Transcript Drugs and Toxicology

Drugs and Toxicology
Introduction
Forensic toxicology helps determine (a) the causeand-effect relationships between exposure to a
drug or other substance and (b) the toxic or
lethal effects from that exposure.
People can be exposed to toxic substances:
• intentionally—by treating illness or relieving
pain
• accidentally—by harmful combinations or
overdoses
• deliberately—by harming or killing others or
by
committing suicide
Poison—Murder, Accidental Overdoses,
and Drug Offences
•
Less than ½ of 1% of all homicides
results from poisoning.
•
Accidental drug overdoses are more
common.
•
More than 50% of the federal prison
population and about 20% of the
population in state prisons consist of
drug offenders.
• Drug – a natural or synthetic
substance that is used to
produce physiological or
psychological effects in humans
or other higher-order animals.
I. Drug Dependence
• Psychological dependence – the
conditioned use of a drug caused by
underlying emotional needs.
• Physical dependence – physiological need
for a drug that has been brought about
by its regular use. Dependence is
characterized by withdrawal sickness
when administration of the drug is
abruptly stopped.
II. Narcotic Drugs
• Narcotic – analgesic or pain-killing
substance that depresses vital body
functions such as blood pressure,
pulse rate, and breathing rate. The
regular administration of narcotics
will produce physical dependence.
• Analgesic – a drug or substance
that lessens or eliminates pain.
• The source of most analgesic
narcotics is opium. Opium
compounds include morphine, heroin,
and codeine.
• Non-opium narcotics are often
called “opiates” due to their similar
physiological effects on the body.
The most well known of these is
Methadone which is used in heroin
addiction treatment programs.
III. Hallucinogens
• Hallucinogens – a substance that
induces changes in mood, attitude,
thought, or perception.
• The most common hallucinogen is
Marijuana. Use of marijuana and its
related products date back almost
three thousand years.
• Marijuana refers to a preparation
derived from the plant Cannabis.
Most botanists believe there is only
one species of the plant, Cannabis
sativa L.
• The marijuana normally consists of
crushed leaves mixed in varying
proportions with the plant’s flower,
stem and seed. The plant secretes
a sticky resin that is known as
hashish.
• Marijuana is a weed that grows wild
under most climatic conditions. The
plant grows to a height of 5 to 15
feet and is characterized by an odd
number of leaflets on each leaf.
Normally, each leaf contains five to
nine leaflets, all having serrated or
saw-tooth edges.
• The chemical substance responsible
for the hallucinogenic properties of
marijuana is tetrahydrocannabinol
or THC.
• The THC content of Cannabis varies
in the different parts of the plant.
The resin is the strongest followed
by the flowers and leaves. Very
little THC is found in the stem,
roots, or seeds.
• Other common hallucinogens include
lysergic acid diethylamide (LSD),
mescaline, and phencyclidine (PCP).
• PCP is often mixed with other
drugs, such as LSD or
amphetamine, and is sold as a
powder (“Angel Dust”), capsule, or
tablet, or as a liquid sprayed on
plant leaves.
• Methylenedioxymethamphetamine,
also know as MDMA or Ecstasy, has
gained worldwide attention as the
latest “designer drug”
• Ecstasy is a synthetic, mindaltering drug that exhibits many
hallucinogenic and amphetamine-like
effects.
IV. Depressants
• Alcohol (Ethyl alcohol) is a drug!
• Depressant - a substance used to
depress the functions of the
central nervous system.
Depressants calm irritability and
anxiety and may induce sleep.
• Alcohol is the most widely used and
abused drug (SURPRISE!)
• Behavioral patterns are varied and
depend on social setting, amount
consumed, and personal expectation of
the individual with regard to alcohol.
• Low doses tend to inhibit the mental
processes of judgment, memory, and
concentration.
• Alcohol has been found to reduce
coordination, inhibit thought processes
and speech patterns, and slow down
reaction times.
• Higher doses of alcohol may cause
the user to become highly irritable
and emotional.
• Overdoses may cause
unconsciousness or coma that may
depress circulatory and respiratory
functions.
• Barbituates are commonly referred
to as “downers” because they relax,
reacte a feeling of well-being, and
produce sleep.
