Clonidine overdose in childhood: implications of increased prescribing

Medications Used for Pediatric Insomnia

Pediatric insomnia can affect physical and mental health and cause cognitive deficits, social deficits and decrease quality of life. There are no Food and Drug Administration approved medications approved for pediatric insomnia. Pharmacologic interventions derive mostly from adult data or pediatric case reports. This review focuses on Food and Drug Administration approved prescription drugs (in adults), over-the-counter drugs, and off-label pediatric insomnia drugs. This review helps the clinician learn general principles, practice guidelines, and pharmacologic considerations for medication selection in the pediatric population. Pharmacologic management should be considered in combination with behavior therapy, which is proven to have long-lasting outcomes.

Pediatric tizanidine toxicity reversed with naloxone: a case report

Background

Tizanidine, an α-2 adrenoceptor agonist, is widely prescribed for the management of spasticity in adults. Case reports on pediatric tizanidine overdose are limited. Here, we report a case of pediatric tizanidine toxicity that was reversed with naloxone.

Case presentation

A 3-year-old male presented to the emergency department with lethargy, bradycardia, and bradypnea after accidental ingestion of multiple tizanidine tablets. Improvements in the level of consciousness and respiratory and heart rates were observed after two intravenous administrations of naloxone at a dose of 0.05 and 0.1 mg/kg, respectively.

Conclusions

This case report provides further evidence regarding the use of naloxone as a viable antidote for centrally acting α-2 receptor agonists and presents additional epidemiologic data on childhood tizanidine poisoning.

Stability of clonidine hydrochloride in an oral powder form compounded for pediatric patients in Japan

BACKGROUND

Clonidine hydrochloride is used to treat sedative agent withdrawals, malignant hypertension, and anesthesia complications. Clonidine is also prescribed off-label to pediatric patients at a dose of 1 μg/kg. The commercially available enteral form of clonidine, Catapres® tablets, is often compounded into a powder form by pharmacists to achieve dosage adjustments for administration to pediatric patients. However, the stability and quality of compounded clonidine powder have not been verified. The objectives of this study were to formulate a 0.2 mg/g oral clonidine hydrochloride powder and assess the stability and physical properties of this compounded product in storage.

METHODS

A 0.2 mg/g clonidine powder was prepared by adding lactose monohydrate to crushed and filtrated clonidine tablets. The powder was stored in polycarbonate amber bottles or coated paper packages laminated with cellophane and polyethylene. The stability of clonidine at 25 °C ± 2 °C and 60% ± 5% relative humidity was examined over a 120-d period in "bottle (closed)," "bottle (in use)," and "laminated paper" storage conditions. Drug dissolution and powder X-ray diffraction analysis were conducted to assess physicochemical stabilities. Validated liquid chromatography-diode array detection was used to detect and quantify clonidine and its degradation product, 2,6-dichloroaniline (2,6-DCA).

RESULTS

Clonidine content was maintained between 90.0 and 110.0% of the initial contents in all packaging and storage conditions. After 120 d of storage, 2,6-DCA was not detected, and no crystallographic and dissolution changes were observed.

CONCLUSIONS

Compounded clonidine powder stability was maintained for 120 d at 25 °C ± 2 °C and 60% ± 5% relative humidity. This information may contribute to the management of clonidine compounded powder in community and hospital pharmacies in Japan.

Medications Used for Pediatric Insomnia

Pediatric insomnia can affect physical and mental health and cause cognitive deficits, social deficits and decrease quality of life. There are no Food and Drug Administration approved medications approved for pediatric insomnia. Pharmacologic interventions derive mostly from adult data or pediatric case reports. This review focuses on Food and Drug Administration approved prescription drugs (in adults), over-the-counter drugs, and off-label pediatric insomnia drugs. This review helps the clinician learn general principles, practice guidelines, and pharmacologic considerations for medication selection in the pediatric population. Pharmacologic management should be considered in combination with behavior therapy, which is proven to have long-lasting outcomes.

Clinical Effects of Pediatric Clonidine Exposure: A Retrospective Cohort Study at a Single Tertiary Care Center

BACKGROUND

Pediatric clonidine ingestions frequently result in emergency department visits and admission for cardiac monitoring. Detailed information on the clinical course and specifically time of vital sign abnormalities of these patients is lacking.

