Risks and benefits of nonsteroidal anti-inflammatory drugs in children: a comparison with paracetamol

Plasma and cerebrospinal fluid pharmacokinetics of flurbiprofen in children

AIMS

This study was designed to characterize paediatric pharmacokinetics and central nervous system exposure of flurbiprofen.

METHODS

The pharmacokinetics of flurbiprofen were studied in 64 healthy children aged 3 months to 13 years, undergoing surgery with spinal anaesthesia. Children were administered preoperatively a single dose of flurbiprofen intravenously as prodrug (n= 27) or by mouth as syrup (n= 37). A single cerebrospinal fluid (CSF) sample (n= 60) was collected at the induction of anaesthesia, and plasma samples (n= 304) before, during and after the operation (up to 20 h after administration). A population pharmacokinetic model was built using the NONMEM software package.

RESULTS

Flurbiprofen concentrations in plasma were well described by a three compartment model. The apparent bioavailability of oral flurbiprofen syrup was 81%. The estimated clearance (CL) was 0.96l h(-1) 70 kg(-1) . Age did not affect the clearance after weight had been included as a covariate. The estimated volume of distribution at steady state (V(ss) ) was 8.1 l 70 kg(-1) . Flurbiprofen permeated into the CSF, reaching concentrations that were seven-fold higher compared with unbound plasma concentrations.

CONCLUSIONS

Flurbiprofen pharmacokinetics can be described using only weight as a covariate in children above 6months, while more research is needed in neonates and in younger infants.

Ketoprofen pharmacokinetics, efficacy, and tolerability in pediatric patients

The NSAID ketoprofen is used widely in the management of inflammatory and musculoskeletal conditions, pain, and fever in children and adults. Pharmacokinetic studies show that drug exposure after a single intravenous dose is similar in children and adults (after dose normalization), and thus similar mg/kg bodyweight dosing may be used in children and adults. Ketoprofen crosses the blood-brain barrier and therefore has the potential to cause central analgesic effects. Ketoprofen has been investigated in children for the treatment of pain and fever, peri- and postoperative pain, and inflammatory pain conditions. The results of four clinical trials in febrile conditions with the oral syrup formulation indicate that ketoprofen is as effective as acetaminophen (paracetamol) and ibuprofen, allowing children to rapidly return to daily activities with improvements in sleep quality and appetite. Studies of ketoprofen in the management of postoperative pain indicate that ketoprofen is a highly effective analgesic when administered perioperatively for a variety of surgical types, by a variety of routes, and whether given preoperatively or postoperatively. For adenoidectomy, intravenous ketoprofen provided superior postoperative analgesic efficacy compared with placebo. Analgesic efficacy was similar with intravenous, intramuscular, or rectal routes of administration, but oral administration just before surgery was inferior to intravenous administration in this setting. In patients undergoing a tonsillectomy, intravenous ketoprofen was superior to intravenous tramadol in terms of the need for postoperative rescue analgesia, but did not remove the need for rescue opioid therapy in these patients. Intravenous ketoprofen had superior postoperative analgesic efficacy to placebo when given as an adjuvant to epidural sufentanil analgesia after major surgery. Oral ketoprofen has shown efficacy in the treatment of juvenile rheumatoid arthritis. Ketoprofen is generally well tolerated in pediatric patients. Most of the adverse events reported are mild and transient, and are similar to those observed with other NSAIDs. Long-term tolerability has not yet been fully established in children, but data from three studies in >900 children indicate that oral ketoprofen is well tolerated when administered for up to 3 weeks after surgery. In conclusion, ketoprofen is effective and well tolerated in children for the control of post-surgical pain and for the control of pain and fever in inflammatory conditions.

Prevention of pain on injection of propofol: a comparison of lidocaine with different doses of paracetamol

BACKGROUND AND OBJECTIVE

The aim of this study was to compare the efficacy of pretreatment with paracetamol 0.5 mg kg(-1), 1 mg kg(-1), 2 mg kg(-1) and lidocaine 0.5 mg kg(-1) for prevention of propofol induced pain.

METHODS

In this double-blind, placebo-controlled study, 250 adult patients ASA I or II, scheduled to undergo elective surgery, were randomly assigned into five groups of 50 each. Group P0.5, group P1 and group P2 received 0.5, 1 and 2 mg kg(-1) paracetamol respectively; group L received 0.5 mg kg(-1) lidocaine; and the control group, group C, received isotonic saline pretreatment in the dorsum of the hand, followed by propofol 1 min later. A blinded researcher assessed the patient's pain level via a four-point scale.

