Toxicology Flashcards
study of the undesirable effects of
xenobiotics in humans
Toxicology
chemicals and drugs that are
not normally found in or produced by the
body
Xenobiotic
can be obtained through the environmental exposure to chemicals or drugs
Xenobiotic
substances that are not
produced within a living cell or
microorganism
Toxicant
commonly used to describe
environmental chemicals
Toxicant
endogenous substances biologically
synthesized either in living cells or in
microorganisms
Toxin
the dose that has a therapeutic effect in 50% of the
population
ED50
the dose that would result in
death in 50% of the population
LD50
the dose that would produce a toxic response in 50% of the population
TD50
The three (3) common routes of exposure
Ingestion, Inhalation, and Transdermal Absorption
have the ability to
diffuse across the cell membrane
Hydrophobic substances
can be absorbed
anywhere along the GIT
Hydrophobic substances
cannot passively diffuse
across membranes
Ionized substances
become protonated in gastric
acid
Weak acids
can be absorbed in the stomach
Weak acids
absorbed in the intestine where
the pH is largely neutral or slightly alkaline
Weak bases
Incidence of defined biological effect in an
exposed population
DOSE-RESPONSE RELATIONSHIP
Implies that there will be an increase in the
toxic response as the dose is increased
DOSE-RESPONSE RELATIONSHIP
Can be described by dose-response curves
DOSE-RESPONSE RELATIONSHIP
Most commonly encountered non drug toxins
seen in a clinical setting
TOXICOLOGY OF SPECIFIC AGENTS
Cause medical emergencies with acute
exposure
TOXICOLOGY OF SPECIFIC AGENTS
Can cause general (depressant on CNS) and
specific effects
Alcohols
Site of metabolism of alcohol
LIVER
Most commonly abused drug
Ethanol
consumption of this during pregnancy may lead to fetal alcohol syndrome
Ethanol
it causes brain damage and growth problems
Fetal Alcohol Syndrome
this promotes adduct formation
Acetaldehyde
product of direct addition of
two or more distinct molecules, resulting in
a single reaction product
Adduct
causes diuresis by inhibiting ADH
Ethanol
Effects of Ethanol Consumption
Toxic hepatitis and Liver cirrhosis
Antidote for chronic intoxication:
DIAZEPAM
two enzymes involved in alcohol metabolism
Alcoholic dehydrogenase and Aldehyde dehydrogenase
Commonly laboratory solvent
Methanol
Effects of Methanol Consumption
Severe metabolic acidosis, Tissue injury, Optic neuropathy, and Death
Kind of alcohol that excessive intake may lead to death
Methanol
The end product of methanol metabolism
Formic Acid
The end product of ethanol metabolism
Acetaldehyde adducts
The end product of isopropanol metabolism
Acetone
Another term for methanol
Wood Alcohol
Another term for Isopropanol
Rubbing Alcohol
Another term for Ethylene Glycol
1,2-ethanediol
Another term for Ethanol
Grain Alcohol
Antidote used for rubbing alcohol
Activated Charcoal
Component of hydraulic fluid and
antifreeze
Ethylene Glycol
Indigestion by children is common due to its ____________
sweet taste
Effects of Ethylene Glycol
Metabolic acidosis and deposition of calcium oxalate crystals in the kidneys
The end product of ethylene glycol metabolism
oxalic acid
What is the alcohol concentration when the symptoms begin?
> 0.05% w/v (>50 mg/dL blood alcohol)
No obvious impairment
0.01 to 0.05
Mild euphoria, decreased inhibitions,
some impairment of motor skills
0.03 to 0.12
Decreased inhibitions, loss of critical
judgment, memory impairment,
diminished reaction time
0.09 to 0.25
Mental confusion, dizziness, strongly
impaired motor skills (staggering,
slurred speech)
0.18 to 0.30
Unable to stand or walk, vomiting,
impaired consciousness
0.27 to 0.40
Coma and possible death
0.35 to 0.50
Presumptive evidence or driving
under influence of alcohol
> 0.10
Colorless, odorless, and tasteless gas that is
rapidly absorbed into the circulation
Carbon Monoxide
This gas binds with hemoglobin to form carboxyhemoglobin (COHb)
Carbon Monoxide
Treatment for CO poisoning
100% O2 therapy
Quantitative assay for carbon monoxide poisoning
Spectrophotometry and Gas chromatography
Effects of Carbon monoxide poisoning
causes a leftward shift in O2-Hb
dissociation curve, resulting in a decrease in
the amount of O2 delivered to the tissues →
hypoxia
The affinity of CO to hemoglobin
200-225x greater
than O2
This color indicates a positive result of the carbon monoxide screening assay
persistent pink color
know as the “Supertoxic” substance
Cyanide
Toxicity of cyanide is expressed by ___________ causes
uncoupling of oxidative phosphorylation that
leads to rapid depletion of cellular ATP as a
result of the inability of O2 to accept electrons
binding to
mitochondrial cytochrome oxidase
Indication of cyanide toxicity
ODOR OF BITTER
ALMONDS breath and altered mental status
The high levels of cyanide toxicity will lead to
seizure, coma, and DEATH
The low levels of cyanide toxicity will lead to
headache, dizziness, and respiratory depression
Assay used for Cyanide
Ion-selective electrode and Photometric analysis
most abundant and
responsible for about ⅓ of all pesticide
poisoning
Organophosphates
Binds with high affinity to several proteins
including cholinesterase resulting to its
inhibition (irreversible inhibition)
Pesticides
What is the laboratory result when exposed to pesticides?
decreased cholinesterase
level
Common homicide or suicide
agent and agent of heavy metal
poisoning
Arsenic
Component of ant poisons,
rodenticides, paints and metal
alloys
Arsenic
Specimens used for evaluating chronic exposure of arsenic
Hair and Nails
white lines of discoloration across the nails of the fingers and toes
Mees lines
Indication of arsenic toxicity
GARLICKY
BREATH ODOR AND METALLIC
TASTE
Antidote for Arsenic
British anti-lewisite
(BAL)
methods used for arsenic
Reinsch test, Atomic
Absorption Spectrophotometry
(AAS)
result from
ingestion of acidic foods stored or
prepared in metal containers made up of metal/metalloids
Cadmium Poisoning
Sources of lead
Paint and Gasoline
Mode of acquisition of lead
Ingestion and inhalation
Poisoning where there is a presence of coarse basophilic stippling in RBC
Lead
Lead chelators
EDTA and
dimercaptosuccinic acid (DMA)
Potent enzyme inhibitor and has
the ability to amalgamate – mix
or merge with other substances
Mercury
Modes of acquisition of mercury
inhalation,
skin absorption, ingestion
General toxic effect of mercury
Organ dysfunction: lungs,
kidney, CNS
Major toxic effect of mercury
Elemental mercury:
➔ Pink disease (acrodynia)
➔ Erethism (hypersensitivity
of an organ to a stimulus)
Alkyl mercury: congenital
Minamata disease
hypersensitivity
of an organ to a stimulus
Erethism
Pink disease
acrodynia
Methods used for mercury
Reinsch test, AAS,
Stripping voltammetry
QUALITATIVE test to detect a heavy metal in
which a strip of clean pure copper foil is
heated with the test material in an acid solution
(HCl) to produce a reaction that will indicate
the presence of a heavy metal
Reinsch Test