OBJECTIVE

The objective of this study was to provide descriptive analysis of the rates and times to vital sign abnormalities, treatment, disposition, and outcomes in a single-center cohort of pediatric patients with report of clonidine poisoning.

METHODS

We performed a retrospective cohort study of patients younger than 21 years who presented to a large, urban, tertiary care center with a report of single substance clonidine exposure between January 2004 and November 2017. Patients were dichotomized into younger (≤9 years or younger) and older (10-21 years) groups based on the expected physiologic and psychologic differences between older and younger children.

RESULTS

Eighty-eight patients met our inclusion criteria. Younger patients (≤9 years or younger; n = 47) were more likely to be exposed to someone else's medication (53%) and older patients (10-21 years; n = 41) overwhelmingly (85%) were exposed to their own medication. Thirty-nine (45%) became bradycardic, 27 (32%) became bradypneic, and 38 (44%) became hypotensive. Eighty percent of patients had depressed mental status. Thirty-three (38%) patients received at least one dose of naloxone (median 0.07 mg/kg; interquartile range 0.03-0.11 mg/kg). Of those who received naloxone, 50% had a documented clinical response.

CONCLUSIONS

In this study of patients at a pediatric tertiary referral center, pediatric patients with report of clonidine exposures were likely to exhibit altered mental status and frequently develop vital sign abnormalities. Naloxone exhibited some effectiveness; given its wide safety margin, high-dose naloxone should be used in critically poisoned non-opioid-dependent patients. Because adolescents are much more likely to ingest their own clonidine medication, counseling with parents and other caregivers regarding safe medication storage is paramount.

Attention-deficit hyperactivity disorder medication use: factors involved in prescribing, safety aspects and outcomes

While treatment of patients with attention-deficit hyperactivity disorder (ADHD) is based on a multimodal approach that combines medication with specific psychological interventions, pharmacotherapy alone is generally considered an essential and cost-effective element. This paper aims to comprehensively and critically review factors involved in prescribing and medication use in individuals diagnosed with ADHD, focusing on the difficulties facing patients with ADHD seeking treatment, as well as the safety and tolerability aspects of ADHD pharmacotherapies, with particular attention on the cardiovascular adverse events and the potential risk of misuse or diversion of ADHD medications. A comprehensive and systematic literature search of PubMed/MEDLINE database was conducted to identify studies published in peer-reviewed journals until 1 August 2016. Children, adolescents and adults often encounter significant difficulties in the process of accessing specialist assessment and treatment for ADHD as a consequence of disparities in service organization and available treatment provision. Despite the well-established efficacy and overall safety profile, ADHD medications are not exempt from adverse events. The cardiovascular safety of pharmacotherapies used for treating individuals with ADHD has raised particular concerns; however there is little evidence of serious cardiovascular adverse events, including no serious corrected QT (QTc) abnormalities associated with stimulants, atomoxetine or α2-adrenergic receptor agonists. Although the abuse of prescription stimulant drugs, particularly, short-acting stimulants is a prevalent and growing problem, nonmedical use of prescription stimulants within the clinical context is very limited. In addition, nonstimulant ADHD medications lack any reinforcing effects and consequently any abuse potential.

Overdose of drugs for attention-deficit hyperactivity disorder: clinical presentation, mechanisms of toxicity, and management

