Adverse Effects of Transdermal Opiates Treating Moderate-Severe Cancer Pain in Comparison to Long-Acting Morphine: A Meta-Analysis and Systematic Review of the Literature

Developing a machine learning-based predictive model for the analgesic effectiveness of transdermal fentanyl in cancer patients: an interpretable approach

BACKGROUND

Cancer-related pain is a common and distressing symptom in patients with malignant tumors, significantly affecting quality of life. Transdermal fentanyl is a convenient opioid option for patients with intestinal obstruction or difficulty swallowing; however, some patients do not experience adequate pain relief. Predicting transdermal fentanyl analgesic effectiveness is crucial to optimize pain management.

AIM

This study aimed to develop a predictive model for transdermal fentanyl effectiveness in cancer patients.

METHOD

Clinical data from adult cancer pain patients at Chongqing University Cancer Hospital were analyzed (January 2020-December 2022). Logistic regression and feature selection were applied, followed by developing nine predictive models using Logistic Regression, Random Forest (RF), and Extreme Gradient Boosting. The receiver operating characteristic (ROC) curves, the Youden index, and the Brier score were used to evaluate the performance of the model. Cross-validation and SHapley Additive exPlanations (SHAP) analysis were used for validation and feature interpretation.

RESULTS

Among 151 patients, 27.2% reported ineffectiveness of transdermal fentanyl. Logistic regression identified key factors of NRS, transdermal fentanyl dosage, BMI, and ALT. Among the nine models, RF Model 8 exhibited the best performance, achieving a ROC-AUC of 0.984 (95% CI: [0.968, 0.999]). This performance was further validated by the confusion matrix metrics and visualization results. The SHAP analysis highlighted BMI, lower doses, NRS, and ALT as predictors of transdermal fentanyl ineffectiveness.

CONCLUSION

The Random Forest model offers a valuable tool for predicting the effectiveness of transdermal fentanyl in cancer pain patients, supporting the refined assessment and management of pain.

Buprenorphine: an old dog with new tricks

PURPOSE OF REVIEW

The survival rate of patients with a cancer or palliative care diagnosis has improved over the years although pain remains a debilitating symptom that many patients still require treatment with opioids. Compared to full mu-opioid receptor agonists such as morphine and oxycodone, buprenorphine continues to remain a second- or third-line choice in this group of patients.We have reviewed the pharmacology and clinical utility of buprenorphine to stimulate debate around the first-line use of buprenorphine in the management of pain in cancer patients.

RECENT FINDINGS

Buprenorphine has a pharmacological profile that is unique and unlike any other opioid. It is associated with many immediate and long-term benefits, with lower risks of adverse effects that make it an ideal first-line choice in the management of cancer pain.

SUMMARY

Buprenorphine appears to be a promising choice of opioid for cancer patients. Studies have found that buprenorphine is a safe and effective choice for many patients, making it a suitable first-line option for the management of cancer pain.

Successful Initiation of Buprenorphine for Chronic Non-Cancer Pain in an Opioid-Experienced Patient: A Case Report

Buprenorphine can be an effective and safe option for patients with chronic pain. We describe a case in which a patient on long-term full opioid agonists for chronic non-cancer pain was safely transitioned from methadone to buprenorphine in the outpatient setting using a low dose buprenorphine initiation protocol. One month after the opioid rotation, the patient reported adequate analgesic effect from the buprenorphine regimen. Further studies are warranted to better guide prescribing of buprenorphine for chronic nonmalignant pain.

Efficacy of prophylactic laxatives against opioid-induced constipation: retrospective propensity score matching analysis

PURPOSE

Opioid-induced constipation (OIC) is problematic for patients with cancer receiving opioid therapy. Some guidelines recommend initiating regular laxatives at the same time as opioid analgesics. However, the effectiveness of prophylactic laxatives on OIC has not been widely demonstrated. We therefore examined the incidence of OIC among patients with and without prophylactic laxatives within one week after initiating strong opioid analgesics and the factors associated with the incidence of OIC.

METHODS

Eligible patients were adults with cancer for whom strong opioid analgesics were initiated after admission and who remained hospitalized for over a week. Propensity score matching analysis was used to compare outcomes after adjusting for patient background.

RESULTS

In total, 928 patients were enrolled, from which 536 were selected after propensity score matching analysis. The incidence of OIC in patients with prophylactic laxatives was not significantly different from that without prophylactic laxatives (48.1% vs 48.9%, odds ratio (OR) = 0.97, 95% confidence interval (CI): 0.69-1.36). In multivariable logistic analysis, age ≥ 65 years (OR = 1.53, 95% CI: 1.07-2.19) and Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 3 (OR = 1.69, 95% CI: 1.04-2.77) were associated with a higher incidence of OIC.

CONCLUSION

Prophylactic laxatives did not affect the incidence of OIC in our study. Our results suggest that prophylactic laxatives are not necessarily required when initiating opioid therapy. In addition, we found that age ≥ 65 years and ECOG PS ≥ 3 were associated in our study with a higher incidence of OIC.

Aloe Vera-Containing Matrix in Transdermal Fentanyl Therapy Improves Adhesion, Skin Tolerance and Quality of Life: Results of a German Multicenter Study with a New Fentanyl Patch

BACKGROUND

Chronic pain represents a significant and costly healthcare problem especially in the older patient. Transdermal opioid therapy is easy to apply and ensures constant supply of active ingredients. However, skin irritation, poor adhesion and systemic side effects complicate transdermal pain therapy.

METHODS

In the Relief study, comprising 54 centers, all in Germany, 252 patients were recruited and data about the general care situation as well as the characteristics, effects and side effects of the Aloe vera fentanyl patch were collected. 92 patients had a prior treatment with fentanyl patch without Aloe vera, allowing a comparative analysis.

RESULTS

Compared to patches without Aloe vera, the new fentanyl patch showed better adhesion. Systemic and local tolerance and pain reduction were also significantly better. Patients also reported improvements in side effects and central parameters of quality of life. The data regarding the care situation in Germany showed remarkably low use of coanalgetics and laxatives in pain patients.

