Long-term patterns of morphine dosage and pain intensity among cancer patients

Synthesis of the Mechanisms of Opioid Tolerance: Do We Still Say NO?

The use of morphine as a first-line agent for moderate-to-severe pain is limited by the development of analgesic tolerance. Initially opioid receptor desensitization in response to repeated stimulation, thought to underpin the establishment of tolerance, was linked to a compensatory increase in adenylate cyclase responsiveness. The subsequent demonstration of cross-talk between N-methyl-D-aspartate (NMDA) glutamate receptors and opioid receptors led to the recognition of a role for nitric oxide (NO), wherein blockade of NO synthesis could prevent tolerance developing. Investigations of the link between NO levels and opioid receptor desensitization implicated a number of events including kinase recruitment and peroxynitrite-mediated protein regulation. Recent experimental advances and the identification of new cellular constituents have expanded the potential signaling candidates to include unexpected, intermediary compounds not previously linked to this process such as zinc, histidine triad nucleotide-binding protein 1 (HINT1), micro-ribonucleic acid (mi-RNA) and regulator of G protein signaling Z (RGSZ). A further complication is a lack of consistency in the protocols used to create tolerance, with some using acute methods measured in minutes to hours and others using days. There is also an emphasis on the cellular changes that are extant only after tolerance has been established. Although a review of the literature demonstrates a lack of spatio-temporal detail, there still appears to be a pivotal role for nitric oxide, as well as both intracellular and intercellular cross-talk. The use of more consistent approaches to verify these underlying mechanism(s) could provide an avenue for targeted drug development to rescue opioid efficacy.

Effectiveness and safety of repetitive transcranial magnetic stimulation for the treatment of morphine dependence: A retrospective study

Morphine dependence (MD) is a very common complication because of the chronic morphine consumption. Studies suggest that repetitive transcranial magnetic stimulation (rTMS) can be used for the treatment of MD. However, there is still lacking evidence to support rTMS for MD. Thus, this retrospective study aimed to investigate the effectiveness and safety of rTMS for patients with MD.In this retrosepctive study, a total of 100 patients with MD were included, and they were divided into a rTMS group (n = 50), and a control group (n = 50). All patients in both groups received occupational therapy. In addition, patients in the rTMS group received rTMS. All patients in both groups received a total of 8 weeks treatment. The outcomes comprised of morphine craving intensity, depression, anxiety, and sleep quality, which were appraised by Visual Analogue Scale (VAS), Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS), and Pittsburgh Sleep Quality Index (PSQI), respectively. In addition, treatment-related adverse events were also considered for assessment.After 8 weeks treatment, patients in the rTMS group exerted better benefits in improving VAS (P < .01), SDS (P < .01), SAS (P < .01), and PSQI (P < .01), than patients in the control group. In addition, this study did not identify treatment-related adverse events in both groups.The findings of this study showed that rTMS treatment showed promising effectiveness on patients with MD. However, future studies should focus on warranting the present findings.

Safety of Intranasal Ketamine for Reducing Uncontrolled Cancer-Related Pain: Protocol of a Phase I/II Clinical Trial

Background

Approximately 12 million Americans are affected with cancer. Of these, 53% experience pain at all stages of cancer. Pain may remain uncontrolled despite high-dose opioid therapy, and opioids have many well-documented harmful side effects. Intranasal ketamine has been shown to be effective in controlling breakthrough noncancer pain in a double-blind randomized control trial (DBRCT) by Carr et al in 2003 as well as to help with depression in a DBRCT by Lapidus et al in 2014. We seek to obtain preliminary data on the safety, feasibility, and utility of this novel technique for the treatment of uncontrolled cancer pain.

Objective

This study aimed to obtain preliminary data via a clinical trial addressing the safety, feasibility, pharmacokinetics, and pharmacodynamics of intranasal ketamine. These initial findings will be applied to a subsequent trial to determine the effectiveness and associated toxicities of ketamine in a larger sample of cancer patients and to address the compelling need to identify new, successful management therapies for cancer pain.

Methods

This is an institutional review board– and investigational new drug–approved, prospective phase I/II trial to investigate the safety and use of intranasal ketamine in patients with uncontrolled pain related to cancer or cancer treatment. Informed consent will be obtained prior to all study procedures. All patients will be assigned to the same investigational treatment arm. After patient selection via inclusion/exclusion criteria, patients will be seen over 5 visits, with each visit conducted 2-7 days apart. Patients will be administered ketamine on visits 1-4 and monitored for 240 minutes with continuous pulse oximetry and regular blood pressure checks. Blood samples as well as patient-reported outcomes will be collected at set time points at baseline and after drug delivery. Patients will receive 10 mg intranasal ketamine on visit 1, 10 mg intravenous ketamine on visit 2, 30 mg intranasal ketamine on visit 3, and 50 mg intranasal ketamine on visit 4. On visit 5, an addition blood sample will be drawn.

