Immediate rescue designs in pediatric analgesic trials: a systematic review and meta-analysis

Rescue designs in analgesic trials from 0 to 2 years of age: scoping review

Pediatric analgesic trials are challenging, especially in newborns and infants. Following an FDA-academic consensus meeting, we analyzed pragmatic rescue designs in postoperative trials of local anesthetics, acetaminophen, opioids, and NSAIDs involving children ages 0-2 years and assessed surgical volumes to provide trial design recommendations. Searches of PubMed, Embase, CINAHL, The Cochrane Library, and Web of Science were conducted. A scoping approach identified trends in analgesic trials with an emphasis on randomized controlled trials (RCTs) utilizing immediate rescue designs. Age-specific surgical volumes were estimated from French national databases. Of 3563 studies identified, 23 RCTs used study medication(s) of interest and immediate rescue paradigms in children ages 0-2 years. A total of 270 studies met at least one of these criteria. Add-on and head-to-head designs were common and often used sparing of non-opioid or opioid rescue medication as a primary outcome measure. According to French national data, inguinal and penile surgeries were most frequent in ages 1 month to 2 years; abdominal and thoracic surgeries comprise approximately 75% of newborn surgeries. Analgesic trials with rescue sparing paradigm are currently sparse among children ages 0-2 years. Future trials could consider age-specific surgical procedures and use of add-on or head-to-head designs. IMPACT: Clinical trials of analgesic medications have been challenging in pediatrics, especially in the group from newborns to 2 years of age. Following an FDA-academic workshop, we analyzed features of completed analgesic trials in this age group. Studies using immediate rescue in placebo control, add-on, and head-to-head trial designs are pragmatic approaches that can provide important information regarding clinical effectiveness, side effects, and safety. Using a French national dataset with a granular profile of inpatient, outpatient, and short-stay surgeries, we provide information to future investigators on relative frequencies of different operations in neonates and through the first 2 years of life.

Comparison of two techniques (intermittent intravenous bolus morphine vs. morphine infusion) for analgesic titration in patients who had advanced cancer with severe pain: a prospective randomised study

OBJECTIVE

To compare the analgesic efficacy of two techniques of morphine titration (intermittent intravenous bolus vs infusion) by calculating rescue dosage in a day at 1 week after analgesic titration.

METHODS

One hundred and forty cancer patients were randomised into two groups. In group 1, intravenous morphine 1.5 mg bolus given every 10 min until Numerical Rating Scale (NRS) pain score <4 is achieved. Total intravenous dose converted to oral dose (1:1) and administered every 4 hours. In group 2, intravenous bolus morphine 0.05 mg/kg body weight administered followed by 0.025 mg/kg/hour intravenous infusion. The NRS pain score was recorded every 10 min but infusion rate was titrated every 30 min if required. The infusion rate of morphine was doubled if the pain score was unchanged and increased to 50% when NRS was between 4 and baseline. If NRS<4, then infusion at same rate was continued. Once the NRS<4 for two consecutive hours, total intravenous dose for 24 hours was calculated and converted to oral morphine in a ratio of 1:3 and divided into six doses given over 24 hours. For rescue (pain score ≥4) analgesia, one-sixth of the total daily oral dose was prescribed. The primary outcome of this study was to note the number of rescue doses of oral morphine in a day at 1 week.

RESULTS

The rescue dosage in a day at 1-week post discharge from the palliative care unit was significantly higher in group 1 as compared with group 2.

CONCLUSION

Intravenous infusion morphine may be a better analgesic titration technique for analgesia in patients with advanced cancer.

TRIAL REGISTRATION NUMBER

CTRI/2018/04/013369.

Comparison of intravenous ibuprofen versus ketorolac for postoperative analgesia in children undergoing lower abdominal surgery: A randomized, controlled, non-inferiority study

BACKGROUND

Non-steroidal anti-inflammatory drugs are often used as part of multimodal analgesia to control postoperative pain. This randomized, controlled, double-blinded, non-inferiority study aimed to compare the postoperative analgesic effects of intravenous ibuprofen versus ketorolac in children undergoing open unilateral lower abdominal surgery. The authors hypothesized that postoperative analgesia produced by intravenous ibuprofen would be non-inferior to that of intravenous ketorolac.

