Analgesia in children with sickle cell crisis: comparison of intermittent opioids vs. continuous intravenous infusion of morphine and placebo-controlled study of oxygen inhalation

Liver Disease and Sickle Cell Disease: Auto-Immune Hepatitis more than a Coincidence; A Systematic Review of the Literature

In patients with SCD, chronic liver damage is a common manifestation. More than 50% of SCD patients have elevated liver enzymes. Common underlying aetiologies include sickle cell hepatic crisis, viral hepatitis, sickle cell intrahepatic cholestasis and hepatic sequestration in the acute setting, and cholelithiasis and iron overload in the chronic setting. Autoimmune hepatitis (AIH) is a rare disease that appears to occur more commonly in the sickle cell disease (SCD) population than in the general population. There are many schools of thought as to why this is the case, including the phosphatidylserine hypothesis, the heme inflammatory hypothesis, the complement generation hypothesis, and the transfusion alloimmunization hypothesis. Due to the natural history of the two illnesses, SCD is almost always diagnosed first in cases of dual pathology. Symptoms such as jaundice, fatigue, and abdominal pain are common in SCD, as are abnormal liver function tests (LFTs). These abnormalities, attributed to the other more frequent liver involvements in SCD, can lead to delays in AIH diagnosis in this population. Corticosteroids, sometimes with other immunosuppressive agents, such as azathioprine, are the cornerstone of acute AIH treatment. However, corticosteroid use in the SCD population has been shown to carry an increased risk of vaso-occlusive crises, providing a treatment dilemma. The following is a review of AIH in the SCD population, where we explore the pathophysiology behind the association between the two disorders, discuss an approach to investigating abnormal LFTs in SCD, and examine treatment options in this population with co-existing diseases.

A case report and review of literature on the role of automated red cell exchange in managing sickle cell crisis in India

Red cell exchanges (RCE) help in the treatment of complications of sickle cell anemia (SCA) by reducing the viscosity of blood and improving the oxygen-carrying capacity. We present a case of sickle cell crisis (SCC) managed with automated RCE and also reviewed the literature to assess the utilization and clinical efficiency of this therapy in India. A 19-year-old gentleman diagnosed with SCA presented with acute chest syndrome. Hemoglobin (Hb) was 8.8 g%, hematocrit (HCT) was 24%, and HbS was 90%. As there was worsening of symptoms with conventional management, the patient underwent two procedures of automated RCE. The clinical condition of the patient was improved, HbS was reduced to 16% and HCT was remained at 21% postprocedure. Articles on automated RCE in SCA conducted in India were reviewed and four articles were analyzed based on the search strategy. All the included articles concluded automated RCE as an effective procedure for complications of SCA. Common indication in India was SCA patients undergoing surgery as a prophylactic measure. Automated RCEs are promising as an acute treatment for indicated sickle cell complications. This therapy is underutilized in the Indian scenario, especially in patients with SCC.

Long-term oxygen therapy in children with sickle cell disease and hypoxaemia

OBJECTIVE

To evaluate the acceptability and safety profile of nocturnal long-term oxygen therapy (LTOT) in children with sickle cell disease (SCD) and chronic hypoxaemia.

DESIGN

Retrospective cohort study.

PATIENTS, SETTING AND INTERVENTION

Children with SCD who started LTOT from 2014 to early 2019 in two tertiary hospitals in London, UK were retrospectively enrolled. Patients who started disease-modifying therapies <12 months before LTOT or while on LTOT were excluded.

MAIN OUTCOME MEASURES

Minor and major adverse events during LTOT were reported. Laboratory and clinical data, transcranial Doppler (TCD) scans and overnight oximetry studies performed at steady state within 12 months before and after starting LTOT were compared.

RESULTS

Nineteen children (10 males; median age 12 years, range 6-15) were included. Nearly half of them (9/19; 47%) were on hydroxyurea at baseline. No child discontinued LTOT because of intolerance or poor adherence. No major adverse events were reported. Laboratory data did not show significant changes in haemoglobin and reticulocyte count after 1 year of follow-up. No statistically significant change in the incidence of vaso-occlusive pain events was noted (median annual rate from 0.5 to 0 episode per patient/year; p=0.062). Overnight oximetry tests performed while on LTOT showed improvements in all oxygen saturation parameters (mean overnight and nadir SpO₂, % of time spent with SpO₂ <90%) compared with the baseline.

CONCLUSION

LTOT is a safe and feasible treatment option for children with SCD and chronic hypoxaemia.

Outcomes of an Emergency Department Observation Unit-Based Pathway for the Treatment of Uncomplicated Vaso-occlusive Events in Sickle Cell Disease

STUDY OBJECTIVE

This was a prospective, pre-post, 13-year observational study documenting the multiyear implementation of an observation unit sickle cell pathway for patients with uncomplicated vaso-occlusive events.

METHODS

The sickle cell pathway begins with rapid triage to identify patients with uncomplicated vaso-occlusive events for immediate transfer to the observation unit and initiation of patient-controlled analgesia followed by repeated evaluations of pain and identification of other complications. Data were abstracted from the electronic medical record or observation unit database. The sickle cell pathway was initiated in April 2006. Major revisions of it were carried out in June 2009 (physician evaluation occurs in sickle cell pathway and only patient-controlled analgesia administration of medications) and October 2010 (multidisciplinary management and individual dosing).

RESULTS

Annual ED visits ranged between 287 and 528. The preimplementation hospital admission rate was 33% (123/368), 3-day return rate 16% (60/368), and 30-day return rate 67% (248/368). Refinements to the sickle cell pathway have resulted in a decrease in admission rate to 20% (258/1276); 3-day return rate, to 3.6% (46/1,276); and 30-day return rate, to 41% (525/1,276) for the past 3 years.

CONCLUSION

The use of a sickle cell pathway for the treatment of uncomplicated vaso-occlusive events has been effective in providing rapid treatment and reducing hospital admissions. However, it was not only the intervention and its refinement that made the sickle cell pathway successful. With the Consolidated Framework for Implementation Research, it was discerned that outer setting factors of organizational commitment to the care of patients with SCD, inner setting factors of learning climate and leadership engagement, individuals, and process contributed to the success of the sickle cell pathway.