DISCUSSION

Aloe vera in transdermal pain treatment improves adhesion and local tolerance of the patch. Pain control and quality of life were also improved. Regional care data concerning cotreatment in pain therapy from this study indicate a lack of penetration of existing guidelines in general practitioners' pain therapy.

Management of Opioid-induced Constipation in Older Adults

Opioid-induced constipation (OIC) is a common condition in older adults who may not be responsive to traditional laxative therapy. OIC is defined as new or worsening constipation symptoms that occur with initiation of or altering the dose of opioid analgesia. For adult patients with OIC and noncancer pain, we recommend considering nonpharmacologic interventions (eg, dietary measures, increased physical activity, and biofeedback training) and over-the-counter laxatives, followed by prescription opioid receptor antagonists (methylnaltrexone, naloxegol, and naldemedine) if traditional over-the-counter laxatives fail. Other options may include lubiprostone, linaclotide, plecanatide, and prucalopride; however, these are not indicated for OIC specifically or studied in older adults. Because of the complex nature of absorption, distribution, metabolism, and excretion in the aging population, all agents used to treat OIC must be evaluated individually and reevaluated as patients continue to age. This review will serve as a guide to managing OIC in older adults.

Comparative evaluation of analgesic efficacy of buprenorphine transdermal patch and fentanyl patch in management of postoperative pain after arthroscopic lower limb surgery: A randomized controlled trial

Background and Aims

Transdermal opioids are newer modality in use for the control of postoperative pain, because of its noninvasiveness, longer duration of action, sustained blood levels, and with minimal side effects. The study was aimed to evaluate the efficacy of analgesia of buprenorphine patch 10, 20 μg·h^-1 and fentanyl patch 25 μg·h^-1 for relief of pain in the postoperative period in patients undergoing arthroscopic lower limb surgeries.

Materials and Methods

It was a randomized, double-blinded, prospective study in which adult patients undergoing lower limb arthroscopic surgery were randomly segregated into three groups. In Group 1 (fentanyl patch 25 μg·h^-1), Group 2 (buprenorphine patch 10 μg·h^-1), and Group 3 (buprenorphine patch 20 μg·h^-1), transdermal patches were applied 12 h prior to surgery. Mean NRS score, total rescue analgesic requirement, drug-related adverse effects, and hemodynamic status were evaluated till 72 h in the postoperative period.

Results

Out of 175 screened patients, 150 patients were finally analyzed. Baseline characteristics were the same among all the three groups. Median NRS score was lowest in Group 3 [P value < 0.05 at 2, 4, 8, 12, and 24 h after surgery (Kruskal Wallis test). The total consumption of postoperative rescue analgesic diclofenac was the lowest in Group 3 as compared to other groups without any significant increase in adverse events.

Conclusions

In arthroscopic lower limb surgery, buprenorphine patch (20 μg·h^-1) applied 12 h prior to surgery is an effective postoperative analgesic and it is not associated with any significant adverse effects.

Opioid-induced constipation in patients with cancer: a "real-world," multicentre, observational study of diagnostic criteria and clinical features

The aim of this study was to investigate opioid-induced constipation (OIC) in a large cohort of "real-world" patients with cancer; the objectives were to determine the prevalence of OIC, the utility of a simple screening question, the accuracy of the Rome IV diagnostic criteria, the clinical features of OIC (physical and psychological), and the impact of OIC (quality of life). One thousand patients with cancer were enrolled in the study, which involved completion of the Rome IV diagnostic criteria for OIC, the Bowel Function Index, the Patient Assessment of Constipation Quality of Life questionnaire, and the Memorial Symptom Assessment Scale-Short Form. Participants also underwent a thorough clinical assessment by an experienced clinician (ie, "gold-standard" assessment of OIC). Fifty-nine percent of patients were clinically assessed as having OIC, 2.5% as having another cause of constipation, and 19% as not having constipation but were taking regular laxatives. The simple screening question produced a number of false-negative results (19% of patients), whereas the Rome IV diagnostic criteria had an accuracy of 81.9%. Patients with OIC had more symptoms overall, higher Memorial Symptom Assessment Scale-Short Form subscale scores (and total score), and higher Patient Assessment of Constipation Quality of Life questionnaire subscale scores (and the overall score). Opioid-induced constipation was not associated with demographic factors, cancer diagnosis, performance status, or opioid equivalent dosage: OIC was associated with opioid analgesic, with patients receiving tramadol and transdermal buprenorphine having less constipation. The study confirms that OIC is common among patients with cancer pain and is associated with a spectrum of physical symptoms, a range of psychological symptoms, and an overall deterioration in the quality of life.

Transdermal buprenorphine patch versus oral celecoxib for pain management after total knee arthroplasty: An open- label, randomized controlled trial

BACKGROUND

This study was performed to evaluate the analgesic efficacy and safety of transdermal buprenorphine (TDB) patched for post-operative pain control after total knee arthroplasty (TKA). The hypothesis was that patients receiving the TDB patch would have less pain in comparison to those treated with the oral COX-2 inhibitor celecoxib without increasing side effects.

PATIENTS AND METHODS

A total of 160 patients scheduled for primary TKA were randomly assigned to two groups: patients provided the TDB patch (10μg/h) (TDB group) and those provided oral celecoxib (CX group). The outcomes were pain scores measured using the visual analogue scale (VAS) during rest and activity, as well as morphine requirement, operated knee functional recovery and adverse events post-operatively.

RESULTS

The total morphine given during the first 72h post-operatively was significantly lower in the TDB group than CX group. The VAS scores were significantly lower in the TDB group than CX group during rest at 2, 4, 6, 12, 24 and 48h post-operatively, and during activity at 12, 24 and 48h and 3 days post-operatively. The mean range of motion on post-operative days (PD) 1, 2 and 3 were significantly greater in the TDB group. In addition, the Lysholm score was significantly higher in the TDB group on PD 3. There were no remarkable adverse events in either group.

DISCUSSION

Use of the TDB patch provides effective pain relief and reduces the requirement for rescue morphine without increasing side effects in comparison with oral celecoxib during the early post-operative stage following TKA.

LEVEL OF EVIDENCE

II.

