analysis of variance.

RESULTS

Of the 44 patients recruited, data from 38 patients were finally analyzed. The pain scores were significantly lower in the NETOIMS group after PPPD (p = 0.01). Although the PCF at each measuring time point did not show inter-group difference (p = 0.20), improvement of PCF from the second day after operation to discharge was greater (p = 0.02) and gait speed improved significantly faster (p < 0.01) in the NETOIMS group than in the control group.

CONCLUSIONS

NETOIMS helps in rapid reduction of postoperative somatic pain developed after PPPD and in improvement of PCF and gait speed.

Patient-controlled subcutaneous analgesia using sufentainil or morphine in home care treatment in patients with stage III-IV cancer: A multi-center randomized controlled clinical trial

Purpose

Patient‐controlled subcutaneous analgesia (PCSA) with sufentanil is an alternative analgesia strategy in patients with stage III‐IV cancer; however, its efficacy and safety have not been fully investigated.

Methods

From May 10, 2017 to November 10, 2017, 120 patients with stage III‐IV cancer suffering from moderate to severe pain were prospectively enrolled from six hospitals and randomized to receive PCSA with morphine (control group) or sufentanil (intervention group). Before the PCSA and on days 1, 3, 7, 14, 28, and 56 after treatment, the numeric rating scale (NRS) and 36‐item Short Form health survey (SF‐36) were completed for each patient and the side effects were also recorded.

RESULTS

No significant differences (P > .05) were observed in the preoperative NRS score and the SF‐36 parameters between the two groups. Patients in the intervention group achieved better pain relief, as indicated by lower NRS scores at days 14 (P = .040), 28 (P < .001), and 56 (P < .001) after PCSA device implantation (vs control group). Furthermore, the patients in the intervention group also achieved a better life quality, as indicated by the physical role, general health, social function body pain, and mental health scores. Finally, the patients receiving sufentanil showed lower levels of nausea and somnolence than those in the control group.

Conclusion

PCSA with sufentanil achieves better pain control and life quality as well as fewer adverse reactions in stage III‐IV cancer patients with pain and may be a promising pain management in these patients.

Trial registration

This study was registered at chictr.org.cn with the trial number: ChiCTR‐IPR‐17011280.

Mitigating the Shadow of the Worldwide Opioid Crisis: A Review for the Foot and Ankle Specialist

The foot and ankle physician is no stranger to the difficulties in achieving optimal pain therapy. There remains much confusion and conflicting information available to nonspecialist prescribers regarding opioid therapy as well as great deal of fear or opiophobia during the prescribing and monitoring of opioids worldwide. The role of the lower extremity specialist provider is to responsibly provide pain management to their patients in an error-free environment. The purpose of this article is to explore the central theme of responsible opioid pain management worldwide. This review focuses on the prescribing strategies of opioid analgesics to treat lower-extremity pain. Pharmacology of opioid agents and opioid prescribing strategies will be presented. Then, the concept of multimodal pain relief criteria for selecting appropriate opioid analgesics and use of adjunctive therapies to prevent opioid misuse as presented in the current medical literature is reported. Finally, a commentary and discussion centered on the actions of pharmaceutical companies of promoting their opioid products and the negative outcomes of their actions in the United States that may go worldwide if behaviors of these companies are not recognized by the foot and ankle specialist.

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.

Chronic Cancer Pain: Diagnostic Dilemma and Management Challenges

A 32-year-old female, diagnosed case of neuroendocrine tumor of pancreas, was admitted to the pain and palliative care unit with complaints of diffuse abdominal pain which was severe in intensity with score on numerical rating scale-9/10. Pain was not relieved even after taking tablet morphine immediate release 360 mg every 4 hourly, paracetamol 500 mg 6 hourly, and gabapentin 300 mg 8 hourly. She had undergone distal pancreatectomy with splenectomy and also received multiple lines of chemotherapy. After making a diagnosis of opioid-induced hyperalgesia, opioid rotation from morphine to fentanyl was done. This case report reflects various conditions where strong opioids fail to relieve cancer pain, and a multimodal approach is needed for its management.