Addressing challenges of clinical trials in acute pain: The Pain Management of Vaso-occlusive Crisis in Children and Young Adults with Sickle Cell Disease Study

Background/aims:

Neuropathic pain is a known component of vaso-occlusive pain in sickle cell disease; however, drugs targeting neuropathic pain have not been studied in this population. Trials of acute pain are complicated by the need to obtain consent, to randomize participants expeditiously while optimally treating pain. We describe the challenges in designing and implementing the Pain Management of Vaso-occlusive Crisis in Children and Young Adults with Sickle Cell Disease Study (NCT01954927), a phase II, randomized, double-blind, placebo-controlled trial to determine the effect of gabapentin for vaso-occlusive crisis.

Methods:

In the Pain Management of Vaso-occlusive Crisis in Children and Young Adults with Sickle Cell Disease Study, we aim to assess the analgesic effect of gabapentin during vaso-occlusive crisis. Difficulties we identified included avoiding delay of notification of study staff of potential participants which we resolved by automated notification. Concern for rapid randomization and drug dispensation was addressed through careful planning with an investigational pharmacy and a single liquid formulation. We considered obtaining consent during well-visits to avoid the time constraints with acute presentations, but the large number of patients and limited duration that consent is valid made this impractical.

Results:

In all, 79% of caregivers/children approached have agreed to participate. The trial is currently active, and enrollment is at 45.8% of that targeted (76 of 166) and expected to continue for two more years. Maintaining staff availability after-hours remains problematic, with 8% of screened patients missed for lack of available staff.

Lessons learned:

Lessons learned in designing a trial to expedite procedures in the acute pain setting include (1) building study evaluations upon a standard-of-care backbone; (2) implementing a simple study design to facilitate consent and data capture; (3) assuring ample, well-trained study staff; and (4) utilizing technology to automate procedures whenever possible.

Conclusion:

This study design has circumvented many of the logistical barriers usually associated with acute pain trials and may serve as a prototype for future studies.

Prevention of Morbidity in sickle cell disease--qualitative outcomes, pain and quality of life in a randomised cross-over pilot trial of overnight supplementary oxygen and auto-adjusting continuous positive airways pressure (POMS2a): study protocol for a randomised controlled trial

BACKGROUND

Sickle cell anaemia (SCA) is an inherited disorder of haemoglobin. Patients experience long-term health care problems, affecting quality of life (QOL) including frequent acute pain, which is difficult to document in trials except as hospital admissions. Pilot data suggests that overnight respiratory support, either supplementary oxygen or auto-adjusting continuous positive airways pressure (APAP), is safe and may have clinical benefit. This pilot trial aims to determine which intervention is more acceptable to participants and whether there are other advantages of one over the other, e.g. in respiratory function or haematological parameters, before conducting the Phase 2 trial of overnight respiratory support funded by the National Institutes of Health Research.

METHODS/DESIGN

This is a pilot cross-over interventional trial with the order of interventions decided by simple randomization. Ten adults (age over 18 years) and 10 children (aged between 8 and 18 years) with homozygous sickle cell disease (haemoglobin SS, HbSS), recruited regardless of symptoms of sleep-disordered breathing, will undergo overnight pulse oximetry and will have two interventions, overnight oxygen and APAP, for a week each in randomised order with a washout week between interventions. Participants will complete online diaries via an iPad throughout the 29 days of the study and will complete QOL questionnaires and have measurement of haematology, biochemistry, spirometry and lung volumes (adults only) at 3 time points, at baseline and after each intervention, as well as in-depth semi-structured qualitative interviews after each intervention, carried out by an experienced psychologist. Both qualitative and statistical methods will be used to analyze the data. The primary outcome is qualitative data looking at participant experience from the transcribed interviews after each intervention. The participant's view on feasibility, acceptability and preference will specifically be explored. The QOL, laboratory and lung function data will be compared with baseline for each arm.

DISCUSSION

Patient and public involvement is an integral part of this trial and the key outcome is the qualitative result, which is dependent on obtaining good quality data to advise on participant feasibility, acceptability and preference. This is being addressed by using a standard interview. The development of a pain endpoint is another important outcome and collecting daily measurements is likely to be challenging. Research results will be used to inform design of the Phase 2 trial.

TRIAL REGISTRATION

ISRCTN46078697 18 July 2014.

Inter-individual variation in morphine clearance in children

Objectives

The aim of the study was to determine the extent of inter-individual variation in clearance of intravenous morphine in children and to establish which factors are responsible for this variation.

Methods

A systematic literature review was performed to identify papers describing the clearance of morphine in children. The following databases were searched: Medline, Embase, International Pharmaceutical Abstracts, CINAHL, and Cochrane library. From the papers, the range in plasma clearance and the coefficient of variation (CV) in plasma clearance were determined.

Results

Twenty-eight studies were identified. After quality assessment, 20 studies were included. Only 10 studies gave clearance values for individual patients. The majority of the studies were in critically ill patients. Inter-individual variability of morphine clearance was observed in all age groups, but greatest in critically ill neonates (both preterm and term) and infants. In critically ill patients, the CV was 16–9 7 % in preterm neonates, 24–87 % in term neonates, 35 and 134 % in infants, 39 and 55 % in children, and 74 % in adolescents. The CV was 37 and 44 % respectively in non-critically ill neonates and infants. The mean clearance was higher in children (32 and 52 ml min^-1 kg^-1) than in neonates (2 to 16 ml min^-1 kg^-1).

Conclusions

Large inter-individual variation was seen in morphine clearance values in critically ill neonates and infants.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-015-1843-x) contains supplementary material, which is available to authorized users.

WITHDRAWN: Pain management for sickle cell disease in children and adults

This review is out of date, and the original authors are no longer available to update it. If you are interested in updating this review, please contact PaPaS: https://papas.cochrane.org/contact‐us

At October 2015, a new author team is preparing a replacement review to focus on acute sickle cell crises in adults.

The editorial group responsible for this previously published document have withdrawn it from publication.

Treatment of the acute sickle cell vaso-occlusive crisis in the Emergency Department: a Brazilian method of switching from intravenous to oral morphine

OBJECTIVES

Describe the treatment of patients with vaso-occlusive crises (VOC) in a Brazilian emergency department (ED) and the successful switch from intravenous to oral morphine.

PATIENTS AND METHODS

We analyzed records of 315 patients with sickle cell disease using two different protocols for pain: one in March 2010 prescribing intravenous morphine every 4 h throughout their stay, and another in March 2011 and 2012 prescribing one initial dose of intravenous morphine followed by equianalgesic doses of oral morphine every 4 h. Patients were triaged into three groups: mild, moderate, and severe VOC. The mild group was treated within 1 h after triage, the moderate within 30 min and the severe was treated immediately. Patients whose pain was not relieved within 6 h after the first dose of morphine were transferred into a different holding area of the ED where they continued to receive the same treatment for 48 h after which they were hospitalized if still in pain.