Management of Osteoarthritis During the COVID-19 Pandemic

The pandemic spread of the new coronavirus disease 2019 (COVID‐19) infection in China first, and all over the world at present, has become a global health emergency due to the rapidly increasing number of affected patients. Currently, a clear relationship between COVID‐19 infection incidence and/or complications due to chronic or occasional treatments for other pathologies is still not clear, albeit the COVID‐19 pandemic may condition the treatment strategy of complex disorders, such as osteoarthritis (OA). Importantly, OA is the most common age‐related joint disease, affecting more than 80% of people older than the age of 55, an age burden also shared with the highest severity in COVID‐19 patients. OA patients often show a large array of concomitant pathologies, such as diabetes, inflammation, and cardiovascular diseases that are again shared with COVID‐19 patients and may therefore increase complications. Moreover, different OA treatments, such as NSAIDs, paracetamol, corticosteroids, opioids, or other molecules have a wide array of iatrogenic effects, potentially increasing COVID‐19 secondary infection incidence or complications. In this review we critically analyze the evidence on either negative or positive effects of drugs commonly used to manage OA in this particular scenario. This would provide orthopedic surgeons in particular, and physicians, pharmacologists, and clinicians in general, a comprehensive description about the safety of the current pharmacological approaches and a decision‐making tool to treat their OA patients as the coronavirus pandemic continues.

Indian Society for Study of Pain, Cancer Pain Special Interest Group Guidelines on Pharmacological Management of Cancer Pain (Part II)

The Indian Society for Study of Pain (ISSP), Cancer Pain Special Interest Group (SIG) guidelines on pharmacological management of cancer pain in adults provide a structured, stepwise approach, which will help to improve the management of cancer pain and to provide the patients with a minimally acceptable quality of life. The guidelines have been developed based on the available literature and evidence, to suit the needs, patient population, and situations in India. A questionnaire, based on the key elements of each sub draft addressing certain inconclusive areas where evidence was lacking, was made available on the ISSP website and circulated by e-mail to all the ISSP and Indian Association of Palliative Care members. We recommend that analgesics for cancer pain management should follow the World Health Organization 3-step analgesic ladder appropriate for the severity of pain. The use of paracetamol and nonsteroidal anti-inflammatory drugs alone or in combination with opioids for mild-to-moderate pain should be used. For mild-to-moderate pain, weak opioids such as tramadol, tapentadol, and codeine can be given in combination with nonopioid analgesics. We recommend morphine as the opioid of the first choice for moderate-to-severe cancer pain. Sustained-release formulations can be started 12 hourly, once the effective 24 h dose with immediate-release morphine is established. Opioid switch or rotation should be considered if there is inadequate analgesia or intolerable side effects. For opioid-induced respiratory depression, μ receptor antagonists (e.g. naloxone) must be used promptly. Antidepressants and/or anticonvulsants should be used to treat neuropathic cancer pain, and the dose should be titrated according to the clinical response and side effects. External beam radiotherapy should be offered to all patients with painful metastatic bone pain. There is evidence on use of ketamine in cancer neuropathic pain, but with no beneficial effect, thus, it is not recommended.

A Scoping Review of Transdermal Buprenorphine Use for Non-surgical Pain in the Pediatric Population

 A preliminary evaluation to review the scope and quality of evidence surrounding transdermal buprenorphine use in the pediatric setting for non-surgical pain was conducted. Our review revealed limited data available on the use of transdermal buprenorphine in pediatric patients. Most studies surrounding this subject involve accidental ingestion of buprenorphine and its use in the treatment of neonatal abstinence syndrome. While indicated for use only in adult populations, small studies have shown encouraging results in reducing pain in children with few, if any, adverse effects. This is reassuring from a clinical perspective, as we hope to highlight the available evidence and invite researchers to expand future studies. Through this review, we have identified significant gaps in the literature surrounding the safety and use of buprenorphine in the pediatric population. To our knowledge, there are no major studies investigating this subject, and it is our hope that future studies will explore the use of transdermal buprenorphine as an alternative pain management technique in pediatrics. The intent of our scoping review is to highlight the lack of research in this area; therefore, future studies may be conducted to support its use in North America.

Long-acting Opioid Use and the Risk of Serious Infections: A Retrospective Cohort Study

BACKGROUND

Although evidence from animal and human studies indicates opioid analgesics increase susceptibility to infections, it is unclear whether the risk varies by specific opioid. We compared the risk of serious infection among patients initiating long-acting opioid analgesics with and without previously reported immunosuppressive properties.

METHODS

We conducted a retrospective cohort study of Tennessee Medicaid enrollees age ≥18 years initiating long-acting opioids (1995-2015). Hospitalizations for serious infection were identified using validated coding algorithms. We used multivariable Poisson regression models to calculate adjusted incidence rate ratios (aIRR) and 95% confidence intervals (CI) to compare the infection risk among patients using long-acting opioids with known immunosuppressive properties (morphine, fentanyl, methadone) to the infection risk among patients using long-acting opioids without known immunosuppressive properties (oxycodone, oxymorphone, tramadol) accounting for demographics, opioid dose, comorbidities and pain conditions, medication use, frailty indicators, and healthcare encounter history using exposure propensity scores. We further compared users of individual long-acting opioids to long-acting morphine users (considered the prototypical immunosuppressive opioid).

RESULTS

Among the 61 240 patients initiating opioids with immunosuppressive properties and 22 811 patients initiating opioids without immunosuppressive properties, we identified 1906 serious infections. Nonimmunosuppressive opioid users had a lower rate of infections than immunosuppressive opioid users (aIRR:0.78 [CI: 0.66-0.91]). Among individual opioids, oxycodone users had a lower rate of infection than morphine users (aIRR:0.73 [CI: 0.60-0.89]). There were no significant differences in the infection risk between other opioids and morphine.

CONCLUSION

The risk of serious infections among long-acting opioid users varies by opioid type. Providers should carefully consider the risk of serious infections when making pain management decisions.

