Novel use of dexmedetomidine for the treatment of anticholinergic toxidrome

Treating Diphenhydramine Overdose: A Literature Review of Currently Available Treatment Methods

From 2019 to 2020, antihistamines were found in 15% of all US drug overdose deaths, often co-administered with fentanyl, with 3.6% of overdose deaths due to antihistamines alone. The most common antihistamine found in all these reported deaths is diphenhydramine, a ubiquitous, over-the-counter and clinically important medication. Currently, there is no antidote for diphenhydramine overdose. This review summarizes the adverse health effects and current emergency medicine treatments for diphenhydramine. Several emergency medicine case reports are reviewed, and the efficacy and outcomes of a variety of treatments are compared. The treatments reviewed include the more traditional antihistamine overdose therapeutics physostigmine and sodium bicarbonate, as well as newer ones such as donepezil, dexmedetomidine, and lipid emulsion therapy. We conclude that more study is needed to determine the ideal therapeutic approach to treating antihistamine overdoses.

Dexmedetomidine in the treatment of toxicologic conditions: a systematic review and review of the toxicology investigators consortium database

INTRODUCTION

Dexmedetomidine is an alpha-2 adrenoceptor agonist which is widely used for sedation. Dexmedetomidine does not suppress the respiratory drive and produces a state of cooperative sedation; it may be associated with beneficial outcomes in the general critical care population. The role of dexmedetomidine in the treatment of toxicologic conditions (excluding alcohol withdrawal) is unclear.

OBJECTIVES

To critically assess and summarize the literature regarding the use of dexmedetomidine in toxicologic conditions other than alcohol withdrawal.

METHODS

We performed a systematic review of the medical literature to identify all existing evidence regarding the use of dexmedetomidine for toxicologic conditions. We excluded reviews and commentary, studies reporting exclusively on alcohol withdrawal, and studies reporting the use of dexmedetomidine to treat iatrogenic sedative withdrawal in the intensive care unit. We also performed a review of the Toxicology Investigators Consortium (ToxIC) database for patients treated with dexmedetomidine.

RESULTS

We identified 98 studies meeting inclusion criteria; 87 of these were case reports or case series, representing 99 unique cases. Eleven articles with other designs were identified, which included 138 patients treated with dexmedetomidine for toxicologic conditions. Ninety-three cases from the ToxIC registry met inclusion criteria. Common indications for dexmedetomidine included stimulant intoxication, sedative withdrawal, serotonin syndrome, antimuscarinic toxidrome, opioid withdrawal, and cannabinoid intoxication. Dexmedetomidine was usually administered by continuous infusion; bolus administration was reported in a minority of cases. Adverse effects were uncommon. The quality of evidence was generally low, given the preponderance of case reports, the rate of missing or poorly reported data, and the near-universal co-administration of other sedatives.

TREATMENT OF STIMULANT POISONING

Fifty-nine patients with stimulant poisoning were treated with dexmedetomidine. There was reasonably good evidence that dexmedetomidine was helpful in the treatment of stimulant poisoning.

TREATMENT OF SEDATIVE WITHDRAWAL

Twenty-two patients with sedative withdrawal were treated with dexmedetomidine. Several case reports of very high-quality suggested efficacy of dexmedetomidine for this indication, particularly for baclofen withdrawal.

TREATMENT OF SEROTONIN SYNDROME

Twenty-six patients with serotonin syndrome were treated with dexmedetomidine. This evidence was of lower quality due to missing clinical details, potential overdiagnosis of serotonin syndrome, and near-universal concomitant treatment with other sedatives.

TREATMENT OF ANTIMUSCARINIC POISONING

Forty-two patients with antimuscarinic poisoning were treated with dexmedetomidine. This evidence was of low quality and was limited by infrequent use of the preferred antidote, physostigmine.

TREATMENT OF OPIOID WITHDRAWAL

Forty-four patients with opioid withdrawal were treated with dexmedetomidine. This evidence was of low quality due to missing clinical details and near-universal concomitant treatment with other agents. The one high-quality trial reported the use of dexmedetomidine in ultra-rapid opioid detoxification, which is not indicated in modern practice.

TREATMENT OF CANNABINOID INTOXICATION

Five patients with cannabinoid intoxication were treated with dexmedetomidine. No definite conclusion can be drawn from the limited available evidence.

DISCUSSION

It is important to distinguish between the use of dexmedetomidine as a general sedative, which is likely to increase as the overall utilization of dexmedetomidine in critical care settings increases, and the use of dexmedetomidine as a specific pharmacologic treatment for a toxicologic condition. Well-established pharmacologic data from animal and human studies suggest dexmedetomidine counteracts stimulant-induced norepinephrine release. The mechanism by which dexmedetomidine treats sedative withdrawal is unclear. Some animal data show that dexmedetomidine may indirectly suppress serotonin release, which may suggest a role for dexmedetomidine in this condition.

CONCLUSIONS

There is a small and generally low-quality body of evidence which suggests that dexmedetomidine may be helpful in the treatment of certain toxicologic conditions, particularly stimulant intoxication and sedative withdrawal. Further high-quality research is needed to clarify the role of dexmedetomidine in patients with toxicologic conditions.

A sabbath in the emergency room or a case of anticholinergic toxicity?