Opioid-induced Hallucinations: A Review of the Literature, Pathophysiology, Diagnosis, and Treatment

Despite their association with multiple adverse effects, opioid prescription continues to increase. Opioid-induced hallucination is an uncommon yet significant adverse effect of opioid treatment. The practitioner may encounter patient reluctance to volunteer the occurrence of this phenomenon because of fears of being judged mentally unsound. The majority of the literature concerning opioid-induced hallucinations arises from treatment during end-of-life care and cancer pain. Because the rate of opioid prescriptions continues to increase in the population, the rate of opioid-associated hallucinations may also conceivably increase. With a forecasted increase in the patient-to-physician ratio, opioid therapy is predicted to be provided by practitioners of varying backgrounds and medical specialties. Hence, knowledge of the pharmacology and potential adverse effects of these agents is required. This review seeks to increase awareness of this potential complication through a discussion of the literature, potential mechanisms of action, diagnosis, and treatment strategies.

Spinal Metastatic Disease: A Review of the Role of the Multidisciplinary Team

Historically, a simple approach centered on palliation was applicable to the majority of patients with metastatic spinal disease. With advances in diagnosis and treatment, a more complicated algorithm has devolved requiring a multidisciplinary approach with institutional commitment and support. We performed a database review including pertinent articles exploring the multidisciplinary management of spinal metastatic disease. The wide variation in clinical presentation and tumor response to treatment necessitates a multidisciplinary approach that integrates the diagnosis and treatment of the cancer, symptom management, and rehabilitation for optimal care of patients with spinal metastases. Advances in the field of radiology have led to earlier and more focused diagnosis of spinal metastasis and acts to guide therapy. Advances in surgical techniques, neurophysiologic monitoring, and anesthetic expertise have allowed surgeons to perform more extensive procedures leading to improved outcomes and reduced morbidity. Radiation oncology input that is essential as external beam radiation therapy can provide significant pain relief. Non-operative measures may include bisphosphonate infusions, management of complications (e.g. hypercalcemia of malignancy), monoclonal antibody infusions, and chemotherapy if indicated in the treatment of the primary malignancy. Input from psychology services is necessary to address the biopsychosocial ramifications of spinal metastasis. Allied health professionals in the form of physiotherapists, social workers, and dieticians also contribute in maximizing patients' quality of life and well-being.

The use of rotation to fentanyl in cancer-related pain

Pain is commonly diagnosed with respect to cancer and heart diseases, being a major symptom in most neoplastic diseases. Uncontrolled pain leads to a decrease in the quality of life and an increase in the morbidity of the patient. Opioids represent the best analgetic supportive therapy and are frequently used in patients suffering from cancer and experiencing a high level of pain. Opioid treatment starts with a gradual titration of the dose until the minimum effective dose and the maximum tolerated dose are determined. Opioid rotation refers to the switch from one opioid to another in order to get a better response to analgetic therapy and reduce side effects. Fentanyl therapy is recommended to be continued during chemotherapy, radiotherapy, or in the case of surgical intervention. Rotation to fentanyl patches is an efficient and elegant solution for cancer patients, with reduced side effects. Opioid rotation, especially to fentanyl, was shown to increase the quality of life in patients with malignant disease. Finally, rotation to fentanyl is also advantageous from an economic point of view.

Attitudes of radiation oncologists toward palliative and supportive care in the United States: Report on national membership survey by the American Society for Radiation Oncology (ASTRO)

PURPOSE

Radiation oncologists are frequently involved in providing palliative and supportive care (PSC) for patients with advanced cancers through delivery of palliative radiation. Whether they are confident in their ability to assess and initiate treatments for pain, nonpain, and psychosocial distress is unknown. The American Society for Radiation Oncology surveyed its practicing members in the United States on self-assessment of their primary PSC skills and access to continuing medical education on PSC.

METHODS

We electronically surveyed 4093 practicing radiation oncologists in the United States. The survey consisted of 16-questions in 5 sections¹: demographics,² PSC training,³ domains of PSC,⁴ perceived barriers as a radiation oncologist to initiate advanced care planning, and⁵ discussion of prognosis.

RESULTS

The survey was e-mailed to 4093 American Society for Radiation Oncology members, and 649 responses were received (response rate 16%). The majority (91%) of radiation oncologists surveyed believe PSC is an important competency for radiation oncologists. Most radiation oncologists reported that they are moderately confident in their ability to assess and manage pain and gastrointestinal symptoms, but less confident in their ability to manage anorexia, anxiety, and depression. Despite areas of decreased confidence, a large number (42%) of radiation oncologists do not receive any additional PSC education beyond their residency training. Lastly, a perceived fear of upsetting referring medical oncologists and lack of clinic time are concerns for radiation oncologists who may want to initiate goals of care/advance care planning discussions with patients and their families.