Opioid-induced constipation: a narrative review of therapeutic options in clinical management

Pain therapy often entails gastrointestinal adverse events. While opioids are effective drugs for pain relief, the incidence of opioid-induced constipation (OIC) varies greatly from 15% to as high as 81%. This can lead to a significant impairment in quality of life, often resulting in discontinuation of opioid therapy. In this regard, a good doctor-patient relationship is especially pivotal when initiating opioid therapy. In addition to a detailed history of bowel habits, patient education regarding the possible gastrointestinal side effects of the drugs is crucial. In addition, the bowel function must be regularly evaluated for the entire duration of treatment with opioids. Furthermore, if the patient has preexisting constipation that is well under control, continuation of that treatment is important. In the absence of such history, general recommendations should include sufficient fluid intake, physical activity, and regular intake of dietary fiber. In patients of OIC with ongoing opioid therapy, the necessity of opioid use should be critically reevaluated in terms of an with acceptable quality of life, particularly in cases of non-cancer pain. If opioids must be continued, lowering the dose may help, as well as changing the type of opioid. If these measures do not suffice, the next step for persistent OIC is the administration of laxatives. If these are ineffective as well, treatment with peripherally active μ-opioid receptor antagonists should be considered. Enemas and irrigation are emergency measures, often used as a last resort.

Consumption trends and prescription patterns of opioids from 2011 to 2016: a survey in a Chinese city

OBJECTIVE

Opioid consumption in China has been very less and has varied widely since 1995. The representatively high level of consumption in Mainland China has never been reported. Our aim was to describe the consumption trends and prescription patterns of opioids in Nanjing, a highly developed city of Mainland China, and compare the results with selected worldwide regions.

METHODS

Application data of opioids in 2011-2016 were extracted from the Jiangsu Medicine Information Institute. Six opioids were included. Consumption was expressed in terms of defined daily doses (DDDs), morphine equivalents (MEs) and expenditure. The correlation between consumption of opioids and gross domestic product (GDP), Human Development Index (HDI) and cancer incidence was analysed by Pearson's correlation test.

RESULTS

DDDs, expenditure and MEs of opioids were, respectively, 256.04, $599.24 and 13.07 g in 2011, and increased to 361.27, $1041.79 and 18.09 g in 2016. DDDs in Nanjing were 2.80-fold that in Mainland China, 1.42-fold that in East and South-East Asia, but only equivalent to 8.89% of the worldwide average level. From 2011 to 2016, the consumption had a linear correlation with GDP, HDI and cancer incidence (p<0.05). However, DDDs varied greatly in countries with similar GDP or HDI. Within 45 Asian countries, the GDP only contributed to 10.47% of change in DDDs, while the HDI contributed to 20.32%. Consumption of non-intravenous opioids or strong opioids always comprised majority of the total consumption. The opioids prescribed predominantly were fentanyl, oxycodone and morphine. Fentanyl and oxycodone account for most of the increase in consumption.

CONCLUSION

Opioid consumption has increased >40% from 2011 to 2016, with consumption of fentanyl and oxycodone accounting for most of that increase. The consumption in Nanjing was higher than the average Chinese level, but lower than the global average. An increase in pain control services might be needed, but this need should be highly regulated.

Health benefits of an adverse events reporting system for chronic pain patients using long-term opioids

BACKGROUND

Safety data from long-term opioid therapy in the real world has been poorly studied in chronic non-cancer pain (CNCP). The aim was to design a pharmacovigilance data recording system and assess whether participation in this recording system improves pain management, enhancing patient's health status.

METHODS

A pharmacovigilance data recording system was conducted during 24 months. Data were self-reported by patients (pain, adverse events [AEs] and healthcare resources use) and physicians (morphine equivalent daily dose [MEDD] prescribed and suspected adverse drug reaction [ADRs]). Outcomes from patients with (case) or without (controls) suspected ADRs and cases follow-up were also compared with Spanish Pharmacovigilance System data.

RESULTS

A total of 753 patients were recruited in 897 visits. Fentanyl and tramadol were the most prescribed opioids, 89% with concomitant drugs, pregabalin being the one with the most potential drug interactions. Cases presented significantly higher pain intensity (VAS 67 ± 26 vs 59 ± 30 mm, P < 0.05), number of AEs (8 ± 6 vs 5 ± 3 AEs/patient, P < 0.01), polypharmacy related to pain (65% vs 34%, P < 0.01) and MEDD (139 ± 130 vs 106 ± 99 mg/d, P < 0.01) than controls. Furthermore, cases presented significant higher changes in pharmacological pain therapy due to pain, unplanned emergency visits and hospital admission than controls. Physicians notified 168 suspected ADRs mostly related to neurological or psychiatric events and 8% of them were previously unknown.

CONCLUSIONS

This data recording system provided important information to achieve a better control of CNCP pharmacological pain therapy, improving patient's health status and reducing costs to the Health System.

Pathophysiology and management of opioid-induced constipation: European expert consensus statement

BACKGROUND

Opioid-induced bowel dysfunction is a complication of opioid therapy, in which constipation is the most common and problematic symptom. However, it is frequently under-recognised and thus effective management is often not instituted despite a number of treatment options.

OBJECTIVE

The central objective of this study is to provide a summary of the pathophysiology and clinical evaluation of opioid-induced constipation and to provide a pragmatic management algorithm for day-to-day clinical practice.

METHODS

This summary and the treatment algorithm is based on the opinion of a European expert panel evaluating current evidence in the literature.

RESULTS

The pathophysiology of opioid-induced constipation is multi-faceted. The key aspect of managing opioid-induced constipation is early recognition. Specific management includes increasing fluid intake, exercise and standard laxatives as well as addressing exacerbating factors. The Bowel Function Index is a useful way of objectively evaluating severity of opioid-induced constipation and monitoring response. Second-line treatments can be considered in those with recalcitrant symptoms, which include gut-restricted or peripherally acting mu-opioid receptor antagonists. However, a combination of interventions may be needed.

CONCLUSION

Opioid-induced constipation is a common, yet under-recognised and undertreated, complication of opioid therapy. We provide a pragmatic step-wise approach to opioid-induced constipation, which should simplify management for clinicians.