RESULTS

There were no significant differences in patient characteristics among the groups. The incidence of propofol injection pain in all treatment groups was significantly lower than in the control group (P < 0.001). When the paracetamol 0.5 mg kg(-1) group was compared with both the paracetamol 1 mg kg(-1) group (P < 0.01) and the paracetamol 2 mg kg(-1) group (P < 0.001), significant differences were observed. In the lidocaine 0.5 mg kg(-1) group propofol injection pain was significantly reduced compared with the paracetamol 0.5 mg kg(-1) group (P < 0.01). However, in the paracetamol 2 mg kg(-1) group pain was more significantly reduced than in the lidocaine 0.5 mg kg(-1) group (P < 0.001). In the paracetamol 2 mg kg(-1) group the incidence of pain was significantly less than in paracetamol 1 mg kg(-1) group (P < 0.001).

CONCLUSION

When given as venous retention pretreatments 1 min before propofol, paracetamol 1 mg kg(-1) and lidocaine 0.5 mg kg(-1) were equally effective in attenuating pain during intravenous (i.v.) injection of propofol whereas pretreatment with paracetamol 2 mg kg(-1) was shown to be the most effective treatment.

Teat tablet with sodium ibuprofen: the effect of sorbitol on therapeutic agent pharmaceutical availability and on physicochemical parameters of a drug form

Dosing pediatric drugs available on pharmaceutical markets of analgesic, antifebrile and anti-inflammatory activity to children up to 3 years of age is not precise and frequently causes problems. The aim of the study was to work out a pediatric teat form of a drug with sodium ibuprofen and to determine the effect of sorbitol content on pharmaceutical availability of the therapeutic agent. Three variants of tablets containing 50 mg of sodium ibuprofen differing in the percentage content of sorbitol (from 37% - batch I to 79% - batch III) were produced. Quality tests of the produced forms of drugs (PPVI) were performed and the tests of therapeutic agent pharmaceutical availability by spatula method and by a method with a teat. Tablets of all batches had a smooth surface and same shape. The content of the therapeutic agent was within the limit of 95-105% of the declared value. The highest value of Q coefficient in the release test by pharmacopeal method and the shortest disintegration time (12 minutes) were obtained for tablets with 79% content of sorbitol. In conclusion, teat tablets with sodium ibuprofen of the highest sorbitol content (79%) demonstrated the expected physicochemical parameters and high pharmaceutical availability.

Nephrotoxicity as a cause of acute kidney injury in children

Many different drugs and agents may cause nephrotoxic acute kidney injury (AKI) in children. Predisposing factors such as age, pharmacogenetics, underlying disease, the dosage of the toxin, and concomitant medication determine and influence the severity of nephrotoxic insult. In childhood AKI, incidence, prevalence, and etiology are not well defined. Pediatric retrospective studies have reported incidences of AKI in pediatric intensive care units (PICU) of between 8% and 30%. It is widely recognized that neonates have higher rates of AKI, especially following cardiac surgery, severe asphyxia, or premature birth. The only two prospective studies in children found incidence rates of 4.5% and 2.5% of AKI in children admitted to PICU, respectively. Nephrotoxic drugs account for about 16% of all AKIs most commonly associated with AKI in older children and adolescents. Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, amphotericin B, antiviral agents, angiotensin-converting enzyme (ACE) inhibitors, calcineurin inhibitors, radiocontrast media, and cytostatics are the most important drugs to indicate AKI as significant risk factor in children. Direct pathophysiological mechanisms of nephrotoxicity include constriction of intrarenal vessels, acute tubular necrosis, acute interstitial nephritis, and-more infrequently-tubular obstruction. Furthermore, AKI may also be caused indirectly by rhabdomyolysis. Frequent therapeutic measures consist of avoiding dehydration and concomitant nephrotoxic medication, especially in children with preexisting impaired renal function.

The safety of concurrent administration of opioids via epidural and intravenous routes for postoperative pain in pediatric oncology patients

Supplementation of epidural opioid analgesia with intravenous opioids is usually avoided because of concern about respiratory depression. However, the choice of adjunct analgesic agents for pediatric oncology patients is limited. Antipyretic drugs may mask fever in neutropenic patients, and nonsteroidal anti-inflammatory agents may exert antiplatelet effects and interact with chemotherapeutic agents. We examined the safety of concurrent use of epidural and intravenous opioids in a consecutive series of 117 epidural infusions in pediatric patients and compared our findings to those reported by other investigators. We observed a 0.85% rate of clinically significant respiratory complications. The single adverse event was associated with an error in dosage. In our experience, the supplementation of epidural opioid analgesia with intravenous opioids has been a safe method of postoperative pain control for pediatric patients with cancer.

Antipyretic drug use in children in French office based medical practice

PURPOSE

To analyse antipyretics (APs) prescriptions profile in children, particularly the frequency of AP combinations.

METHODS

APs (acetylsalicylic acid, paracetamol, ibuprofen or ketoprofen) prescribed to children below 12 years and refunded by a public health insurer in 2003, throughout France, were examined.

