Introduction
The management of the poisoned, intoxicated, or overdosed patient must be organized
and deliberate. Preventing complications and avoiding iatrogenic injury are at least as
important as identifying the toxin and providing specific antidotal therapy. The poisoning
emergencies you face may range from acute ethanol intoxication to hazardous materials
exposures and smoke inhalation, to ingestion of prescription or over the counter (OTC)
medication in suicidal attempts, to accidental oral or dermal exposures in the pediatric
population. While it is beyond the scope of this chapter to discuss in detail the
presentation and management of specific toxins, some general principles guide the
treatment of any poisoned patient. The GMO should have a reference text and the telephone
number of the regional poison control center readily available for specific information.
History
The history obtained from a poisoned patient is often inaccurate or
incomplete, but the following information should still be sought from any source
available.
Physical Exam
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Complete vital signs noting any trends.
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Mental status.
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Focused exam: pulmonary, cardiovascular, abdomen, neurological systems as well as
evidence of trauma and abdominal exam, (useful in identifying toxidromes).
Diagnostic Studies
Request an electrocardiogram (ECG) for patients with an abnormal or irregular pulse or
who have ingested a cardiotoxic drug. A flat plate and upright abdominal x-ray (KUB) may
be helpful in identifying radiopaque substances such as heavy metals or enteric coated
tablets.
Laboratory Studies
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Electrolytes, glucose, BUN/creatinine.
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Arterial blood gas
(ABG).
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Aspirin, acetaminophen, ETOH levels.
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CBC.
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Qualitative urine or serum drug screens seldom alter treatment or immediate disposition,
but may be useful for later documentation of psychiatric evaluation.
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Qualitative levels of specific drug toxins are useful in the following limited number of
agents: acetaminophen, aspirin, ethanol, methanol, ethylene glycol, iron, digoxin,
theophylline, lithium, and anticonvulsants.
Principles of treatment
Five principles of treatment should be considered in the management of every poisoned
patient. They may need to occur simultaneously in some patients while in other patients
some of them may be inappropriate or even dangerous and have no role.
ABC's (Airway-Breathing-Circulation).
Ensuring and protecting an adequate airway and maintaining effective ventilation are
paramount in managing the poisoned patient. Many agents produce sedation, leading to loss
of airway protection and the risk of vomiting and aspiration. Maintaining adequate
perfusion of the brain, heart, and kidneys can usually be accomplished with intravenous
fluids and pressors such as dopamine. In the patient with altered mental status, the
following drugs are given.
Decontamination.
The first goal in managing the adequately resuscitated poisoned patient is minimizing
further exposure to the toxin by decontamination. For dermal exposures, decontamination of
the skin should be accomplished quickly by removing all contaminated clothing and washing
the skin thoroughly with soap and water while protecting care providers from secondary
exposure. Ocular decontamination is accomplished by copious irrigation using tap water or
normal saline. Gastrointestinal decontamination may be accomplished by the following
methods:
Note: The single most effective method to decontaminate the GI tract is with the use of
activated charcoal.
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Emesis
Syrup of ipecac has a very limited role currently because of the risk of aspiration in
the patient whose mental status may decline, and because it is less effective than
activated charcoal alone. It is contraindicated in caustic ingestions or in patients with
an altered mental status or in the ingestion of any agent which may lead to seizures or
coma. Complications include aspiration, Mallory Weiss tear, esophageal tears, and
electrolyte imbalance.
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Gastric Lavage
May be more effective than emesis, but is of limited use if more than an hour has
passed from the ingestion. Lavage is performed using a large (36F) orogastric tube with
the patient in the left lateral decubitus position. Use saline in small aliquots of
100-200cc lavage with a total of 2 liters or until the return is clear
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Adsorbent (activated charcoal)
Administration of 1 to 2 gm/kg of activated charcoal orally (PO) or via a nasogastric (NG)
tube is adequate gut decontamination for the majority of patients. Activated charcoal does
not bind iron, heavy metals, hydrocarbons, or alcohols well, but should be given in the
event other co-ingestants are present.
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Whole-bowel Irrigation.