METHODS

Sixty-six children aged 2 to 8 years who were scheduled to undergo unilateral lower abdominal surgery, were recruited. Patients in the ibuprofen group received 10mg/kg/6h intravenous ibuprofen. Patients in the ketorolac group were given 0.5mg/kg/6h intravenous ketorolac. The primary outcome measure was 24-h postoperative morphine consumption. The secondary outcome measures were postoperative pain score, the incidence of early postoperative fever and the incidence of ibuprofen and ketorolac adverse effects including pain during drug infusion, vomiting, epigastric pain and allergic reaction.

RESULTS

Fifty-nine patients completed the study (30 ibuprofen, 29 ketorolac). There was no significant difference (P=0.305) in the mean (SD) 24-h postoperative morphine consumption (μ/kg) between intravenous ibuprofen, 16.00 (5.31), and ketorolac, 14.65 (4.61). The reported pain scores were similar in both groups. The incidence of postoperative fever was significantly lower (p=0.039) in the ibuprofen group (3%) than the ketorolac group (20%). The incidence of adverse effects was similar in both ibuprofen and ketorolac groups.

CONCLUSIONS

Intravenous ibuprofen can be used as an alternative to ketorolac for postoperative analgesia in children undergoing unilateral lower abdominal surgery because both drugs similarly provide safe and effective postoperative analgesia.

Comparison of Monotherapy Versus Combination of Intravenous Ibuprofen and Propacetamol (Acetaminophen) for Reduction of Postoperative Opioid Administration in Children Undergoing Laparoscopic Hernia Repair: A Double-Blind Randomized Controlled Trial

BACKGROUND

Extensive efforts have been made toward reducing postoperative opioid use in children. In this study, we assessed whether propacetamol, or a nonsteroidal anti-inflammatory drug (NSAID), or their combination could effectively reduce opioid use in children after laparoscopic inguinal hernia repair.

METHODS

This randomized, double-blind clinical trial included 159 children aged 6 months to 6 years. Children were allocated into 1 of the following 3 groups: group I was treated with 10 mg·kg-1 ibuprofen, group P was treated with 30 mg·kg-1 propacetamol, and group I + P was treated with both drugs in their respective concentrations. If the face-legs-activity-crying-consolability (FLACC) score was ≥4 during the postanesthesia care unit stay, 1.0 µg·kg-1 fentanyl was administered as a rescue analgesic. The number of patients who received rescue fentanyl in the postanesthesia care unit was defined as the primary outcome; this was analyzed using the χ2 test. The secondary outcomes included the FLACC and the parents' postoperative pain measure (PPPM) scores until the 24-hour postoperative period.

RESULTS

Among the 144 enrolled patients, 28.6% in group I, 66.7% in group P, and 12.8% in group I + P received rescue fentanyl in the postanesthesia care unit (P < .001). The highest FLACC score was lower in group I + P than in either group I or P (P = .007 and P < .001, respectively). Group I + P presented significantly lower PPPM scores than group P at 4 and 12 hours postoperative (P = .03 and .01, respectively).

CONCLUSIONS

The use of ibuprofen plus propacetamol immediately following laparoscopic hernia repair surgery in children resulted in the reduced use of an opioid drug compared with the use of propacetamol alone.

"Placebo by Proxy" and "Nocebo by Proxy" in Children: A Review of Parents' Role in Treatment Outcomes

The "placebo (effect) by proxy" (PbP) concept, introduced by Grelotti and Kaptchuk (1), describes a positive effect of a patient's treatment on persons in their surrounding such as family members or healthcare providers, who feel better because the patient is being treated. The PbP effect is a complex dynamic phenomenon which attempts to explain a change in treatment outcome arising from an interaction between a patient and an effect from proxies such as parents, caregivers, physicians or even the media. By extension the effect of the proxy can also have a negative or adverse effect whereby a proxy feels worse when a patient is treated, giving rise to the possibility of a "nocebo (effect) by proxy" (NbP), and by extension can influence a patient's treatment response. While this has yet to be systematically investigated, such an effect could occur when a proxy observes that a treatment is ineffective or is perceived as causing adverse effects leading the patient to experience side effects. In this narrative review, we take these definitions one step further to include the impact of PbP/NbP as they transform to affect the treatment outcome for the patient or child being treated, not just the people surrounding the individual being treated. Following a systematic search of literature on the subject using the Journal of Interdisciplinary Placebo Studies (JIPS) database (https://jips.online) and PubMed (NCBI) resulted in very few relevant studies, especially in children. The effect of PbP per se has been studied in parents and their children for temper tantrums, acupuncture for postoperative symptoms, as well as for neuroprotection in very preterm-born infants. This paper will review the PbP/NbP concepts, show evidence for its presence in children's treatment outcome and introduce clinical implications. We will also offer suggestions for future research to further our understanding of the role of the proxy in promoting or distracting from treatment benefit in children. Increasing an appreciation of the PbP and NbP phenomena and the role of the proxy in children's treatment should improve research study design and ultimately harness them to improve clinical child healthcare.