RESULTS

A total of 513 034 prescriptions were refunded for 240 720 children. The mean number of AP prescriptions per child was the highest in children aged 6 months to 2 years. Paracetamol was the main AP prescribed, but its prescription declined with age, from 90.8% below 3 months old to 57.4% between 6 and 12 years old. Ibuprofen-only prescriptions were rare below 3 months and maximal between 2 and 6 years. The ibuprofen/paracetamol combination was prescribed from 6 months old, and its frequency was maximal between 2 and 6 years old (21.7%).

CONCLUSIONS

The clear predominance of paracetamol prescriptions suggests that French prescribers are relatively aware of the relative risk-benefit ratio of the different APs. Studies are required to determine if the APs are prescribed to be used alternately or when a monotherapy fails. Guidelines to manage fever in children are needed in France to restrict APs combination to the case of paracetamol failure.

Upper gastrointestinal complications associated with NSAIDs in children

OBJECTIVE

To analyse serious upper gastrointestinal (UGI) complications associated with non-salicylate non-steroidal anti-inflammatory drugs (NSAIDs) in children.

METHODS

All serious UGI complications associated with non-salicylate NSAIDs approved in France to treat moderate pain or fever in children, spontaneously reported to the French Pharmacovigilance system or to the companies, between the launching of each study drug in France to December 31, 2000.

RESULTS

Serious UGI complications were reported in 61 children aged from 11 months to 15 years during treatment with niflumic acid (27), ibuprofen (23) and tiaprofenic acid (11). No case was reported with ketoprofen. UGI manifestations were UGI bleeding (15) and 46 gastrointestinal symptoms with endoscopic lesions i.e. gastritis (18), gastric ulcer (13), duodenal ulcer (7), duodenitis (4) and oesophageal ulcer (4). NSAID was combined with a salicylate in 36% of cases, given by the parents in self medication in 6.6% of cases and used outside its product licence in 33.8% of cases.

CONCLUSION

NSAIDs used in children for fever or moderate pain are associated with a risk of serious UGI complications which increases with length, dose and association with a salicylate.

Use of nonsteroidal anti-inflammatory drugs in infants. A survey of members of the Association of Paediatric Anaesthetists of Great Britain and Ireland

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used as perioperative analgesics. Many are currently used off label. Diclofenac is currently licensed for use in children over 1 year of age for the treatment of juvenile rheumatoid arthritis, while ibuprofen is licensed for use in children weighing over 7 kg. The dose and interval in children is currently extrapolated from adult studies, as the pharmacokinetic (PK) and pharmacodynamic (PD) data are lacking in infants.

METHODS

A postal questionnaire was sent to members of the Association of Paediatric Anaesthetist of Great Britain and Ireland seeking to clarify members' prescribing patterns of NSAIDs, especially in infants. Information regarding the choice of NSAIDS, route of administration, lower age limit, dose interval, dose and practice in two specific perioperative contexts (adenotonsillectomy and open heart surgery) was sought.

RESULTS

The response rate was 80%. NSAIDs are used by 86% of responders in infants. Diclofenac is most commonly used intraoperatively (78%); while ibuprofen (73%) was used more frequently postoperatively. NSAIDs are used by 21% of respondents in ICU. Commonest routes of administration were oral (81%) and rectal (80%), rarely intravenously (9%). The commonest dose for diclofena is 1 mg x kg(-1) (59%); the dosing schedule employed being 8 hourly in 53% of cases. NSAIDs are used by 57% of responders as part of their analgesic regime for adenotonsillectomies.

CONCLUSION

Members of the Association of Paediatric Anaesthetists of Great Britain and Ireland commonly prescribe NSAIDs in infants. This is despite the dearth of PK and PD data in this age group.

[Ibuprofen in childhood: evidence-based review of efficacy and safety]

Ibuprofen is the non-steroidal anti-inflammatory drug most prescribed for the treatment of fever and moderate pain in childhood. Its analgesic and antipyretic efficacy is now well documented: at equal doses ibuprofen appears slightly more effective than acetaminophen in the treatment of fever and is equivalent for analgesia. However, adverse effects should be taken into account in the choice between ibuprofen and acetaminophen. Lot of studies (case reports, cohort studies, case-control studies and one multicenter double-blind randomized control trial) have reported ibuprofen adverse effects at therapeutics doses. These data suggest there is an increased risk of invasive group A streptococcal infection after chickenpox and of acute renal failure in case of hypovolemia after a treatment by ibuprofen. Gastroduodenal and hemorrhagic adverse events could also happen, but the causality with ibuprofen is not demonstrated. Therefore, ibuprofen is not recommended for the treatment of fever or moderate pain during chickenpox or during a disease with a risk of dehydration, until other pharmacoepidemiology studies more accurately quantify the risk of adverse events of ibuprofen in children.

