What we don't know about paracetamol in children

Hyoscine butylbromide versus acetaminophen for nonspecific colicky abdominal pain in children: a randomized controlled trial

BACKGROUND

Less than two-thirds of children with abdominal pain in the emergency department receive analgesia. We sought to determine whether hyoscine butylbromide was superior to acetaminophen for children with nonspecific colicky abdominal pain.

METHODS

We randomly allocated children aged 8-17 years with nonspecific colicky abdominal pain who presented to the pediatric emergency department of London Health Sciences Centre, London, Ontario to receive hyoscine butylbromide, 10 mg given orally, or acetaminophen, 15 mg/kg given orally (maximum 975 mg). We considered the minimal clinically important difference for the primary outcome (self-reported pain at 80 min) to be 13 mm on a 100 mm visual analogue scale. Secondary outcomes included administration of rescue analgesia, adverse effects and pain score less than 30 mm at 80 minutes.

RESULTS

A total of 236 participants (120 in the hyoscine butylbromide group and 116 in the acetaminophen group) were included in the trial. The mean visual analogue scale scores at 80 minutes were 29 mm (standard deviation [SD] 26 mm) and 30 mm (SD 29 mm) with hyoscine butylbromide and acetaminophen, respectively (adjusted difference 1, 95% confidence interval -7 to 7). Rescue analgesia was administered to 4 participants (3.3%) in the hyoscine butylbromide group and 1 participant (0.9%) in the acetaminophen groups (p = 0.2). We found no significant differences in rates of adverse effects between hyoscine butylbromide (32/116 [27.6%]) and acetaminophen (28/115 [24.3]) (p = 0.5); no serious adverse effects were observed. The proportion with a pain score less than 30 mm at 80 minutes was 66 (55.0%) with hyoscine butylbromide and 63 (54.3%) with acetaminophen (p = 0.9).

INTERPRETATION

Hyoscine butylbromide was not superior to acetaminophen in this setting. Both agents were associated with clinically important pain reduction, and either can be considered for children presenting to the emergency department with nonspecific colicky abdominal pain. Trial registration: Clinicaltrials.gov, no. NCT02582307.

Antipyretic Efficacy of Acetaminophen and Ibuprofen in Critically Ill Pediatric Patients

OBJECTIVES

To determine the antipyretic efficacy of acetaminophen (IV, enteral, rectal) and ibuprofen (enteral) in critically ill febrile pediatric patients.

DESIGN

Retrospective cohort study.

SETTING

Quaternary care pediatric hospital ICUs.

PATIENTS

Pediatric patients less than 19 years old who were febrile (≥ 38.0°C), received a dose of IV acetaminophen, enteral acetaminophen, rectal acetaminophen, or enteral ibuprofen and had at least one temperature measurement in the following 6 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 3,341 patients (55.8% male, median age 2.5 yr [interquartile range, 0.63-9.2 yr]) met study criteria. Baseline temperature was median 38.6°C (interquartile range, 38.3-38.9°C) measured via axillary (76.9%) route. Patients became afebrile (87.5%) at median 1.4 hours (interquartile range, 0.77-2.3 hr) after the first dose of medication, a -2.9 ± 1.6% change in temperature. Antipyretic medications included as follows: enteral acetaminophen (n = 1,664), IV acetaminophen (n = 682), rectal acetaminophen (n = 637), and enteral ibuprofen (n = 358). Enteral ibuprofen had a significantly greater odds of defervescence on multivariable logistic regression analysis (p = 0.04) with a decrease of -1.97 ± 0.89°C while IV acetaminophen was significant for a decreased time to defervescence at median 1.5 hours (interquartile range 0.8-2.3 hr) after a dose (p = 0.03). Patient age, presence of obesity, and baseline temperature were significant for decreased antipyretic efficacy (p < 0.05).

CONCLUSIONS

Enteral ibuprofen was the most efficacious antipyretic and IV acetaminophen had the shortest time to defervescence.