The prevalence of attention-deficit hyperactivity disorder (ADHD) in the USA is estimated at approximately 4-9% in children and 4% in adults. It is estimated that prescriptions for ADHD medications are written for more than 2.7 million children per year. In 2010, US poison centers reported 17,000 human exposures to ADHD medications, with 80% occurring in children <19 years old and 20% in adults. The drugs used for the treatment of ADHD are diverse but can be roughly separated into two groups: the stimulants such as amphetamine, methylphenidate, and modafinil; and the non-stimulants such as atomoxetine, guanfacine, and clonidine. This review focuses on mechanisms of toxicity after overdose with ADHD medications, clinical effects from overdose, and management. Amphetamine, dextroamphetamine, and methylphenidate act as substrates for the cellular monoamine transporter, especially the dopamine transporter (DAT) and less so the norepinephrine (NET) and serotonin transporter. The mechanism of toxicity is primarily related to excessive extracellular dopamine, norepinephrine, and serotonin. The primary clinical syndrome involves prominent neurological and cardiovascular effects, but secondary complications can involve renal, muscle, pulmonary, and gastrointestinal (GI) effects. In overdose, the patient may present with mydriasis, tremor, agitation, hyperreflexia, combative behavior, confusion, hallucinations, delirium, anxiety, paranoia, movement disorders, and seizures. The management of amphetamine, dextroamphetamine, and methylphenidate overdose is largely supportive, with a focus on interruption of the sympathomimetic syndrome with judicious use of benzodiazepines. In cases where agitation, delirium, and movement disorders are unresponsive to benzodiazepines, second-line therapies include antipsychotics such as ziprasidone or haloperidol, central alpha-adrenoreceptor agonists such as dexmedetomidine, or propofol. Modafinil is not US FDA approved for treatment of ADHD; however, it has been shown to improve ADHD signs and symptoms and has been used as an off-label pharmaceutical for this diagnosis in both adults and children. The mechanism of action of modafinil is complex and not fully understood. It is known to cause an increase in extracellular concentrations of dopamine, norepinephrine, and serotonin in the neocortex. Overdose with modafinil is generally of moderate severity, with reported ingestions of doses up to 8 g. The most common neurological effects include increased anxiety, agitation, headache, dizziness, insomnia, tremors, and dystonia. The management of modafinil overdose is largely supportive, with a focus on sedation, and control of dyskinesias and blood pressure. Atomoxetine is a selective presynaptic norepinephrine transporter inhibitor. The clinical presentation after overdose with atomoxetine has generally been mild. The primary effects have been drowsiness, agitation, hyperactivity, GI upset, tremor, hyperreflexia, tachycardia hypertension, and seizure. The management of atomoxetine overdose is largely supportive, with a focus on sedation, and control of dyskinesias and seizures. Clonidine is a synthetic imidazole derivative with both central and peripheral alpha-adrenergic agonist actions. The primary clinical syndrome involves prominent neurological and cardiovascular effects, with the most commonly reported features of depressed sensorium, bradycardia, and hypotension. While clonidine is an anti-hypertensive medication, a paradoxical hypertension may occur early with overdose. The clinical syndrome after overdose of guanfacine may be mixed depending on central or peripheral alpha-adrenoreceptor effects. Initial clinical effects may be drowsiness, lethargy, dry mouth, and diaphoresis. Cardiovascular effects may depend on time post-ingestion and may present as hypotension or hypertension. The management of guanfacine overdose is largely supportive, with a focus on support of blood pressure. Overdose with ADHD medications can produce major morbidity, with many cases requiring intensive care medicine and prolonged hospital stays. However, fatalities are rare with appropriate care.

Pharmacology of sleep disorders in children and adolescents

There is a high prevalence of sleep disorders in children and an apparent increasing need for pharmacologic management. However, because of the paucity of data available with regards to dosing, efficacy, tolerability, and safety profiles of medications as well as a lack of adequate well-designed clinical trials, medications are currently not approved for the pediatric population by the US Food and Drug Administration. There are no pharmacologic guidelines for the specific sleep disorders or the different pediatric age ranges. Additional research is needed for evidence-based pediatric sleep pharmacotherapy. This article reviews pediatric sleep disorders and the pharmacologic therapeutic options.

Deadly ingestions

More than 50% of the toxic-exposure calls to US poison centers involve children. Although most of these exposures are nontoxic, there are several products and medications that are widely available to the pediatric population that can lead to severe toxicity or even death. With some of these medications, death or severe symptoms can occur with the ingestion of only a small amount. It is important that the clinician be familiar with presenting signs and symptoms of potentially toxic ingestions and is able to initiate a therapeutic and life-saving intervention. This article reviews some of the deadlier ingestions that children may be exposed to.