Developing a pediatric pain data repository

The management of pediatric pain typically consists of individualized treatment plans and interventions that have not been systematically evaluated. There is an emerging need to create systems that can support the translation of clinical discoveries, facilitate the assessment of current interventions, and improve the collection of patient-centered data beyond routine clinical information. We present the development of the pediatric pain data repository, a custom-built system developed at Boston Children’s Hospital by a multidisciplinary pain treatment service. The Repository employs a web platform to collect standardized patient-reported outcomes and integrates this with electronic medical record data. To date, we have collected information on 2577 patients and anticipate adding approximately 500 new patients per year. Major strengths of the Repository include collection of extensive longitudinal patient-reported outcomes, automated clinical data abstraction, and integration of the system into clinical workflows to support medical decision making.

Efficacy and safety of multiple doses of tapentadol oral solution in the treatment of moderate to severe acute pain in children aged 2 to <18 years - a randomized, double-blind, placebo-controlled trial

Background

Well-controlled trials of analgesics in the pediatric population are scarce. Tapentadol is a strong centrally acting analgesic which has undergone a pediatric development program investigating its suitability for treating moderate to severe acute pain across the entire pediatric age range from birth to adolescence. Here, we report data from a pivotal Phase III trial performed as part of this development program.

Patients and methods

This randomized, double-blind, placebo-controlled, multicenter clinical trial investigated efficacy and safety/tolerability of multiple tapentadol oral solution doses (OS; target dose 1.25 mg/kg) in the treatment of postsurgical acute pain. Data for patients aged 2 to <18 years are reported here. The main objective of the trial was to investigate if oral tapentadol administration compared to placebo reduces the use of supplemental opioid analgesic medication within the first 24 hrs of treatment. Other investigated parameters included taste and palatability of the trial medication, adverse events (AEs), vital signs, and laboratory parameters.

Results

A total of 160 patients were included (placebo n=52, tapentadol n=108). It was shown that the total amount of supplemental opioid analgesic medication used in the first 24 hrs was significantly lower in tapentadol patients than placebo patients (p=0.0154). Taste and palatability of tapentadol OS was well perceived by most patients. Treatment-emergent AEs were reported in 50% of patients treated with placebo vs 57.4% in those exposed to tapentadol, most commonly vomiting, nausea, and constipation in both treatment groups.

Conclusion

Tapentadol OS was effective and generally well tolerated in children (≥2 years) for the treatment of moderate to severe acute pain. Across all age groups, palatability and acceptability of tapentadol OS were sufficient to ensure intake compliance. This trial provides evidence that tapentadol OS can be effectively used to treat pain in young patients for whom currently limited labelled treatment options are available.

Local Anesthesia With General Anesthesia for Pediatric Bone Marrow Procedures

BACKGROUND

Pediatric patients with cancer undergo repeated painful procedures, including bone marrow aspirations and biopsies (BMABs). Optimal management of procedure-related pain can reduce discomfort, anxiety, and distress.

METHODS

Children with neuroblastoma were randomly assigned to 1 of 2 arms on a prospective, single-blind, crossover trial conducted at Memorial Sloan Kettering Cancer Center from October 2016 to January 2018 (www.clinicaltrials.gov, identifier NCT02924324). Participants underwent 2 sequential BMABs: one with general anesthesia (GA) alone, the other with GA plus local anesthesia (LA) (GA + LA). The objective was to assess procedure-related pain and its interference with quality of life (QoL) with GA versus GA + LA. Primary outcome was percentage of participants requiring postprocedural opioids. Secondary outcomes were total opioid and nonopioid analgesics, pain scores, time to first analgesic, QoL, and toxicity. Management of postprocedural pain was standardized.

