Pro-con debate: is codeine a drug that still has a useful role in pediatric practice?

Health Canada advisory impacts on the prevalence of oral codeine use in the Pediatric Canadian population: comparative study across provinces

Health Canada (HC) has, since 2013, issued safety alerts restricting the use of codeine-containing drugs among breastfeeding women and children/adolescents under 18 years of age. These products are linked to breathing problems among ultra-rapid CYP2D6 metabolizers and early use of opioid can lead to future opioid misuse. Using a multi-province population-based cohort study, we estimate the impact of federal safety alerts on annual rates of codeine use in the Canadian pediatric population. We analyzed data from 8,156,948 children/adolescents in five Canadian provinces between 1996 and 2021, using a common protocol. Children/adolescents were categorized as: ≤ 12 years (children) or > 12 years (adolescents). We defined codeine exposure by ≥ 1 prescription filled for codeine alone or combined with other medications. For both age categories, we obtained province-specific codeine prescription filling rates per calendar year by dividing the number of children/adolescents with ≥ 1 codeine prescription filled by the number of person-time. Annual rates of codeine use per 1000 persons vary by province from 3.0 (Quebec) to 10.1 (Manitoba) in children, and from 5.5 to 51.3 in adolescents. After the 2013 HC advisory, exposure decreased in all provinces (adjusted level change from - 0.6 to - 18.4%) in children and from - 2.1 to - 17.9% in adolescents after the 2016 advisory. Annual rates declined over time in all provinces, following HC safety alerts specific to each of the two age categories.

Short-acting versus long-acting opioids for pediatric postoperative pain management

INTRODUCTION

Opioids are potent analgesics commonly used to manage children's moderate to severe perioperative pain in children. A wide range of short and long-acting opioids are used to treat surgical pain and will be reviewed in this article.

AREAS COVERED

Both short- and long-acting opioids contain unique therapeutic benefits and adverse effects; however, due to the side effect profile and safety concerns, lack of familiarity, and evidence with long-acting opioids to treat surgical pain, shorter-acting opioids have traditionally been used in children. Almost all opioids work by binding to the mu receptor. Methadone, a long-acting opioid, is an exception because it also has beneficial N-methyl-D-aspartate antagonist properties. Clinically methadone's properties could translate to improved analgesic outcomes, reduced risk of adverse events, less risk for acute hyperalgesia, tolerance and abuse potential, faster recovery, and reduced risk for chronic persistent surgical pain. This review article summarizes and compares the evidence of commonly used short and long-acting opioids for perioperative pain control in the pediatric population.

EXPERT OPINION

Individualized methadone therapy using pharmacogenomics has the potential to transform opioid use in pain management by improving patient safety and analgesic outcomes, thereby addressing the gaps in current standardized ERAS protocols.

Nanoarchitectonics for Abused-Drug Biosensors

Rapid, accessible, and highly accurate biosensors for the detection of addictive and abused drugs are needed to reduce the adverse personal and societal impacts of addiction. Modern sensors that utilize next-generation technologies, e.g., nanobiotechnology and nanoarchitectonics, have triggered revolutionary progress in the field as they allow accurate detection and tracking of trace levels of major classes of drugs. This paper reviews advances in the field of biosensors for the detection of commonly abused drugs, both prescribed such as codeine and morphine, and illegal narcotics like cocaine.

Pediatric Urologic Surgery: Reducing Opioid Use

Adequate pain management is important for successful postoperative recovery after any surgical procedure. Unfortunately, the USA and many other parts of the world are in the midst of an opioid epidemic, and healthcare providers are thus tasked with balancing the comfort and recovery of their patients after an operation against the individual and societal harms of the over-prescription of opioids. The goal of this article is to discuss the range of opioid formulations currently in use, examine why this may be problematic, and explore alternatives that provide similar efficacy and may improve overall safety in the pediatric population after urologic surgery. Improving the way opioids are prescribed through clinical practice guidelines as well as considering alternatives to opioids can ensure patients have access to safer and more effective pain treatments and potentially reduce opioid misuse.

A Review of Analytical Methods for Codeine Determination

Codeine is derived from morphine, an opioid analgesic, and has weaker analgesic and sedative effects than the parent molecule. This weak opioid is commonly used in combination with other drugs for over-the-counter cough relief medication. Due to the psychoactive properties of opioid drugs, the easily obtained codeine often becomes subject to misuse. Codeine misuse has emerged as a concerning public health issue due to its associated adverse effects such as headache, nausea, vomiting, and hemorrhage. Thus, it is very important to develop reliable analytical techniques to detect codeine for both quality control of pharmaceutical formulations and identifying drug misuse in the community. This review aims to provide critical outlooks on analytical methods applicable to the determination of codeine.