Effects of smoking and body mass index on the exposure of fentanyl in patients with cancer

The transdermal fentanyl patch is widely used to treat cancer-related pain despite its wide inter- and intrapatient variability in pharmacokinetics. The aim of this study was to investigate whether smoking and body size (i.e. body mass index) influence fentanyl exposure in patients with cancer. These are factors that typically change during treatment and disease trajectories. We performed an explorative cohort study in patients with cancer using transdermal fentanyl patches (Durogesic®), by taking a blood sample for pharmacokinetic analysis one day after applying a patch in patients with a stable fentanyl dose. A total of 88 patients were evaluable. Although no statistically significant difference was found, the plasma concentrations of non-smokers was 28% (95% CI [-14%; +89-%]) higher than those of smokers normalizing for a dose of 25μg/min. Patients with a low BMI (< 20 kg/m2) had almost similar (10% (95% CI [-39%; +97%]) higher) plasma concentrations compared to patients with a high BMI (> 25 kg/m2). A wider variation in fentanyl plasma concentrations was found in this study than anticipated. Due to this variation, studies in larger patient cohorts are needed to further investigate the effect of smoking on plasma concentration of fentanyl and thereby clarify the clinical significance of our findings.

Consumption trend and prescription pattern of opioid analgesics in China from 2006 to 2015

Objectives

To investigate the consumption trend and prescription pattern of opioids in China from 2006 to 2015, and compare the results with those of selected countries and regions, and identify the pain relief level of China.

Methods

Nine different opioid drugs were included in our survey, based on the whole population of China. Consumption of each type of opioid was calculated in grams in reports of the Chinese Food and Drug Administration and the International Narcotics Control Board. Then it was converted to the terms of defined daily doses and morphine equivalents. The correlation between consumption of opioids and gross domestic product, human development index and cancer incidence was analysed by Pearson's correlation test.

Results

Defined daily doses increased by 7.89% per year since 2006, and reached 91.05 in 2015. Morphine equivalents increased by 10.57% per year since 2006, and reached 7.24 g in 2015. The average defined daily doses and morphine equivalents were 85.44 and 5.70 g respectively in 2006-2015. Annual defined daily doses of China were lower than the global average. Consumption was related to gross domestic product, but not human development index and cancer incidence. Furthermore, defined daily doses varied greatly in countries with similar gross domestic product or the human development index. Strong opioids or non-intravenous opioids always constituted the majority of opioids, and sustained an increasing tendency in consumption. The predominantly prescribed opioids were fentanyl and morphine. Consumption of oxycodone had a tendency to increase, whereas pethidine tended to decrease.

Conclusion

Consumption of opioids has shown an increasing tendency and in the meantime the prescription pattern has changed, indicating the progress of pain relief in China, though it remained far lower than the average global level.

Progress in understanding mechanisms of opioid-induced gastrointestinal adverse effects and respiratory depression

Opioids evoke analgesia through activation of opioid receptors (predominantly the μ opioid receptor) in the central nervous system. Opioid receptors are abundant in multiple regions of the central nervous system and the peripheral nervous system including enteric neurons. Opioid-related adverse effects such as constipation, nausea, and vomiting pose challenges for compliance and continuation of the therapy for chronic pain management. In the post-operative setting opioid-induced depression of respiration can be fatal. These critical limitations warrant a better understanding of their underpinning cellular and molecular mechanisms to inform the design of novel opioid analgesic molecules that are devoid of these unwanted side-effects. Research efforts on opioid receptor signalling in the past decade suggest that differential signalling pathways and downstream molecules preferentially mediate distinct pharmacological effects. Additionally, interaction among opioid receptors and, between opioid receptor and non-opioid receptors to form signalling complexes shows that opioid-induced receptor signalling is potentially more complicated than previously thought. This complexity provides an opportunity to identify and probe relationships between selective signalling pathway specificity and in vivo production of opioid-related adverse effects. In this review, we focus on current knowledge of the mechanisms thought to transduce opioid-induced gastrointestinal adverse effects (constipation, nausea, vomiting) and respiratory depression.

Bioanalytical methods for the quantification of hydromorphone, fentanyl, norfentanyl, morphine, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma

The aim of this study was to develop an assay for the quantification of hydromorphone, morphine, fentanyl and the metabolites norfentanyl, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma to support pharmacokinetic studies investigating the large interpatient variability in response to opioid treatment. For the quantitation of hydromorphone, morphine, fentanyl and its metabolite norfentanyl aliquots of 200μL human potassium EDTA plasma were deproteinized with deuterated internal standards in a mixture of acetonitrile and acetone, followed by a liquid-liquid extraction with 4% ammonium hydroxide and ethyl acetate. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were extracted by a solid phase extraction using 10mM ammonium carbonate pH 8.8 and a deuterated internal standards solution. Morphine, hydromorphone, fentanyl and norfentanyl were separated on an Aquity UPLC^® BEH C18 column 1.7μm, 100mm×2.1mm at 50°C. Separation, was achieved on a gradient of methanol with an overall run time of 6min. The compounds were quantified by triple-quadrupole mass spectrometry in the positive ion electrospray ionization mode. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were separated on a VisionHT C18-P; 3μm 2.1×50mm, column at 40°C on a gradient of acetonitrile, with an overall run time of 10min. Both methods were precise and accurate, with within-run and between-run precisions within acceptable limits and accuracy ranging from 84.0 to 105.5%. The methods were successfully applied to support clinical pharmacological studies in patients treated with opioids for the treatment of moderate to severe cancer-related pain.

Efficacy of transdermal buprenorphine patch on post-operative pain relief after elective spinal instrumentation surgery

BACKGROUND AND AIMS

Transdermal buprenorphine patch (TDB) is increasingly used for chronic pain management because of non-invasive dosing, longer duration of action and minimal side effects. However its role in acute post-operative pain management for spinal instrumentation surgery is not well established. The aim of this study was to evaluate the analgesic efficacy of buprenorphine patch for postoperative pain relief in patients undergoing spinal instrumentation surgery.

METHODS

In this randomised, placebo-controlled, double-blinded, prospective study, 70 adult patients undergoing elective spinal instrumentation surgery were randomly allocated into two groups-TDB Group (buprenorphinepatch) and TDP Group (placebo patch). Time to first rescue analgesic requirement was the primary outcome. All patients also were monitored for total rescue analgesic requirement, drug-related adverse effect and haemodynamic status till 48 h after surgery. Statistical analysis was carried out using student independent t-test if normally distributed or with Mann-Whitney U-test if otherwise.

