Transcript Chapter08

Toxicology: Poisons and Alcohol
“If all those buried in our cemeteries who were poisoned could raise their
hands, we would probably be shocked by the numbers.”
—John Harris Trestrail, Criminal Poisoning
Toxicology: Poisons and Alcohol
Toxicology
 Toxicology—the study of the adverse effects of
chemicals or physical agents on living organisms
 Types of Toxicology:
Environmental—air, water, soil
Consumer—foods, cosmetics, drugs
Medical – ER, poisonings, drugs
Forensic –
Postmortem—medical examiner or coroner
Criminal—motor vehicle accidents (MVA)
Workplace—drug testing
Sports—human and animal
Environment—industrial, catastrophic, terrorism
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Toxicology
• Acute: immediate effects of toxins (i.e. death)
• Chronic: long-term effects of toxins (i.e.
cancer)
• Synergism: The combination of drugs can
have magnified effects. For example: a
person takes barbiturates and drinks alcohol
and then dies. By themselves, the drugs
wouldn’t have killed the person, but taken
together they have a lethal effect.
• Antagonism: Combined effect of substances
that decreases their individual effects (opposite
of synergism)
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Toxicology: Poisons and Alcohol
Symptoms of Various Types of Poisoning
Type of Poison
Symptom/Evidence
Caustic poison (lye)
Carbon monoxide
Sulfuric acid
Hydrochloric acid
Nitric acid
Phosphorus
Cyanide
Arsenic, mercury
Isopropyl (rubbing) alcohol
Burns around the lips and mouth
Red/pink patches on the chest & thigh
Black vomit
Greenish-brown vomit
Yellow vomit
Coffee-brown vomit, onion or garlic odor
Burnt almond odor
Extreme diarrhea
Nausea, vomiting, unconsciousness, blindness
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Drug Intake and Absorption
 Drug Intake: swallowing powders,
tablets, capsules; inhaling vapors;
injection with a syringe
 Absorption: Once a drug has
entered the body, it is absorbed into
the bloodstream and circulated
throughout the body. Some drugs
tend to concentrate in certain areas:
 Pesticides in fatty tissue
 Heavy metals: teeth, gums, hair
 LSD and marijuana: brain
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Addiction vs. Dependence
 Tolerance: Occurs when increasing doses are required to keep
the same level of effects on the person. If a person tries to quit a
drug, withdrawal symptoms can sometimes be fatal because the
body has become dependent on the drug.
 Drug addiction: physical process. Biochemical changes
occur in the body to help tolerate the drug.
 The body may then require the drug on a regular basis.
 If the drug is not used, withdrawal symptoms may occur:
sleeplessness, restlessness, nausea, hallucinations, headaches
 Dependence: psychological craving for the drug. Withdrawal
symptoms do not occur if drug use is stopped.
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Toxicology: Poisons and Alcohol
Lethal Dose
 LD50 refers to the dose of a substance that kills half the test
population, usually within four hours
 Expressed in milligrams of substance per kilogram of body weight
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Toxicology: Poisons and Alcohol
Elimination of Drug From Body
 Half-life: time it takes for the concentration
of a drug to drop to half of its concentration
 Cocaine’s half-life: 60-90 minutes
 Heroin’s half-life: 3 minutes
 Liver: can change a drug into a different
substance, forming a metabolite.
 For example, the metabolite of heroin is
morphine.
 Toxicologists often look for metabolites
when trying to detect drugs
 Elimination of Drugs From Body:
 Exhaled in breath
 Sweat
 Urine
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Toxicology: Poisons and Alcohol
Alcohol—Ethyl Alcohol (C2H5OH)
 Most abused drug in America
 About 40% of all traffic deaths are
alcohol-related
 Depressant
 Alcohol appears in blood within
minutes of consumption; 30–90
minutes for full absorption
 Detoxification—about 90% in the liver
 About 5% is excreted in breath,
perspiration, & urine
 Neurotoxin: kills nerve cells (one
ounce of ethanol can kill about
10,000 nerve cells)
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Toxicology: Poisons and Alcohol
BAC: Blood Alcohol Content
 Expressed as percent weight per
volume of blood (grams of alcohol
present in 100mL of blood)
 Legal limit in all states is 0.08%
 Parameters influencing BAC:
• Body weight/physiology of consumer
• Alcohol content of beverage
• Number of beverages consumed
• Time alcohol is consumed within
• Quantity & type of food consumed
• Time since consumption
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Blood Alcohol Concentration (BAC)
 BAC and effects:
 0.04: feeling of
relaxation
 0.06: less able to make
rational decisions
 0.08: impairment in
motor coordination skills
(driver intoxication)
 0.12: vomiting
 0.40: loss of
consciousness
 0.45: death
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Drunk Driving Laws
 Implied Consent: when you
sign your driver’s license you
are giving consent that you will
submit to a blood or breath test
if you are stopped for drunk
driving.
 Refusal to submit can result in the loss
of your license for 90-180 days.
 Field Sobriety Testing: walk
and turn, stand on one foot,
horizontal gaze nystagmus (eyes
watch a pencil as it moves)
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