Tropane Alkaloid Poisoning Treatment & Management

Updated: Sep 18, 2019
  • Author: Richard A Wagner, MD, PhD, FACEP, FAAEM; Chief Editor: Asim Tarabar, MD  more...
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Treatment

Prehospital Care

Transport patient to the nearest emergency facility with capabilities for advanced life support (ALS), at minimum. Primary assessment should focus on airway and respiratory, circulatory, and neurologic systems. Unless the patient is extremely agitated, obtain intravenous access and monitor vital signs frequently.

Consider administration of naloxone and thiamine. Defer administration of activated charcoal, unless a prolonged transport time is anticipated. Assess for hypoglycemia and other causes of altered mental status. Manage seizures with benzodiazepines. Physostigmine is not recommended in the  prehospital setting.

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Emergency Department Care

As in all cases of suspected poisoning, follow the ABCDEs of emergency medicine (airway, breathing, circulation, disability, exposure), then the ABCDEs of toxicology (antidotes, basics, change absorption, change distribution, change elimination).

Provide oxygen and intubate if significant CNS or respiratory depression exists and no gag reflex is present. Assess circulation and initiate cardiac and pulse oximetry monitoring. Obtain a 12-lead ECG and evaluate for QRS prolongation, ischemia, and evidence of arrhythmia.

Sinus tachycardia is common and does not require treatment in a stable patient. Obtain blood for laboratory analysis and bedside glucose measurement while obtaining IV access. Inspection after full-body exposure should be performed to assess for signs of trauma or seizure.

Agitated or hallucinating patients often respond to reassurance and a darkened room. If chemical restraint is required, benzodiazepines are the drugs of choice. Early consultation with a poison control center is frequently helpful.

Consider GI decontamination foremost. Ipecac is contraindicated because of the potential for seizures. Gastric lavage is controversial; while it is commonly performed, no reliable data on outcomes exist to support its use, and the risk of aspiration and other complications is increased. Administer activated charcoal (1-2 g/kg) orally or per nasogastric or orogastric tube. One or 2 additional doses may be given at 1- or 2-hour intervals to ensure adequate gut decontamination.

Ileus without distension is not a contraindication to a single dose of charcoal, and charcoal given alone may be as effective or more effective than emesis and lavage procedures. Use of cathartics to hasten elimination from the GI tract remains controversial. Sorbitol may be used with a first dose of charcoal; further use may cause serious fluid shifts to the intestine, diarrhea, dehydration, and hypernatremia.

Tropane alkaloids are lipophilic and cross the blood-brain barrier; hemodialysis and hemoperfusion are generally ineffective. No effective methods of changing distribution or elimination of tropane alkaloids exist.

The specific antidote for tropane alkaloid toxicity is physostigmine salicylate, a reversible acetylcholinesterase inhibitor capable of directly antagonizing CNS manifestations of anticholinergic toxicity. Physostigmine (at doses lower than those producing peripheral side effects of salivation, lacrimation, urination, defecation, emesis) can reverse central anticholinergic effects such as coma, seizures, agitation, and severe dyskinesias.

However, unless relative certainty can be established that the toxicity present is due to tropane alkaloid poisoning and not to co-ingestants or other substances, confirmatory peripheral manifestations of anticholinergic toxicity should coexist prior to administration of physostigmine.

Physostigmine has been used as a diagnostic tool for tropane alkaloid poisoning, but this use is controversial.

Physostigmine can induce a life-threatening cholinergic crisis (eg, seizures, bronchospasm, asystole). Since most patients can be safely treated without this antidote, physostigmine preferably should be used in consultation with a poison control center and generally should be used only for patients in the following states:

  • Unresponsive to supportive measures
  • Tachydysrhythmias and subsequent hemodynamic compromise
  • Intractable seizures unresponsive to benzodiazepines
  • Extremely severe agitation or psychosis

Physostigmine is contraindicated in patients receiving tricyclic antidepressants, disopyramide, quinidine, procainamide, cocaine, or other agents producing cardiac conduction abnormalities. Relative contraindications include reactive airway disease, intestinal obstruction, and administration of depolarizing paralytic agents.

Following GI decontamination, most patients rarely require more than physiologic monitoring and psychological support. Patients experiencing agitation and hallucinations usually respond to reassurance and benzodiazepines. Most phenothiazines are contraindicated because of their anticholinergic properties. If signs or symptoms of urinary retention exist, Foley catheterization should be performed for bladder decompression.

Base admission decisions on patient's signs and symptoms. Admit symptomatic patients to an ICU setting for monitoring and treatment. They may be discharged after a symptom-free period of 6 hours without use of supportive therapy or antidotes and after appropriate consultations and follow-up have been arranged.

Asymptomatic patients without signs of anticholinergic toxicity or altered mental status may be discharged after 6 hours of observation.

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Consultations

Early consultation with a toxicologist or poison control center is frequently useful for toxic exposures or ingestions to help in decision-making with regard to decontamination and therapeutic interventions. This is particularly true with the use of physostigmine in cases of tropane alkaloid poisoning.

Psychiatric consultation is important for all intentional ingestions.  Contact with the patient's primary care provider is optimal for all hospital admissions or cases of serious illness.

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