RESULTS

Time to first post-operative rescue analgesic (tramadol) requirement was much delayed in TDB Group than TDP Group (708.0 ± 6.98 min vs 54 ± 0.68 min, P < 0.001) and the total tramadol requirement was higher in TDB Group (490.60 ± 63.09 averagevs. 162.93 ± 63.91 mg, P < 0.001). Intra-and post-operative haemodynamic status was also stable in TDB Group without any adverse event.

CONCLUSION

A TDB patch (10 μg/hour) applied 24 hours before surgery can be used as a postoperative analgesic for lumber fixation surgery without any drug-related adverse effect.

Adductor canal block with local infiltrative analgesia compared with local infiltrate analgesia for pain control after total knee arthroplasty: A meta-analysis of randomized controlled trials

BACKGROUND

This meta-analysis aimed to evaluate the efficiency and safety of the combined adductor canal block with peri-articular infiltration versus periarticular infiltration alone for pain control after total knee arthroplasty (TKA).

METHODS

PubMed, Medline, Embase, Web of Science, and the Cochrane Library were searched to identify articles comparing the combined adductor canal block with peri-articular infiltration and periarticular infiltration alone for pain control after TKA. Main outcomes were numeric rating scale (NRS) at postoperative day (POD) 0-2 and opioid consumption. Meta-analysis was performed using Stata 11.0 software.

RESULTS

Four randomized controlled trial (RCTs) including 297 patients met the inclusion criteria. The present meta-analysis indicated that there were significant differences between the groups regarding NRS score at POD 0 (weighted mean difference [WMD] = -0.849, 95% confidence interval [CI]: -1.345 to -0.353, P = .001), POD 1 (WMD = -0.960, 95% CI: -1.474 to -0.446, P = .000), and POD 2 (WMD = -0.672, 95% CI: -1.163 to -0.181, P = .007) after TKA. Significant differences were found in terms of opioid consumption at POD 0 (WMD = -3.761, 95% CI: -6.192 to -1.329, P = .002), POD 1 (WMD = -4.795, 95% CI: -8.181 to -1.409, P = .006), and POD 2 (WMD = -2.867, 95% CI: -4.907 to -0.827, P = .006).

CONCLUSION

Combined adductor canal block with peri-articular infiltration could significantly reduce NRS scores and opioid consumption in comparison with periarticular infiltration alone following TKA. Additionally, there is a lower incidence of nausea and vomiting in the combined groups.

Transcutaneous electrical nerve stimulation for postoperative pain control after total knee arthroplasty: A meta-analysis of randomized controlled trials

BACKGROUND

This meta-analysis aimed to evaluate the efficiency and safety of transcutaneous electrical nerve stimulation (TENS) for pain control after total knee arthroplasty.

METHODS

A systematic search was performed in Medline (1966 to June 2017), PubMed (1966 to June 2017), Embase (1980 to June 2017), ScienceDirect (1985 to June 2017), and the Cochrane Library. Only randomized controlled trial (RCT) was included. The fixed/random effect model was used according to the heterogeneity tested by I statistic. Meta-analysis was performed using Stata 11.0 software.

RESULTS

Five RCTs including 472 patients met the inclusion criteria. The present meta-analysis indicated that there were significant differences between groups in terms of visual analogue scale score at 12 hours (average: 3.58 vs 4.34, SMD = -0.260, 95% CI: -0.442 to -0.078, P = .005), 24 hours (average: 3.18 vs 3.52, SMD = -0.244, 95% CI: -0.426 to -0.063, P = .008), and 48 hours (average: 2.70 vs 2.96, SMD = -0.214, 95% CI: -0.395 to -0.033, P = .021) after total knee arthroplasty. Significant differences were found regarding opioid consumption at 12 hours (average: 14.44 vs 18.54, SMD = -0.503, 95% CI: -0.687 to -0.319, P = .000), 24 hours (average: 16.10 vs 18.40, SMD = -0.262, 95% CI: -0.443 to -0.080, P = .005), and 48 hours (average: 12.92 vs 15.12, SMD = -0.183, 95% CI: -0.364 to -0.002, P = .048).

CONCLUSION

TENS could significantly reduce pain and opioid consumption after total knee arthroplasty. In addition, there were fewer adverse effects in the TENS groups. Higher quality RCTs are required for further research.

Methadone versus Fentanyl in Patients with Radiation-Induced Nociceptive Pain with Head and Neck Cancer: A Randomized Controlled Noninferiority Trial

BACKGROUND

Pain is still a burden for many patients with cancer. A recent trial showed the superiority of methadone over fentanyl in neuropathic pain, and we expect that this finding could influence the number of patients treated with methadone.

METHODS

We performed a randomized controlled noninferiority trial in patients with nociceptive pain. Eighty-two strong-opioid-naïve patients with head and neck cancer with substantial pain (pain numeric rating scale [NRS] score ≥ 4) due to radiation therapy were included. Forty-two patients were treated with methadone, and 40 with fentanyl. Patients were evaluated at 1, 3, and 5 weeks. The primary outcomes were reduction in average pain and clinical success (50% pain decrease). We set the predefined noninferiority margin at 1 on the NRS and 10% clinical success. Secondary outcomes were pain interference, global perceived effect (GPE), side effects, and opioid escalation index.

RESULTS

Noninferiority was shown for decrease in NRS for maximum and mean pain scores at 1 and 3 weeks. Noninferiority was shown for clinical success at 1 week only. The opioid escalation index was lower in the methadone group at 3 and 5 weeks as compared to fentanyl (1.44 vs. 1.99, P = 0.004; and 1.50 vs. 2.32, P = 0.013). The pain interference in the methadone group was significantly decreased at 3 weeks only. GPE and side effects were not different.

CONCLUSION

This is the first study to show noninferiority of methadone compared to fentanyl at 1 and 3 weeks in the treatment of radiation-induced nociceptive pain in patients with head and neck cancer.