Codeine and opioid metabolism: implications and alternatives for pediatric pain management

PURPOSE OF REVIEW

Use of perioperative opioids for surgical pain management of children presents clinical challenges because of concerns of serious adverse effects including life-threatening respiratory depression. This is especially true for children with history of obstructive sleep apnea. This review will explore current knowledge of clinically relevant factors and genetic polymorphisms that affect opioid metabolism and postoperative outcomes in children.

RECENT FINDINGS

Within the past several years, an increasing number of case reports have illustrated clinically important respiratory depression, anoxic brain injuries and even death among children receiving appropriate weight-based dosages of codeine and other opioids for analgesia at home setting particularly following tonsillectomy. Several national and international organizations have issued advisories on use of codeine in pediatrics, based on cytochrome P450 family 2 subfamily D type 6 (CYP2D6) pharmacogenetics. We have discussed the pros and cons of alternatives to codeine for pain management.

SUMMARY

Although routine preoperative genotyping to identify children at risk and personalized opioid use for pediatric perioperative pain management is still a distant reality, current known implications of CYP2D6 pharmacogenetics on codeine use shows that pharmacogenetics has the potential to guide anesthesia providers on perioperative opioid selection and dosing to maximize efficacy and safety.

Safety considerations of anesthetic drugs in children

INTRODUCTION

Great strides have been made in the last twenty years in providing safe anesthesia care for infants and children. Despite a historical record of safety, recent findings have called to question the toxicities of many anesthetic agents. Observations concerning the inherent safety of these agents, their appropriate management in infants, and new findings which suggest overlooked toxicities will be discussed. Areas covered: A literature search using Pub Med identified journal articles relating to the safety of anesthetic agents in infants and children. From this group, representative classical articles, as well as more recent offerings, were chosen that were germane to the topic of anesthetic drug safety in children. Expert opinion: Anesthetic agents used in children in the US are generally safe in the short term and are administered to thousands of children daily without demonstrable harm. The question of a deleterious effect of anesthetics on the developing central nervous system when used for long periods and on multiple occasions continues to be open to debate. Conservative elective management of these agents in infants and young children is reasonable until such time as more is known about the toxicities on the central nervous system.

Experiences of Codeine Use, Misuse and Dependence: Application of Liese and Franz's Cognitive Developmental Model of Substance Abuse

BACKGROUND

Misuse of codeine-containing medicines is an emerging public health issue.

AIMS

We present the application of Liese and Franz's (1996) cognitive developmental model of substance abuse to the trajectory from legitimate codeine use for pain, towards that of therapeutic and other forms of misuse, and physical and psychological dependence. It illustrates a cognitive behavioural analysis of the experiences of codeine misusers - which 'surfaces' the specific beliefs, thoughts, emotions and behaviours of this group of hidden codeine dependent individuals, who are distinct and unique from other opioid-dependent cohorts.

METHOD

In-depth one-to-one interviews with codeine misusers and dependent individuals in Ireland (n = 21) and South Africa (n = 25) are analysed and applied to Liese and Franz's (1996) cognitive developmental model of substance abuse.

RESULTS

Misuse and dependence pathways are maintained by the interplay between physiological determinants relating to pain, withdrawal and tolerance, and psychological influences such as therapeutic need, pre-empting of anticipated physical pain, pleasure from the dreamy sedative opiate effect of codeine and relief of emotional distress. Progression towards habitual use and misuse for therapeutic and intoxication purposes appears to be mediated by external environmental triggers pertaining to availability, internal meta-cognitions around physical pain and emotional distress, and increasing importance of codeine in the life of the user.

CONCLUSION

The concept mapping of codeine misuse and dependence presented here could provide psychological therapists working with individuals experiencing problems with codeine, misusing codeine and those with iatrogenic dependence, with an enhanced understanding of the key concepts involved in misuse and recovery pathways.