RESULTS

The number of patients who stayed <24 h in the ED increased significantly from 63 in 2010 to 87 in 2012, and the number of admissions decreased from 26 in 2010 to 10 in 2012. The incidence of acute chest syndrome decreased from 8.5% in 2010 to 1.9% in 2012.

CONCLUSION

Patients treated with oral morphine stayed a shorter time in the ED, had more pain relief, were admitted less frequently, and had less acute chest syndrome. These differences may be due to environmental, cultural, psychological, and pharmacogenetic factors.

Morphine is associated with acute chest syndrome in children hospitalized with sickle cell disease

OBJECTIVE

To determine if intravenous morphine is associated with acute chest syndrome (ACS) in children with homozygous for hemoglobin S sickle cell disease (SCD) hospitalized with acute pain.

METHODS

Health records of patients with homozygous for hemoglobin S SCD aged 2 to 18 years hospitalized with acute pain were reviewed. Patients developed ACS at least 12 hours after emergency department triage; controls did not develop ACS. Survival analyses were performed.

RESULTS

There were 38 cases and 45 randomly selected controls. The mean hourly dose of morphine 1, 2, and 3 hours before ACS and cumulative mean morphine dose up to 5 hours before ACS were significantly associated with ACS (P < .05). Adjusted analysis showed that 1 hour before ACS, the mean morphine dose was significantly higher in cases (40 microg/kg) compared with controls (34 microg/kg), and the risk of ACS increased by 23% for each additional 10 microg/kg of morphine received (P = .02).

CONCLUSIONS

We recommend close observation for ACS in hospitalized patients with SCD who are receiving morphine.

Hypoxemia in sickle cell disease: significance and management

Hypoxemia is common in SCD and likely exacerbates SCD vasculopathy. Pulse oximeter correlation with arterial oxygen tension in patients with SCD may at times be poor and arterial blood gas confirmation is required in hypoxic patients. Supplemental oxygen should be administered for the correction of hypoxemia, which if untreated creates a risk of multi-organ failure. Transfusion and hydroxyurea can improve oxygen delivery to tissues and organs. The role of supplemental oxygen therapy in preventing or reversing SCD vasculopathy is controversial. Nitric oxide therapy for VOC pain has not fulfilled promise to date. On the other hand, lung distension (CPAP, incentive spirometry, PEP therapy) are promising treatments requiring further study.

Sickle cell disease: management options and challenges in developing countries

Sickle Cell Disease (SCD) is the most common genetic disorder of haemoglobin in sub-Saharan Africa. This commentary focuses on the management options available and the challenges that health care professionals in developing countries face in caring for patients with SCD. In a developing countries like Ghana, new-born screening is now about to be implemented on a national scale. Common and important morbidities associated with SCD are vaso-occlusive episodes, infections, Acute Chest Syndrome (ACS), Stroke and hip necrosis. Approaches to the management of these morbidities are far advanced in the developed countries. The differences in setting and resource limitations in developing countries bring challenges that have a major influence in management options in developing countries. Obviously clinicians in developing countries face challenges in managing SCD patients. However understanding the disease, its progression, and instituting the appropriate preventive methods are paramount in its management. Emphasis should be placed on early counselling, new-born screening, anti-microbial prophylaxis, vaccination against infections, and training of healthcare workers, patients and caregivers. These interventions are affordable in developing countries.

Review: Management of Painful Vaso-Occlusive Crisis of Sickle-Cell Anemia: Consensus Opinion

Sickle-cell disease (SCD) is a wide-spread inherited hemolytic anemia that is due to a point mutation, leading to the substitution of valine for glutamic acid, causing a spectrum of clinical manifestations in addition to hemolysis and anemia. Acute painful crisis is a common sequela that can cause significant morbidity and negatively impact the patient’s quality of life. Remarkable improvements in the understanding of the pathogenesis of this clinical syndrome and the role of cell adhesion, inflammation, and coagulation in acute painful crisis have led to changes in the management of pain. Due to the endemic nature of SCD in various parts of the Middle East, a group of physicians and scientists from the United States and Middle East recently met to draw up a set of suggested guidelines for the management of acute painful crisis that are reflective of local and international experience. This review brings together a detailed etiology, the pathophysiology, and clinical presentation of SCD, including the differential diagnoses of pain associated with the disease, with evidence-based recommendations for pain management and the potential impact of low-molecular-weight heparin (LMWH), from the perspective of physicians and scientists with long-term experience in the management of a large number of patients with SCD.

Diagnosis and management of sickle cell disorders

Sickle cell disease (SCD) is a wide-spread inherited hemolytic anemia that is due to a point mutation leading to a valine/glutamic acid substitution in the beta-globin chain, causing a spectrum of clinical manifestations in addition to hemolysis and anemia. Acute painful crisis is a common sequela that can cause significant morbidity and negatively impact the patient's quality of life. Remarkable improvements in our understanding of the pathogenesis of this clinical syndrome and the role of cell adhesion, inflammation, and coagulation in acute painful crisis have led to changes in the management of pain. Due to the endemic nature of SCD in various parts of the Middle East, a group of physicians and scientists from the United States and Middle East recently met to draw up a set of suggested guidelines for the management of acute painful crisis that are reflective of local and international experience. This chapter brings together a detailed etiology, pathophysiology, and clinical presentation of SCD, including the differential diagnoses of pain associated with the disease, with evidence-based recommendations for pain management and the potential impact of low-molecular weight heparin (LMWH), from the perspective of physicians and scientists with long-term experience in the management of a large number of SCD patients.

Anesthesia and hemoglobinopathies

Hemoglobinopathies are diseases involving abnormalities of the structure or production of hemoglobin. Examples include sickle cell disease, the thalassemias, and rare hemoglobin variants producing cyanosis. Recent advances in the understanding of the consequences of hemoglobin dysfunction on nitric oxide signaling have led to a reassessment of the pathophysiology of sickle cell disease and thalassemia. Chronic vascular inflammation and damage is now recognized as playing an important role in disease expression. Hemoglobinopathies may present to the anesthesiologist as the primary cause of a surgical procedure, as an incidental complicating factor of a surgical patient, or with a problem arising from the disease itself. This article reviews the common types of hemoglobinopathies, presents a basic summary of the pathophysiology relevant to anesthesia, and outlines current perioperative management.