Fifteen-minute consultation: Pain relief for children made simple-a pragmatic approach to prescribing oral analgesia in the postcodeine era

What are the most effective doses of simple oral analgesics such as paracetamol and ibuprofen for pain relief in children? Why can't I prescribe codeine phosphate for children anymore? Is oral morphine really a safe alternative to codeine phosphate, and if so what dose should I prescribe? These questions are frequently asked by clinicians who wish to give analgesics to children for pain relief. In this article I will address these questions and describe a pragmatic approach for pain relief using oral analgesics based on the best evidence available and my experience as a consultant paediatric anaesthetist.

Are some people at increased risk of paracetamol-induced liver injury? A critical review of the literature

Purpose

Paracetamol is one of the world’s most commonly used drugs. In overdose, it is well established to be hepatotoxic. The aim of this review was to identify factors that have been, or actually are, associated with the development of liver injury after paracetamol exposure in humans.

Method

Google Scholar and PubMed were searched on various dates between December 2016 and March 2017. Papers identified had their references analysed for further studies that might be relevant.

Results

At the time of writing, there was little good quality clinical evidence—from studies of paracetamol overdose or therapeutic use—to suggest that any groups of people are relatively protected from, or are at greater risk of, liver injury. The factors that were historically used to indicate higher risk in the UK have no good quality clinical evidence to support their re-introduction into clinical practice. The safe (and still effective) oral dose of paracetamol in patients weighing less than 50 kg has not been established.

Conclusion

There is no patient group that is unequivocally at elevated risk of paracetamol-induced liver toxicity. We propose two clinical scenarios that warrant further research. Firstly, there is a need to establish whether the dose of paracetamol should be reduced in patients with low body weight. Secondly, if or when genomic information regarding individual patients becomes readily available to inform prescribing, we propose the contribution of the genome to paracetamol toxicity should be re-investigated with robustly designed studies. Such studies could enhance the safe use of one of the most frequently taken drugs.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2356-6) contains supplementary material, which is available to authorized users.

Enduring large use of acetaminophen suppositories for fever management in children: a national survey of French parents and healthcare professionals' practices

The pharmacological specificities of the rectal formulation of acetaminophen led to a debate on its appropriateness for managing fever in children, but few data are available on the formulation's current use and determinants of use. In a national cross-sectional study between 2007 and 2008, healthcare professionals were asked to include five consecutive patients with acute fever. Among the 6255 children (mean age 4.0 years ± 2.8 SD) who received acetaminophen given by parents or prescribed/recommended by healthcare professionals, determinants of suppository use were studied by multilevel models. A suppository was given by 27 % of parents and prescribed/recommended by 19 % of healthcare professionals, by 24 and 16 %, respectively, for children 2 to 5 years old, and by 13 and 8 %, respectively, for those 6 to 12 years old. Among children who received suppositories from parents and healthcare professionals, 83 and 84 %, respectively, did not vomit. Suppository use was independently associated with several patient- and healthcare professional-level characteristics: young age of children, presence of vomiting, or lack of diarrhea.

CONCLUSION

We report an enduring large use of suppositories in France for the symptomatic management of fever in children, including in non-vomiting and/or older children. The rational for such use should be questioned.

WHAT IS KNOWN

• The pharmacological specificities of the rectal formulation of acetaminophen have led to a debate on its appropriateness for managing fever in children. Few data are available on the formulation's current use and determinants of the use. What is New: • In a national cross-sectional study, we observed a large use of suppositories in France for symptomatic management of fever in children. Suppositories were frequently used for the youngest children but also for older and/or non-vomiting children.

[Pediatric perioperative systemic pain therapy: Austrian interdisciplinary recommendations on pediatric perioperative pain management]

BACKGROUND

Many analgesics used in adult medicine are not licensed for pediatric use. Licensing limitations do not, however, justify that children are deprived of a sufficient pain therapy particularly in perioperative pain therapy. The treatment is principally oriented to the strength of the pain. Due to the degree of pain caused, intramuscular and subcutaneous injections should be avoided generally.