Oral clonidine pretreatment prior to venous cannulation

Clonidine is a preferential alpha-2 agonist drug that has been used for over 35 years to treat hypertension. Recently, it has also been used as a preoperative medication and as a sedative/anxiolytic drug. This randomized, double-blind, placebo-controlled crossover clinical trial characterized the effects of oral clonidine pretreatment on intravenous catheter placement in 13 patients. Parameters measured included the bispectral index (BIS), Observer's Assessment of Alertness/Sedation Scale (OAA/S), frontal temporal electromyogram (EMG), 30-Second Blink Count (Blink), Digit Symbol Substitution Test (DSST), State Anxiety Inventory (SAI), fingertip versus forearm skin temperatures, and multiple questionnaires. Oral clonidine significantly decreased SAI scores, OAA/S, EMG, and Blink, but did not cause statistically significant BIS or DSST reductions. Subjects preferred oral clonidine pretreatment prior to venipuncture compared to placebo. Questionnaires also indicated that clonidine provided minimal sedation, considerable anxiolysis, and some analgesia. Fingertip versus forearm skin temperature differentials were decreased. Reduced fingertip versus forearm temperature differentials suggest increased peripheral cutaneous blood flow prior to venous cannulation. Oral clonidine pretreatment not only helped control patient anxiety and pain but also provided cardiovascular stability.

Do adrenergically active drugs have a role in the first-line treatment of attention-deficit/hyperactivity disorder?

Adrenergically active drugs used for the treatment of attention-deficit/hyperactivity disorder (ADHD) include the alpha-agonists, monoamine oxidase inhibitors, tricyclics and the selective noradrenergic re-uptake inhibitors. In addition to a longer duration of treatment effect than the predominantly dopaminergic psychostimulant drugs, a theoretical advantage of the adrenergically active drugs is a lesser tendency to aggravate common comorbidities of ADHD, such as anxiety, obsessionality, depression and tics. Nevertheless, adrenergically active drugs have always been considered second-line treatments to the psychostimulant drugs. No study has demonstrated superiority of adrenergically active drugs over the psychostimulants in reducing the core symptoms of ADHD, although several small trials have suggested 'equivalence'. The case for superiority of the adrenergically active drugs over psychostimulants in alleviating comorbid symptoms remains largely unproven, as there have been few comparative trials. Safety data have favoured the psychostimulant drugs. The advantage of once daily or morning and evening dosing of the adrenergically active drugs has been diminished since the introduction of sustained release preparations of methylphenidate and amphetamine. Although adrenergically active drugs may be the preferred treatment in the presence of severe comorbidity, for the most part they remain second-line treatment for ADHD.

The ADHD and sleep conundrum: a review

The relationship between attention-deficit hyperactivity disorder (ADHD) and sleep is a complex one that poses many challenges in clinical practice. Recent studies have helped to elucidate the nature of the brain mechanisms and neuromodulator systems underlying the theoretical associations among sleepiness, arousal, and attention. Studies of sleep disturbances in children with academic and behavioral problems have also underscored the role that primary sleep disorders such as obstructive sleep apnea hypopnea syndrome play in the clinical presentation of symptoms of inattention and behavioral dysregulation. In addition, new methodologies used in examining sleep and sleep patterns in children diagnosed with ADHD have shed further light on the prevalence, type, risk factors for, and impact of sleep disturbances in these children. The following discussion of the multilevel relationships among sleep quality and quantity, neurobehavioral functioning, and the clinical syndrome of ADHD expands on previous reviews of the literature and synthesizes what is currently known about the interaction of sleep and attention/arousal in children to propose possible underlying mechanisms, integrate more recent findings, and highlight important areas for future study. In addition, guidelines are provided for a clinical approach to evaluation and management of children with ADHD and sleep problems.

Toxic clonidine ingestion in children

OBJECTIVES

We performed a prospective case series to seek dosage or clinical parameters to better identify patients who need direct medical evaluation.

STUDY DESIGN

All clonidine ingestions in children younger than 12 years of age reported to 6 poison centers were followed for a minimum of 24 hours. Exclusion criterion was polydrug ingestion.

