Toxicology Flashcards
Study of poisons
TOXICOLOGY
The basic science of poisons (old)
TOXICOLOGY
The study of the adverse effects of chemical
agents on biological systems (new)
TOXICOLOGY
any substance that causes harmful effects
upon exposure
Poison
Substances not absorb produces local effects
Poison
Major areas of Toxicology
Clinical
Descriptive
Forensic
Mechanistic
study inter relationships between
toxic exposure and disease states
Clinical
results from animal
experiments to predict what level of
exposure will cause harm in humans; risk
assessment
Descriptive
primary concern in medico-legal
in toxic exposure consequences
Forensic
cellular and biochemical
effects of toxins
Mechanistic
A substance with a capacity to produce
injury or illness
TOXIC SUBSTANCE
Types of Toxic Hazardous materials
- Chemical Agents and Drugs of Abuse
- Physical Agents
- Biological Agents
EFFECTS OF TOXICANTS
Irreversible
Acute Effects
Chronic Effects
Irreversible
- Carcinogens
- Mutagen
- Reproductive hazards
- Teratogen
Acute Effects
- Short term
- Appears shortly after exposure (<24 hrs)
- Can be form single exposure
Chronic Effects
- With latency
- It takes a long period of time before you see the
effects (>3 months) - Exposure can be due to repeated doses
MAJOR FACTORS THAT INFLUENCE TOXICITY
- Route of admission
- Duration and Frequency of exposure
- Dose or Concentration
What are the Route of admission
Inhalation
Ingestion
Injection
via mouth/nose, then to the
lungs, and to the bloodstream
Inhalation
mouth to stomach to
bloodstream
Ingestion
cuts/punctures/wounds and
then to the bloodstream
Injection
The frequency of the exposure affects the
concentration at the target site – can build
up to a steady level
Duration and Frequency of exposure
The frequency of the exposure affects the
concentration at the target site can build
up to a ?
Steady level
the amount of chemical entering the
body
Dose or Concentration
MEASURE OF TOXICITY/EFFECTIVE DOSE
LD50
TD50
ED50
the dose of a chemical which produces death
in 50% of a population.
LD50
the dose that would be predicted to produce
a toxic response in 50% of the population.
TD50
the dose that would be predicted to be
effective or have therapeutic benefit in 50% of the population.
ED50
is the biotransformation of
chemicals into something less harmful
Detoxification
ELIMINATION OF TOXINS
- Excretion through the kidneys, liver, and lungs
- Detoxification is the biotransformation of
chemicals into something less harmful - Storage in fatty issue
What are the organs involved in the excretion process in the human body?
kidneys, liver, and lungs
Common CNS depressants
Causes disorientation, euphoria, and
confusion
ALCOHOLS
“grain alcohol”
Ethanol
Most common
Converted to Acetic acid – hangover is due to acetaldehyde (via alcohol dehydrogenase
activity)
Fatal dose: 300-400 mL
Ethanol
Ethanol is converted to?
Hangover is due to______ (via ____________ activity)
Acetic acid; acetaldehyde ; alcohol dehydrogenase
Fatal dose of Ethanol
300-400 mL
Stages of impairment by Ethanol
0.01 – 0.05- No obvious impairment,
some changes observable during testing
0.03 – 0.12 -Mild euphoria, low
inhibitions, some impairment of motor skills
0.09 – 0.25- Low inhibitions, loss critical
judgement, memory impairment, low reaction time
0.18 – 0.30-Mental confusion, dizziness,
strong impaired motor skills
0.27 – 0.40- Unable to stand and walk,
vomiting, impaired consciousness
0.36 – 0.50 COMA and POSSIBLE DEATH
“Wood alcohol”
Methanol
-Common solvent, contaminant to homemade liquors
-Converted to formaldehyde and then to formic acid in the liver
-Fatal dose: 60-250 Ml
Methanol
Fatal Dose of Methanol
60-250 Ml
How is methanol metabolized in the body?
it is converted to formaldehyde and then to formic acid in the liver
“Rubbing alcohol”
Isopropanol
How is isopropanol metabolized in the body?
It is converted to acetone by hepatic alcohol dehydrogenase
Fatal Dose of Isopropanol
250 mL
Colorless, Odorless, Tasteless
From gasoline, and cigarette smoke
CARBON MONOXIDE
-Few amounts are produced in the body from metabolism
-With high affinity to hemoglobin that leads
to carboxyhemoglobin formation and to
tissue hypoxia
CARBON MONOXIDE
How is carbon monoxide poisoning identified and measured?
Indicator: Cherry red color of the face
Method: Carboxyhemoglobin measurement
Can be solid or gas
A super toxic substance in insecticides,
rodenticides, pyrolysis products
CYANIDE
Binds to iron-binding substances and may
cause cellular hypoxia (fast acting)
CYANIDE
How is cyanide poisoning identified?
“Odor of Bitter Almonds”
HEAVY METALS
Arsenic
Cadmium
Lead
What are the symptoms associated with Cyanide
Tachypnea (rapid breathing)
Convulsions
Coma
They are toxic if ingested and absorbed by the body
Heavy Metals
common component of poisons,
rodenticides, paints
ARSENIC
Arsenic
With high affinity to _____
Commonly used in ______
Inhibits ______
Toxicity is via _______
Can cross ______
-keratin
-homicides, suicide agents, and heavy metal poisoning
-sulfhydryl enzymes
-binding to thiol groups in proteins
-PLACENTA