RESULTS

Of 56 participants randomly assigned (3-16.5 years old), 46 completed both procedures. There was no significant difference in percentage of participants requiring opioids with GA versus GA + LA (24% vs 20%, P = .5). Pain scores in the recovery room were significantly lower for GA + LA versus GA (median [IQR]: 0 [0-2] vs 2 [0-4], P = .002). There were no statistically significant differences in total opioid or nonopioid analgesic, 6- and 24-hour pain scores, median time to first analgesic, or pain interference. No adverse events occurred.

CONCLUSIONS

LA was associated with significant improvement in pain scores in the immediate recovery period. LA did not reduce postprocedural opioid use, nor did it improve QoL for patients undergoing BMAB with GA.

The challenge of developing pain medications for children: therapeutic needs and future perspectives

It is broadly accepted that children of all age groups including (preterm) neonates and young infants can perceive pain and that there is an absolute need to treat their pain safely and effectively. The approved treatment options for children, particularly (preterm) neonates and young infants, are very limited with only a few medications specifically labelled for this population. This article presents the challenges of developing pain medications for children. A short overview gives information on pain in children, including pain perception, prevalence of pain and the long-term consequences of leaving pain untreated in this vulnerable population. Current pain management practices are briefly discussed. The challenges of conducting pediatric clinical trials in general and trials involving analgesic medications in particular within the regulatory framework available to develop these medications for children are presented. Emphasis is given to the operational hurdles faced in conducting a pediatric clinical trial program. Some suggestions to overcome these hurdles are provided based on our experience during the pediatric trial program for the strong analgesic tapentadol used for the treatment of moderate to severe acute pain.

Patient- and Nurse-Controlled Analgesia: 22-Year Experience in a Pediatric Hospital

OBJECTIVES

Pediatric pain management has rapidly changed over the last 2 decades. In this study, we describe the changing practices and adverse events (AEs) related to patient-controlled analgesia (PCA) and/or nurse-controlled analgesia (NCA) over a 22-year period.

METHODS

After institutional review board approval, retrospective data from a single tertiary-care pediatric hospital were collected between 1994 and 2016. Subgroup analyses were done for surgical and medical case patients. We reported the number of times that PCA and/or NCA was ordered annually, the median and interquartile ranges for age, PCA and/or NCA duration and length of stay, and AE frequencies.

RESULTS

Over 22 years, 32 338 PCAs and/or NCAs were ordered in this institution. Morphine and hydromorphone were used most commonly. Between 1994 and 2006, initial orders for PCA and/or NCA increased 2.5-fold. After 2007, initial orders for PCA and/or NCA rapidly decreased; after 2013, the decrease continued at a slower rate, with a total of 1007 orders in 2016. This decrease occurred despite increased hospital admissions and surgeries. Between 2007 and 2012, peripheral nerve blocks rapidly increased (10-fold). After 2002, 146 AEs were reported (1.0%). Of those, 50.5% were nonintercepted, and 20.6% were intercepted AEs; 5.5% and 6.2% were preventable and nonpreventable AEs, respectively.

CONCLUSIONS

PCA and/or NCA usage continues to be common in pediatric patients, although usage has declined and stabilized in the setting of other emerging methods of analgesia and increases in the number of minimally invasive surgical procedures. The overall rate of AEs was extremely low. However, improvements to eliminate all errors are needed, especially with medications with a great risk of harm (such as opioids).

Ketorolac for postoperative pain in children

BACKGROUND

Children who undergo surgical procedures in ambulatory and inpatient settings are at risk of experiencing acute pain. Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce moderate to severe pain without many of the side effects associated with opioids. However, NSAIDs may cause bleeding, renal and gastrointestinal toxicity, and potentially delay wound and bone healing. Intravenous administration of ketorolac for postoperative pain in children has not been approved in many countries, but is routinely administered in clinical practise.

OBJECTIVES

To assess the efficacy and safety of ketorolac for postoperative pain in children.

SEARCH METHODS

We searched the following databases, without language restrictions, to November 2017: CENTRAL (The Cochrane Library 2017, Issue 10); MEDLINE, Embase, and LILACS. We also checked clinical trials registers and reference lists of reviews, and retrieved articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials that compared the analgesic efficacy of ketorolac (in any dose, administered via any route) with placebo or another active treatment, in treating postoperative pain in participants zero to 18 years of age following any type of surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently considered trials for inclusion in the review, assessed risk of bias, and extracted data. We analyzed trials in two groups; ketorolac versus placebo, and ketorolac versus opioid. However, we performed limited pooled analyses. We assessed the overall quality of the evidence for each outcome using GRADE, and created a 'Summary of findings' table.

