A 4-Year-Old With Altered Mental Status and Bradycardia After Clonidine Overdose.

This case presentation describes the clinical management of a pediatric patient during transport after a single-drug overdose of clonidine. Clonidine overdose closely resembles opiate intoxication, and treatment is largely supportive; however, the patient in this case presentation had a declining altered mental status with evidence of airway compromise within 1 to 2 hours after ingestion, which warranted protective airway management. The patient was extubated the following day with a successful outcome.

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.

Clonidine Overdose in a Toddler Due to Accidental Ingestion of a Compounding Cream.

A 22-month-old girl without any significant medical history accidentally consumed a small amount of a therapeutic compounding cream that contained camphor, gabapentin, clonidine, ketoprofen, and lidocaine. Upon presentation to the emergency department, the child exhibited immediate onset of altered mental status with wide fluctuation in her vital signs, which included intermittent apnea requiring bag-valve mask assistance and endotracheal intubation. Serum laboratory analysis measured a clonidine level of 2.6 ng/mL and undetectable camphor, gabapentin, and ketoprofen levels. While on mechanical ventilation, the patient exhibited hypothermia, bradycardia, and hypotension; all of which responded to supportive care. After approximately 12 hours in the intensive care unit, the patient was successfully extubated and remained asymptomatic. This unique case of a patient with brief, unintentional oral exposure to a compounding cream, who demonstrated severe toxicity despite only a measured, supratherapeutic clonidine concentration, is discussed. Emergency physicians and pediatricians should be alert to the potential for exposure of pediatric patients to these medicinal compounds. Furthermore, parents must be made aware of the potential dangers of compounded medications and ensure their proper usage and storage.

Adult clonidine overdose: prolonged bradycardia and central nervous system depression, but not severe toxicity.

CONTEXT: There are limited reports of adult clonidine overdose. We aimed to describe the clinical effects and treatment of clonidine overdose in adults. METHODS: This was a retrospective review of a prospective cohort of poisoned patients who took clonidine overdoses (>200 µg). Demographic information, clinical effects, treatment, complications (central nervous system and cardiovascular effects) and length of stay (LOS) were extracted from a clinical database or medical records. RESULTS: From 133 admissions for clonidine poisoning (1988-2015), no medical record was available in 14 and 11 took staggered ingestions. Of 108 acute clonidine overdoses (median age 27 years; 14-65 years; 68 females), 40 were clonidine alone ingestions and 68 were clonidine with co-ingestants. Median dose taken was 2100 µg (interquartile range [IQR]: 400-15,000 µg). Median LOS was 21h (IQR: 14-35 h) and there were no deaths. Glasgow coma score [GCS] <15 occurred in 73/108 (68%), and more patients taking co-ingestants (8/68; 12%) had coma (GCS <9) compared to clonidine alone (2/40; 5%). Miosis occurred in 31/108 (29%) cases. Median minimum HR was 48 bpm (IQR: 40-57 bpm), similar between clonidine alone and co-ingestant overdoses. There was a significant association between dose and minimum HR for clonidine alone overdoses (p = 0.02). 82/108 (76%) had bradycardia, median onset 2.5 h post-ingestion (IQR: 1.7-5.5 h) and median duration 20 h (2.5-83 h), similar for clonidine alone and co-ingestant overdoses. There were no arrhythmias. Three patients ingesting 8000-12,000 µg developed early hypertension. Median minimum systolic BP was 96 mmHg (IQR: 90-105 mmHg) and hypotension occurred in 26/108 (24%). 12/108 patients were intubated, but only 2 were clonidine alone cases. Treatments included activated charcoal (24), atropine (8) and naloxone (23). The median total naloxone dose was 2 mg (IQR: 1.2-2.4 mg), but only one patient given naloxone was documented to respond with partial improvement in GCS. DISCUSSION: Clonidine causes persistent but not life-threatening clinical effects. Most patients develop mild central nervous system depression and bradycardia. Naloxone was not associated with improved outcomes.

Use of naloxone for clonidine intoxication in the pediatric age group: case report and review of the literature.

The incidence of clonidine overdose is increasing worldwide, possibly because of the broadening of indications to include several psychiatric conditions, yet there is a paucity of new information regarding treatment options for clonidine toxicity. We report a case in whom naloxone was used and discuss the literature on this topic. A 2-year-old male infant presented with a history of lethargy. Vital signs were notable for hypotension, pupillary constriction, and hypotonia. The Glasgow Coma score progressively worsened, precipitating intubation. Naloxone was given without response. Urine toxicology revealed high concentrations of clonidine but no opiates. Rapid boluses of isotonic crystalloids and intravenous atropine 0.02 mg/kg were administered with good response. The patient was subsequently discharged home with pediatric and community services follow-up. The use of naloxone in the treatment of clonidine intoxication is unclear, and empirical use does not seem to be justified.