[Analgesic/Antipyretic treatment: ibuprofen or acetaminophen? An update]

Because of the adverse effects associated with aspirin, especially Reye's syndrome in children, practitioners currently use as first line therapy drugs such as ibuprofen or acetaminophen. Their pharmacokinetic characteristics are not quite identical: both are absorbed rapidly and have high bioavailability, however, unlike acetaminophen, ibuprofen is characterized by high plasma protein binding and a limited distribution volume. Both drugs are metabolized essentially in the liver into inactive hydroxylated or glucoronidated metabolites by conjugation but acetaminophen is also transformed into an oxidation compound--normally reduced by glutathione--which, in the case of acute overdosing with depletion of endogenous glutathione stores, may lead to severe hepatotoxicity. Old age and light to moderate renal or hepatic failure do not significantly modify their pharmacokinetic parameters, and thus do not call for dose adjustment. Clinical trials have shown both drugs to have comparable efficacy on pain and fever, with perhaps a slight advantage for ibuprofen. In practice, the choice will depend on the prescription habits of the practitioner, patient's (or parents') preferences and, above all, the pathological context and possible contra-indications.

Pain control: non-steroidal anti-inflammatory agents

The non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen (paracetamol) are the most common analgesic drugs used in neonates and infants despite limited pharmacodynamic data. Both drugs act through inhibition of cyclooxygenase enzymes. Neonatal acetaminophen clearance is reduced in premature neonates (0.7 L h(-1) x 70 kg(-1)) and increases to 5 L h(-1) x 70 kg(-1) at term (40% adult rates); adult rates are reached within the first year of life; NSAID clearance follows similar trends. Volume of distribution is increased in the neonatal period. Dosing of both drug groups is tempered by concerns about toxicity. Acetaminophen hepatotoxicity is less common in neonates than in older children and adults, possibly due to reduced oxidative enzyme activity (e.g. CYP 2E1). Data concerning NSAID adverse effects in the neonatal period are few. Renal function is reduced 20% after NSAID use for patent ductus arteriosus closure in premature neonates and there is no increased frequency of intraventricular haemorrhage. No significant difference in the change in cerebral blood volume, change in cerebral blood flow, or tissue oxygenation index was found between administration of ibuprofen or placebo in neonates. Future studies should define concentration-response relationships for these drugs that are age and pathology specific.

Report of an Anaphylactoid and an Anaphylactic Reaction to Ketorolac in Two Pediatric Surgical Patients

Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its potential adverse effects. The diagnostic and ethical challenges of 2 children who had unpredictable adverse drug reactions to ketorolac are reported. Case 1: A 3-year-old boy received ketorolac 1 mg/kg for prevention of postoperative pain at the end of an orthopedic surgical procedure. Ten minutes later, he had bilateral palpebral edema, erythema in thorax, hypotension, and tachycardia. The adverse event was classified as a mixed reaction probably related to ketorolac. Case 2: A 7-year-old girl, who had previously received ketorolac in 2 different surgical procedures, underwent a third orthopedic surgery. She received ketorolac 1 mg/kg as pre-emptive analgesia at 1.5 hours of anesthetic time (approximately 1 hour of surgical time). The patient developed palpebral edema 5 minutes later in addition to erythema in thorax, hypotension, tachycardia, tachypnea, oxygen desaturation, and wheezing. The adverse event was classified as a systemic reaction probably related to ketorolac. The 2 patients were successfully treated with symptomatic therapy. Although rare in its frequency, ketorolac administration may be associated to anaphylactic and anaphylactoid reactions in children with or without history of previous exposure. Because ketorolac is off-licensed for pediatric patients, it should be administered only after the risks and benefits have been discussed with the child's parents in the preanesthetic consultation.

Analgesia and local anesthesia during invasive procedures in the neonate

BACKGROUND

Preterm and full-term neonates admitted to the neonatal intensive care unit or elsewhere in the hospital are routinely subjected to invasive procedures that can cause acute pain. Despite published data on the complex behavioral, physiologic, and biochemical responses of these neonates and the detrimental short- and long-term clinical outcomes of exposure to repetitive pain, clinical use of pain-control measures in neonates undergoing invasive procedures remains sporadic and suboptimal. As part of the Newborn Drug Development Initiative, the US Food and Drug Administration and the National Institute of Child Health and Human Development invited a group of international experts to form the Neonatal Pain Control Group to review the therapeutic options for pain management associated with the most commonly performed invasive procedures in neonates and to identify research priorities in this area.

OBJECTIVE

The goal of this article was to review and synthesize the published clinical evidence for the management of pain caused by invasive procedures in preterm and full-term neonates.

METHODS

Clinical studies examining various therapies for procedural pain in neonates were identified by searches of MEDLINE (1980-2004), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2004), the reference lists of review articles, and personal files. The search terms included specific drug names, infant-newborn, infant-preterm, and pain, using the explode function for each key word. The English-language literature was reviewed, and case reports and small case series were discarded.