Codeine: Time to Say "No"

Codeine has been prescribed to pediatric patients for many decades as both an analgesic and an antitussive agent. Codeine is a prodrug with little inherent pharmacologic activity and must be metabolized in the liver into morphine, which is responsible for codeine's analgesic effects. However, there is substantial genetic variability in the activity of the responsible hepatic enzyme, CYP2D6, and, as a consequence, individual patient response to codeine varies from no effect to high sensitivity. Drug surveillance has documented the occurrence of unanticipated respiratory depression and death after receiving codeine in children, many of whom have been shown to be ultrarapid metabolizers. Patients with documented or suspected obstructive sleep apnea appear to be at particular risk because of opioid sensitivity, compounding the danger among rapid metabolizers in this group. Recently, various organizations and regulatory bodies, including the World Health Organization, the US Food and Drug Administration, and the European Medicines Agency, have promulgated stern warnings regarding the occurrence of adverse effects of codeine in children. These and other groups have or are considering a declaration of a contraindication for the use of codeine for children as either an analgesic or an antitussive. Additional clinical research must extend the understanding of the risks and benefits of both opioid and nonopioid alternatives for orally administered, effective agents for acute and chronic pain.

Factors affecting recovery of postoperative bowel function after pediatric laparoscopic surgery

BACKGROUND AND AIMS

Laparoscopic pediatric surgery allows a rapid postoperative rehabilitation and hospital discharge. However, the optimal postoperative pain management preserving advantages of this surgical technique remains to be determined. This study aimed to identify factors affecting the postoperative recovery of bowel function after laparoscopic surgery in children.

MATERIAL AND METHODS

A retrospective analysis of factors affecting recovery of bowel function in children and infants undergoing laparoscopic surgery between January 1, 2009 and September 30, 2009, was performed. Factors included were: Age, weight, extent of surgery (extensive, regional or local), chronic pain (sickle cell disease or chronic intestinal inflammatory disease), American Society of Anaesthesiologists status, postoperative analgesia (ketamine, morphine, nalbuphine, paracetamol, nonsteroidal anti-inflammatory drugs [NSAIDs], nefopam, regional analgesia) both in the Postanesthesia Care Unit and in the surgical ward; and surgical complications. Data analysis used classification and regression tree analysis (CART) with a 10-fold cross validation.

RESULTS

One hundred and sixty six patients were included in the analysis. Recovery of bowel function depended upon: The extent of surgery, the occurrence of postoperative surgical complications, the administration of postoperative morphine in the surgical ward, the coadministration of paracetamol and NSAIDs and/or nefopam in the surgical ward and the emergency character of the surgery. The CART method generated a decision tree with eight terminal nodes. The percentage of explained variability of the model and the cross validation were 58% and 49%, respectively.

CONCLUSION

Multimodal analgesia using nonopioid analgesia that allows decreasing postoperative morphine consumption should be considered for the speed of bowel function recovery after laparoscopic pediatric surgery.

Pediatric Burn Resuscitation

Children have unique physiologic, physical, psychological, and social needs compared with adults. Although adhering to the basic tenets of burn resuscitation, resuscitation of the burned child should be modified based on the child's age, physiology, and response to injury. This article outlines the unique characteristics of burned children and describes the fundamental principles of pediatric burn resuscitation in terms of airway, circulatory, neurologic, and cutaneous injury management.

Pharmacogenetics for Safe Codeine Use in Sickle Cell Disease

After postoperative deaths in children who were prescribed codeine, several pediatric hospitals have removed it from their formularies. These deaths were attributed to atypical cytochrome P450 2D6 (CYP2D6) pharmacogenetics, which is also implicated in poor analgesic response. Because codeine is often prescribed to patients with sickle cell disease and is now the only Schedule III opioid analgesic in the United States, we implemented a precision medicine approach to safely maintain codeine as an option for pain control. Here we describe the implementation of pharmacogenetics-based codeine prescribing that accounts for CYP2D6 metabolizer status. Clinical decision support was implemented within the electronic health record to guide prescribing of codeine with the goal of preventing its use after tonsillectomy or adenoidectomy and in CYP2D6 ultra-rapid and poor metabolizer (high-risk) genotypes. As of June 2015, CYP2D6 genotype results had been reported for 2468 unique patients. Of the 830 patients with sickle cell disease, 621 (75%) had a CYP2D6 genotype result; 7.1% were ultra-rapid or possible ultra-rapid metabolizers, and 1.4% were poor metabolizers. Interruptive alerts recommended against codeine for patients with high-risk CYP2D6 status. None of the patients with an ultra-rapid or poor metabolizer genotype were prescribed codeine. Using genetics to tailor analgesic prescribing retained an important therapeutic option by limiting codeine use to patients who could safely receive and benefit from it. Our efforts represent an evidence-based, innovative medication safety strategy to prevent adverse drug events, which is a model for the use of pharmacogenetics to optimize drug therapy in specialized pediatric populations.