[Clonidine poisoning in a child: a case report]. / Intoxication pédiatrique sévère avec une faible dose de clonidine : à propos d'un cas.

Clonidine poisoning's clinical feature is well documented in the medical literature, but the minimal toxic dose has not yet been established. The effectiveness of naloxone is also controversial. The authors describe a clonidine overdose in a 9-year-old boy (25 kg) during a growth hormone test: he received tenfold the prescribed clonidine dose (0.23 mg instead of 0.023 mg) with 6.2 mg betaxolol. About 40 min later, he became drowsy and then complained of low blood pressure, bradycardia, and myosis. By maintaining the Trendelenburg position, administering fluids as well as salbutamol and naloxone (three doses of 0.2 mg were required), he recovered and was discharged from the hospital on day 2. The minimal clonidine toxic dose, the clinical picture, and the effectiveness of naloxone administration are discussed in this paper.

Common ocular effects reported to a poison control center after systemic absorption of drugs in therapeutic and toxic doses.

PURPOSE OF REVIEW: Ocular effects resulting from medications assist toxicologists in determining substances involved when treating a poisoned patient. The intention of this review is to discuss the most common ocular effects, the medications that cause them, and the mechanisms by which they occur. RECENT FINDINGS: According to National Poison Data System, the most common reported ocular effects following a drug ingestion/injection/inhalation are mydriasis, miosis, and nystagmus. The most common drug/drug classes reported to a regional poison control center causing these ocular effects include the following: first, mydriasis - amphetamines and diphenhydramine; second, miosis - clonidine and opioids; third, nystagmus - dextromethorphan. However, many other drugs/substances can cause these effects along with other systemic effects. SUMMARY: Ocular findings are a pertinent component of any patient assessment involving therapeutic and/or toxic exposure to medications and other substances.

Significance of the imidazoline receptors in toxicology.

INTRODUCTION: The alpha-2 adrenergic (AA-2) receptor agonists and imidazolines are common exposures in the American Association of Poison Control Centers (AAPCC) National Poison Data System (NPDS). Although the interaction between the AA-2 receptor and imidazoline receptors has been extensively studied, it largely remains unknown to health-care professionals. This review describes these interactions and mechanisms by which agonists affect physiologic responses binding to these receptors. METHODS: Papers published in English from 1960 to 2013 were retrieved from PubMed. A total of 323 original articles were identified and 173 were included. Background. The toxicity associated with clonidine (e.g., bradycardia, miosis, and hypotension) is largely assumed to be secondary to the functional overlap of the AA-2 receptors and the mu receptors. However, the effects at the AA-2 receptor could not fully account for these symptoms. Subsequently, clonidine was found to produce its pharmacologic effect in the central nervous system (CNS) by interaction not only with the AA-2 receptor but also on selective imidazoline receptors. IMIDAZOLINE RECEPTORS: Since their discovery, three distinct classes of imidazoline receptors, also known as imidazoline binding sites or imidazoline/guanidinium receptive sites, have been characterized. Imidazoline-1 (I-1) receptors are involved in the hypotensive activity of clonidine and related compounds supporting the idea that the I-1 receptors are upstream from the AA-2 receptor and work in tandem for its effect on blood pressure. Additionally, stimulation of N-type Calcium-2 channels, G-protein inwardly rectifying potassium channel, adenosine receptors, phosphatidyl-choline-specific phospholipase C, and nicotinic receptors have been implicated to be involved. Previous studies have shown that I-1 receptors may also be involved in other physiologic responses beyond cardiac function. Imidazoline-2 (I-2) receptors interact with monoamine oxidase A and monoamine oxidase B leading to research that has focused on the effect of I-2 receptors and depression and the suggestion of a possible antidepressant action of the imidazolines. I-2 receptor ligands may have substantial antinociceptive activity and work synergistically with opioids in acute pain. Imidazoline-3 (I-3) receptors are located on the pancreatic ß-cells and modulate glucose homeostasis. IMIDAZOLINE LIGANDS: Four endogenous compounds have been found to bind and include clonidine-displacing substance, agmatine, harmane, and imidazole acetic acid. Significant interest in developing new agents with higher selectivity and affinity for I-1 receptors has resulted. Toxicology. Alpha-2 adrenoceptor and imidazoline receptor agonists such as clonidine and tetrahydrozoline are common ingestions reported to poison control centers. The most common toxic effects of clonidine are similar to those of the over-the-counter imidazolines and include CNS depression, bradycardia, hypotension, respiratory depression, miosis, hypothermia, and hypertension (early and transient). Based on their structure and subsequent studies, imidazoline receptors seem to be the primary binding site for these chemicals. Case reports typically illustrate rapid onset of action with serious side effects following ingestion of relatively small amounts. These agents have been reportedly used in drug-assisted sexual assaults. CONCLUSION: Much of the toxicity associated with drugs such as clonidine, guanfacine, and tetrahydrozoline are due to their binding to imidazoline receptors. Knowledge of the imidazoline receptors may lead to new therapeutic agents and inform management of patients with imidazoline overdose.