Pain syndromes in sickle cell disease: an update

OBJECTIVE

Pain has a critical role in the management of sickle cell disease (SCD). Patients may suffer from several pain syndromes, which may be or not may be associated with other clinical complications, such as anemia, organ failures, and infections.

DESIGN

Data for review were identified by using PubMed to search MEDLINE, limiting the search to abstract/articles in English, Italian, French, and Dutch. The key words pain, sickle cell disease, anemia, hemoglobin, hemoglobinopathy, analgesics, opioids, morphine, acetaminophen, paracetamol, nonsteroidal anti-inflammatory drugs, hematology, and quality of life were variously combined in the title, abstract, and key word search list. The abstract database of most hematological congresses and the bibliographies of most relevant articles were also considered.

RESULTS

There are two major types of SCD pain: acute and chronic. Sometimes, mixed and neuropathic pain can be also observed. Acute pain is mostly related to vaso-occlusion. Chronic pain may be due to some SCD complications, such as leg ulcers and avascular necrosis.

CONCLUSIONS

Pain management in the SCD setting needs multidisciplinary approaches, given the several syndromes and the pathogenic mechanisms that are likely involved. Pain management is not standardized and often difficult, so that many patients with SCD are still poorly treated. Further efforts to develop care plans and treatment protocols as well as management guidelines are required.

Pharmacokinetic and pharmacodynamic study of morphine and morphine 6-glucuronide after oral and intravenous administration of morphine in children with cancer

The aim of this study was to characterize the pharmacokinetics and pharmacodynamics of morphine and morphine 6-glucuronide (M6G) in children with cancer. Serum concentrations of morphine and M6G in children who received single oral or short term continuous intravenous morphine were determined by HPLC and ELISA assays, respectively. The serum C(max) of morphine and M6G after i.v. morphine administration was 560.5 and 309.0 nM and the T(max) was 61 and 65 min, respectively. The elimination half-life was 140.0 and 328.7 min, respectively. After oral administration of morphine, the serum C(max) of morphine and M6G was 408.34 and 256.3 nM and the T(max) was 40.0 and 60 min, respectively. The half-life was 131.0 and 325.8 min, respectively. The side effects were: drowsiness (100%), nausea and/or vomiting (57%), pruritus (28%) and urinary retention (14%). There were no reports of respiratory complications. This study showed that pharmacokinetics factors of morphine and M6G in children were significantly different from adults. Therefore the required dose for children should be different from that of adults and should be based on studies performed on children rather than on studies on adults. Some adverse effects, particularly nausea and pruritus, may be commoner than is usually thought, while others, particularly respiratory problems did not occur.

Hormonal regulation of hepatic drug-metabolizing enzyme activity during adolescence

Activities of drug-metabolizing enzymes (DMEs) are known to change throughout the course of physical and sexual maturation, with the greatest variability noted during infancy and adolescence. The mechanisms responsible for developmental regulation of DME are currently unknown. However, the hormonal changes associated with puberty/adolescence provide a theoretical framework for understanding the biochemical regulation of DME activity during growth and maturation. Important information regarding potential influences of growth and sex hormones can also be extrapolated from studies that evaluate changes in activities of DMEs occurring as a consequence of physiological, pathological, and/or pharmacological hormonal fluctuations. Collectively, current data support the hypothesis that isoform-specific alterations in DME activity during adolescence are mediated by sex and/or growth hormones. Characterization of the underlying biochemical alterations responsible for developmental changes in DME activity will require additional studies in which relationships between DMEs and important hormonal axes are evaluated during the course of pubertal development.

Quality of life and pain management in sickle-cell disease

Sickle-cell disease is the most common genetic disorder worldwide and is characterized by intermittent severe painful episodes and other complications such as stroke, priapism, cholecystitis and acute chest syndrome. This review outlines the causes and characteristics of pain in children with sickle cell disease, how pain can be assessed and how painful episodes can be prevented. Sickle cell disease can have a significant impact on the patient’s quality of life, and the ways in which this can manifest, how it can be measured and how interventions such as cognitive behavioral therapy can be used to manage it are outlined. Medical management of acute painful episodes both in the community and in the hosptial setting are discussed, including the role of different analgesic and adjuvant agents. Prevention of painful episodes with hydroxycarbamide is discussed.

Pharmacogenetics of morphine: Potential implications in sickle cell disease

Morphine is frequently used to treat painful episodes associated with sickle cell disease (SCD) but may fail to provide adequate analgesia in many patients. This concise review focuses on unique disease related changes in physiologic variables associated with SCD that impacts pharmacokinetics and pharmacodynamics of morphine and may contribute to the variability in analgesia. Emerging evidence suggests that the allelic variants in the genes involving the opioid (UGT2B7, OPRM1, and ABCB1 genes) and nonopioid system (COMT gene) can alter the efficacy of morphine.

UGT2B7 promoter variant -840G>A contributes to the variability in hepatic clearance of morphine in patients with sickle cell disease

The purpose of the study was to determine if UDP-glucuronosyltransferase (UGT) 2B7 allelic variants encoding for UGT2B7, primary enzyme responsible for morphine glucuronidation contribute to the variability in the hepatic clearance of morphine in sickle cell disease (SCD). Twenty-four hour PK study of morphine and UGT2B7 variants genotyping was performed in 20 SCD patients in a steady state of health. Presence of the -840G allele (GG and GA) was associated with lower morphine metabolites/morphine AUC ratio compared with AA genotype (1.8 +/- 0.5 vs. 3.0 +/- 1.8 for M6G/M and 10.1 +/- 2.7 vs. 15.7 +/- 9.4 for M3G/M) (P = 0.03). Presence of UGT2B7 -840G allele is associated with significantly reduced glucuronidation of morphine and thus contributes to the variability in hepatic clearance of morphine in SCD.

Management of vasoocclusive pain events in sickle cell disease

Pain is the clinical hallmark of sickle cell disease (SCD). Vasoocclusive pain events (VOEs) are the primary cause of morbidity and account for most emergency department visits and hospitalizations for patients with SCD in the United States and Europe. The nature of VOE makes its management extremely challenging. There are no large controlled trials of analgesic regimens for VOE, and smaller trials have generally failed to produce an optimal course of therapy. Therefore, treatment recommendations are largely based on expert opinion and anecdotal experience. Although VOEs are not life-threatening, inadequate treatment may result in unnecessary morbidity and life-threatening complications. Health care providers caring for patients with SCD must be well informed about the management of VOE. This continuing medical education article will provide a summary of the management of acute pain events in SCD with particular emphasis on adequate analgesia.