RESULTS

The most commonly performed invasive procedures in neonates included heel lancing, venipuncture, IV or arterial cannulation, chest tube placement, tracheal intubation or suctioning, lumbar puncture, circumcision, and SC or IM injection. Various drug classes were examined critically, including opioid analgesics, sedative/hypnotic drugs, nonsteroidal anti-inflammatory drugs and acetaminophen, injectable and topical local anesthetics, and sucrose. Research considerations related to each drug category were identified, potential obstacles to the systematic study of these drugs were discussed, and current gaps in knowledge were enumerated to define future research needs. Discussions relating to the optimal design for and ethical constraints on the study of neonatal pain will be published separately. Well-designed clinical trials investigating currently available and new therapies for acute pain in neonates will provide the scientific framework for effective pain management in neonates undergoing invasive procedures.

Current management of pediatric postoperative pain

Pain is a common complaint in children after surgery. Four out of five children require analgesia even after minor surgery, and after more extensive surgery, significant postoperative pain may last for weeks. Severe pain during, and after surgery may aggravate long-lasting negative effects to the body and mind. In order to prevent harmful effects, all children should be provided with effective analgesia. Pain management should be safe and easy to administer. Postoperative pain management in children has improved substantially during the last 5 years. Recent trials indicate that children may undergo major surgery with minimal untoward effects when effective proactive pain management is provided. This review will focus on new clinical strategies on pain management in children. Since most pediatric surgery is performed as a day-case or short-stay basic recommendations for parental guidance and pain management after discharge are also presented.

NSAIDs in neuroblastoma therapy

Cyclooxygenases (COX) catalyse the conversion of arachidonic acid to prostaglandins. COX-2 is upregulated in several adult epithelial cancers. In neuroblastoma it has been shown that the majority of primary tumours and cell lines express high levels of COX-2, whereas normal adrenal medullas from children do not express COX-2. Treatment of neuroblastoma cells with nonsteroidal anti-inflammatory drugs (NSAIDs), inhibitors of COX, induces caspase-dependent apoptosis via the intrinsic mitochondrial pathway. Established neuroblastoma xenografts in nude rats treated with the dual COX-1/COX-2 inhibitor, diclofenac, or the COX-2 specific inhibitor, celecoxib significantly inhibits neuroblastoma growth in vivo. In vitro, arachidonic acid and diclofenac synergistically induces neuroblastoma cell death. This effect is further pronounced when lipoxygenases is inhibited simultaneously. Proton MR-spectroscopy (1H MRS) of neuroblastoma cells treated with COX-inhibitors demonstrates accumulation of polyunsaturated fatty acids and depletion of choline compounds. Thus, 1H MRS, which can be performed with clinical MR-scanners, is likely to provide pharmacodynamic markers of neuroblastoma response to COX-inhibition. Taken together, these data suggest the use of NSAIDs as a novel adjuvant therapy for children with neuroblastoma.

[Familial use of ibuprofen in febrile children: a prospective study in the emergency room of an hospital in Lille]

AIM OF THE STUDY

To assess the place of ibuprofen in the treatment of fever in children.

PATIENTS AND METHODS

An anonymous self-questionnaire was submitted to the parents of 156 children aged less than 15 years and 3 months consulting for a fever in a pediatric emergency care unit. Questions related antipyretic drugs availability at home and their administration modality to the febrile child.

RESULTS

Acetaminophen (liquid or rectal) was the first drug owned by families (N = 149, 96%). Ibuprofen was owned by 79 families (51%). The antipyretic drug administered as a first intention treatment was acetaminophen in 131 children (77%), ibuprofen in 27 (17%) and aspirin in 6 children (4%). An antipyretic bi-therapy was received by 58 children (35%), nearly always acetaminophen and ibuprofen (N = 48, 87%). The use of a bi-therapy was more frequent when ibuprofen was the first drug used. Children who received an antipyretic bi-therapy as compared to those who received a monotherapy exhibited significantly a higher fever level and long lasting fever period. Antipyretic drugs given to the sick children were prescribed by a physician in more than 90% of cases.

CONCLUSION

Ibuprofen was largely used in febrile children. This drug has almost always been prescribed by a physician. However, due to its side effects, ibuprofen should be used only in high and badly tolerated fever that is not altered by a well conducted acetaminophen monotherapy.