Results

As of March 2019, enrollment is in progress, and a total of 7 subjects have completed the study. Enrollment is expected to be completed by April 2019. Final data analysis will commence soon after, and the results are expected to be submitted for publication in 2019.

Conclusions

If intranasal ketamine can be utilized for pain control in cancer patients, it could provide superior analgesia and better quality of life, without the risk of significant respiratory depression and constipation associated with opioid medications. These findings will be an important initial step toward testing the effectiveness of intranasal ketamine as a nonopioid medication for cancer pain and as potential maintenance outpatient therapy.

Trial Registration

ClinicalTrials.gov NCT03146806; https://clinicaltrials.gov/ct2/show/NCT03146806.

International Registered Report Identifier (IRRID)

DERR1-10.2196/12125

Multimodal intrathecal analgesia in refractory cancer pain

Background and aims

Cancer pain treatment has improved over the last decades. The majority of this population can be treated effectively with analgesics following the Guidelines of the original World Health Organisation (WHO). Unfortunately 10–15% of these patients still suffer from severe and refractory cancer pain, especially in the terminal phases of disease and require additional pain management modalities. Therefore, end-stage clinical interventions are particularly needed to minimize the perception of pain. With intrathecal therapy (ITT), drugs are delivered close to their site of action in the central nervous system avoiding first-pass metabolism and blood–brain barrier. It may improve analgesia with a smaller dose and possibly achieve a reduction in systemic or cerebral side effects compared to oral supplied medication alone. Multimodal analgesia enables further dose reduction with improved analgesia and fewer side effects.

Methods

In this retrospective research we investigated the effectiveness and side-effect profile of intrathecal morphine, bupivacaine and clonidine. Patients were followed until death occurred. Pain scores and side effects were recorded before initiating ITT (T0), just after initiating ITT (T1), at hospital discharge (T2), in the ambulant setting (T3) and the last obtained scores before death occurred (T4).

Results

Nine patients were included who suffered from severe and refractory cancer pain, not reacting to conventional pain management or had intolerable side effects. Primary tumour location was pancreatic (4), urothelial (3) and prostate (2). Primary pain was considered neuropathic or mixed neuropathic-nociceptive. The treatment team consisted of an anaesthetist, specialized nurse in coordination with primary physician, treating oncologist and specialized home care.

All patients were free of pain after initiation of the intrathecal therapy. The average follow-up period was 11 weeks in which there was a slight increase in NRS-score. In the last days before death occurred, half the patients were still free of pain. There were no problems during insertion of the catheter, device malfunction or infection. No severe adverse events defined as hypotension requiring inotropes, respiratory depression or neurological deficits were observed. Three patients experienced mild hypotension which gradually decreased after clonidine dose adjustment. Lower extremity weakness occurred in three patients as well. After bupivacaine dose adjustment the weakness disappeared in two patients and in one patient the lower extremity weakness persisted as a result of conus compression by tumour.

Conclusion and implications

Multimodal IT treatment with morphine, bupivacaine and clonidine is effective and safe for treating refractory cancer pain in the terminal phase of disease.

The study offers an important contribution to literature where there is still lack of convincing evidence about the benefits and harms of this type of pain management in patients with otherwise refractory cancer pain.

Palliative Interventional Oncology

Interventional oncologists are playing an ever greater role in improving the quality of life of their patients through minimally invasive procedures, many of which can be performed on an outpatient basis. Some of the most common palliative procedures currently performed will be discussed including management of intractable ascites and pleural effusions, neurolytic plexus blocks, and palliation of pain and bleeding associated with metastatic tumors.

Efficacy of Compound Kushen Injection in Relieving Cancer-Related Pain: A Systematic Review and Meta-Analysis

Despite widespread popular use of complementary and alternative medicine (CAM) therapies, a rigorous evidence based on the efficacy of compound kushen injection (CKI) for cancer-related pain is lacking. In this study, we evaluated the efficacy and safety of compound kushen injection and provided information for current or future research and clinical application. Sixteen trials were identified with a total of 1564 patients. The total pain relief rate of CKI plus chemotherapy is better than chemotherapy except for colorectal cancer. The treatment groups achieved a reduction in the incidences of leukopenia and gastrointestinal, hepatic, and renal functional lesion. However, there is paucity of multi-institutional RCTs evaluating compound kushen injection for cancer pain with adequate power, duration, and sham control. The quantity and quality of RCTs are lower so that we still have to boost the research level through scientific design and normative report.