CONCLUSION

Radiation oncologists are more confident in their ability to assess and manage pain than in their ability to manage depression, anxiety, anorexia, and fatigue. There is a need for increasing continuing medical educational efforts in PSC for practicing radiation oncologists, and strengthening PSC training in residency programs.

Methadone for cancer pain: What have we learned from clinical studies?

The analgesic ladder guideline proposed by the World Health Organization has been shown to be effective in controlling cancer pain in about 80 percent of patients, but the remaining 20 percent still experience pain. Several strategies have been used to manage refractory cancer pain and opioid toxicity. Switching opioids, alternative routes of opioid administration, optimizing adjuvants, and invasive procedures are proposed treatments. Extensive medical literature corroborates each one of those treatments. Rotation from one opioid to another is a noninvasive strategy to overcome opioid side effects and refractory pain. Frequently, methadone is used during opioid rotation. However, there is a lack of consensus on how to proceed on rotation from morphine to methadone. In the current era of evidence-based medicine, the medical literature fails to answer some cancer pain-management issues. The purpose of this review is to clarify a process for transitioning from morphine to methadone.

Hyperalgesia and opioid switching

Opioids, intended to abolish pain, can unexpectedly produce hyperalgesia, particularly during rapid opioid escalation. Opioid switching could be a therapeutic option in a condition of opioid-induced tolerance or hyperalgesia, but conversion ratios between opioids are difficult to apply in this context and require strict surveillance and expertise.

This situation is challenging, because the rapid escalation of opioid doses, possibly due to the development of opioid-induced tolerance, can cause hyperalgesia. To avoid this adverse effect, clinicians need to refine their assessment of pain treatment and consider opioid switching. The authors present a case report in which switching from fentanyl to methadone was effective in a patient who developed hyperalgesia as a consequence of a rapid opioid escalation. Regardless of the expected clinical improvement of opioid switching using lower doses of the second opioid, the final dose of the second opioid was exaggeratedly low, probably as a consequence of the disappearance of hyperalgesia induced by the first opioid.

The results of this case and others like it may help practitioners develop a meaningful approach during opioid escalation, possibly anticipating the need for opioid switching or other alternative measures for patients with uncontrolled cancer pain.

Pain Management in Elderly Patients

In elderly patients, persistent pain negatively impacts quality of life. An interdisciplinary approach to pain management and emphasis on quality improvement will help to achieve better therapeutic outcomes. Managing pain in the geriatric population is challenging because of age-related changes in pain perception, cognition, pharmacokinetics, and drug effects. Improvement and maintenance of physical and emotional function is the goal. Pharmacotherapy should be initiated conservatively and titrated to effective doses with minimal adverse effects. Milder pain should be treated with non-opioid analgesics with a progression toward opioids and/or adjuvant medications as the pain intensifies. Acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and adjuvant medications represent most of the analgesic agents used in pain management. Knowing the underlying mechanism of pain will help guide pharmacologic therapy. The patient should be monitored initially, with every dose change, and periodically to assess efficacy and severity of adverse effects.

The Opioid Rotation Ratio From Transdermal Fentanyl to "Strong" Opioids in Patients With Cancer Pain

CONTEXT

One-third of cancer patients require opioid rotation (OR) to treat uncontrolled pain or opioid-induced neurotoxicity. Although fentanyl is the most frequently rotated opioid in cancer patients, the accurate opioid rotation ratio (ORR) from transdermal fentanyl (TDF) to other so-called "strong" opioids is unknown.

OBJECTIVES

We aimed to determine the ORR of TDF to strong opioids, as measured by morphine equivalent daily dose (MEDD).

METHODS

We reviewed 2471 consecutive patient visits (938 patients) to our supportive care center for an OR from TDF to strong opioids. Information regarding demographics, symptoms, and MEDD was collected in patients who followed up within six weeks. Linear regression analysis was used to estimate the ORR between TDF dose and net MEDD (MEDD after OR minus MEDD of the breakthrough opioid used along with TDF before OR).

RESULTS

Among 47 eligible patients, the median age was 54 years, 53% were male, and 77% had advanced cancer. The median time to follow-up was 14 days. Uncontrolled pain (83%) was the most common reason for OR. In patients with OR and no worsening of pain at follow-up (n = 41), the median ORR (range) from TDF mg/day to net MEDD mg/day was 100 (12.5-217) and from TDF mcg/hour to net MEDD was 2.4 (0.3-5.2); the correlation of TDF dose to net MEDD was 0.60 (P < 0.0001).