[Transplacental or breast milk intoxication to clonidine: a case of neonatal hypotonia and drowsiness]. / Intoxication transplacentaire ou par lait maternel à la clonidine : un cas de somnolence et d'hypotonie néonatale.

We report a case of clonidine poisoning in a breastfed newborn. At 2 days of life, this boy presented a consciousness deficit with drowsiness, hypotonia, and suspected generalized seizures. There were no cardiorespiratory problems outside of progressive central apneas beginning the 5th day. Further initial investigations were normal (extensive biological exams, cranial ultrasonography and transfontanellar Doppler, electroencephalography, and brain MRI study), excluding the main causes of neonatal hypotonia (encephalitis, infection, metabolic disorder). However, new medical questioning revealed maternal daily intake of 0.15 mg clonidine for hypertension during and after pregnancy. Since it was impossible to quantify clonidine quantification in newborn serum and breast milk, a weaning test was performed the 9th day. Twenty-four hours after cessation of breastfeeding, complete regression of symptoms was obtained. Poisoning by clonidine after fetal and neonatal exposure through breast milk is rare but severe enough to simulate a neurological disease. Diagnosis is based on the search for drug use and the cessation of breastfeeding if doubt persists. Recovery of normal examination results is then rapid and complete.

Unintentional pediatric exposures to central alpha-2 agonists reported to the National Poison Data System.

OBJECTIVE: To investigate national trends in unintentional pediatric exposures to 3 common alpha-2 agonists: clonidine, guanfacine, and tizanidine. Secondary objectives were to describe outcomes, symptoms, treatments, and death. STUDY DESIGN: Retrospective chart review from the American Association of Poison Control Centers National Poison Data System from January 2000 to December 2011 for unintentional exposure to clonidine, guanfacine, and tizanidine in children ≤ 12 years of age. RESULTS: From 2000-2011, there was a significant increase (5.9% per year, CI 3.6, 8.2) in unintentional pediatric exposures to National Poison Data System for central alpha-2 agonists. There were 27,825 clonidine exposures (67.3% male, median age: 4 years), 6143 guanfacine exposures (69.8% male, median age: 6 years), and 856 tizanidine exposures (51.9% male, median age: 2 years). Guanfacine had the greatest proportional increase among the medications. Clonidine was associated with the most respiratory (799, 2.9%) and central nervous system symptoms (12,612, 45.3%), as well as the most episodes of bradycardia (2847, 10.2%) and hypotension (2365, 8.5%). Seven-hundred twenty-eight (2.0%) patients were intubated, and 141 patients (0.5%) were administered vasopressors. There were 7 cardiac arrests and 3 deaths from clonidine. CONCLUSIONS: The number of unintentional pediatric exposures to alpha-2 agonists increased from 2000-2011. Clonidine exposures were the most commonly reported, more symptomatic, and associated with 3 deaths. Despite central nervous system depression, bradycardia, and hypotension being common, the need for intubation and vasopressors was rare.

Dermal exposure to a compounded pain cream resulting in severely elevated clonidine concentration.

INTRODUCTION: Clonidine is an imidazoline derivative antihypertensive medication that is also used as adjunctive therapy for neuropathic pain disorders via topical administration. Clonidine overdose can manifest both central and peripheral alpha-adrenergic agonist effects. CASE REPORT: A 23-year-old man presented to an emergency department with altered mental status, bradycardia, and hypertension after suspected overdose. He had rubbed a specially compounded medicinal cream over his entire body containing clonidine 0.2 % (w/w), gabapentin 6 %, imipramine 3 %, ketamine 10 %, lidocaine 2 %, and mefenamic acid 1 %. The patient presented with severe hypertension, bradycardia, and altered mental status. He was found to have a subarachnoid hemorrhage and was treated for hypertensive emergency. Toxicological analysis of initial blood samples revealed a serum clonidine concentration of 5,200 ng/ml. At 6-month follow-up, the patient had made a full recovery. DISCUSSION: There are limited reports of topical clonidine toxicity, and to our knowledge, this case involves the highest concentration yet reported following clonidine overdose by any route of exposure. The severely elevated serum clonidine concentration found in our patient demonstrates the possibility of toxicity resulting from inappropriate use of such a product. At high serum concentrations, the pharmacodynamic effects of clonidine appear to cause significant peripheral alpha-1 adrenergic stimulation. Toxicologists should be aware of the increasing use of topical clonidine preparations for the treatment of neuropathic pain and the potential for toxicity.