Evidence-based Clinical Practice Guidelines for Interventional Pain Management in Cancer Pain

Intractable cancer pain not amenable to standard oral or parenteral analgesics is a horrifying truth in 10-15% of patients. Interventional pain management techniques are an indispensable arsenal in pain physician's armamentarium for severe, intractable pain and can be broadly classified into neuroablative and neuromodulation techniques. An array of neurolytic techniques (chemical, thermal, or surgical) can be employed for ablation of individual nerve fibers, plexuses, or intrathecalneurolysis in patients with resistant pain and short life-expectancy. Neuraxial administration of drugs and spinal cord stimulation to modulate or alter the pain perception constitutes the most frequently employed neuromodulation techniques. Lately, there is a rising call for early introduction of interventional techniques in carefully selected patients simultaneously or even before starting strong opioids. After decades of empirical use, it is the need of the hour to head towards professionalism and standardization in order to secure credibility of specialization and those practicing it. Even though the interventional management has found a definite place in cancer pain, there is a dearth of evidence-based practice guidelines for interventional therapies in cancer pain. This may be because of paucity of good quality randomized controlled trials (RCTs) evaluating their safety and efficacy in cancer pain. Laying standardized guidelines based on existing and emerging evidence will act as a foundation step towards strengthening, credentialing, and dissemination of the specialty of interventional cancer pain management. This will also ensure an improved decision-making and quality of life (QoL) of the suffering patients.

Treatment of multifocal pain with spinal cord stimulation

INTRODUCTION

We report a retrospective case study of combined treatment of cancer-related pain and chronic low back and lower extremity pain related to postlaminectomy syndrome (PLS) with one spinal cord stimulation (SCS) system.

METHODS

The patient underwent an uneventful SCS trial with percutaneous placement of two temporary eight-electrode leads (Medtronic Inc., Minneapolis, MN) placed at the level of T8-T9-T10 and T5-T6-T7.

RESULTS

After successful trial, he was implanted with permanent leads and generator, reporting sustained pain relief at 12-month follow-up visit.

DISCUSSION

SCS is a trialable, reversible, and interactive therapy permitting patients to control the level of stimulation they feel based on their degree of pain.

CONCLUSION

SCS provides an effective, alternative treatment for select patients with cancer-related chest wall pain and pain related to PLS who have failed conservative treatment.

Cancer pain management: basic information for the young pain physicians

Cancer pain is multifactorial and complex. The impact of cancer pain is devastating, with increased morbidity and poor quality of life, if not treated adequately. Cancer pain management is a challenging task both due to disease process as well as a consequence of treatment-related side-effects. Optimization of analgesia with oral opioids, adjuvant analgesics, and advanced pain management techniques is the key to success for cancer pain. Early access of oral opioid and interventional pain management techniques can overcome the barriers of cancer pain, with improved quality of life. With timely and proper anticancer therapy, opioids, nerve blocks, and other non-invasive techniques like psychosocial care, satisfactory pain relief can be achieved in most of the patients. Although the WHO Analgesic Ladder is effective for more than 80% cancer pain, addition of appropriate adjuvant drugs along with early intervention is needed for improved Quality of Life. Effective cancer pain treatment requires a holistic approach with timely assessment, measurement of pain, pathophysiology involved in causing particular type of pain, and understanding of drugs to relieve pain with timely inclusion of intervention. Careful evaluation of psychosocial and mental components with good communication is necessary. Barriers to cancer pain management should be overcome with an interdisciplinary approach aiming to provide adequate analgesia with minimal side-effects. Management of cancer pain should comprise not only a physical component but also psychosocial and mental components and social need of the patient. With risk–benefit analysis, interventional techniques should be included in an early stage of pain treatment. This article summarizes the need for early and effective pain management strategies, awareness regarding pain control, and barriers of cancer pain.