RESULTS

The study included 113 patients, of whom 63 were male. Mean age was 3.8 years (+/-2.4 SD). Clinical effects were common, but severe adverse effects occurred in <10% of patients. The dose ingested was reported for 90 patients (80%); 61 (68%) children ingested <0.3 mg and none had coma, respiratory depression, or hypotension. The lowest dose ingested by history with coma and respiratory depression was 0.3 mg (0.015 mg/kg). Prior clonidine therapy did not affect outcome. Onset of full clinical effects in all cases was complete within 4 hours of ingestion.

CONCLUSIONS

We recommend direct medical evaluation for (1) all children 4 years of age and younger with unintentional clonidine ingestion of >or=0.1 mg, (2) ingestion of >0.2 mg in children 5 to 8 years of age, and (3) ingestion of >or=0.4 mg in children older than 8 years of age. Observation for 4 hours may be sufficient to detect patients who will develop severe effects.

Clonidine poisoning in children: a recent experience

OBJECTIVES

To identify cases of clonidine poisoning presenting to a tertiary paediatric hospital and to investigate trends in presentation, outcome and prevention. Furthermore, any public health implications of the use of clonidine in children are to be explored.

METHODS

Cases of clonidine poisoning presenting to Royal Children's Hospital were reviewed over the period from 1997 to 2001 (inclusive), with significant data obtained from coded medical records.

RESULTS

Twenty-four cases of clonidine poisoning were identified over the 5-year period. Nine patients ingested their own medication, which was prescribed for attention-deficit hyperactivity disorder. Clonidine was prescribed for a child in 16 cases (67%). Impaired conscious state and bradycardia were the most common presenting features. Activated charcoal was given in 14 cases and volume expansion in six. There were 12 children (50%) who required admission to intensive care for monitoring, including three who received mechanical ventilation. The average length of stay was 25.7 h with no long-term complications.

CONCLUSIONS

This is the largest series of clonidine poisoning in children recorded in Australia, with morbidity considerable. Emphasis needs to be placed on educating parents of clonidine's dangers in overdose to their own children as well as others.

Are one or two dangerous? Clonidine and topical imidazolines exposure in toddlers

Clonidine and the imidazolines, commonly found in topical ophthalmic and nasal decongestants, are chemically related drugs that have been responsible for many pediatric poisonings. These medications can cause significant morbidity in small doses. A review of the available literature reveals that young children have exhibited severe signs and symptoms after ingesting as little as one to two clonidine tablets or 2.5 ml of a topical imidazoline product. Central nervous system depression, respiratory depression, and cardiovascular instability are the most common features of poisoning. Signs and symptoms develop rapidly, within 4-6 h. Care is supportive. Death is rare, but many poisoned patients require monitoring in an intensive care setting.

A randomized controlled trial of clonidine added to psychostimulant medication for hyperactive and aggressive children

OBJECTIVE

To compare clonidine with placebo added to ongoing psychostimulant therapy for the treatment of attention-deficit/hyperactivity disorder with comorbid oppositional defiant disorder or conduct disorder.

METHOD

Children 6 to 14 years of age recruited through 2000 to 2001 were randomized to receive clonidine syrup 0.10 to 0.20 mg/day (n = 38) or placebo (n = 29) for 6 weeks. Primary outcome measures were the Conduct and Hyperactive Index subscales of the parent-report Conners Behavior Checklist. Side effects were monitored using physiological measures and the Barkley Side Effect Rating Scale.

RESULTS

Evaluable patient analysis showed that significantly more clonidine-treated children than controls were responders on the Conduct scale (21 of 37 versus 6 of 29; chi2(1) = 8.75, p <.01) but not the Hyperactive Index (13 of 37 versus 5 of 29). Compared with placebo, clonidine was associated with a greater reduction in systolic blood pressure measured standing and with transient sedation and dizziness. Clonidine-treated individuals had a greater reduction in a number of unwanted effects associated with psychostimulant treatment compared with placebo.

CONCLUSIONS

The findings support the continued use of clonidine in combination with psychostimulant medication to reduce conduct symptoms associated with attention-deficit/hyperactivity disorder. Treatment is well tolerated and unwanted effects are transient.

Pharmacy prescription dispensing errors reported to a regional poison control center

OBJECTIVES

To identify the incidence, types, associations, and outcomes of pharmacy prescription dispensing errors reported to a regional poison control center.