NON-OPIOIDS

The basis of systemic pain therapy for children are non-opioids and primarily non-steroidal anti-inflammatory drugs (NSAIDs). They should be used prophylactically. The NSAIDs are clearly more effective than paracetamol for acute posttraumatic and postoperative pain and additionally allow economization of opioids. Severe side effects are rare in children but administration should be carefully considered especially in cases of hepatic and renal dysfunction or coagulation disorders. Paracetamol should only be taken in pregnancy and by children when there are appropriate indications because a possible causal connection with bronchial asthma exists. To ensure a safe dosing the age, body weight, duration of therapy, maximum daily dose and dosing intervals must be taken into account. Dipyrone is used in children for treatment of visceral pain and cholic. According to the current state of knowledge the rare but severe side effect of agranulocytosis does not justify a general rejection for short-term perioperative administration.

OPIOIDS

In cases of insufficient analgesia with non-opioid analgesics, the complementary use of opioids is also appropriate for children of all age groups. They are the medication of choice for episodes of medium to strong pain and are administered in a titrated form oriented to effectiveness. If severe pain is expected to last for more than 24 h, patient-controlled anesthesia should be implemented but requires a comprehensive surveillance by nursing personnel.

KETAMINE

Ketamine is used as an adjuvant in postoperative pain therapy and is recommended for use in pediatric sedation and analgosedation.

A randomized controlled trial of the effectiveness of educating parents about distraction to decrease postoperative pain in children at home after tonsillectomy

Today, parents are more involved with postoperative pain management, because children are discharged as early as possible after surgery. The purpose of this randomized controlled trial was to determine the effectiveness of educating parents to provide distraction in addition to pharmacologic pain management in decreasing postoperative pain at home for children ages 3 to 7 years. Ninety-three children aged 3-7 years having tonsillectomy at Landspitali, The National University Hospital of Iceland, and their parents were randomized to one of two intervention groups. The interventions were pharmacologic pain management education (control group) and pharmacologic pain management education with distraction (experimental group). Pain was measured by parent's report of pain behavior during the evening on postoperative days 1 and 2 and child's report of pain intensity on eight time points on postoperative days 1 and 2. Sixty-nine children had complete data. The results from RM-ANCOVA showed that when adjusting for pain intensity in the morning on postoperative day 1 that educating parents about distraction in addition to educating them about pain medication management decreases mean pain behavior scores (p < .001). There was no difference in pain intensity between the groups using RM-ANCOVA. However, there was association between pain intensity in the morning on postoperative day 1 and follow-up pain intensity (p < .001). The results from this study support the importance of educating parents of children having tonsillectomy about distraction in addition to educating them about pain medication management.

Paracetamol and fever management

Paracetamol is one of the most commonly used legal drugs in the western world. Its availability is good, cost is low, and its uses include `over-the-counter' (OTC) distribution, primary care prescribed therapy, secondary care `post-operative' application and emergency treatment. Stated benefits of paracetamol include: the drug's analgesic effects, preference to aspirin in avoidance of Reye's syndrome, good patient tolerance, and iatrogenic complications are infrequent and minor. Stated cautions include hepatotoxic effect following minor doses and short duration use and users may incur compromised immune integrity. This paper is concerned with paracetamol's role in fever management. Public concern regarding, in particular, childhood fever and febrile convulsions is largely unwarranted. Despite paracetamol's reputation as a popular fever-reducing agent the drug is poorly effective in the control of febrility and febrile convulsions showing no important advantage compared with placebo. Paracetamol is probably grossly over-prescribed for fever management and its value more perceived than real. Greater efforts are needed to inform patients of the natural benefits of the biological strategy of fever and of the highly limited and in some cases contraindicated use of paracetamol in fever management.