Spinal cord stimulation as a treatment option for intractable neuropathic cancer pain

Nearly 6,750,000 people suffer moderate to severe cancer-related pain each year. Unfortunately, 10% to 15% of these patients fail to achieve acceptable pain relief with conventional management. Spinal cord stimulation (SCS) has been used with increased frequency for successful treatment of intractable cancer pain. We present two cases of intractable, refractory-to-conventional treatment cancer pain that were successfully treated with SCS. Case 1 reports a 51-year-old male with burning pain at the left groin site of inguinal metastases, post-surgical and intraoperative radiation therapy for treatment of squamous cell carcinoma of the anus. Case 2 reports a 43-year-old woman with intractable, burning, throbbing, and shooting pain, post-debulking followed by radiation of a metastatic colon carcinoma. In both cases SCS implantation provided 90% to 100% pain relief, improved functioning and sleep, and discontinuation of pain medications, sustained through 12 months.

Review of oral oxymorphone in the management of pain

Chronic cancer and nonmalignant pain (CNMP) is a common and major health problem afflicting approximately 40 million persons in the US. Most cancer patients, and many patients with CNMP, require opioid analgesics to obtain adequate pain relief. Oral oxymorphone is a new formulation of an existing parenteral opioid that has become available for the treatment of significant pain: acute postoperative, chronic arthritis, chronic low back, and chronic cancer pain. Oxymorphone is a typical mu-opioid agonist that is effective in both immediate- and extended-release (IR and ER) formulations. Oxymorphone is more lipid soluble than morphine, resulting in a rapid onset of action when given in tablet formulation, with a duration of action of approximately 4-6 hours in IR and 12 hours in ER preparations. Oxymorphone provides excellent pain relief for significant pain, with typical opioid side effects that are usually mild or moderate in intensity. Multiple double-blind, prospective, placebo-controlled clinical trials have demonstrated the clinical efficacy and safety of this new oral opioid preparation. Oral oxymorphone is an effective opioid that provides a new therapeutic option for the physician.

Chronic forced swim stress inhibits ultra-low dose morphine-induced hyperalgesia in rats

Ultra-low doses of morphine (UL-morphine) induce hyperalgesia, which is assumed to be mediated by stimulatory G proteins (G(alphas)) signaling pathway. G(alphas) pathway inhibition and chronic stress both attenuate development of tolerance to analgesic effect of morphine. This study evaluated the effect of chronic stress on UL-morphine-induced hyperalgesia to find out if chronic stress interacts with the G(alphas) signaling pathway. Repeated daily forced swim stress was applied to induce chronic stress. UL-morphine (1 microg/kg, intraperitoneal)-induced hyperalgesia was assessed using the tail-flick test on day 6, in male rats that during days 1-5 received different treatments of swim stress, dexamethasone, swim stress following adrenalectomy (ADX) or swim stress after sham operation. Chronic stress by itself induced hyperalgesia in control and sham-operated rats but inhibited UL-morphine-induced hyperalgesia. In ADX animals, chronic stress did not produce hyperalgesia and could not inhibit UL-morphine-induced hyperalgesia. Chronic dexamethasone produced hyperalgesia but did not change the UL-morphine-induced hyperalgesia. Inhibition of UL-morphine hyperalgesia by chronic stress suggests that chronic stress interacts with the G(alphas) signaling pathway, which is responsible for UL-morphine-induced hyperalgesia. The absence of this effect in the ADX-rats or after repetitive dexamethasone administration demonstrates that hypothalamic-pituitary-adrenal (HPA) axis activation is necessary for controlling UL-morphine-induced hyperalgesia. Finally, the interaction of stress with the G(alphas) signaling pathway may provide an explanation for the inhibitory effect of stress on development of tolerance to the analgesic effect of morphine.

Neuraxial pain relief for intractable cancer pain

Most patients with cancer pain achieve good analgesia using traditional analgesics and adjuvant medications; however, an important minority of patients (2% to 5%) suffers from severe and refractory cancer pain. For these individuals, spinal analgesics (intrathecal or epidural) provide significant hope for pain relief over months or years of treatment to help improve quality of life. Spinal analgesics have been suggested as the fourth step in the World Health Organization guidelines in the management of cancer pain, and thus the pain physician should be familiar with principles of use. Most patients achieve pain relief using spinal analgesics, with a minimum of complications that are easily managed at home. A variety of opioids, local anesthetics, clonidine, ketamine, and other analgesics are available for the spinal route of administration and should be titrated to clinical effect or intolerable side effect. This article discusses the appropriate selection of patients for spinal analgesics, reviews current recommended infusion systems and current spinal analgesics, discusses possible complications, and includes practical suggestions for patient management.