Quantification of analgesic use in children with sickle cell disease

OBJECTIVES

The purposes of this study were: (1) to quantify analgesic use in children with sickle cell disease who were hospitalized for a vaso-occlusive episode, using the Medication Quantification Scale (MQS) and (2) to examine the relationships between pain intensity scores, number of painful areas marked on a body outline diagram, number of word descriptors of pain quality, and amount of analgesic medications administered.

METHODS

Children (5 to 19 y) were asked daily to provide pain intensity ratings and describe the location and quality of their pain. The nursing flowsheets were also reviewed to determine the dose, routes, and the number of times analgesic medications were administered in the previous 24 hours.

RESULTS

Mean worst pain intensity score on the day of admission was 84.0+/-9.9 (range 63.8 to 100) on the 0 to 100 Oucher numeric rating scale. The mean MQS score administered on the day of admission was 15.7+/-4.9 (range 6 to 24). This score decreased significantly by 1.2+/-0.5 (P<0.0001; range 0.9 to 2.5) each day of hospitalization. Significant correlations were found between various pain characteristics and total MQS scores prescribed at time of admission.

DISCUSSION

The MQS was a useful and sensitive measure to quantify analgesic use in patients with sickle cell disease who were hospitalized for an acute painful episode. The MQS score accounted for variations in the types of analgesic medications, routes of administration, dosing schedules, and opioid dosing requirements.

Pain management for sickle cell disease

BACKGROUND

Sickle cell disease is an inherited genetic disorder characterized by an abnormality of haemoglobin that predisposes to polymerization and consequent deformation ("sickling"). Sickle cell disease can cause episodes of acute severe pain. Chronic pain may also occur. Currently, pain is inadequately managed.

OBJECTIVES

The primary aim of the review was to assess the effectiveness of pharmacological analgesic interventions for pain management in sickle cell disease, including the treatment of acute and chronic pain in children and adults.

SEARCH STRATEGY

A pre-defined search strategy was used to electronically search the MEDLINE and EMBASE databases. Searches were also conducted on the Cochrane Controlled Trial Register (CCTR) and the Oxford pain randomised controlled trials citation database. The search period covered from January 1965 through to June 2002. Bibliographies of retrieved studies were searched for additional references. No language restriction was used.

SELECTION CRITERIA

All randomised controlled trials involving pharmacological treatment of acute or chronic pain in children or adults with sickle cell disease were selected. Patients with haemoglobin SS, haemoglobin S ss thalassaemia and the haemoglobin SC group were included.

DATA COLLECTION AND ANALYSIS

Trials were quality rated using the Oxford quality scale. Continuous measures of outcome were combined using weighted mean differences. Overall effect size was calculated with 95% confidence intervals.

MAIN RESULTS

Nine randomised controlled trials were identified. All studies involved small numbers of patients with acute sickle cell pain only. Interventions included NSAIDs (versus placebo in four studies; versus strong opioids in one study), strong opioids (oral versus parenteral in one study; morphine versus alternate in one study) and corticosteroids (versus placebo in two studies). Lack of data, small patient numbers, variations in study design and outcome measures limited the review. Due to heterogeneity of methodologies and reporting, it was not possible to perform meaningful meta-analyses.

AUTHORS' CONCLUSIONS

There were no studies addressing chronic pain in sickle cell disease. There is limited evidence for analgesic interventions in acute pain crises. Studies have been under-powered. There is not enough data for inter-trial comparisons. In one trial, there was no difference in the efficacy of sustained-release oral versus parenteral morphine, which suggests that oral morphine should be considered for acute pain. Parenteral corticosteroids appear to shorten the period over which analgesics are required and hospital length-of-stay, without producing short-term major adverse effects. More research is needed to improve pain management in sickle cell disease.

Postoperative morphine consumption in children with sickle-cell disease

BACKGROUND

Effective pain control is a primary goal in the perioperative management of patients with sickle-cell disease. To understand analgesic requirements better, the authors compared postoperative morphine consumption and pain scores in sickle and non-sickle children who had undergone laparoscopic cholecystectomy.

METHODS

We reviewed the medical records of all sickle and non-sickle children referred to the Acute Pain Service of a tertiary care teaching hospital for patient-controlled analgesia (PCA) following laparoscopic cholecystectomy from 1996 to 2003. Data collected included postoperative morphine consumption, visual analogue pain scores, and perioperative outcome.

RESULTS

Total postoperative morphine consumption in sickle children (n = 12) (1.58 +/- 0.78 mg.kg(-1)) was more than double when compared with non-sickle children (n = 10) (0.65 +/- 0.32 mg.kg(-1)) (P < 0.005). Duration of PCA use among sickle children (51 +/- 25 h) was more than double when compared with non-sickle children (21 +/- 11 h) (P < 0.005). Sickle patients had greater pain scores in the initial 24 h after surgery (P < 0.05) and used more adjuvant analgesics (P < 0.05). Duration of postoperative hospital stay was 3.4 +/- 1.6 days and 1.5 +/- 0.5 days for sickle and non-sickle children, respectively (P < 0.005).

CONCLUSIONS

Sickle children self-administered more than double the amount of morphine, reported more intense pain, and remained hospitalized for more than twice as long as nonsickle children undergoing the same surgical procedure. These findings probably have a multifactorial origin, and might be attributable in part to alterations in pain perception, opioid pharmacokinetics, opioid tolerance, and psychosocial variables.

Opioid selection during sickle cell pain crisis and its impact on the development of acute chest syndrome

BACKGROUND

The hallmark of sickle cell disease (SCD) is recurrent, painful vaso-occlusive episodes (VOC) and is the most common reason for hospitalization in SCD patients. Narcotics, particularly morphine, along with fluid hydration are standard treatments for painful episodes but have been associated with the development of acute pulmonary events commonly referred to as acute chest syndrome (ACS). The development of ACS is often preceded by acute infections, painful episodes, rib infarction, bone marrow infarction, and fat embolism. Its pathophysiology remains multifactorial and has become the most common reason for early mortality. Previous episodes of ACS increase the likelihood of repeated acute pulmonary events and subsequent pulmonary hypertension. Nalbuphine hydrochloride (Nubain) is an opioid with the pain relieving potency of morphine but has not been studied for its association in the development of ACS or compared with morphine in its efficacy of pain control in the sickle cell population.