Postoperative pain treatment for ambulatory surgery

One of the most significant changes in surgical practice during the last two decades has been the growth of ambulatory surgery. Adequate postoperative analgesia is a prerequisite for successful ambulatory surgery. Recent studies have shown that large numbers of patients suffer from moderate to severe pain during the first 24-48 hr. The success of fast-tracking depends to a considerable extent on effective postoperative pain management routines and the cost saving of outpatient surgery may be negated by unanticipated hospital admission for poorly treated pain. Depending on the intensity of postoperative pain current management includes the use of analgesics such as paracetamol, NSAIDs including coxibs and tramadol as single drugs or in combination as part of balanced (multimodal) analgesia. However, in the ambulatory setting many patients suffer from pain at home in spite of multimodal analgesic regimens. Sending patients home with perineural, incisional, and intra-articular catheters is a new and evolving area of postoperative pain management. Current evidence suggests that these techniques are effective, feasible and safe in the home environment if appropriate patient selection routines and organization for follow-up are in place.

When to add supplemental rectal paracetamol for postoperative analgesia with caudal bupivacaine in children? A prospective, double-blind, randomized study

BACKGROUND

The aim of this study was to investigate whether a supplemental dose of rectal paracetamol at the third or fourth hour would enhance the quality of analgesia provided by caudal epidural blockade in children.

METHODS

Two hundred and two ASA I patients aged 1-12 years undergoing inguinal surgery were randomized into three groups in the postanesthesia care unit by drawing lots. Patients in the control group did not receive any analgesic until they had a pain score of 5 or higher, patients in the group P3 received rectal paracetamol (20-25 mg x kg(-1)) at the third hour, and patients in the group P4 received the same dose of rectal paracetamol at the fourth hour after caudal epidural injection. Pain was assessed by VAS (Visual Analog Scale) and supplementary rescue analgesic need was recorded.

RESULTS

There was no difference between the demographic data or the duration and variety of surgery among the groups. A significantly lower number of patients required rescue analgesia at the sixth postoperative hour in group P3 and also lower pain scores were again obtained in group P3 at the sixth and eighth postoperative hours.

CONCLUSIONS

Supplemental rectal paracetamol at the third hour of caudal blockade enhances the quality of postoperative analgesia better than its addition at the fourth hour in children undergoing inguinal surgery.

Paracetamol: new vistas of an old drug

Paracetamol (acetaminophen) is one of the most popular and widely used drugs for the treatment of pain and fever. It occupies a unique position among analgesic drugs. Unlike NSAIDs it is almost unanimously considered to have no antiinflammatory activity and does not produce gastrointestinal damage or untoward cardiorenal effects. Unlike opiates it is almost ineffective in intense pain and has no depressant effect on respiration. Although paracetamol has been used clinically for more than a century, its mode of action has been a mystery until about one year ago, when two independent groups (Zygmunt and colleagues and Bertolini and colleagues) produced experimental data unequivocally demonstrating that the analgesic effect of paracetamol is due to the indirect activation of cannabinoid CB(1) receptors. In brain and spinal cord, paracetamol, following deacetylation to its primary amine (p-aminophenol), is conjugated with arachidonic acid to form N-arachidonoylphenolamine, a compound already known (AM404) as an endogenous cannabinoid. The involved enzyme is fatty acid amide hydrolase. N-arachidonoylphenolamine is an agonist at TRPV1 receptors and an inhibitor of cellular anandamide uptake, which leads to increased levels of endogenous cannabinoids; moreover, it inhibits cyclooxygenases in the brain, albeit at concentrations that are probably not attainable with analgesic doses of paracetamol. CB(1) receptor antagonist, at a dose level that completely prevents the analgesic activity of a selective CB(1) receptor agonist, completely prevents the analgesic activity of paracetamol. Thus, paracetamol acts as a pro-drug, the active one being a cannabinoid. These findings finally explain the mechanism of action of paracetamol and the peculiarity of its effects, including the behavioral ones. Curiously, just when the first CB(1) agonists are being introduced for pain treatment, it comes out that an indirect cannabino-mimetic had been extensively used (and sometimes overused) for more than a century.