We report the case of a 32-year-old Italian man admitted to our emergency room for visual disturbances with blurred vision, anisocoria and temporal headache suddenly occurred in absence of other neurological symptoms. A diagnosis of Datura stramoniuminduced anticholinergic toxicity was done. With our work, we want to highlight the importance of a meticulous clinical examination, including papillary diameter and reflexes, combined with a detailed history of the patient in the emergency room. Anticholinergic toxicity is a medical emergency. The diagnosis is always clinical, and it can represent a challenge for the emergency clinicians because it can mimic several neurological diseases, including acute stroke and seizures, but early diagnosis is crucial to avoid severe complications and management errors.

The Role of Dexmedetomidine in Pediatric Patients Presenting with an Anticholinergic Toxidrome

Background

We report two pediatric cases of anticholinergic toxidrome, including the youngest reported to date, in which standard therapeutic strategies were either contraindicated or ineffective, while treatment with dexmedetomidine was rapidly efficacious with no adverse effects. Moreover, with the recent shortage of physostigmine, we highlight an alternative treatment in this clinical setting. Case Summaries. In case 1, a two-year-old had an overdose presenting with an anticholinergic toxidrome. However, his hypopnea precluded the use of benzodiazepines due to the high likelihood of intubation. In case 2, a 14-year-old had a polypharmacy overdose inducing agitated delirium that was refractory to high-dose benzodiazepines. Due to the unknown ingestion, physostigmine was avoided. In both cases, dexmedetomidine helped the patient remain calm and metabolize the ingestions.

Conclusion

Our experience suggests that dexmedetomidine may be a useful adjunct in anticholinergic presentations in the setting of polypharmacy, when standard therapy is proven ineffective, contraindicated, or unavailable.

Dexmedetomidine Infusion as a Novel Supportive Therapy for Fluphenazine-Induced Neuroleptic Malignant Syndrome in a 10-Year-Old Boy: A Case Report and Review of Literature

A 10-year-old male child patient developed symptoms of neuroleptic malignant syndrome (NMS) 1 month following initiation of fluphenazine for behavioral therapeutic management. Dexmedetomidine infusion was able to adequately control the symptoms of NMS with resolution of encephalopathy. This was the first report of novel dexmedetomidine utilization for the treatment of NMS. We suggest using dexmedetomidine as an adjunctive agent to control NMS symptomatology without attendant risk of respiratory depression.

QT interval prolongation and rhabdomyolysis associated with diphenhydramine toxicity: a case report

Diphenhydramine is a widely available, over-the-counter medication used for allergies and as a sleeping aid. When used in prescription doses, it is generally safe.

Overdose of the medication has been associated with dangerous and life-threatening outcomes. Our case describes diphenhydramine toxicity manifesting with two rare but potentially

life-threatening complications, rhabdomyolysis, and QT prolongation. Laboratory testing for diphenhydramine levels are not widely available. We recommend a high degree of suspicion for these complications when evaluating patients with diphenhydramine overdose, to adequately manage and prevent untoward outcomes.

Differentiating Delirium From Sedative/Hypnotic-Related Iatrogenic Withdrawal Syndrome: Lack of Specificity in Pediatric Critical Care Assessment Tools

OBJECTIVES

To identify available assessment tools for sedative/hypnotic iatrogenic withdrawal syndrome and delirium in PICU patients, the evidence supporting their use, and describe areas of overlap between the components of these tools and the symptoms of anticholinergic burden in children.

DATA SOURCES

Studies were identified using PubMed and EMBASE from the earliest available date until July 3, 2016, using a combination of MeSH terms "delirium," "substance withdrawal syndrome," and key words "opioids," "benzodiazepines," "critical illness," "ICU," and "intensive care." Review article references were also searched.

STUDY SELECTION

Human studies reporting assessment of delirium or iatrogenic withdrawal syndrome in children 0-18 years undergoing critical care. Non-English language, exclusively adult, and neonatal intensive care studies were excluded.

DATA EXTRACTION

References cataloged by study type, population, and screening process.

DATA SYNTHESIS

Iatrogenic withdrawal syndrome and delirium are both prevalent in the PICU population. Commonly used scales for delirium and iatrogenic withdrawal syndrome assess signs and symptoms in the motor, behavior, and state domains, and exhibit considerable overlap. In addition, signs and symptoms of an anticholinergic toxidrome (a risk associated with some common PICU medications) overlap with components of these scales, specifically in motor, cardiovascular, and psychiatric domains.

CONCLUSIONS

Although important studies have demonstrated apparent high prevalence of iatrogenic withdrawal syndrome and delirium in the PICU population, the overlap in these scoring systems presents potential difficulty in distinguishing syndromes, both clinically and for research purposes.

Dexmedetomidine Infusion to Control Agitation due to Anticholinergic Toxidromes in Adolescents, a Case Series

Dexmedetomidine is an α2-adrenergic agonist approved by the US Food and Drug Administration for the sedation of adults who are intubated on mechanical ventilation and in non-intubated adults who are undergoing surgical procedures. However, it has also recently become a commonly used sedative agent in varied clinical settings for the pediatric patient as well. We present the use of dexmedetomidine for sedation in a unique clinical scenario, the severely agitated and combative patient following the intentional misuse of anticholinergic drugs. Its applications in this situation are discussed, and previous reports in the literature are reviewed.