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Plant Poisoning, Alkaloids - Tropane: Treatment & Medication

Author: Richard A Wagner, MD, PhD, FACEP, Staff Physician, St. Joseph's / St. Mary's Hospitals, Tucson; Consultant, Arizona Drug and Poison Information Center
Coauthor(s): Samuel M Keim, MD, Associate Professor, Department of Emergency Medicine, University of Arizona College of Medicine
Contributor Information and Disclosures

Updated: Sep 23, 2009

Treatment

Prehospital Care

Transport patient to 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 patient is extremely agitated, obtain IV access and monitor vital signs frequently.
• Consider administration of naloxone and thiamine.
• Do not use ipecac and 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 prehospital setting.

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 for 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 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.
  • An 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 GI tract remains controversial. Sorbitol may be used with 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.
• 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 effects of the following conditions:
    • Coma
    • Seizures
    • Hallucinations
    • Agitation
    • Severe dyskinesias
    • Respiratory depression
  • 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, respiratory depression, 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 psychologic 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.

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 primary care provider is optimal for all hospital admissions or cases of serious illness.

Medication

Activated charcoal is indicated for all tropane alkaloid poisonings, within an hour of ingestion, with the possible exception of poisoning from smoking leaves. Benzodiazepines are first-line agents for agitation and seizures. Physostigmine should be used only for life-threatening complications.

GI decontaminant

Activated charcoal is used after a drug or plant ingestion to limit adsorption of toxins. Traditionally given after the stomach has been emptied by emesis or lavage, recent evidence indicates that it may be used alone, without lavage.

Activated charcoal (Liqui-Char)

Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. An extremely important component of tropane alkaloid poisoning. May decrease severity and duration of poisoning. Does not dissolve in water.
For maximum effect, administer within 30 min after ingesting poison.

Benzodiazepines

First-line agents for treatment of tropane-alkaloid-induced seizures. Lorazepam is thought to be most effective and has a longer seizure half-life than diazepam.

Lorazepam (Ativan)

Sedative hypnotic with short onset of effects and relatively long half-life. DOC if IV access is available.
Increasing the action of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter in the brain, may depress all levels of CNS, including limbic and reticular formation.
Monitoring patient's blood pressure after administering dose is important. Adjust prn.

Midazolam (Versed)

Used as alternative in termination of refractory status epilepticus. Because midazolam is water soluble, it takes approximately 3 times longer than diazepam to peak EEG effects. Thus clinician must wait 2-3 min to fully evaluate sedative effects before initiating procedure or repeating dose. Published reports of IM and anecdotal reports of nasal use exist (when IV access is not possible).

Diazepam (Valium)

Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA. Frequently used in prehospital systems since refrigeration is not required.

Cholinergic agents

Physostigmine is indicated only for reversal of life-threatening complications of tropane alkaloid poisoning (eg, tachydysrhythmias with hemodynamic compromise, seizures refractory to other therapeutic interventions, and severe agitation or hallucinations unresponsive to other therapy). The decision to use physostigmine ideally should be made in consultation with a toxicologist or poison control center.

Physostigmine (Antilirium)

Reversible anticholinesterase inhibitor that increases the concentration of acetylcholine at cholinergic synapses. The only reversible anticholinesterase inhibitor that readily crosses the blood-brain barrier to produce the desired CNS effects. Some recommend repeated slow IV pushes of 0.1-0.3 mg q3min to a maximum of 2 mg to decrease potential for life-threatening cardiovascular adverse effects.

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