Prescribing safely for children

This paper is the second in a series of two and will attempt to highlight important issues in prescribing for children, including principles of safe prescribing, adverse drug reaction assessment and common drugs including paracetamol and ibuprofen. A list of drug information resources is included, which may be useful for clinicians.

Acetaminophen-induced hepatic failure with encephalopathy in a newborn

We report a case of oral acetaminophen toxicity in a term newborn infant successfully treated with a 20 h intravenous N-acetylcysteine infusion protocol without any adverse effects. This case report supports the use of N-acetylcysteine to treat neonatal acetaminophen toxicity and highlights the need for better education of parents regarding the appropriate use and dosage of acetaminophen in newborns.

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.

Postoperative Schmerztherapie nach Tonsillektomie im Kindesalter

OBJECTIVE

We investigated the efficacy and side-effects of a concept for pain therapy after tonsillectomy in children.

PATIENTS AND METHODS

A total of 100 children aged between 6 and 14 years were treated according to the following protocol for pain therapy after tonsillectomy: after induction of anaesthesia the children received 35-40 mg/kg acetaminophen rectally and 0.1 mg/kg piritramide i.v.. Additionally, boluses of 0.05 mg/kg pitritramide i.v. were allowed in the recovery room and 2 doses of 20 mg/kg acetaminophen were given rectally every 6 h on the day of surgery. On the following day the children received 30 mg/kg acetaminophen 3 times per day and from the second postoperative day onwards 1 mg/kg diclofenac was given 3 times a day. The rescue therapy was 5 mg/kg metamizol orally. The severity of the postoperative pain was evaluated by a visual pain scale (VAS) (0-100), side-effects such as vomiting and postoperative haemorrhage were documented. The Friedman test was used for testing the time course of pain intensity.

RESULTS

The median of the VAS was 42 on the day of surgery, 35 on the first postoperative day and fell continuously to 10 by the 6th postoperative day. The decrease of pain severity was statistically significant (p <0.05). A rescue therapy was necessary in 6 patients on the day of surgery and in 9 patients on the first postoperative day. 7 patients suffered a postoperative haemorrhage, 4 out of the 7 needed a surgical revision and 2 out of 100 patients vomited.

CONCLUSION

We conclude that this protocol for pain therapy after tonsillectomy was effective. The incidence of postoperative haemorrhage and vomiting was low.

Accuracy in the alteration of acetaminophen suppositories

Many pediatric anesthesiologists divide acetaminophen suppositories to achieve an approximate dose. In this three-part study we first surveyed pediatric anesthesiologists regarding their attitudes and frequency of this clinical practice. Second, acetaminophen suppositories were divided for analysis of acetaminophen content. Finally, the accuracy of pediatric anesthesiologists in dividing suppositories was assessed. The survey indicated 50% of anesthesiologists believed acetaminophen was nonuniform and 62% believed the alteration of suppositories was inaccurate. The laboratory investigation revealed uniform distribution of acetaminophen but poor accuracy in achieving the target dose. The findings suggest using only intact suppositories for improved accuracy.

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.

Evaluation of adding preoperative or postoperative rectal paracetamol to caudal bupivacaine for postoperative analgesia in children

BACKGROUND

Our aim was to investigate whether effects of caudal analgesia could be extended by preoperative or postoperative rectal paracetamol administration in children undergoing surgical repair of hypospadias.

METHODS

The group consisted of 60 ASA I boys, aged 3-12 years, who were operated for surgical repair of hypospadias. The patients were randomized into three groups: patients in group I received rectal paracetamol (20-25 mg x kg(-1)) just before the operation. Group II received only caudal bupivacaine. Group III patients received rectal paracetamol (20-25 mg x kg(-1)) at the end of the operation. Pain was assessed by Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and the degree of sedation was evaluated. During the first 24 h, time to the patients' first analgesic requirement and the number of supplementary analgesics needed were recorded.

RESULTS

There was no difference between the demographic and haemodynamic data of the three groups. In addition, the duration of surgery and anaesthesia, pain scores and sedation scores of the groups were not significantly different.