MAIN RESULTS

We included 13 studies, involving 920 randomised participants. There was considerable heterogeneity among study designs, including the comparator arms (placebo, opioid, another NSAID, or a different regimen of ketorolac), dosing regimens (routes and timing of administration, single versus multiple dose), outcome assessment methods, and types of surgery. Mean study population ages ranged from 356 days to 13.9 years. The majority of studies chose a dose of either 0.5 mg/kg (as a single or multiple dose regimen) or 1 mg/kg (single dose with 0.5 mg/kg for any subsequent doses). One study administered interventions intraoperatively; the remainder administered interventions postoperatively, often after the participant reported moderate to severe pain.There were insufficient data to perform meta-analysis for either of our primary outcomes: participants with at least 50% pain relief; or mean postoperative pain intensity. Four studies individually reported statistically significant reductions in pain intensity when comparing ketorolac with placebo, but the studies were small and had various risks of bias, primarily due to incomplete outcome data and small sample sizes.We found limited data available for the secondary outcomes of participants requiring rescue medication and opioid consumption. For the former, we saw no clear difference between ketorolac and placebo; 74 of 135 (55%) participants receiving ketorolac required rescue analgesia in the post-anaesthesia care unit (PACU) versus 81 of 127 (64%) receiving placebo (relative risk (RR) 0.85, 95% confidence interval (CI) 0.71 to 1.00, P = 0.05; 4 studies, 262 participants). For opioid consumption in the PACU, we saw no clear difference between ketorolac and placebo (P = 0.61). For the time period zero to four hours after administration of the interventions, participants receiving ketorolac received 1.58 mg less intravenous morphine equivalents than those receiving placebo (95% CI -2.58 mg to -0.57 mg, P = 0.002; 2 studies, 129 participants). However, we are uncertain whether ketorolac has an important effect on opioid consumption, as the data were sparse and the results were inconsistent. Only one study reported data for opioid consumption when comparing ketorolac with an opioid. There were no clear differences between the ketorolac and opioid group at any time point. There were no data assessing this outcome for the comparison of ketorolac with another NSAID.There were insufficient data to allow us to analyze overall adverse event or serious adverse event rates. Although the majority of serious adverse events reported in those receiving ketorolac involved bleeding, the number of events was too low to conclude that bleeding risk was increased in those receiving ketorolac perioperatively. There was not a statistically significant increase in event rates for any specific adverse event, either in pooled analysis or in single studies, when comparing ketorolac and placebo. When comparing ketorolac with opioids or other NSAIDs, there were too few data to make any conclusions regarding event rates. Lastly, withdrawals due to adverse events were vary rare in all groups, reflecting the acute nature of such studies.We assessed the quality of evidence for all outcomes for each comparison (placebo or active) as very low, due to issues with risk of bias in individual studies, imprecision, heterogeneity between studies, and low overall numbers of participants and events.

AUTHORS' CONCLUSIONS

Due to the lack of data for our primary outcomes, and the very low-quality evidence for secondary outcomes, the efficacy and safety of ketorolac in treating postoperative pain in children were both uncertain. The evidence was insufficient to support or reject its use.

Clinical trial designs and models for analgesic medications for acute pain in neonates, infants, toddlers, children, and adolescents: ACTTION recommendations

Clinical trials to test the safety and efficacy of analgesics across all pediatric age cohorts are needed to avoid inappropriate extrapolation of adult data to children. However, the selection of acute pain models and trial design attributes to maximize assay sensitivity, by pediatric age cohort, remains problematic. Acute pain models used for drug treatment trials in adults are not directly applicable to the pediatric age cohorts-neonates, infants, toddlers, children, and adolescents. Developmental maturation of metabolic enzymes in infants and children must be taken into consideration when designing trials to test analgesic treatments for acute pain. Assessment tools based on the levels of cognitive maturation and behavioral repertoire must be selected as outcome measures. Models and designs of clinical trials of analgesic medications used in the treatment of acute pain in neonates, infants, toddlers, children, and adolescents were reviewed and discussed at an Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) Pediatric Pain Research Consortium consensus meeting. Based on extensive reviews and continuing discussions, the authors recommend a number of acute pain clinical trial models and design attributes that have the potential to improve the study of analgesic medications in pediatric populations. Recommendations are also provided regarding additional research needed to support the use of other acute pain models across pediatric age cohorts.