[Study of the extent and rate of bioavailability of ibuprofen tablets]

The extent and rate of bioavailability of ibuprofen tablets were determined in a crossover clinical trial in 18 healthy subjects of both sexes. The study was approved by the local ethical committee and was authorized by the Spanish Medicines Agency. Volunteers signed an informed consent form and were included in accordance with the standard procedures for this type of study. In two distinct sessions participants received a single 600 mg ibuprofen dose as Gelofeno(®) 600 mg tablets (Laboratorios Gelos S.L.), or as the reference formulation, Neobrufen(®) 600 mg tablets. Ibuprofen concentrations in plasma were determined immediately before (0 h) and 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12 and 24 h after drug administration. The pharmacokinetic parameters were then calculated. In all subjects, Gelofeno(®) 600 mg tablets produced plasma concentrations above the quantification limit between 15 and 30 minutes after administration, and in 9 (50%) of these subjects maximal plasma concentrations were reached at 1 h. The median t(max) was 1.25 h, and the average maximal plasma concentration was 40.7 mg/l. Gelofeno(®) 600 mg tablets were bioequivalent both in extent and in rate of bioavailability compared with the reference drug. The formulation showed good tolerability and no medication-related adverse effects were observed.

Analgesia and anesthesia for neonates: Study design and ethical issues

OBJECTIVE

The purpose of this article is to summarize the clinical, methodologic, and ethical considerations for researchers interested in designing future trials in neonatal analgesia and anesthesia, hopefully stimulating additional research in this field.

METHODS

The MEDLINE, PubMed, EMBASE, and Cochrane register databases were searched using subject headings related to infant, newborn, neonate, analgesia, anesthesia, ethics, and study design. Cross-references and personal files were searched manually. Studies reporting original data or review articles related to these topics were assessed and critically evaluated by experts for each topical area. Data on population demographics, study characteristics, and cognitive and behavioral outcomes were abstracted and synthesized in a systematic manner and refined by group members. Data synthesis and results were reviewed by a panel of independent experts and presented to a wider audience including clinicians, scientists, regulatory personnel, and industry representatives at the Newborn Drug Development Initiative workshop. Recommendations were revised after extensive discussions at the workshop and between committee members.

RESULTS

Designing clinical trials to investigate novel or currently available approaches for analgesia and anesthesia in neonates requires consideration of salient study designs and ethical issues. Conditions requiring treatment include pain/stress resulting from invasive procedures, surgical operations, inflammatory conditions, and routine neonatal intensive care. Study design considerations must define the inclusion and exclusion criteria, a rationale for stratification, the confounding effects of comorbid conditions, and other clinical factors. Significant ethical issues include the constraints of studying neonates, obtaining informed consent, making risk-benefit assessments, defining compensation or rewards for participation, safety considerations, the use of placebo controls, and the variability among institutional review boards in interpreting federal guidelines on human research. For optimal study design, investigators must formulate well-defined study questions, choose appropriate trial designs, estimate drug efficacy, calculate sample size, determine the duration of the studies, identify pharmacokinetic and pharmacodynamic parameters, and avoid drug-drug interactions. Specific outcome measures may include scoring on pain assessment scales, various biomarkers and their patterns of response, process outcomes (eg, length of stay, time to extubation), intermediate or long-term outcomes, and safety parameters.

CONCLUSIONS

Much more research is needed in this field to formulate a scientifically sound, evidence-based, and clinically useful framework for management of anesthesia and analgesia in neonates. Newer study designs and additional ethical dilemmas may be defined with accumulating data in this field.

Prevention and treatment of postoperative pain with particular reference to children

Pain therapy is an important aspect of medical practice for patients of all ages, to optimize care, to obtain an adequate quality of life and to improve their general conditions. Pain is among the most prevalent symptoms experienced by patients undergoing surgery. The success of postoperative pain therapy depends on the ability of the clinician to assess the presenting problems, identify and evaluate pain syndromes and formulate a plan for comprehensive continuing care. The prevalence of acute pain has led to the need to develop techniques for the assessment and management of this symptom in order to focus the attention on an interdisciplinary therapeutic approach (including pharmacologic, cognitive-behavioral, psychologic and physical treatment) and on the timing of different interventions (pre and postoperative). In this chapter we describe the principal therapeutic approaches to control pain in post-operative patients, such as non-opioid, opioid and adjuvant analgesics with particular attention in paediatric age. Moreover we report the principal scales to assess the pain intensity in the post-operative period. The need of a multidisciplinatory team and of a pre and postoperative pain management program represents an important goal in order to obtain effective pain relief and optimize pediatric care and rapid recovery. The introduction of a perioperative team service will improve the approach to pain management programs and it is considered the most important challenge for future.

Diclofenac and metabolite pharmacokinetics in children

BACKGROUND

Data concerning metabolism of diclofenac in children are limited to intravenous and enteric coated oral formulations. There are no data examining diclofenac or its hydroxyl metabolite pharmacokinetics after rectal administration in children.

METHODS

Infants (n = 26) undergoing tonsillectomy were given diclofenac 2 mg.kg(-1) followed by 1 mg.kg(-1) 8 h as suppository formulation for postoperative analgesia. Serum was assayed for diclofenac, 4'-hydroxydiclofenac and 5'-hydroxydiclofenac concentrations during the procedure and 1, 2 and 4 h postoperatively. The formation clearances of diclofenac to hydroxyl metabolites were estimated using nonlinear mixed effects models. A single compartment, first order absorption and first order elimination model was used to describe diclofenac pharmacokinetics. Published data from 11 children given enteric-coated diclofenac tablets were used to assess relative bioavailability.