CONCLUSIONS

Addition of preoperative or postoperative rectal paracetamol in the doses used did not show an effect on the duration and intensity of postoperative analgesia obtained by caudal bupivacaine.

Pain management in ambulatory surgery

Successful ambulatory surgery is dependent on analgesia that is effective, has minimal adverse effects, and can be safely managed by the patient at home after discharge. A number of studies have identified that the provision of effective postoperative analgesia is inadequate for a significant proportion of patients. The following discussion details the current available analgesic options for ambulatory surgery patients and the rationale for their use. Preemptive analgesia should be given to all patients unless there are specific contraindications. Consideration should be given to the use of long-acting oral COX-2 selective nonsteroidal anti-inflammatory drugs (NSAIDs) and long-acting oral opioids to treat postoperative pain. A standardized multimodal postdischarge analgesic regimen tailored to the patient's expected postoperative pain levels should be prescribed. Patient follow-up by telephone questionnaire will confirm those surgical procedures that result in mild or moderate-to-severe postoperative pain and the effectiveness of treatment plans.

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.

Pharmacokinetics of single dose intravenous propacetamol in neonates: effect of gestational age

AIM

To investigate the pharmacokinetics and pharmacodynamics of single dose propacetamol in preterm and term infants on the first day of life.

METHODS

Neonates were stratified by gestational age. Preterm (< 37 weeks) and term (37-41 weeks) infants received a single dose of propacetamol in the first 24 hours of life when they had minor, painful procedures or as additional treatment in infants receiving opioids. Blood samples were taken from an arterial line, and pain was evaluated by a multidimensional pain scale. Results were reported as mean (SD). Student's t and Wilcoxon tests were used to compare the groups.

RESULTS

Thirty neonates were included, 10 of which were term infants. Serum half life was 277 (143) minutes in the preterm infants and 172 (59) minutes in the term infants (p < 0.05). Clearance was 0.116 (0.08) litre/kg/h in the preterm infants and 0.170 (0.06) litre/kg/h in the term infants (p < 0.05). Gestational age correlated with serum half life (r = -0.46). No effect of sex or administration of prenatal steroids was found on the pharmacokinetics of paracetamol. In neonates who only received propacetamol (n = 15), the level of analgesia seemed to be associated with the therapeutic (> 5 mg/l) level.

CONCLUSIONS

A correlation was found between gestational age and the serum half life of propacetamol. The maturational trend of clearance and half life in preterm and term neonates is in line with data on the pharmacokinetics of propacetamol beyond the newborn period.

Analgesic efficacy and tolerability of ketoprofen lysine salt vs paracetamol in common paediatric surgery. A randomized, single-blind, parallel, multicentre trial

BACKGROUND

In this study, we compared the analgesic efficacy of ketoprofen lysine salt (OKi) suppositories) vs paracetamol, in children undergoing minor surgery. We also studied the side-effects of the treatment.

METHODS

Eighty-five children of both sexes, aged 6-14 years, were enrolled in a multicentre, randomized, single-blind, parallel-group study design. In all patients postsurgical pain was evaluated by visual analogue scale (VAS) and degree of distress (night-time awakening, crying, behaviour and defence posture).

RESULTS

Ketoprofen lysine was more effective than paracetamol in reducing postoperative pain (P = 0.008) with earlier onset and longer duration (8 h) of the antinociceptive effect. Evaluation of area under the curve, an aggregated measure of VAS, and of distress, confirm the time profile of pain reduction. No adverse effects related to the treatment were observed.

CONCLUSIONS

Ketoprofen lysine salt can be considered a potent therapeutic approach to control postsurgery pain in children, and an alternative to other established drug regimens.

Analgesic effect of i.v. paracetamol: possible ceiling effect of paracetamol in postoperative pain

BACKGROUND

Despite the widespread use of paracetamol for many years, the analgesic serum concentrations of paracetamol are unknown. Therefore the correlation between serum paracetamol concentrations and the analgesic effect was studied.

