Clonidine poisoning--an emerging problem: epidemiology, clinical features, management and preventative strategies

Reality of clonidine poisoning in children and adolescents

AIM

We aimed to describe the severity of clonidine poisonings in a paediatric population referred to a tertiary toxicology service.

METHODS

We undertook a retrospective review of all presentations of clonidine poisoning in children or adolescents reported to a tertiary toxicology service from March 2014 to February 2020. Cases were divided into young children (0-6 years), older children (7-11 years) and adolescents (12-17 years). We report clinical effects: bradycardia, hypotension and abnormal Glasgow coma score (GCS), based on standard paediatric observation charts, interventions, length of emergency department stay, proportion admitted to a medical ward or paediatric intensive care unit.

RESULTS

We identified 111 clonidine poisonings, 41 young children, 9 older children and 61 adolescents. There were more females in the adolescent group and slightly more males in the younger age groups. The median dose ingested was 13 mcg/kg (interquartile range: 7-38 mcg/kg), which varied across ages. Clonidine alone was ingested in 78 cases (70%) and co-ingestion was more common in adolescents (24/61; 39%). Thirty-seven patients (33%) were admitted and 23 (21%) were admitted to paediatric intensive care unit. Median length of emergency department stay was 16.4 h, longer for adolescents. At least one abnormal observation occurred in 101 of 111 (91%) cases: 76 of 106 (72%) bradycardia, 76 of 110 (69%) hypotension and 4 of 99 (4%) GCS < 9. Thirteen (12%) had severe bradycardia, more common in young children and 23 (21%) had severe hypotension, more common in adolescents. For 27 children (0-11 years) ingesting 5-10 mcg/kg, 3 (11%) had severe bradycardia or severe hypotension and 1 received naloxone (4%). No cases ingesting <5 mcg/kg developed moderate/severe bradycardia or hypotension. Four cases received naloxone with no significant change, two patients got atropine with a transient response. One patient was intubated to facilitate safe inter-hospital transfer.

CONCLUSION

Paediatric clonidine poisoning commonly results in bradycardia, hypotension and decreased GCS, but rarely severe or requiring major interventions. Children ingesting <5 mcg/kg do not require admission.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40780-021-00214-x.

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.

Outcomes following clonidine ingestions in children: an analysis of poison control center data

Background

This paper sought to characterize pediatric clonidine ingestions, report trends in incidence, and evaluate outcomes using the Florida Poison Center’s data over a period of 15 years, from 2002 to 2016.

Results

There were 3444 total exposures. Forty percent of the cohort was female. The median age was 5 years. The age distribution changed over time to a higher proportion of teenagers exposed (p < 0.0001). From 2002 to 2016, exposures increased from 182 to 378 with a rise in incidence from 4.8 to 9.1 per 100,000 children. Acute on chronic exposures increased from 29.3% to 42.2% (p < 0.0001). Female intentional ingestions increased from 52 to 70% (p < 0.0001). Twenty-four percent were managed at home, 34% were discharged from the emergency department, 8% were admitted to the floor, and 25% were admitted to the intensive care unit (ICU). Major medical outcomes were associated with older age (p = 0.0043, 95% CI 0.0015 to 0.0080) and higher clonidine dose (p < 0.0001, 95% CI 0.0347 to 0.0600). Older children were more likely to ingest a larger dose of clonidine (p < 0.001, 95% CI 0.0531 to 0.0734), while younger children were more likely to be admitted to the ICU (p < 0.001, 95% CI − 0.0092 to − 0.0033). Males were more likely to have acute on chronic ingestions (p < 0.001, 95% CI − 0.1639 to − 0.0982); females were significantly more likely to be admitted to the ICU (p < 0.0001, 95% CI 0.0380 to 0.0969).

Conclusions

Our analysis shows an increase in the incidence in pediatric clonidine exposures over time despite adjustment for population growth.

Clonidine exposures in children under 6 (2004-2017): a retrospective study

OBJECTIVE

To describe trends in clonidine exposures in children under 6. Clonidine has become increasingly popular for management of paediatric behavioural disorders. Clonidine has a narrow therapeutic index, and toxicity can occur with inadvertent double dosing. Clonidine is not recommended for use in children under 6 years.