‘Codeine is my companion’: misuse and dependence on codeine containing medicines in Ireland

Objectives

Global concern around over the counter availability of codeine containing products and risk of misuse, dependence and related harms are evident. A phenomenological study of lived experiences of codeine misuse and dependence was undertaken in Ireland, following the Pharmaceutical Society of Ireland’s 2010 guidelines for restricted supply of non-prescription codeine containing products.

Methods

In-depth interviews were conducted with a purposive sample of adult codeine misusers and dependents (n=21), both actively using, in treatment and in recovery. The narratives were analysed using the Empirical Phenomenological Psychological five-step method (Karlsson, 1995). A total of 10 themes with 82 categories were identified. Two concepts at a higher level of abstraction above the theme-level emerged during the final stage of analysis. The concepts identified were ‘emotional pain and user self-legitimization of use’ and ‘entrapment into habit-forming and invisible dependent use’. These concepts were reported in different ways by a majority of participants.

Results

Findings are presented under the following themes: (1) profile and product preferences; (2) awareness of habit forming use and harm; (3) negotiating pharmacy sales; (4) alternative sourcing routes; (5) the codeine feeling; (6) the daily routine; (7) acute and chronic side effects; (8) social isolation; (9) withdrawal and dependence and (10) help-seeking and treatment experiences.

Conclusions

There is a public health and regulatory imperative to develop proactive responses tackling public availability of codeine containing medicines, risk minimisation in consumer self-treatment for pain, enhanced patient awareness of potential for habit forming use and its consequences and continued health professional pharmacovigilence.

“Doctor shopping and pharmacy hopping”: practice innovations relating to codeine

Purpose

– The misuse of pharmaceutical opioid analgesics is identified as a global public health concern. Codeine represents an interesting quandary in terms of its regulated status, with individuals varying in their metabolism of codeine, estimation of safe dosages, risk of adverse health consequences and abuse potential. Efforts to quantify and address hidden non-compliant medical codeine use, overuse and intentional misuse is compromised by availability to the public in prescribed and over the counter forms. The paper aims to discuss these issues.

Design/methodology/approach

– A review of literature on codeine use, misuse and dependence, and associated innovative medical and pharmacy interventions is presented, and was conducted as part of a larger scoping review on codeine.

Findings

– The review highlights the complexities associated with monitoring public health awareness of codeine's abuse potential, and customer/patients trends in non-compliant codeine use for therapeutic and recreational purposes. Aberrant codeine behaviours centre on visiting multiple doctors for prescriptions, repeated lost or stolen prescriptions, forging prescriptions and use of multiple pharmacies. Innovations to monitor misuse of codeine include national prescription databases and recent developments in real-time monitoring of dispensing activity.

Practical implications

– Further development of real-time monitoring processes with process evaluation is advised.

Originality/value

– This viewpoint is intended to demonstrate how efforts to quantify and address codeine use are compromised by its availability. It intends to encourage further policy and practitioner dialogue on how to monitor, support and intervene with consumers misusing codeine.

Pain care for patients with epidermolysis bullosa: best care practice guidelines

BACKGROUND

Inherited epidermolysis bullosa (EB) comprises a group of rare disorders that have multi-system effects and patients present with a number of both acute and chronic pain care needs. Effects on quality of life are substantial. Pain and itching are burdensome daily problems. Experience with, and knowledge of, the best pain and itch care for these patients is minimal. Evidence-based best care practice guidelines are needed to establish a base of knowledge and practice for practitioners of many disciplines to improve the quality of life for both adult and pediatric patients with EB.

METHODS

The process was begun at the request of Dystrophic Epidermolysis Bullosa Research Association International (DEBRA International), an organization dedicated to improvement of care, research and dissemination of knowledge for EB patients worldwide. An international panel of experts in pain and palliative care who have extensive experience caring for patients with EB was assembled. Literature was reviewed and systematically evaluated. For areas of care without direct evidence, clinically relevant literature was assessed, and rounds of consensus building were conducted. The process involved a face-to-face consensus meeting that involved a family representative and methodologist, as well as the panel of clinical experts. During development, EB family input was obtained and the document was reviewed by a wide variety of experts representing several disciplines related to the care of patients with EB.