CONCLUSION

The median ORR from TDF mg/day to MEDD is 100 and from TDF mcg/hour to MEDD is 2.4, suggesting that TDF 100 mcg/hour is equivalent to an MEDD of 240 mg.

MicroRNAs Are Involved in the Development of Morphine-Induced Analgesic Tolerance and Regulate Functionally Relevant Changes in Serpini1

Long-term opioid treatment results in reduced therapeutic efficacy and in turn leads to an increase in the dose required to produce equivalent pain relief and alleviate break-through or insurmountable pain. Altered gene expression is a likely means for inducing long-term neuroadaptations responsible for tolerance. Studies conducted by our laboratory (Tapocik et al., 2009) revealed a network of gene expression changes occurring in canonical pathways involved in neuroplasticity, and uncovered miRNA processing as a potential mechanism. In particular, the mRNA coding the protein responsible for processing miRNAs, Dicer1, was positively correlated with the development of analgesic tolerance. The purpose of the present study was to test the hypothesis that miRNAs play a significant role in the development of analgesic tolerance as measured by thermal nociception. Dicer1 knockdown, miRNA profiling, bioinformatics, and confirmation of high value targets were used to test the proposition. Regionally targeted Dicer1 knockdown (via shRNA) had the anticipated consequence of eliminating the development of tolerance in C57BL/6J (B6) mice, thus supporting the involvement of miRNAs in the development of tolerance. MiRNA expression profiling identified a core set of chronic morphine-regulated miRNAs (miR's 27a, 9, 483, 505, 146b, 202). Bioinformatics approaches were implemented to identify and prioritize their predicted target mRNAs. We focused our attention on miR27a and its predicted target serpin peptidase inhibitor clade I (Serpini1) mRNA, a transcript known to be intricately involved in dendritic spine density regulation in a manner consistent with chronic morphine's consequences and previously found to be correlated with the development of analgesic tolerance. In vitro reporter assay confirmed the targeting of the Serpini1 3'-untranslated region by miR27a. Interestingly miR27a was found to positively regulate Serpini1 mRNA and protein levels in multiple neuronal cell lines. Lastly, Serpini1 knockout mice developed analgesic tolerance at a slower rate than wild-type mice thus confirming a role for the protein in analgesic tolerance. Overall, these results provide evidence to support a specific role for miR27a and Serpini1 in the behavioral response to chronic opioid administration (COA) and suggest that miRNA expression and mRNA targeting may underlie the neuroadaptations that mediate tolerance to the analgesic effects of morphine.

Opioid rotation versus combination for cancer patients with chronic uncontrolled pain: a randomized study

Background

For cancer patients with inadequate pain relief, a switch to an alternative opioid is the preferred option for symptomatic improvement. However, multiple opioids are often simultaneously administered for anecdotal reasons. This prospective study evaluated pain response to either opioid rotation or combination in patients with uncontrolled cancer pain.

Methods

Patients suffering with uncontrolled cancer pain despite dose titration were randomly assigned to opioid rotation group or opioid combination group. Patients answered a questionnaire that included items on pain severity (0 to 10) and interferences at baseline and after one week.

Results

Of the 50 patients registered, 39 patients answered the questionnaire after one week of treatment. After one week, the mean pain scores were significantly improved in both groups. Ten patients (42 %) in the rotation group and 16 patients (62 %) in the combination group reported that they achieved relief from pain (p = 0.08). The incidence of adverse events was similar in both groups, but fewer patients experienced constipation with opioid rotation than with combination (17 % vs. 42 %, respectively; p = 0.05). The frequency of rescue analgesics (50 % vs. 69 %; p = 0.17) and dose modification (29 % vs. 38 %; p = 0.49) were similar in the rotation and combination groups.

Conclusions

For patients with chronic uncontrolled cancer pain, both opioid rotation and combination strategies appear to provide significant relief of pain and improved patient satisfaction.

Trial registration

This study was registered in advance to ClinicalTrials.gov (no. NCT00478101).

Interaction of fentanyl with various cyclodextrins in aqueous solutions

OBJECTIVES

Water-soluble fentanyl citrate salt has been used in sublingual or buccal formulations for the breakthrough pain treatment. However, fentanyl absorption through the lipid mucosal membrane may be improved by enhancing the non-ionic lipophilic fentanyl base solubility. Therefore, the interaction between cyclodextrins (CDs) and fentanyl base has been evaluated to obtain basic information for its application.