DESIGN AND SETTING

A retrospective review of clonidine exposures in children under 6 reported to the New South Wales Poisons Information Centre (NSWPIC, Australia's largest poison centre), 2004-2017. This was compared with community clonidine utilisation using dispensing data from Australian Statistics on Medicines, 2004-2015. Australian trends were compared with clonidine exposure calls to US poison centres, 2006-2016.

MAIN OUTCOME MEASURES

Trends in poisonings and dispensing; demographics, dose, exposure type, clonidine source, symptoms, disposition.

RESULTS

There were 802 clonidine exposures in the NSWPIC database, increasing 4.9% per year, 2004-2017 (95% CI 3.1% to 6.7%, p<0.001), correlated with increased dispensing, r=0.846 (95% CI 0.529 to 0.956, p<0.001). 78.6% were hospitalised and medical toxicologists were consulted in 7.2%, indicating high risk and/or morbidity. Clonidine was prescribed for the patient in at least 27.8%, providing evidence for prescribing outside of recommendations. US data reveals 19 056 clonidine exposures, with 3.7% increase per year, 2006-2016 (95% CI 2.2% to 5.3%, p<0.001).

CONCLUSIONS

Clonidine exposures in children under 6 are increasing, and this trend is not isolated to Australia. Exposures have a high hospital referral rate and high morbidity. Caution should be exercised when prescribing clonidine, and parent/carer education is important for safe storage and increased vigilance when dosing.

[Tolerance of the oral clonidine test in 180 patients: efficacy of the volemic expantion in controlling arterial hypotension]

Clonidine stimulation test is widely used to evaluate growth hormone secretion. Side effects are somnolence (35%) and arterial hypotension (AH) (5%). The aims of this paper were to evaluate the tolerance to this test regarding blood pressure (BP) decrease, sedation and the efficacy of saline resuscitation to prevent AH. BP was measured at basal, 60 and 120 min. Sedation was determined by the Ramsay scale. Patients were divided into two groups: Group 1 (n = 80) received saline resuscitation only upon severe AH (drop of mean BP [MBP] > 20% from initial MBP) and/or postural hypotension; Group 2 (n = 100) received saline resuscitation from the beginning of the test. Both groups presented a significant MBP fall and 75% presented somnolence at 60 min. MBP drop did not correlate with either sedation or the clonidine dose. Group 1 presented more hypotension (59% x 28%) and greater MBP drop at 60 min. Only one patient had an asthma attack. We conclude that the hypotension effects caused by oral clonidine diminish with saline resuscitation since the beginning of the test. This test must have specialized medical support with strict BP evaluation and precocious intervention when needed.

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.

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.

Munchausen syndrome by proxy (MSBP): an extreme form of child abuse with a special forensic challenge

Munchausen syndrome by proxy (MSBP) is a special form of child abuse in which an adult repeatedly produces symptoms of illness in a person under his/her care. In most cases the perpetrators are mothers who repeatedly and in different ways produce or feign symptoms of illness in their children in order to obtain medical treatment for them. MSBP is thus a special form of child abuse that is also of importance in the field of forensic medicine and a particular challenge to the medicolegal expert. We report two cases of poisoning with different substances (clozapine and clonidine) detected by toxicological investigations at our Department of Legal Medicine. The relevance of the problem for the medicolegal expert and the importance of an interdisciplinary co-operation are pointed out.

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.

Pediatric methylphenidate exposures: 7-year experience of poison centers in the United States

This study was undertaken to evaluate trends and toxicity of pediatric methylphenidate exposures; 1993 to 1999 national poison center data were analyzed. There were 12,917 exposures, increasing from 927 in 1993 to 2,445 in 1999. The majority of children during the entire study period experienced no effect (60.3%) or minor effects (28.7%), with no fatalities. Most common reasons were unintentional general or therapeutic errors in children under 13 years and suicide attempt in adolescents. Adolescents were more likely to experience clinical toxicity, hospitalizations and more serious outcomes. The trend of increasing frequency of methylphenidate exposures reported to poison centers exactly parallels increasing therapeutic use.

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.

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.