PROCEDURE

We reviewed the medical records retrospectively of patients between the age of 5 and 19 years, admitted for vaso-occlusive crisis to the three children's hospitals in Atlanta between January 1999 and December 2002. A computerized search tool was used to identify patients using the International Classification of Diseases Ninth Revision (ICD-9) diagnosis code 282.60 and 282.62. The final discharge diagnosis of ACS was defined as a new pulmonary infiltrate on chest radiograph after admission and before discharge. We calculated the need for 160 patient admissions for 85% power to detect a difference of approximately 20% in incidence of ACS between the two treatment groups.

RESULTS

There were a total of 37 (21%) episodes of ACS. Of these, 26 (29%) were in the morphine group and 11 (12%) were in the Nubain group (P < 0.01). Patients receiving morphine were more likely to have higher white cell counts on admission (P < 0. 05), and to use continuous infusion for medication administration (49% vs. 3%), P < 0. 001. They also had longer hospital stays than patients who received Nubain (median stay 3 days vs. 4 days, morphine), P < 0. 001.

CONCLUSIONS

The development of ACS during painful episodes is multi-factorial, but opioid selection may increase this rate. Patients on Nubain were less likely to develop ACS, and they had shorter hospital stays. These results were confounded by use of continuous analgesia infusion with PCA. However, Nubain may provide an alternative to morphine in the treatment of sickle cell pain episodes. A prospective clinical trial comparing these two analgesics would be a preferable next step.

Painful Dilemmas: An Evidence-based Look at Challenging Clinical Scenarios

Difficult clinical decisions are a part of every emergency practitioner's life. Dealing with difficult patients and recalcitrant consultants is seldom enjoyable, but can be made more palatable through the use of some of the clinical strategies contained in this article. Knowledge of the current best evidence and a willingness to discard outdated practice ideas will help ensure that emergency practitioners continue to provide state-of-the-art medical care. Expressions of care, concern, and respect for patients' problems, and development of a therapeutic alliance with these patients will maximize patient, and ultimately physician, satisfaction.

[Sickle cell disease pain management following the World Health Organization's protocol]

Twenty-four percent of the Gabonese population has sickle cell trait, and 1-3% has sickle cell disease. Patients' management must follow well-defined protocols that take into account the debilitating effect of severe pain episodes.

OBJECTIVES

To evaluate the three-step analgesic ladder for control of pain for sickle cell disease pain crises.

METHODOLOGY

This is a prospective and descriptive study based on surveys filled between February 2000 and March 2001. Surveys were restricted to sickle cell disease patients having developed pain crises before and during their stay at the hospital. The assessment of the pain was based on the DEGR and EVA scales. The treatment followed the World Health Organisation's analgesic ladder. The criteria used for estimate pain severity and sedation duration were measured before, 2 and 24 h after treatment administration began (H0, H2 and H24) to evaluate its effectiveness.

RESULTS

Sixty children were included. All the social layers of the population were represented. The school level was variable. Fifty-six percent of the patients suffered their first pain crisis before they were 1 year old. Thirty-one percent had annual crises and 20% monthly crises. Pain was located in joints in 35% of the cases, and in joints and bones in 15% of the cases. Eighty-one percent of the pain crises were successfully treated in stage I. The passage to stage II occurred in the remaining cases (18.3% of the cases).

CONCLUSION

The WHO's three-step analgesic ladder for control of pain is effective for the sickle cell disease pain episodes. Stage I drugs relieved the pain for 81.6% of the patients in a relatively short time (2-16 h). It was not possible to go to stage III.

Pain management in children with sickle cell disease

Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. The disease is characterized by chronic hemolytic anemia, as well as acute and chronic complications. One of the most intractable problems encountered by children with SCD is the painful episode that results from tissue ischemia due to vaso-occlusion. Pain related to SCD is unique among pain syndromes due to the unpredictable, recurrent, and often persistent nature of the disease, as well as the recurring and essential need for the use of opioids. Painful vaso-occlusive episodes (VOE) are a principal cause of morbidity and account for a significant number of emergency department and hospital admissions. When untreated or inadequately managed, the pain of VOE may cause both short- and long-term consequences. Despite the fact that pain is an almost universal feature of the disease, children with SCD may form one of the most undertreated and understudied populations. One of the factors contributing to poor pain management is conflicting perceptions between patients, their families, and healthcare professionals about pain that is reported and analgesia that is required. Pain management guidelines have recently been published in an effort to overcome barriers in the assessment and management of pain related to SCD. Although there is considerable variability in the way SCD pain is managed, the standard treatment protocol for painful episodes has been rest, rehydration, and analgesia. However, pain control for children with SCD is often a difficult and complex process, and one that requires frequent systematic pain assessments and continuous adjustment of comfort measures, especially analgesics. There are a variety of analgesic agents to choose from, such as acetaminophen (paracetamol), oral or parenteral nonsteroidal anti-inflammatory drugs, and oral or parenteral opioids. Each of these options has advantages and disadvantages to their use. Continuous infusions of analgesics and patient controlled analgesia have been shown to be effective and widely used in hospital settings to manage severe pain. However, the opioid dose required to achieve pain relief varies considerably within each painful episode, from one episode to another, and between individual patients. Although not yet curable in humans, pain related to SCD can be effectively managed in most patients by using a comprehensive approach that incorporates pharmacologic, psychologic, behavioral, and physical pain management strategies.

Management of vaso-occlusive pain in children with sickle cell disease

PURPOSE

A descriptive, longitudinal design was used to evaluate the pain management strategies used in children with sickle cell disease who were experiencing pain during a vaso-occlusive episode.

METHODS

A list of the medications (name, amount, mode of delivery, and frequency) prescribed and administered for pain management for each participant was recorded on the Medication Quantification Scale Worksheet, starting from day 1 of hospitalization to the day of discharge. Children were asked once each evening to provide three separate ratings of how much the pain medication helped them during the day, evening, and night using a 0-to-10 rating scale.

RESULTS

Using patient-controlled analgesia (PCA), children self-administered only 35% of the analgesic medications that were prescribed and reported little pain relief. No significant relationships were found between changes in pain relief scores and the amount of analgesics administered.

CONCLUSIONS

Clinicians need to monitor the amount of analgesics delivered in relationship to pain relief and assist children to titrate PCA administration of analgesics to achieve optimal pain control, or to advocate for changes in the PCA regimen when children cannot assume control of pain management.