METHODS

Sixty-four women undergoing laparoscopic sterilization were included in a double-blind, placebo-controlled, randomized study. Patients were given i.v. propacetamol 40 mg kg(-1) (group H), 20 mg kg(-1) (group I), 10 mg kg(-1) (group L) or placebo after surgery. Alfentanil was available via patient-controlled analgesia (PCA) during the 4-h postoperative study period. The patients' self-reported pain was registered on the visual analog scale (VAS). A pharmacokinetic model was fitted to the paracetamol data.

RESULTS

One to 3 h after injection of propacetamol the alfentanil consumption was significantly (P = 0.01-0.04) higher in the placebo group compared with groups H, I, and L receiving propacetamol. There were no significant differences between the amounts of alfentanil consumed in groups H, I, and L. Initial VAS-scores were moderate (5.4-6.2), and declined significantly (P < 0.0001) over time, with no difference between groups. Paracetamol followed an open two-compartment model with i.v. administration and first order elimination. The estimated concentrations immediately (t = 0) after injection were 56 mg l(-1) (H), 28 mg l(-1) (I) and 14 mg l(-1) (L).

CONCLUSION

We showed a significant opioid-sparing effect of paracetamol in the immediate postoperative period. Pharmacokinetic data were in accordance with other studies. Our results suggest that a ceiling effect of paracetamol may be present at i.v. doses of 5 mg kg(-1), i.e. a serum concentration of 14 mg l(-1), which is a lower dose than previously suggested.

Treatment with paracetamol in infants

BACKGROUND

Paracetamol (N-acetyl-p-amino-phenol) or acetaminophen has become the most widely used analgesic and antipyretic in children. However, there is a wide discrepancy between the extent to which paracetamol is used and the limited available pharmacological data in small infants. The purpose of this article is to present a review of the current literature regarding the use of paracetamol in neonates and infants with a particular emphasis on pharmacological issues.

METHODS

A MEDLINE search (up to March 2000) was conducted to identify relevant English-language publications using paracetamol, children, infants and neonates as search terms. Additional studies were identified from bibliographies of the reviewed literature.

RESULTS

Pharmacological studies on paracetamol in infants are few. Most studies have focused on the administration of one single paracetamol dose, and the problem of cumulative toxicity with repeated dosing has not been addressed. Plasma paracetamol concentration should be 10-20 mg ml(-1) to achieve antipyretic and analgesic effects. The bioavailability of the different formulations and routes of administration vary with age. Rectal absorption is slower and more erratic than the oral; however, in the very young, rectal bioavailability is higher than in older patients. Volume of distribution seems to be age-independent, whereas clearance is reduced in neonates and particularly in preterm babies. Neonates and infants are capable of forming the reactive intermediate metabolite that causes hepatocellular damage, particularly after multiple doses. They have an immature glucuronide conjugation system, but the rate constant for the sulphation metabolic pathway is larger than in older children, and this is the most important route of metabolism.

CONCLUSIONS

The pharmacokinetics and pharmacodynamics of paracetamol differ substantially in neonates and infants from those in older children and adults; hence, dosing should be adjusted accordingly.

Effects of rectally administered paracetamol on infants delivered by vacuum extraction

OBJECTIVE

To evaluate whether paracetamol (20 mg/kg rectally) relieves pain in infants delivered by vacuum extraction, and improves clinical condition.

METHODS

Prospective, randomised, double-blind, placebo-controlled study. Infants delivered by vacuum extraction were randomised either to the study group (n=61) and given paracetamol or to the control group (n=61) receiving placebo. Pain assessment was performed by a validated pain score and by scoring the clinical condition. Both scores and clinical symptoms in these groups were compared with symptoms in a reference group (n=66) with uncomplicated pregnancy and delivery in vertex position without vacuum extraction.

RESULTS

Pain score did not differ between groups; clinical condition in the study group improved only after the first dose. There was a significant difference (P<0.05) in objective clinical symptoms in the vacuum extraction groups, compared to the reference group.