RESULTS

Mean (sd) age and weight of the patients were 4.5 (1.5) years and 20.5 (4.1) kg. The formation clearance to 4'-hydroxydiclofenac (% CV) and to 5'-hydroxydiclofenac were 8.41 (8.1) and 3.41 (113) l.h(-1) respectively, standardized to a 70 kg person using allometric '1/4 power' models. Clearance by other routes contributed 33.0 (64) l.h(-1) 70 kg(-1). Elimination clearance of hydroxyl metabolites was fixed at 27.5 l.h(-1) 70 kg(-1). The volumes of distribution of parent diclofenac and its hydroxyl metabolite were 22.8 (19.0) and 45.3 (l.70) kg(-1). The suppository formulation had an absorption half-life of 0.613 (33.2) h with a lag time of 0.188 (24.9) h. Interoccasion variability of formation clearance to 4'-hydroxydiclofenac, diclofenac volume of distribution, absorption half-time and lag time for the suppository was 36%, 55%, 14% and 119%, respectively. The relative bioavailability of the suppository compared with an enteric-coated tablet was 1.26.

CONCLUSION

The formation clearance of the active metabolite 4'-hydroxydiclofenac contributed 19% of total clearance (44.82 l.h(-1) 70 kg(-1)). The rectum is a suitable route for administration of diclofenac in children 2-8 year of age and was associated with a higher relative bioavailabilty than enteric-coated tablets and an earlier maximum concentration (50 vs. 108 min). This pharmacokinetic profile renders diclofenac suppository a suitable formulation for short duration surgery.

Postoperative pain control in children: a guide to drug choice

Postoperative pain in children can usually be well controlled with a combination of analgesics, including acetaminophen (paracetamol), NSAIDs, opioids, and local/regional anesthesia. Recent research has shown that the dosage of acetaminophen required to provide analgesia is higher than the traditional dosages used for the regulation of elevated body temperature. Rectal administration of acetaminophen gives a lower and more variable bioavailability compared with oral administration. There is growing experience with the use of NSAIDs in children and several studies have demonstrated the relatively strong analgesic potential of these drugs. Titration of opioids to analgesic effect, and the use of nurse- and patient-controlled continuous opioid infusions in children have gained widespread use and, with proper education and supervision, are considered excellent methods of pain control. Local peripheral and central blocks decrease the need for anesthetics during surgery and provide effective postoperative pain relief.

Population pharmacokinetics of high dose ibuprofen in cystic fibrosis

AIMS

To evaluate ibuprofen population pharmacokinetics in a large series of data collected in children with cystic fibrosis (CF) treated with high doses of ibuprofen (59 patients; 2-18 years), and to identify the main causes responsible for the considerable interindividual variability in ibuprofen serum levels.

METHODS

Blood samples were collected during routine clinical care; serum ibuprofen concentrations were determined by HPLC. Fitting of the concentration/time data to a one compartment kinetic population model was performed by a non-linear mixed effect regression method.

RESULTS

Body weight, dose, and ibuprofen dosage form (lysinate salt or the free acid form), for elimination clearance (CL/F); and body weight, dose, and fasting status for the apparent distribution volume (Vd/F) proved to be the covariates with influence in the model. The four factors identified helped to explain part of the interindividual variability observed, but the remaining unexplained variability made therapeutic drug monitoring absolutely essential.

An evaluation of the safety and efficacy of administering rofecoxib for postoperative pain management

The goal of our study was to evaluate the analgesic efficacy and safety of administering rofecoxib (1 mg/kg), a cyclo-oxygenase (COX)-2 selective nonsteroidal antiinflammatory drug, before pediatric tonsillectomy. Sixty-six patients, aged 3-11 yr, scheduled to undergo tonsillectomy received either placebo or rofecoxib (1 mg/kg). There were no significant differences between the two study groups with respect to demographics and blood loss. We found that the pain scores were significantly lower in the rofecoxib group compared with the control group at 2 h (P < 0.05) and 24 h (P < 0.006). The incidence of nausea (P < 0.03) and vomiting (P < 0.004) at home was more frequent in the control group than in the rofecoxib group. We conclude that a single preoperative dose of rofecoxib resulted in less vomiting and lower 24-h pain scores in pediatric patients undergoing an elective tonsillectomy.

IMPLICATIONS

In children undergoing tonsillectomy, a single preoperative dose of rofecoxib decreases 2- and 24-h pain and decreases nausea and vomiting at home.