Treatment of sickle cell pain

Sickle cell disease affects 70,000 Americans who experience an average of 0.8 painful episodes each year. The pathophysiology of sickle cell pain is not completely understood. The disease is characterized by both acute and chronic pain syndromes. Patients with sickle cell pain often encounter barriers to receiving appropriate care, including lack of continuity of care and perceived opiate addiction. Studies describing pharmacotherapy for sickle cell pain have been primarily retrospective and uncontrolled. In analyzing the available literature regarding pathophysiology, assessment, and treatment of sickle cell pain, we found a need for increased practitioner education and intervention to improve the level of care provided to patients with this disease.

Transdermal fentanyl for pain relief in a paediatric palliative care population

This multicentre, observational study examined the efficacy of the therapeutic transdermal fentanyl system (TTS-fentanyl) in children requiring opioids for pain in life-threatening disease. Forty-one children receiving oral morphine (median dose 60 mg/day) transferred to transdermal fentanyl (median dose 25 micrograms/h according with the manufacturer's dose conversion guidelines). Twenty-six children completed the 15-day treatment phase, seven died due to disease progression and eight were withdrawn because of adverse events, inadequate analgesia or a change to parenteral opioids. After 15 days, the median fentanyl dose was 75 micrograms/h (range 25-250). No serious adverse events were attributed to fentanyl. There was a trend toward improved side-effects and convenience with fentanyl. Twenty-three of 26 parents (three missing) and 25 of 26 investigators considered transdermal fentanyl to be better than previous treatment. For all records available (at 15 days or on withdrawal if earlier), 75% (27/36) reported that fentanyl treatment was 'good' or 'very good'. The findings suggest that transdermal fentanyl is both effective and acceptable for children and their families.

The management of pain in sickle cell disease

The pain of vaso-occlusive crisis in patients with sickle cell disease is excruciating, incapacitating, and sometimes refractory to even the most advanced analgesic treatments. A comprehensive, multimodal approach to therapy that includes education, cognitive therapies, anti-inflammatory drugs, opioids, and psychostimulant adjuvant drugs has been presented. Until a cure for the underlying disease is found, these are the best approaches available. The authors hope that future research will find even better modalities of analgesic care.

Judging the effectiveness of analgesia for children and adolescents during vaso-occlusive events of sickle cell disease

The effectiveness of analgesia during sickle cell crisis was examined in this descriptive, exploratory study. Pain scores (using the African-American Oucher and the Adolescent Pediatric Pain Tool) and analgesics administered were examined during a 2-hour observation/interview in the hospital while children/adolescents with sickle cell disease (SCD) experienced a vaso-occlusive episode (VOE). A convenience sample of twenty-one 6- to 16-year olds with SCD was included. Evidence indicated that 15 of the 21 children in the sample were in moderate to severe pain during their interviews, indicating that the analgesics did not effectively control their pain. Most participants (17) had received nalbuphine as the primary analgesic by intravenous infusion drip and/or patient-controlled analgesia pump. Many reasons were identified for the inadequate analgesia. The results suggested that the pain of SCD is very complex, requiring continuous adjustment of comfort measures, especially analgesics. More research is needed to examine pain control in children with SCD.

Population pharmacokinetics of oral morphine and its glucuronides in children receiving morphine as immediate-release liquid or sustained-release tablets for cancer pain

OBJECTIVES

(1) To determine the pharmacokinetics of morphine, morphine-6-glucuronide (M6G), and morphine-3-glucuronide (M3G) in children with cancer receiving morphine as immediate-release morphine liquid or sustained-release tablets. (2) To determine differences with age within the group and from adults. (3) To explore relationships between plasma concentration and pain measurements.

STUDY DESIGN

Blood samples were collected and plasma analyzed by high-performance liquid chromatography with electrochemical and fluorescence detection. Population pharmacokinetic parameters were derived with the program P-PHARM.

RESULTS

Forty children with a median age of 11.4 years (range 1.7 to 18.7 years) received a median dose of 1.4 mg/kg/d (range 0.4 to 24.6 mg/kg/d). A median of 4 blood samples per child was collected. Plasma clearance of morphine was 23.1 mL/min per kg body weight. The volume of distribution was 5.2 L/kg. Molar ratios of M3G/morphine, M6G/morphine, and M3G/M6G were 21.1, 4.7, and 4.2, respectively. Children <11 years had significantly higher clearance and larger volume of distribution for morphine and its glucuronides than older children and adults. Regression analysis indicated average plasma morphine concentration equal to dose (mg/kg/d) x 8.6 (95% confidence interval 7.4 to 9.9). Significant pain was present in 30% of the children. Higher pain scores were recorded in children with average morphine concentrations <12 ng/mL (P <.01 MW).

CONCLUSION

Age differences in morphine pharmacokinetics exist within children and compared with adults. The study supports a starting dose of 1.5 to 2. 0 mg/kg/d to provide plasma morphine concentrations >12 ng/mL in children with cancer pain unrelieved by mild to moderate strength analgesia.

Morphine and morphine-6-glucuronide in the plasma and cerebrospinal fluid of children

AIMS

To measure morphine and morphine-6-glucuronide in the plasma and cerebrospinal fluid of children following a single intravenous dose of morphine.

METHODS

Twenty-nine paired samples of cerebrospinal fluid and plasma were collected from children with leukaemia undergoing therapeutic lumbar puncture. An intravenous dose of morphine was administered at selected intervals before the procedure. Concentrations of morphine and morphine-6-glucuronide (M6G) were measured in each sample. Morphine was measured using a specific radioimmunoassay (r.i.a.) and M6G was measured using a novel enzyme-linked immunosorbent assay (ELISA).

RESULTS

The ELISA for measuring M6G was highly sensitive. The intra-and interassay variations were less than 15%. Using a two-compartment model for plasma morphine, the area under the curve to infinity (AUC, 7143 ng ml-1 min), volume of distribution (3.6 l kg-1 ) and elimination half-life (88 min) were comparable with those reported in adults. Clearance (35 ml min-1 ) was higher than that in adults. Morphine-6-glucuronide was readily synthesized by the children in this study. The elimination half-life (321 min) and AUC (35507 ng ml-1 min) of plasma M6G were much greater than those of morphine.

CONCLUSIONS

Extensive metabolism of morphine to M6G in children with cancer has been demonstrated. These data provide further evidence to support the importance of M6G accumulation after multiple doses. There was no evidence that morphine passed more easily into the CSF of children than adults.