Randomized Controlled Feasibility Trial of Intranasal Ketamine Compared to Intranasal Fentanyl for Analgesia in Children with Suspected Extremity Fractures

OBJECTIVES

We compared the tolerability and efficacy of intranasal subdissociative ketamine to intranasal fentanyl for analgesia of children with acute traumatic pain and investigated the feasibility of a larger noninferiority trial that could investigate the potential opioid-sparing effects of intranasal ketamine.

METHODS

This randomized controlled trial compared 1 mg/kg intranasal ketamine to 1.5 μg/kg intranasal fentanyl in children 4 to 17 years old with acute pain from suspected isolated extremity fractures presenting to an urban Level II pediatric trauma center from December 2015 to November 2016. Patients, parents, treating physicians, and outcome assessors were blinded to group allocation. The primary outcome, a tolerability measure, was the frequency of cumulative side effects and adverse events within 60 minutes of drug administration. The secondary outcomes included the difference in mean pain score reduction at 20 minutes, the proportion of patients achieving a clinically significant reduction in pain in 20 minutes, total dose of opioid pain medication in morphine equivalents/kg/hour (excluding study drug) required during the emergency department (ED) stay, and the feasibility of enrolling children presenting to the ED in acute pain into a randomized trial conducted under U.S. regulations. All patients were monitored until 6 hours after their last dose of study drug or until admission to the hospital ward or operating room.

RESULTS

Of 629 patients screened, 87 received the study drug and 82 had complete data for the primary outcome (41 patients in each group). The median (interquartile range) age was 8 (6-11) years and 62% were male. Baseline pain scores were similar among patients randomized to receive ketamine (73 ± 26) and fentanyl (69 ± 26; mean difference [95% CI] = 4 [-7 to 15]). The cumulative number of side effects was 2.2 times higher in the ketamine group, but there were no serious adverse events and no patients in either group required intervention. The most common side effects of ketamine were bad taste in the mouth (37; 90.2%), dizziness (30; 73.2%), and sleepiness (19; 46.3%). The most common side effects of fentanyl were sleepiness (15; 36.6%), bad taste in the mouth (9; 22%), and itchy nose (9; 22%). No patients experienced respiratory side effects. At 20 minutes, the mean pain scale score reduction was 44 ± 36 for ketamine and 35 ± 29 for fentanyl (mean difference = 9 [95% CI = -4 to 23]). Procedural sedation with ketamine occurred in 28 ketamine patients (65%) and 25 fentanyl patients (57%) prior to completing the study.

CONCLUSIONS

Intranasal ketamine was associated with more minor side effects than intranasal fentanyl. Pain relief at 20 minutes was similar between groups. Our data support the feasibility of a larger, noninferiority trial to more rigorously evaluate the safety, efficacy, and potential opioid-sparing benefits of intranasal ketamine analgesia for children with acute pain.

[Chronic primary pain disorders in children and adolescents]

AIM

Chronic and debilitating pediatric pain has a prevalence of 5% and as such constitutes a considerable health problem. The aim of this article is to provide an overview of current research activities on pediatric pain, available health care for children with chronic pain and education and training programs for health professionals.

METHOD

This overview is based on the authors' personal experience, information available from medical, research and professional associations, as well as a PubMed literature search for the time period 2012-2015 using "children";"pain" and "Germany" as search terms.

RESULTS

There are numerous research activities in Germany focusing on the epidemiology, the underlying psychobiological mechanisms and on the multimodal treatment of chronic pediatric pain. This research is internationally widely acknowledged and makes a significant contribution to current developments in pediatric pain research. By contrast, health services and basic science research is clearly lacking in Germany. Moreover, specialized health care for youth with chronic pain is far less institutionalized when compared to adults suffering from chronic pain. Indeed, primary and secondary care services have rarely been studied or even evaluated.