Transdermal buprenorphine and fentanyl patches in cancer pain: a network systematic review

Treatment of cancer pain is generally based on the three-step World Health Organization (WHO) pain relief ladder, which utilizes a sequential approach with drugs of increasing potency. Goals of pain management include optimization of analgesia, optimization of activities of daily living, minimization of adverse effects, and avoidance of aberrant drug taking. In addition, it is recommended that analgesic regimens are individualized and simplified to help ensure patient compliance and should provide the least invasive, easiest, and safest route of opioid administration to ensure adequate analgesia. Buprenorphine and fentanyl are two opioids available for the relief of moderate-to-severe cancer pain. Available clinical data regarding the transdermal (TD) formulations of these opioids and the extent to which they fulfill the recommendations mentioned earlier are systematically reviewed, with the aim of providing additional information for oncologists and pain specialists regarding their comparative use. Due to lack of studies directly comparing TD buprenorphine with TD fentanyl, data comparing these with other step-3 opioids are also evaluated in a network fashion.

Palliative care in ovarian carcinoma patients-a personalized approach of a team work: a review

Most ovarian cancer patients are diagnosed in an advanced stage; and after the initial treatment experience disease recurrence, which eventually becomes palliative. Many questions arise in this setting including how to address patients in the palliative setting, how to discuss end-of-life issues, and how to manage symptoms. In this review, we discuss the timing and setting of end-of-life discussion in the context of end-stage ovarian cancer. We review the approach to relieving disease burden by improving and decreasing symptoms. These symptoms include recurrent ascites, bowel obstruction, pain, pulmonary effusion, and deep vein thrombosis.

The Basic Pharmacology of Opioids Informs the Opioid Discourse about Misuse and Abuse: A Review

Morphine and other opioids are widely used to manage moderate to severe acute pain syndromes, such as pain associated with trauma or postoperative pain, and they have been used to manage chronic pain, even chronic nonmalignant pain. However, recent years have seen a renewed recognition of the potential for overuse, misuse, and abuse of opioids. Therefore, prescribing opioids is challenging for healthcare providers in that clinical effectiveness must be balanced against negative outcomes-with the possibility that neither are achieved perfectly. The current discourse about the dual 'epidemics' of under-treatment of legitimate pain and the over-prescription of opioids is clouded by inadequate or inaccurate understanding of opioid drugs and the endogenous pain pathways with which they interact. An understanding of the basic pharmacology of opioids helps inform the clinician and other stakeholders about these simultaneously under- and over-used agents.

Options for Treating Pain in Cancer Patients with Dysphagia

Patients with chronic pain often develop dysphagia during the course of an advanced disease such as cancer. Opioids are the cornerstone of the management of cancer pain and are commonly administered orally. However, the oral route does not suit patients with dysphagia, who require alternative methods to administer analgesic drugs. Opioids given by parenteral or transdermal routes provide adequate pain control, being at least as efficacious as the oral route, but knowledge and experience in conversion ratios are mandatory when using these routes of administration. For breakthrough pain, transmucosal fentanyl preparations should be the preferred option and these can be given as needed due to the route of absorption. In addition, a new class of opioid formulations has been developed for use in dysphagic patients that are administered via nasogastric or enteral tubes while maintaining their sustained-release properties.

Opioidergic effects on enteric and sensory nerves in the lower GI tract: basic mechanisms and clinical implications

Opioids are one of the most prescribed drug classes for treating acute pain. However, chronic use is often associated with tolerance as well as debilitating side effects, including nausea and dependence, which are mediated by the central nervous system, as well as constipation emerging from effects on the enteric nervous system. These gastrointestinal (GI) side effects limit the usefulness of opioids in treating pain in many patients. Understanding the mechanism(s) of action of opioids on the nervous system that shows clinical benefit as well as those that have unwanted effects is critical for the improvement of opioid drugs. The opioidergic system comprises three classical receptors (μ, δ, κ) and a nonclassical receptor (nociceptin), and each of these receptors is expressed to varying extents by the enteric and intestinal extrinsic sensory afferent nerves. The purpose of this review is to discuss the role that the opioidergic system has on enteric and extrinsic afferent nerves in the lower GI tract in health and diseases of the lower GI tract, particularly inflammatory bowel disease and irritable bowel syndrome, and the implications of opioid treatment on clinical outcomes. Consideration is also given to emerging developments in our understanding of the immune system as a novel source of endogenous opioids and the mechanisms underlying opioid tolerance, including the potential influence of opioid receptor splice variants and heteromeric complexes.

New Options in Constipation Management

Constipation is common in the general population and for those on opioids and/or who are suffering from advanced cancer. Self-management consists of dietary changes, exercise, and laxatives. However, responses to self-management efforts are often inadequate to relieve the subjective and objective experience of constipation. Multiple new anti-constipating medications have recently been tested in randomized trials and the following are available commercially: probiotics, prucalopride, lubiprostone, linaclotide, elobixibat, antidepressants, methylnaltrexone, alvimopan, and naloxegol. This review will discuss the evidence-based benefits of these medications and outline an approach to managing constipation.

Safety concerns with long-term opioid use

INTRODUCTION

The benefits of opioid therapy must be balanced by any adverse effects. In recent years, prescription opioids have been increasingly prescribed, but have also been associated with increased abuse, overdose and death.

AREAS COVERED

This review will categorize the common risks of opioid administration. Recognized adverse effects of opioid therapy include constipation, tolerance, endocrinopathies, sleep disorders, cognitive effects, respiratory depression, overdose and addiction. Studies have shown that there is increased risk of overdose and death with higher daily opioid doses, particularly above a morphine equivalent oral daily dose of 100 milligrams. Extended-release/long acting (ER/LA) opioid formulations may be beneficial for the compliant patient, yet may expose a higher risk for abuse if used inappropriately since each tablet carries a larger dose of medication.

EXPERT OPINION

Prospective, controlled one-year trials are needed to establish the efficacy and safety profile of chronic opioid therapy. In addition to the well known side effects of chronic opioid therapy, the influence and serious effect of opioids on sleep and central sleep apnea is only recently being investigated. The lowest possible daily opioid must be used to manage chronic pain, and all clinicians should be cautious in the use of daily morphine equivalent doses above 50-100 milligrams.

Treatment with subcutaneous and transdermal fentanyl: results from a population pharmacokinetic study in cancer patients

Purpose

Transdermal fentanyl is effective for the treatment of moderate to severe cancer-related pain but is unsuitable for fast titration. In this setting, continuous subcutaneous fentanyl may be used. As data on the pharmacokinetics of continuous subcutaneous fentanyl are lacking, we studied the pharmacokinetics of subcutaneous and transdermal fentanyl. Furthermore, we evaluated rotations from the subcutaneous to the transdermal route.