RESULTS

The first evidence-based care guidelines for the care of pain in EB were produced. The guidelines are clinically relevant for care of patients of all subtypes and ages, and apply to practitioners of all disciplines involved in the care of patients with EB. When the evidence suggests that the diagnosis or treatment of painful conditions differs between adults and children, it will be so noted.

CONCLUSIONS

Evidence-based care guidelines are a means of standardizing optimal care for EB patients, whose disease is often times horrific in its effects on quality of life, and whose care is resource-intensive and difficult. The guideline development process also highlighted areas for research in order to improve further the evidence base for future care.

End-of-life care for hospitalized children

High-quality palliative care is the standard for children with life-threatening illness, especially when a cure is not possible. This review outlines a model for clinical practice that integrates clinical, psychosocial, and ethical concerns at the end of life (EOL) into a standard operating procedure specifically focused on inpatient deaths. Palliative care for children at EOL in the hospital setting should encompass the personal, cultural, and spiritual needs of the child and family members and aim to minimize suffering and increase support for all who are involved, including hospital staff.

Current practices regarding codeine administration among pediatricians and pediatric subspecialists

Pharmacogenomic studies have revealed a wide variation in the metabolism of codeine to its active metabolite, morphine. A particular subset of patients, known as ultrarapid metabolizers, possesses multiple copies of the CYP2D6 gene responsible for codeine metabolism. This has been linked to serious morbidity and mortality in pediatric patients leading to considerable debate regarding the use of codeine for analgesia in the pediatric population. The current study surveyed the current practice of codeine prescription in pediatric health care providers from a single tertiary care pediatric hospital. Of the 298 responders, 43.3% (129 of 298) continue to prescribe codeine for pain management in children. The vast majority of codeine prescribers were primary health care providers (89.1%). Most of the primary care practitioners were in office-based (42.6%) or hospital-based (45.7%) group practices. There was no significant difference in codeine use based on years of experience. Given the risks associated with this practice, increased education targeting this group appears warranted.

Codeine-related adverse drug reactions in children following tonsillectomy: a prospective study

OBJECTIVES/HYPOTHESIS

To prospectively determine factors associated with codeine's adverse drug reactions (ADRs) at home in a large homogenous population of children undergoing outpatient tonsillectomy.

STUDY DESIGN

Prospective, genotype blinded, observational study with a single group and repeated ADR measures documented by parents at home.

METHODS

A total of 249 children 6 to 15 years of age scheduled for tonsillectomy were enrolled. The primary outcome was number of daily codeine-related ADRs. We examined the number and type of ADR by race and by days and further modeled factors potentially associated with ADR risk in a subcohort of white children. Sedation following a dose of codeine was a secondary outcome measure. Parents recorded their children's daily ADRs and sedation scores during postoperative days (POD) 0 to 3 at home.

RESULTS

Diaries were returned for 134 children, who were given codeine. A total of 106 (79%) reported at least one ADR. The most common ADRs were nausea, lightheadedness/dizziness for white children and nausea, and vomiting for African American children. In a subcohort of white children ≤ 45 kg, increased ADR risk was associated with the presence of one or more full function CYP2D6 alleles (P < 0.001), POD (P < 0.001), and sex (P = 0.027). Increased pain intensity (P = 0.009) and PODs 0 and 1 (P = 0.001) contributed to a higher sedation risk. Neither obstructive apnea nor predicted CYP2D6 phenotype were associated with sedation risk.

CONCLUSIONS

Our results provide evidence that multiple factors are associated with codeine-related ADRs and support the FDA recommendation to avoid codeine's routine use following tonsillectomy in children.

Pharmacogenetics and individualized therapy in children: immunosuppressants, antidepressants, anticancer and anti-inflammatory drugs

Pharmacogenetic polymorphisms that change the amino acid sequences in coding regions only account for part of the interindividual differences in disease susceptibility and drug response. Additional pharmacogenomic and epigenetic factors are also involved. In children, pharmacogenetic studies are limited, although it has been clear for many years that the interactions between developmental patterns of drug-metabolizing enzymes and transporters have a major impact on dose exposure with age-specific dosage requirements. This article will analyze the factors affecting variability in drug response in children and focus on the pharmacogenetic polymorphisms of immunosuppressants, antidepressants, anticancer and anti-inflammatory drugs. Additional pharmacogenetic and epigenetic studies should be performed to allow the individualization of therapy in children.