CONCLUSION

Similar to international trends, research on chronic pediatric pain has also grown and advanced in Germany. Indeed, not only the amount of research has increased but also its scope. Nonetheless, there is clearly a need for more research efforts with regard to the understanding of (pediatric) pain mechanisms, clinical studies and, especially, investigations on health care services. It is particularly important to focus on the implementation, improvement and systematic evaluation of specialized health care services which would be available and accessible for children and adolescents with chronic pain and not be restricted to tertiary care.

The Psychological Dimensions of Placebo-Studies

Abstract. The placebo effect involves a complex network of psychological variables that are often disregarded by studies enquiring into this effect. It is hence little surprising that these psychological variables confound study outcomes and that experiments investigating the placebo effect often yield radically different results. The current article identifies three categories of psychological and methodological factors that are not systematically considered in placebo research: psychological confounds (Hawthorne effects and demand effects); methodological and data-analysis issues; and clinicians’ expectancy effects. These factors are not necessarily to be seen as mere artifacts, however, because they may constitute favorable components of the placebo effect. A set of benchmark criteria is therefore proposed to allow researchers to capitalize on these components during placebo research rather than have their results confounded by them; and to allow for a more reliable interpretation of study outcomes.

Conduct, Oversight, and Ethical Considerations of Clinical Trials in Companion Animals with Cancer: Report of a Workshop on Best Practice Recommendations

Development of effective and safe treatments for companion animals with cancer requires the collaboration of numerous animal health professionals and the full engagement of animal owners. Establishing ‘Best Practice Recommendations’ for clinical trials in veterinary oncology represents an important step toward meeting the goal of rigorous clinical trial design and conduct that is required to establish valid evidence. Likewise, optimizing patient welfare and owner education and advocacy is crucial to meet the unique ethical obligations to both owners and animals enrolled in these clinical trials and to ensure trust in the team conducting the research. To date, ‘Best Practice Recommendations’ for clinical trial conduct have not been reported for veterinary oncology. This document summarizes the consensus of a workshop held in November, 2014 to identify relevant ethical principles and to ensure responsible conduct of clinical research in companion animals with cancer. It is intended as a working document that will be updated as advances in science and ethical considerations require. To the extent possible, existing guidelines for the conduct and oversight of clinical trials in humans have been adapted for veterinary trials to avoid duplicative effort and to facilitate integration of clinical trials such that translational research with benefits for both companion animals and humans are encouraged.

Considerations when using pharmacokinetic/pharmacodynamic modeling to determine the effectiveness of simple analgesics in children

INTRODUCTION

Assessment of analgesic drugs includes comparative studies to other analgesics and local anesthesia blockade, number needed to treat estimates and opioid sparing descriptions. An additional methodology is to define the concentration-response relationship using pharmacokinetic/pharmacodynamic (PK/PD) modeling.

AREAS COVERED

A concentration-response relationship allows analgesic effect comparison between drugs for different acute pain types. Covariates such as size, age and organ function impact greatly on PK in children. The cumulative effect of confounding factors (e.g., pharmacogenetics, placebo and changes in baseline pain over time) complicates PD. Other factors (outcome measures, method of measurement, failure to account for study attrition) impact on outcome. Population PK/PD modeling approaches allow us to account for these various factors to some extent.

EXPERT OPINION

Nonlinear mixed effects models help interpret analgesic data and their use is increasing. The PK is relatively well understood. The next investigative step will involve investigation into covariate effects for PD. Mathematical functions for both placebo models and dropout models are well described and should be incorporated into analgesic effectiveness studies that investigate a range of doses. Improvements in pain assessment tools and a greater understanding of pharmacogenomics factors will help individualize analgesic therapy.

Pain and placebo in pediatrics: a comprehensive review of laboratory and clinical findings

Pain modulation by placebo mechanisms is one of the most robust and best-studied phenomena, yet almost all research investigating the mechanisms and implications of the placebo analgesia are based on adult research. After highlighting crucial aspects that need to be considered in studying pain modulation in children, this comprehensive review examines studies related to pain modulation with an emphasis on factors such as age, neural development and pain measures. We critically discuss psychological mechanisms underlying placebo effects, including (1) verbally induced expectations, (2) conditioning and learning mechanisms, and (3) child-parent-physician interactions. Taken together, research suggests that placebo mechanisms can affect therapeutic outcomes and potentially be exploited clinically to improve clinical outcomes in pediatric population. Recommendations for further investigating the mechanistic bases and harnessing placebo effects for supportive therapeutic applications are given.