Using Go-Lytely, 2L/hour PO or via a nasogastric tube for 5-6 hours. This may be
indicated after ingestion of substances poorly bound to charcoal (iron, lithium),
extended-release preparations (Theodur, calcium channel
blockers), foreign bodies (button
batteries), and drug packets (heroin, cocaine, condoms).
Enhanced Elimination
Techniques for removing toxins after they have already been absorbed into the systemic
circulation are seldom indicated or applicable, but at times they may be central to the
management of certain toxins.
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Alkaline diuresis (salicylates): alkalinize the urine to a pH of 8.0 by administering
normal saline with 1-2amps of bicarbonate per liter and adequate potassium replacement.
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Repeat-dose
activated charcoal (theophylline,
phenobarbital, carbamazepine): 0.5gm/kg PO
or NG every 4 hours to produce gut dialysis and interrupt enterohepatic recirculation.
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Hemodialysis (salicylates, methanol, ethylene glycol, lithium): consult with a
toxicologist or nephrologist for recommendations.
Specific Antidotes
Appropriately administered antidotes may prevent further complications, morbidity and
mortality, but most antidotes have potential adverse effects and may not be indicated in a
given patient. Seek advice when considering the use of an antidote. The following list
includes some of the more useful antidotes.
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Acetaminophen
Mucomyst 140mg/kg 1st dose, then 70mg/kg every 4 hours for 17 additional doses.
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Tricyclic antidepressants
Sodium bicarbonate 1 to 2 amps IV push, then infusion of bicarbonate in D5W to keep
the arterial pH 7.50.
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Isoniazid (INH)
Pyridoxine (vitamin B6) same amount as INH ingested if known; if unknown, give 5gm IV.
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Narcotics
Naloxone (Narcan) 2mg IV push (some narcotics may require larger doses or continuous
infusions).
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Cyanide
Lilly Cyanide Antidote Kit (amyl nitrate pearls, sodium nitrite, sodium thiosulfate
vials-see insert for directions).
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Carbon Monoxide
100 percent oxygen followed by hyperbaric oxygen.
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Iron
Deferoxamine 10 to 15mg/kg/hr.
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Beta blockers
Glucagon 1 to 5mg IV push, repeat as necessary.
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Anticholinegics
Physostigmine 1 to 2mg IV push - (use only for dysrhythmias with hypotension,
intractable seizures, or coma with respiratory compromise; intubation should be performed
first; contraindicated in TCA overdose).
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Insecticides/organophosphates
Atropine IV (may require large doses), followed by Pralidoxime (2- PAM )
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Benzodiazepines
Flumazenil (Romazicon) 0.5 to1mg increments IV, total dose rarely to exceed 3mg (do
not use if coingestion of an epileptogenic drug).
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Oral hypoglycemics
For intractable hypoglycemia, not responsive to IV glucose, use diazoxide 300mg IVPB
over 30 minutes.
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Calcium Channel
Blockers:
Calcium
chloride, 1 to 2amps (100 to 200mg) over 2 to 5 minutes. May repeat to effect,
and may need continuous infusion. Consider atropine 1 to 2 mg or glucagon 3 to 10mg for
A-V block or profound bradycardia. May require pressors and pacing.
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Cocaine
Control seizures with benzodiazepines, control hypertension with lopressor and
nitroprusside. Caution: the use of beta blockade alone increases mortality due to
unopposed alpha effects.
Disposition
If after evaluation and treatment, a patient is asymptomatic, has a normal mental
status exam, normal pertinent labs, and normal vital signs (including pulse rate), the
patient is medically cleared, the patient should then be referred to psychiatry. However,
some drugs or agents, i.e., acetaminophen, iron, and mushrooms, have a latent period
during which the patient may be completely asymptomatic.
Contributing authors include CAPT David W. Munter, MC, USN, Department of
Emergency Medicine, Naval Medical Center, Portsmouth, VA and CDR Paul D. Pearigen, MC,
USNR, Department of Emergency Medicine, Naval Medical Center, San Diego, CA. Reviewed by
CDR Pearigen (1999).
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