Analgesic prescribing practices can be improved by low-cost point-of-care decision support

CONTEXT

Codeine has become a controversial choice for analgesia in children compared with other commonly available drugs.

OBJECTIVES

To evaluate whether an educational campaign shifted resident prescribing patterns away from codeine toward more appropriate analgesics.

METHODS

Our intervention consisted of a pocket-sized reference card given to all trainees and key staff in an inpatient pediatric acute care unit; pediatrics residents also had the option to attend a one-hour lecture. The pocket card recommended against codeine (including rationale) and gave prescription guidance for our institution's preferred formulary alternative analgesics, which include tramadol and hydrocodone. We used inpatient prescribing data to track the prescribing of codeine and alternative medications over time.

RESULTS

Following the interventions, there was a significant decrease in the percentage of patients receiving codeine (13.5% of patients received the drug in the year before, 5.4% in the year after, P < 0.0001). Use of hydrocodone-containing analgesics increased overall during the same period (7.4%-16%, P < 0.0001) as did tramadol use (0.2%-2.6%, P < 0.0001). There were no changes in pain management satisfaction scores.

CONCLUSION

A simple low-cost educational campaign consisting primarily of a pocket guide to analgesics markedly improved analgesic prescribing patterns, and that improvement extended to services not targeted by the didactic component of our educational campaign. Point-of-care decision support by means of a pocket card may be sufficient for effecting change in medication prescribing patterns of trainees.

A randomised controlled trial of two analgesic techniques for paediatric tonsillectomy*

Investigators from Bristol described a fentanyl- and diclofenac-based analgesic technique for tonsillectomy with low postoperative nausea and vomiting rates and low pain scores. This study compared the effectiveness of a modified Bristol technique with a codeine-based regimen with respect to PONV and analgesia. Sixty-five children, ASA 1-2, were randomly assigned to either the Bristol group (fentanyl 1-2 μg.kg(-1) and diclofenac 1-2 mg.kg(-1)) or codeine group (codeine 1.5 mg.kg(-1)). All children received paracetamol 15 mg.kg(-1) and dexamethasone 0.1 mg.kg(-1) . Postoperative nausea and vomiting and pain scores were recorded hourly, and fitness for discharge was assessed at 4 h. The overall incidence of postoperative nausea and vomiting was 21% with no difference between groups (Bristol group 8/30, codeine group 5/32, p = 0.29). Children in the Bristol group required analgesia earlier than those in the codeine group (p < 0.005), but maximum pain scores were not different (Bristol group median (IQR [range) 4.5 (3-5 [0-5]), codeine group 4.0 (2-5 [1-5]), p = 0.15). Twenty-three per cent of children were assessed as not fit for discharge at 4 h. The codeine-based regimen may have a small advantage over the Bristol regimen, but neither technique seems ideally suited for a day-case service without a longer period of observation. You can respond to this article at http://www.anaesthesiacorrespondence.com.

Developmental pharmacology of tramadol during infancy: ontogeny, pharmacogenetics and elimination clearance

AIMS AND OBJECTIVES

To illustrate the complex interaction between ontogeny, i.e., age-dependent maturation, genetic polymorphisms and renal elimination clearance during infancy, based on developmental disposition of intravenous tramadol during infancy.

BACKGROUND

Tramadol (M) is metabolized by O-demethylation (cytochrome P450 [CYP] 2D6) to the pharmacodynamic active metabolite O-demethyl tramadol (M1). This metabolite is subsequently eliminated by renal route while M1 formation will in part depend on ontogeny, i.e., age-dependent activity and CYP2D6 polymorphisms. However, these pathways do not mature simultaneously.

METHODS

A pooled pharmacokinetic analysis of earlier reported time-concentration profiles in neonates and infants was performed with subsequent simulation of the impact of ontogeny, polymorphisms and renal elimination clearance during infancy.

RESULTS

Tramadol plasma time-concentration profile changes with postmenstrual age. The highest metabolite concentrations occur in the 52-week infant, where M1 formation clearance (hepatic, CYP2D6) is already mature but metabolite elimination clearance (through glomerular filtration rate) is immature.

DISCUSSION

The phenotypic observations might in part explain unanticipated (side-)effects of tramadol. In addition to the compound-specific clinical implications, it is important to stress that the maturational trends in the elimination processes described can be considered for other compounds (e.g., codeine) that undergo similar elimination routes.