METHODS

Parent CDs (α-, β- and γ-CD) as well as α- and β-CD derivatives were used for solubility studies with fentanyl base. Nuclear magnetic resonance (NMR) studies were applied in a system including β-CD or glucosyl-β-CD (G1-β-CD) with fentanyl base or fentanyl citrate. (1) H- and (13) C-NMR studies and a two-dimensional rotating frame Overhauser effect spectroscopy (ROESY) study were conducted to confirm inclusion complexes formation.

KEY FINDINGS

Parent CDs displayed BS type phase solubility diagrams; β-CD exhibited a strong interaction with fentanyl base. Hydrophilic β-CD derivatives, such as G1-β-CD, displayed AL type phase diagrams and higher solubilizing effects compared with parent CDs. ROESY study suggested that fentanyl phenyl groups were included in β-CD cavity.

CONCLUSIONS

This study revealed that hydrophilic β-CD derivatives, such as G1-β-CD, could be useful pharmaceutical additives for oral mucosal formulations because of the improved fentanyl base solubility via inclusion complexation.

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.

Efficacy of fentanyl transdermal patch in the treatment of chronic soft tissue cancer pain

Background:

Cancer pain may be a major problem for health care providers worldwide. According to different studies reporting the pain severity, one-third of patients reported to have moderate to severe pain. Management of cancer pain is one of the most important goals of palliative care. Recently, different research results on the efficacy of opioid analgesics in chronic pain management have played a role to implement standards in pain control by government agencies worldwide.

Objectives:

This study aimed to investigate the efficacy of fentanyl transdermal patch in the treatment of chronic soft tissue cancer pain.

Patients and Methods:

In a prospective descriptive study, we evaluated 86 patients with soft tissue tumors with chronic pain referred to cancer institute of Imam Khomeini Hospital, Tehran, Iran, during 2006-2007. For all patients, transdermal fentanyl patch (25 μg/h) was administered. The appearance of patches was the same. Pain severity was measured by Visual Analogue Scale (VAS) initially and 24, 48 and 72 hours after the initiation of treatment.

Results:

Patients' characteristics and VAS score before the treatment were not significantly different (P > 0.05). According to our findings, the pain severity was significantly reduced after the treatment (P = 0.001). The incidence of adverse events in patients was significantly high (72%). The most common adverse events were sleepiness, nausea and vomiting in 30.2% and 18.6%, respectively.

Conclusions:

Transdermal fentanyl patch was an effective and safe method to reduce pain in patients with soft tissue tumors. Moreover, it could improve the quality of life in these patients, but adverse events occurred in approximately 72% of patients.

Opioid switch from low dose of oral oxycodone to transdermal fentanyl matrix patch for patients with stable thoracic malignancy-related pain

BACKGROUND

The effectiveness and safety of switch from oral oxycodone to fentanyl patch is little known. Here, we investigated if early phase opioid switch from low dose of oral oxycodone to transdermal fentanyl matrix patch provided any benefits for patients with thoracic malignancy and stable cancer-related pain.

METHODS

This open-label two-centered prospective study enrolled patients with thoracic malignancy suffering persistent malignancy-related pain with numeric rating scale of pain intensity ≤ 3 which had been controlled by oral oxycodone ≤ 20 mg/day. Eligible patients switched from oral oxycodone to 12.5 μg/h of transdermal fentanyl matrix patch. The dose was allowed to be titrated upwards every 3 day by 25-50%, except for the first increase from 12.5 μg/hr to 25 μg/hr,until achieving adequate pain control. The data on patients' global assessment scores measured on a five-step scale, an 11-point numeric rating scale of pain intensity, the severity of adverse effects using a four-point categorical rating scale, and the Epworth sleepiness scale questionnaire were collected for 15 days.

RESULTS

Forty-nine eligible patients were analyzed. Overall patients' satisfaction score significantly improved from day 1 (2.7 ± 0.9) to day 15 (2.3 ± 0.9) (p < 0.05), and 90% and 78% of patients remained to receive the minimum dose of fentanyl patch on day 8 and 15 from the opioid switch. There was a significant difference in sleepiness throughout the study period, though no difference was detected in pain intensity and other adverse effects.