Nonsteroidal anti-inflammatory drugs for postoperative pain: a focus on children

Pain is a common symptom after surgery in children, and the need for effective pain management is obvious. For example, after myringotomy, despite the brief nature of the procedure, at least one-half of children have significant pain. After more extended surgery, such as tonsillectomy, almost all children have considerable pain longer than 7 days. Nonsteroidal anti-inflammatory drugs (NSAIDs) are useful for postoperative pain management because surgery causes both pain and inflammation. Several pediatric studies indicate NSAIDs are effective analgesics in the management of mild and moderate pain. In the treatment of severe pain, NSAIDs should be given with acetaminophen (paracetamol) or opioids, and the use of an appropriate regional analgesic technique should be considered. NSAIDs are more effective in preventing pain than in the relief of established pain. Pain following surgery is best managed by providing medication on a regular basis, preventing the pain from recurring. This proactive approach should be implemented for any procedure where postoperative pain is the likely outcome. In children, the choice of formulation can be more important than the choice of drug. Intravenous administration is preferred for children with an intravenous line in place; thereafter mixtures and small tablets are feasible options. Children dislike suppositories, and intramuscular administration should not be used in nonsedated children. Ibuprofen, diclofenac, ketoprofen and ketorolac are the most extensively evaluated NSAIDs in children. Only a few trials have compared different NSAIDs, but no major differences in the analgesic action are expected when appropriate doses of each drug are used. Whether NSAIDs differ in the incidence and severity of adverse effects is open to discussion. Because NSAIDs prevent platelet aggregation they may increase bleeding. A few studies indicate that ketorolac may increase bleeding more so than other NSAIDs, but the evidence is conflicting. Severe adverse effects of NSAIDs in children are very rare, but it is important to know about adverse effects in order to recognize and treat them when they do occur. NSAIDs are contraindicated in patients in whom sensitivity reactions are precipitated by aspirin (acetylsalicylic acid) or other NSAIDs. They should be used with caution in children with liver dysfunction, impaired renal function, hypovolemia or hypotension, coagulation disorders, thrombocytopenia, or active bleeding from any cause. In contrast, it seems that most children with mild asthma may use NSAIDs.

Nonsteroidal anti-inflammatory agents in neonates

The use of NSAIDs has become routine for adults and children in the management of pain. NSAIDs (other than aspirin [acetylsalicylic acid]) are also enjoying greater popularity as antipyretics since the recognition of Reye's syndrome's putative association with aspirin. In neonates, NSAIDs have been used for many years in an attempt to pharmacologically close the ductus arteriosus. This review examines the various NSAIDs and their potential and real applications in the neonatal population. For completeness, acetaminophen (paracetamol), which has weak NSAID activity and is a widely used analgesic and antipyretic in this patient group, was also included. The prostaglandin system is important for healthy development, and conversely there are unique risks posed by pharmacologic interference with this system in the neonatal period. The prostanoid system in neonates has the capacity to modulate nociception, but comes at the expense of interfering with nearly every organ system. Physiologic effects of inhibition of prostaglandin synthesis applicable to neonates include disruption of the sleep cycle, increased risk of pulmonary hypertension, alterations in cerebral blood flow, decreased renal function, disrupted thermoregulation, and alterations in hemostasis balance, among others. Prostaglandins are also important for the normal development of the central nervous, cardiovascular, and renal systems, and there is evidence that the proper genesis of these systems may be adversely effected by NSAID exposure in utero and in the neonatal period. Gastrointestinal adverse effects have provided the impetus for the development and marketing of selective cyclo-oxygenase type 2 (COX-2) inhibitors. These agents' reputation for safety in adults may not be applicable to neonates. COX-2 is involved in the development of several organ systems, and its inhibition may induce a prothrombotic state. The advent of parenteral formulations of cyclo-oxygenase inhibitors, including COX-2-selective agents, increases the therapeutic flexibility of NSAIDs. However, objective data on the safety of these agents have not kept pace with their clinical availability.

Working toward better cancer pain management for children

PURPOSE

Management of the pain experienced by children with cancer is critical to minimize the psychological distress and physiologic responses to their illness and its treatment.

OVERVIEW

A team approach to providing care, using guidelines for pharmacologic management intertwined with nonpharmacologic strategies, while individualizing the care of a specific child, is required. Pain management must start with assessment using tools that are age appropriate and well suited to the clinical situation. Dosages of the recommended opioid and nonopioid medications that are suitable for children as well as the role of locally, systemically, and epidurally administered anesthetic agents are described by the authors.

CLINICAL IMPLICATIONS

By following this practical approach, children can be prepared and supported during the various intensive oncology therapies often associated with pain that are now offered in the hope of improving the survival of children with cancer.

[Postoperative analgesia in pediatric neurosurgery]

Pain management in paediatric neurosurgery must be a daily concern for surgeons and anaesthetists. Pain assessment in infants and small children is difficult to perform because of limitations associated with these patients. The association of safe and effective analgesics allows good pain relief together with good safety conditions. However, neuropathic pain, which may occur following neurosurgical procedures, will require further studies.