Prolonged delirium after quetiapine overdose.

Quetiapine is an atypical antipsychotic agent increasingly used to treat schizophrenia and bipolar disorder in pediatric patients. Few published data exist concerning quetiapine's effects in therapeutic settings or short-term overdose in pediatric and adolescent populations. In this report, we describe a 15-year-old adolescent girl who experienced continued delirium 5 days after an overdose of quetiapine, trazodone, and clonidine. The patient initially presented with sedation and stable vital signs. After 3 days of gradual improvement, she experienced episodes of delirium coinciding with an increase in resting heart rate. On the basis of suspicion for quetiapine-associated antimuscarinic effects, the patient was administered intravenously with physostigmine on the fifth day after ingestion. Treatment resulted in a brief resolution of symptoms. Serum quetiapine levels measured 1 day and 5 days after ingestion were 3400 and 4800 ng/mL, respectively. The use of physostigmine and interpretation of serum levels are discussed further.

Small dose... big poison.

BACKGROUND: It is not possible to identify all toxic substances in a single journal article. However, there are some exposures that in small doses are potentially fatal. Many of these exposures are particularly toxic to children. Using data from poison control centres, it is possible to recognise this group of exposures. OBJECTIVE: This article provides information to assist the general practitioner to identify potential toxic substance exposures in children. DISCUSSION: In this article the authors report the signs and symptoms of toxic exposures and identify the time of onset. Where clear recommendations on the period of observation and known fatal dose are available, these are provided. We do not discuss management or disposition, and advise readers to contact the Poison Information Service or a toxicologist for this advice.

Toxicity from a clonidine suspension.

BACKGROUND: Clonidine is frequently prescribed to children. Clonidine overdose in children has resulted in major clinical effects and deaths. CASE REPORT: A 3.5-year-old male with a history of a seizure disorder and night terrors presented following difficulty walking, excessive sleeping, agitation when awake, and possible seizure activity. Chronic medications were valproic acid (VPA) and clonidine. On presentation, he alternated between poor responsiveness and agitation, with initial vitals: blood pressure, BP 144/76 mmHg; heart rate, 65 bpm; respiratory rate, 18 bpm; temperature 99.5 degrees F; and pulse oximetry 96% on room air. VPA level was 35 microg/mL. A toxicology consult the next day noted a dry mouth, 2-mm pupils, intermittent gasping, and central nervous system (CNS) depression, with a diagnostic impression of clonidine overdose. The caregiver had been giving 1 mL (0.1 mg) qd of a pharmacy-compounded clonidine suspension by a provided syringe. The pharmacy procedure record agreed with the physicians order. The amount dispensed was a 30-day supply but the bottle was empty on day 19, leading us to suspect a possible accelerated dosing error. The concentration in the bottle thus could not be confirmed. The child slowly returned to his baseline state over 48 hours. A serum clonidine level drawn approximately 18 hours after his last dose later returned at 300 ng/mL (reference range = 0.5-4.5 ng/mL). CASE DISCUSSION: Compounding and liquid dosing errors are common in children and may result in massive overdoses. There was an accelerated dosing error, but whether a compounding or suspension error or even an acute overdose occurred as well is unknown. CONCLUSION: Particular care should be taken with medications that have low therapeutic indices, that are extemporaneously compounded, and are prepared as liquids, where medication errors are more likely.

Central alpha-2 adrenergic eye drops: case series of 3 pediatric systemic poisonings.

Three pediatric patients presented with systemic central alpha-2 agonist poisoning-2 cases of bradycardia and apnea resulting from ingestion of ingestion of apraclonidine, with 1 case requiring intubation, and 1 case of bradycardia and altered mental status requiring intensive care monitoring resulting from therapeutic ophthalmic application of brimonidine. Pediatric poisonings involving central alpha-2 adrenergic agonists have been well described, particularly with the prototypical agent clonidine. Characteristic symptoms include sympatholytic effects such as central nervous system depression, respiratory depression, hypotension, bradycardia, miosis, hypothermia, and hyporeflexia. Although structurally similar to clonidine, these compounds are presumed to be safer for pediatric use because they are more polar and less lipophilic than clonidine, thereby limiting their ability to cross the blood-brain barrier and reducing incidence of centrally mediated effects. Systemic toxicities of alpha-2 agonist ophthalmic preparations in pediatric patients are similar to those seen with clonidine poisonings. Symptomatic patients should be treated in the same manner as patients with clonidine poisoning. Treatment of systemic poisoning is primarily supportive. Periodic tactile stimulation seems to be an effective nonpharmacological intervention to improve alpha-2 adrenergic agonist-induced central nervous system depression and respiratory depression. Intubation should be considered when tactile stimulation is not effective.