Management of sickle cell pain crisis in the emergency department at teaching hospitals

The purpose of this study is to determine the frequency and variety of strategies being used in the Emergency Department (ED) management of sickle cell pain crisis (SCPC). One thousand randomly selected academic emergency physicians received a multiple-choice survey; 549 (55%) completed the survey. Forty-five percent of respondents treat patients with SCPC every week or almost every shift. Twenty percent use protocols for management of SCPC. Respondents consider pain refractory to outpatient treatment if it is persistent after two (23%) or three (53%) doses of parenteral analgesic. Meperidine or morphine is the most common initial analgesic. In the routine management of uncomplicated SCPC, i.v. analgesics, i.v. hydration, oxygen therapy, and complete blood counts are often or always used by 67, 71, 66, and 82% of respondents, respectively. Some patterns in the diagnostic and therapeutic management of patients with SCPC in the ED are identified, but overall practice is highly variable. Some popular elements of care are divergent from those suggested by the scientific literature.

Randomised trial of oral morphine for painful episodes of sickle-cell disease in children

BACKGROUND

Oral controlled-release morphine can provide effective analgesia through a non-invasive route and may facilitate outpatient management of severe episodes of sickle-cell pain. We compared the clinical efficacy and safety of oral morphine with continuous intravenous morphine in children with severe episodes of sickle-cell pain, by a double-blind, randomised, parallel-group design.

METHODS

56 children aged 5-17 years received loading doses of intravenous morphine of up to 0.15 mg/kg, followed by randomly assigned oral morphine 1.9 mg/kg every 12 h plus intravenous placebo (saline), or intravenous morphine 0.04 mg kg-1 h-1, plus placebo tablet. Breakthrough pain was treated with oral, immediate-release morphine 0.4 mg/kg every 2-3 h as required. Pain was assessed daily at 0900 h, 1300 h, 1700 h, and 2100 h with a picture face scale, a pictorial scale (Oucher), a behavioural-observational scale (CHEOPS), and by an investigator.

FINDINGS

50 children completed the study (28 boys, 22 girls; mean age 11.2 years [SD 3.5]; mean oral morphine dose 2.99 mg/kg daily [0.75]; mean intravenous morphine dose, 0.81 mg/kg daily [0.30]). Mean overall pain scores were similar for oral and intravenous morphine (CHEOPS, 6.3 [1.5] vs 6.4 [1.4], p = 0.8; Oucher, 31.5 [25.4] vs 39.2 [21.7], p = 0.3; Faces, 2.2 [1.4] vs 2.4 [1.3], p = 0.6; clinical rating, 1.7 [0.7] vs 1.9 [0.5], p = 0.3). Opioid analgesia was required for a mean of 4.2 days (1.7) and 5.4 days (2.6), respectively (p = 0.0591). Pain scores from all scales correlated significantly (r = 0.5865-0.8980, p = 0.0001). Frequency of rescue analgesia did not differ significantly between the oral and intravenous morphine groups (0.7 [0.8] vs 0.9 [0.7] doses daily, p = 0.2). Frequency and severity of adverse events did not differ significantly.

INTERPRETATION

Oral, controlled-release morphine is a reliable, non-invasive alternative to continuous intravenous morphine for the management of painful episodes of sickle-cell disease in children.

Recommended use of morphine in neonates, infants and children based on a literature review: Part 2--Clinical use

The indication for morphine use is primarily pain, but also a combined analgesic and sedative effect may be the rationale behind morphine administration. Paediatric morphine regimens have been reported for children with postoperative pain, pain related to cancer, sickle cell crisis pain, burns and AIDS. No dose response curve for morphine in neonates, infants or children has been established, and different levels for the minimum effective plasma concentration have been estimated. The side effects observed in neonates, infants, and children are similar to those observed in adults, and neonates do not seem to be more susceptible to respiratory depression than older children. Despite shortcomings in the knowledge of the pharmacodynamics of morphine, it can be considered safe to administer morphine to neonates, infants or children. Initial regimens has been calculated from the pharmacokinetic parameters of morphine, but treatment must be adjusted according to analgesic effect and incidence of side effects.

A review of evidence about factors affecting quality of pain management in sickle cell disease

OBJECTIVE

To assess the evidence for pharmacological, behavioural, and interpersonal influences on quality of pain management in sickle cell disease.

DATA SOURCES

English-language reports from the research literature up to 1995, identified using Medline, Psychlit, and the Bath Information Data Service.

STUDY SELECTION

Studies are reviewed that (a) reported quantitative clinical outcomes for particular analgesic methods used to treat painful episodes or (b) provide data on patient factors, interpersonal treatment factors, or levels of drug dependence in relation to pain management in sickle cell disease.

DATA SYNTHESIS

Findings vary on the effectiveness of longer-acting opiates, patient-controlled or continuously infused analgesia, and behavioural analgesic techniques, with better results for trials where interpersonal aspects of pain management were also addressed. Risks for poorer pain management are greatest for patients in adverse social circumstances, who are more severely affected by painful episodes and who are poorly adjusted and have less effective personal strategies for coping with pain, but the limited evidence on drug dependence indicates very low levels by comparison with risk and exposure factors.

CONCLUSIONS

Analgesic methods and approaches should continue to be developed and evaluated, but conflicting perceptions between patients and staff about pain that is reported and analgesia that is required probably contribute most to poor pain management in sickle cell disease. Promising areas for future research include the assessment of patients' everyday pain coping styles and patterns of drug use in relation to their hospital experiences of pain management, and the evaluation of psychological interventions to improve patients' styles and strategies for coping with pain.

Intravenous morphine pharmacokinetics in pediatric patients with sickle cell disease

To examine the pharmacokinetics of parenteral opioids, such as morphine, in patients with sickle cell disease, we determined the plasma morphine clearances in 18 patients (aged 6 to 19 years) who were receiving continuous intravenous infusions, and the pharmacokinetics of morphine in an additional six patients after single intravenous doses. Plasma morphine clearances ranged from 6.2 to 59.1 ml min-1 kg-1 (35.5 +/- 12.4, mean +/- SD) during steady-state infusions. There was a negative correlation between clearance values and age over the age range studied (p = 0.013). A significant difference (p = 0.042) was also observed in clearance values between patients who had serious adverse symptoms (23.4 +/- 10.7 ml min-1 kg-1) and those who had less serious symptoms (36.3 +/- 6.4 ml min-1 kg-1) when morphine was given at high dosage rates (> or = 0.15 mg kg-1 hr-1). Pharmacokinetic modeling of plasma morphine concentrations adequately fit a two-compartment model with a short initial distribution phase (mean half-life = 4.5 minutes) and a rapid terminal elimination half-life (77.6 +/- 19.2 minutes). These findings suggest that considerable individualization of morphine dosing may be necessary to achieve optimal analgesia and minimal adverse effects in these patients.