Slide 1


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Among important toxicological principles that are
applied in evaluating the poisoned individual are
Exposure

and aspects related to reducing

absorption
Dose response considerations
Target tissue and systemic effects
Chemical interactions
Chemical antagonism as a management approach
Acute versus Chronic effects


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1) Supportive Care (to sustain the vital signs)
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A Airway Clearance
B Breathing maintenance
C Circulation enhancement
D Decontamination

2) Treat the patients depressed mental status
3) Rule out or treat hypoglycemia


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4) Obtain history of the exposure
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What substance was exposed
How much was consumed or exposed
Route of ingestion or exposure
Time since exposure

5) Identify Signs and symptoms of poisoning
Breathing rate, heart rate, dilation of pupil, Fits,
injuries or diseases associated to the symptoms
6) Neurologic Examination
Slurred speech, imbalancement, tremors
unconsciousness, seizures, confusion, headache


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

Advantages
› Can confirm the poisoning agent
› Predict anticipated toxic effects or severity of

exposure
› Confirm the diagnosis
› Help in guiding therapy


Limitations
› All chemical agents cannot be possibly screened
› These are usually time consuming and cannot be

provided as soon as treatment starts
› The results may not apply to the diagnosis of all
patients alike


Slide 6



Is performed when percutaneous
absorption of a substance may result in
systemic toxicity or when the toxic
substance may produce local toxic effects
e.g. burns caused by acid

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Clothing should be removed and skin
should be irrigated by sufficient
quantities of Water

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Neutralization should not be attempted.
This will only cause more pain to the
patient and worsen the poisoning


Slide 7

It involves removal or ingestant from the
gastrointestinal system and maybe carried out by the
following
 Emesis
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› Should not be attempted in Children or Depressed

patients
› Should not be attempted with Acid or Hydrocarbon
poisonings
› Should not be attempted with substances with an
extremely rapid onset of action
› Usually done by Ipecac syrup in a hospital, emesis
starts in 30 minutes and lasts 2 hours and produces 3
episodes of emesis


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Gastric Lavage
› It is employed in patients who

have consumed life threatening
amounts of a drug within 1-2 hours
 Used in patients who are not
alert or not recommended with
emesis
 Lavage is performed after an
endotracheal tube secures the
airways
 After aspiration of the gastric
contents 250-300mL of water or
saline is instilled and then
aspirated
 The sequence is repeated until
the liquid returning becomes
clear


Slide 9

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Activated Charcoal
 Adsorbs almost all commonly ingested chemicals and
medicines and usually administered to overdose patients
within 30minutes to 2 hours
 It greatly reduces oral absorption of nearly all
pharmaceuticals but should not be given if a patient is
already vomiting


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It has been shown to be effective where activated charcoal
lacks efficacy
Usually a cathartic solution like Poly ethyl glycol (PEG) is
given orally through a nasogastric tube (1-2L/hr) until rectal
affluent is clear

Cathartics
Administration of a cathartic agent may help in removal of
toxins from the gastrointestinal tract and reduce absorption
 Sorbitol (70%) is the most preferred cathartic agent



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Forced Diuresis and urinary pH manipulation
 Maybe used to enhance elimination of
substances whose route of elimination is
primarily renal and those that show little protein
binding
› Acid Diuresis by Sodium bicarbonate :

 promotes ionization of weak acids thereby
preventing their reabsorption in the kidneys e.g
barbiturates
› Alkaline Diuresis by Ascorbic Acid :

 Promotes elimination of weak bases e.g quinolones


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Heamodialysis
› For chemicals already

absorbed into the blood and
in severe cases of
intoxication heamodialysis is
recommended
› Substances removed by

heamodialysis generally are
water soluble and have a
small volume of distribution
so are not protein bound


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Heamoperfusion
› It is a technique where
anticoagulated blood is passed
through a column containing
activated charcoal or resin

particles.
› this is more rapid than
heamodialysis but it does not
correct fluid or electrolyte
abnormalities as in case of
hemodialysis


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An antidote can simply be defined as a clinical
treatment using a chemical to counteract the effects
of another
 The ultimate goal is to reduce toxicity by interacting
with the toxicant in ways that
 Directly inhibit its effect through modification
of its chemical properties
 Inhibit its effect by altering its physical
properties
 Reduce effects at its sites of action
 Facilitate its elimination



Slide 15

Poison

Antidote

Acetaminophen

N-acetyl Cysteine

Carbon monoxide

Oxygen

Cyanide

Sodium nitrite/sodium thiosulfate

Digoxin

Digoxin immune Fab

Heavy Metals

DMSA (dimercaptosuccinic acid)

Opiates

Naloxone


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Rapid assessment of patient with management
Consider need for clinical chemistry
Whether it is possible to limit further absorption or
attempt its elimination
Considering antidotes
Considering further advice and information