Methods

Fifty-two patients treated with subcutaneous and/or transdermal fentanyl for moderate to severe cancer-related pain participated. A population pharmacokinetic model was developed and evaluated using non-linear mixed-effects modelling. For rotations from subcutaneous to transdermal fentanyl, a 1:1 dose conversion ratio was used while the subcutaneous infusion was continued for 12 h (with a 50 % tapering after 6 h). A 6-h scheme with 50 % tapering after 3 h was simulated using the final model.

Results

A one-compartment model with first-order elimination and separate first-order absorption processes for each route adequately described the data. The estimated apparent clearance of fentanyl was 49.6 L/h; the absorption rate constant for subcutaneous and transdermal fentanyl was 0.0358 and 0.0135 h⁻¹, respectively. Moderate to large inter-individual and inter-occasion variability was found. Around rotation from subcutaneous to transdermal fentanyl, measured and simulated plasma fentanyl concentrations rose and increasing side effects were observed.

Conclusions

We describe the pharmacokinetics of subcutaneous and transdermal fentanyl in one patient cohort and report several findings that are relevant for clinical practice. Further research is warranted to study the optimal scheme for rotations from the subcutaneous to the transdermal route.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-015-2005-x) contains supplementary material, which is available to authorized users.

The effectiveness of buprenorphine for treating cancer pain: an abridged Cochrane review

OBJECTIVES

To assess the effectiveness and tolerability of buprenorphine for cancer pain in adults and children.

METHODS

We searched CENTRAL, MEDLINE, EMBASE, ISI Web of Science, ISI BIOSIS, ClinicalTrials.gov, metaRegister of Controlled Trials, WHO International Clinical Trials Registry Platform and the Proceedings of the Congress of the European Federation of International Association for the Study of Pain to early 2015.

RESULTS

We included 19 randomised controlled trials comparing buprenorphine with placebo, buprenorphine or another active drug for cancer pain. The trials included 1421 patients and examined 16 different intervention comparisons. Of the 11 studies that compared buprenorphine to another drug, 5, 3 and 3 studies, respectively, found that buprenorphine was superior, no different or inferior to the alternative treatment in side effects profile or patient preference/acceptability. Pain intensity ratings did not differ significantly between intramuscular buprenorphine and buprenorphine suppository, although intramuscular treatment was associated with more adverse events (1 study). One study found faster onset of pain relief after sublingual than subdermal buprenorphine, with similar analgesia duration and adverse event rates. 2 studies found transdermal buprenorphine superior to placebo, whereas a third study found no difference between placebo and different doses of transdermal buprenorphine. No clear dose-response relationship was found for transdermal buprenorphine. The quality of this evidence base was limited by under-reporting, small sample sizes and attrition.

CONCLUSIONS

Buprenorphine might be considered as a fourth-line option compared with the more standard therapies of morphine, oxycodone and fentanyl, and even then it would only be suitable for some patients.

Comparison between Transdermal Buprenorphine and Transdermal Fentanyl for Postoperative Pain Relief after Major Abdominal Surgeries

INTRODUCTION

Opioid is generally regarded as an important part of multimodal, perioperative analgesia, especially for moderate to severe pain. Amongst the various modes of delivery transdermal route has several potential benefits over oral and parentral administration. These include noninvasive dosing, better absorption and lack of first-pass metabolism. A transdermal drug delivery system provides steady and continuous drug delivery resulting in steady plasma concentration. Bolus dosing of systemic analgesic results in supra and sub therapeutic plasma resulting in toxic and sub analgesic plasma drug concentration. It also improves patient compliance.

MATERIALS AND METHODS

Sixty patients undergoing major abdominal surgery under GA were randomly divided in two groups (n=30). Group A received buprenorphine 10 mcg/h TDS and group B received 25 mcg/h fentanyl TDS, 6 hours prior to surgery. Patients were followed for three days for postoperative pain relief and adverse effects.

RESULTS

Baseline and demographic variables are comparable in both groups. The mean level of VAS was significantly lower in group B as compared to group A at Day 1, 2 and 3. The mean level of sedation score was significantly lower in Group B than Group A. Haemodynamic variables in both groups (SBP, DBP and HR), shows comparable values in both groups and no significant difference was observed. Five out of 30 (16.7%) patients in group A required single dose of rescue analgesic while 0 out of 30 patients (0.00%) in group B required rescue analgesic. This difference in rescue analgesic requirement in not quiet statistically significant (p-value 0.0522). Twenty percent patient in fentanyl group and 16.7% patients in buprenorphine group experienced some adverse effects. Nausea and vomiting were main side effects of the drugs. The incidence of nausea and vomiting were 6.7% and 10% in buprenorphine and fentanyl group respectively.

CONCLUSION

Fentanyl and buprenorphine TDS were effective and safe in controlling postoperative pain. Fentanyl is better than buprenorphine in this respect.

Management of opioid-induced constipation for people in palliative care

Constipation is common in the palliative population. Opioid medications, which are frequently prescribed to this cohort, represent a significant risk factor for this condition. Opioid-induced constipation may be of such severity that opioid doses are reduced or missed, and analgesia and quality of life are therefore reduced. However, underlying chronic constipation, local and systemic disease effects, and other medications may also precipitate constipation in this population. The assessment and treatment of constipation in a palliative individual should be undertaken in a fashion similar to that used in non-palliative patients. Initial management should include minimising exposure to predisposing factors and general measures such as encouraging hydration, fibre intake and mobility. Pharmacological treatment should commence with a stool softener and a stimulant laxative. Recently published literature demonstrates that newer laxatives, including lubiprostone (a chloride channel activator) and prucalopride (a 5-HT4 receptor agonist) can effectively treat opioid-induced constipation. For patients not responding to laxatives, opioid antagonists (non-specific or peripherally acting μ-opioid receptor antagonists) can be co-prescribed with laxatives. These agents have also proven efficacy in treating opioid-induced constipation. This review discusses the recent literature regarding the management of opioid-induced constipation and provides a rational approach to assessing and managing constipation in the palliative population.