CONCLUSION

One dose of paracetamol given to neonates delivered by vacuum extraction significantly improved their clinical condition, but did not result in a significant change in objective pain scores. Subsequent doses of paracetamol did not show any effect on the clinical symptoms or appearance of the neonates studied.

Pharmacokinetics of rectal paracetamol after repeated dosing in children

Twenty-three children (aged between 9 weeks and 11 yr) were given paracetamol suppositories 25 mg kg-1 every 6 h (maximum 5 days) after major surgery and serum and saliva concentrations were measured. There was a good correlation (r = 0.91, P < 0.05) between saliva and serum concentrations. A one-compartment linear model with first-order elimination and absorption and lag-time was fitted to the data (ADAPT II). At steady state, the mean (SD) concentration was 15.2 (6.8) mg litre-1. Mean (SD) time to reach 90% of the steady state concentration was 11.4 (8.6) h. Body weight, age and body surface area were well correlated (P < 0.05) with clearance and apparent volume of distribution. There was no evidence of accumulation leading to supratherapeutic concentrations during this dosing schedule for a mean of approximately 2-3 days.

Update: the clinical importance of acetaminophen hepatotoxicity in non-alcoholic and alcoholic subjects

Acetaminophen (paracetamol) is one of the most commonly used over-the-counter medications. Taken in doses greater than 150 mg/kg/day (>10 g), it usually causes acute liver failure. The authors review mainly the management of acetaminophen toxicity in both users and nonusers of alcohol. Chronic alcoholics are a special subgroup, who risk serious toxicity when taking acetaminophen, even in therapeutic doses. The acetaminophen-alcohol interaction is complex, because acute and chronic ethanol have opposite effects. This review also considers physiological and clinical changes, as well as the diagnosis and treatment of acetaminophen poisoning.

Management of the paediatric patient

Recent introduction of new fast-onset short-duration anaesthetic drugs and the use of regional anaesthesia techniques in children have resulted in good control of anaesthesia and perioperative pain with few adverse effects. Ambulatory surgery has gained popularity in paediatric practice, particularly as children are often otherwise healthy and usually undergo minor surgery.

Paracetamol-induced fulminant hepatic failure in a child after 5 days of therapeutic doses

We report the case of a two and a half year-old girl who developed fulminant hepatic failure following 5 days of regular oral ingestion of paracetamol, approximately 90 mg x kg-1 x day-1. She presented with the typical findings of hepatomegaly, encephalopathy, high ammonia levels, high transaminases, hypoglycaemia and lactic acidosis. After stabilization, she was transferred to a specialist paediatric liver failure unit and fortunately she made a full recovery with intensive medical management.

[Propacetamol: from basic action to clinical utilization]

OBJECTIVE

To review pharmacology and therapeutic use of propacetamol, an injectable prodrug of acetaminophen (paracetamol).

DATA SOURCES

Extraction from the Medline database of French and English articles on pharmacology and clinical use of propacetamol.

STUDY SELECTION

Articles providing new data into the mechanisms of the analgesic action of paracetamol. Selection of controlled studies (original articles and abstracts of oral communications on therapeutic trials with propacetamol as a single agent or part of balanced analgesia protocols). Case reports and letters to the editor were not considered in this analysis.

DATA EXTRACTION

Clinical articles were selected for advantages and adverse effects of propacetamol. Articles dealing with mechanisms of action of propacetamol and paracetamol were selected for the more recent data, excluding those reporting outdated theories not confirmed or abandoned.

DATA SYNTHESIS AND CONCLUSION

Mechanisms of action of paracetamol differ from those of NSAIDs, giving account of a low risk of adverse renal, gastrointestinal and haematological effects. Thanks to their high therapeutic index, prescription of propacetamol and paracetamol is quite simple and safe. Main indications of both drugs are painful conditions, especially but not exclusively in the postoperative period, not requiring opioids and also in combination with other analgesic drug and/or techniques (balanced or multimodal analgesia). Because of cost, IV propacetamol is changed for oral paracetamol as soon as possible.