CONCLUSION

Transdermal fentanyl matrix patch is an alternative analgesic option for a stable cancer pain in patients with thoracic malignancies.

Dosing considerations with transdermal formulations of fentanyl and buprenorphine for the treatment of cancer pain

Opioids continue to be first-line pharmacotherapy for patients suffering from cancer pain. Unfortunately, subtherapeutic dosage prescribing of pain medications remains common, and many cancer patients continue to suffer and experience diminished quality of life. A large variety of therapeutic options are available for cancer pain patients. Analgesic pharmacotherapy is based on the patient’s self-report of pain intensity and should be tailored to meet the requirements of each individual. Most, if not all, cancer pain patients will ultimately require modifications in their opioid pharmacotherapy. When changes in a patient’s medication regimen are needed, adequate pain control is best maintained through appropriate dosage conversion, scheduling immediate release medication for withdrawal prevention, and providing as needed dosing for breakthrough pain. Transdermal opioids are noninvasive, cause less constipation and sedation when compared to oral opioids, and may improve patient compliance. A relative potency of 100:1 is recommended when converting the patient from oral morphine to transdermal fentanyl. Based on the limited data available, there is significant interpatient variability with transdermal buprenorphine and equipotency recommendations from oral morphine of 75:1–110:1 have been suggested. Cancer patients may require larger transdermal buprenorphine doses to control their pain and may respond better to a more aggressive 75–100:1 potency ratio. This review outlines the prescribing of transdermal fentanyl and transdermal buprenorphine including how to safely and effectively convert to and use them for those with cancer pain.

State of art of managing pain in patients with cancer

Pain in cancer patients involves complex interactions between physiological, psychological, sociocultural, sensory, cognitive, and behavioral dimensions. Pain management interventions will be most effective when pharmacological and nonpharmacological treatments are individualized after exploring the various contributors to pain and suffering, and the patient and family are educated and involved in decision making. This entails a systematic multidimensional approach with frequent reassessments of pain and related outcomes.

The need for a multidisciplinary approach to pain management in advanced cancer: A clinical case

Advanced cancer patients are often affected by multiple complex symptoms brought about by persistent nociceptive stimuli and intense psychosocial distress. One such complex symptom, cancer pain, has continued to pose a challenge in medical management even though the concept of total pain was described several years ago by Cicely Saunders. Oftentimes, the application of a multidisciplinary approach is delayed after numerous opioid dose escalations and invasive procedures have been performed. The case presented here highlights the importance of timely multidisciplinary intervention and the use of an acute palliative care unit, which resulted in adequate pain control after multiple medical and invasive procedures that caused toxicities.

Brief review: Neuraxial analgesia in refractory malignant pain

PURPOSE

This narrative review aims to inform health care practitioners of the current literature surrounding the use of intrathecal (IT) and epidural analgesia in cancer patients with refractory pain at end of life. Topics discussed and reviewed include: patient selection, treatment planning, procedure, equipment, medications, complications, policies and procedures, as well as directions for future research.

PRINCIPAL FINDINGS

Cancer pain is inadequately treated in an estimated 10% of patients with malignant pain despite the implementation of the World Health Organization three-step analgesic ladder. This has prompted some to advocate for the addition of a fourth step that would include neuraxial interventions. There is moderate evidence supporting the safety and efficacy of IT drug therapy in cancer patients with refractory pain. A detailed assessment and interdisciplinary team approach is necessary to develop and implement care plans for patients requiring neuraxial analgesia. Neuraxial analgesia can significantly improve pain and reduce side effects, but this must be balanced against the increased complexity of care and the risk of uncommon but serious complications.

CONCLUSION

Neuraxial drug delivery gives clinicians more options to manage refractory pain at end of life and should be offered to patients with intractable cancer pain. Teams should be interprofessional with clear delineation of roles and responsibilities. They should discuss advanced discharge planning with the patient prior to implantation as well as provide on-call support.

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.

Opioid rotation in patients initiated on oxycodone or morphine: a register study

Purpose

Strong opioids are recommended for the treatment of moderate to severe pain. However, some patients do not achieve a successful treatment outcome due to intolerable adverse events and/or inadequate analgesia, thus may benefit from switching to another opioid, a procedure known as “opioid rotation.” The type of opioid at treatment initiation may influence the risk of opioid rotation and the objective of this study was to assess such rotation after treatment initiation with two alternative treatments, controlled-release (CR) oxycodone versus CR morphine in patients suffering from non-cancer pain.