METHODS

Retrospective chart review over a 35-month period.

RESULTS

Of 77,992 drug exposures reported, there were 6450 unintentional therapeutic exposures. Forty were the result of pharmacy prescription dispensing errors. Of these, 20 (50%) were medication substitution errors (wrong drug), 17 (42.5%) were labeling errors (correct drug, wrong formulation or instructions), and 3 (7.5%) were compounding errors (incorrect liquid dilution or capsule preparation). Both compounding and labeling errors were significantly more likely than substitution errors to be order-of-magnitude amounts. Compounding errors were also significantly more likely than labeling errors to be order-of-magnitude amounts. Labeling errors were significantly more likely to be liquids prescribed to children than substitution errors. Compounding errors had significantly more serious outcomes compared with substitution or labeling errors.

CONCLUSIONS

Substitution and labeling errors are the most common pharmacy prescription dispensing errors reported to a regional poison control center. Compounding errors have the greatest potential for serious outcomes. Children are particularly at risk because of the increased potential for error in the preparation and use of liquids. Inclusion of scenarios of prescription dispensing errors in the Toxic Exposure Surveillance System database would improve error detection and tracking. Poison control centers may be a source of valuable feedback to physicians and pharmacists.

Clonidine toxicity revisited

The incidence of clonidine overdose is increasing, yet there is a paucity of new information regarding treatment options for clonidine toxicity. Reported treatment approaches vary widely, demonstrating the lack of science on which current treatment is based. Available research needs to be reassessed. Neurotransmitters, receptors, endogenous opioids, and baseline sympathetic tone determine the clinical response to clonidine as well as the potential response to drug therapy following clonidine overdose. This article reviews aspects of clonidine toxicity that need to be further investigated. Multicenter research trials will be required to evaluate new treatment options.

Pediatric toxicologic concerns

Pediatric poisonings account for significant morbidity in the United States each year. Clinicians must keep current with advances in toxicology to be familiar with the latest recommended treatment regimens and antidotes. They also must be familiar in identifying toxidromes and important physical examination findings. Having these skills can enable the clinician to determine who is at risk for significant morbidity or mortality and to provide the appropriate medical care.

Childhood poisoning in Queensland: an analysis of presentation and admission rates

OBJECTIVE

To determine the presentation rates for paediatric poisoning by ingestion and the determinants of hospital admission.

METHODOLOGY

Cross-sectional survey using an injury surveillance database from emergency departments in South Brisbane, Mackay and Mt Isa, Queensland, from January 1998 to December 1999. There were 1516 children aged 0-14 years who presented following ingestional poisoning.

RESULTS

The presentation rates for poisoning were 690, 40 and 67 per 100000 population aged 0-4, 5-9 and 10-14 years, respectively. The admission rates to hospital for poisoning were 144, 14 and 22 per 100000 population aged 0-4, 5-9 and 10-14 years, respectively. Although presentation rates for poisoning were higher in the rural centres the admission rates were disproportionately high for the 0-4 years age group. The agents most frequently ingested were paracetamol, Dimetapp, rodenticides and essential oils.

CONCLUSION

There is a need to design and implement interventions aimed at reducing poison exposures and unnecessary hospital admissions in the 0-4 years age group.

A 1000-fold overdose of clonidine caused by a compounding error in a 5-year-old child with attention-deficit/hyperactivity disorder

A 5-year-old child who weighed 17.5 kg received 50 mg of clonidine. The amount ingested was confirmed by analysis of the suspension administered (clonidine HCl 9.78 mg/mL). To our knowledge, this represents the largest ingestion in a child and the largest ingestion on a milligram per kilogram basis in the medical literature. The child's initial presentation included hyperventilation, an unusual feature of clonidine toxicity. The child was discharged without sequela 42 hours after admission. A serum concentration of clonidine 17 hours postingestion was 64 ng/mL, the highest reported to date in a pediatric patient. The intoxication was traced to a pharmacy compounding error in which milligrams were substituted for micrograms. Increased prescribing of clonidine in young children coupled with the requirement to compound clonidine in a suspension and the narrow therapeutic index suggests that the frequency of severe ingestions in children will increase in the future.