Method

The study reported here was a real-life study based on Swedish register data: the Prescribed Drug, National Patient, and Cause of Death registers. The captured data cover the entire Swedish population treated in specialist care. A statistical analysis plan was agreed and signed before data were accessed.

Results

Data from 50,223 cases were included in the analyses. The risk of rotation was 19% higher in patients initiating treatment with morphine compared with oxycodone (hazard ratio 1.19; 95% confidence interval 1.11–1.27; P < 0.001), after adjusting for such baseline variables that were both significantly correlated with the outcome variable (time to rotation) and significantly different between the groups; age at index date, osteoarthritis and number of pain-related drugs.

Conclusion

Patients with non-cancer pain who initiated treatment with CR morphine had a higher risk of opioid rotation than patients initiated with CR oxycodone.

Effectiveness and gastrointestinal tolerability during conversion and titration with once-daily OROS® hydromorphone extended release in opioid-tolerant patients with chronic low back pain

Purpose

To describe the efficacy and safety of hydromorphone extended-release tablets (OROS hydromorphone ER) during dose conversion and titration.

Patients and methods

A total of 459 opioid-tolerant adults with chronic moderate to severe low back pain participated in an open-label, 2- to 4-week conversion/titration phase of a double-blind, placebo-controlled, randomized withdrawal trial, conducted at 70 centers in the United States. Patients were converted to once-daily OROS hydromorphone ER at 75% of the equianalgesic dose of their prior total daily opioid dose (5:1 conversion ratio), and titrated as frequently as every 3 days to a maximum dose of 64 mg/day. The primary outcome measure was change in pain intensity numeric rating scale; additional assessments included the Patient Global Assessment and the Roland–Morris Disability Questionnaire scores. Safety assessments were performed at each visit and consisted of recording and monitoring all adverse events (AEs) and serious AEs.

Results

Mean (standard deviation) final daily dose of OROS hydromorphone ER was 37.5 (17.8) mg. Mean (standard error of the mean [SEM]) numeric rating scale scores decreased from 6.6 (0.1) at screening to 4.3 (0.1) at the final titration visit (mean [SEM] change, −2.3 [0.1], representing a 34.8% reduction). Mean (SEM) change in Patient Global Assessment was −0.6 (0.1), and mean change (SEM) in the Roland–Morris Disability Questionnaire was −2.8 (0.3). Patients achieving a stable dose showed greater improvement than patients who discontinued during titration for each of these measures (P < 0.001). Almost 80% of patients achieving a stable dose (213/268) had a ≥30% reduction in pain. Commonly reported AEs were constipation (15.4%), nausea (11.9%), somnolence (8.7%), headache (7.8%), and vomiting (6.5%); 13.0% discontinued from the study due to AEs.

Conclusion

The majority of opioid-tolerant patients with chronic low back pain were successfully converted to effective doses of OROS hydromorphone ER within 2 to 4 weeks.

[Pain therapy in the elderly:7-day transdermal buprenorphine patch in clinical practice. Results of a non-interventional study]

BACKGROUND

Chronic pain in the elderly is common. Especially in the elderly inadequate treatment of pain can cause significant functional impairmentand deterioration of qualityof life.

METHODS

Theaim of this post-marketing surveillance study was to collect data from clinical practice on the analgesic efficacy and safety of the 7-day transdermal buprenorphine patch in patients with chronic non-malignant pain pre-treated with opioids. A total of 2713 elderly multimorbid patients were switched to 7-day transdermal buprenorphine patch from previous opioid treatment mainly due to inadequate analgesia. 83% of patients received a 7-day transdermal buprenorphine patch dosage > or = 10 microg/h. During the 8-weekobservation period, data on pain intensity, quality of sleep/life (NRS-11 point scales) and safety wererecorded.

RESULTS

Mean pain intensity decreased by 4 points with 7-day transdermal buprenorphine patch (p < or = 0.001). Quality of sleep and life as well as social activities and self-reliance improved significantly. Compliance and tolerability were assessed as very good/good in > 90% of patients. Adverse drug reactions (ADRs) occurred in 3% of patients and corresponded to 90.1% to the already-known spectrum of ADRs of 7-daytransdermal buprenorphinepatch.

CONCLUSIONS

The results confirm that elderly patients with opioid pre-treatment benefit from a switch to 7-day transdermal buprenorphine patch with regard to reduction of pain and improved quality of life.