• Derivatives of barbituric acid.
• 25 varieties commonly used in
medicine in the U.S.
• Five most common are amobarbital,
secobarbital, phenobarbital,
pentobarbital, and butabarbital.
• Slang terms usually indicate color “yellow jackets” ”blue devils” “reds”
• Normally taken orally - 10-70 mg
per dose.
• Some act slower than others.
• Normally not physically addictive
unless intake exceeds recommended
amount.
• Withdrawal must be supervised to
avoid death.
• Quaalude - (methaqualone) is a
nonbarbituate depressant that is a
powerful sedative and muscle
relaxant that possesses properties
of barbituates.
• Tranquilizers - differ from
barbituates in that they act on the
central nervous system. They does
not impair higher level thinking or
induce sleep
• Mild tranquilizers include
meprobamate(Miltown),
chlordiazepoxide (Librium), and
diazepam (Valium)
• Tranquilizers do produce physical
and psychological dependence with
repeated and high levels of use.
• Glue Sniffing - includes the sniffing
of materials containing solvents.
• Volatile or gaseous substances are
primarily central nervous system
depressants.
• Toluene seems to be most popular
but others include naphtha, methyl
ethyl ketone, gasoline, and
tricholoethylene.
• Immediate effects - feeling of
exhilaration and euphoria combined
with slurred speech, impaired
judgment, and double vision.
• Creates psychological dependence
but not physical dependence.
• Exposure to these chemicals can be
damaging to the liver, heart, and
brain.
V.
Stimulants
• Stimulant - a substance taken to
increase alertness or activity.
• Amphetamines - A group of
synthetic drugs that stimulate the
central nervous system.
• Commonly referred to as “uppers”
or “speed”.
• Therapeutic doses of 5-20 mg per
day provide feeling of well-being
and increased alertness.
• Most common abuse is
methamphetamine.
• Creates a “rush” followed by
intense pleasure.
• Smokable form of methamphetamine
is “ice”. Effects are similar to
crack cocaine but last longer.
• Cocaine - powerful stimulant to the
central nervous system extracted
from the leaves of the Erythroxylon
coca plant found in South America
and Asia.
• Effects include increased alertness
and vigor accompanied by the
suppression of hunger, fatigue, and
boredom.
• Most commonly sniffed or “snorted”
• Popular form is “crack”. Made by
mixing ordinary cocaine with baking
soda and water into a solution that
is heated in a pot. The material is
then dried and broken into chunks.
Users then smoke it in a glass pipe.
• Crack, like cocaine, produces a
feeling of euphoria by stimulating
the pleasure center in the base of
the brain.
VI. Anabolic Steroids
• Anabolic steroids - steroids that
promote muscle growth. They are
synthetic compounds chemically
related to the male sex hormone
testosterone.
• Two effects - secondary male
characteristics (androgen effects)
and accelerated muscle growth.
VII. Drug-Control Laws
• Medical and legal classifications
often differ.
• U.S. federal law - Controlled
Substances Act. Many state laws
based on this.
• Controlled Substances Act - five
schedules of classification for
controlled dangerous substances.
VIII. Toxicology of Alcohol
• Forensic toxicology - the detection
and isolation of drugs in the body
for the express purpose of
determining their influence on
human behavior.
• Alcohol or ethyl alcohol - a
colorless liquid normally diluted with
water and consumed as a beverage.
The Fate of Alcohol in the Body
• Absorption - passage of alcohol across the
wall of the stomach and small intestine into
the blood stream.
• Absorption is variable and can be affected
by factors such as body weight, food
present, alcohol content of the drink, and
time taken to consume.
• Alcohol is a depressant with its principal
effect on the central nervous system,
particularly the brain.
• Evidence supports the idea that
because blood containing alcohol is
carried through the body tissues
including the brain, the blood alcohol
concentration is directly proportional
to the concentration of alcohol in the
brain.
Bacterial Toxins
Tetanus
• Lockjaw, as it is sometimes called, is produced by
the Clostridium tetani bacteria.
• Its poison can cause violent muscle spasms.
Botulism
• Produced by the bacteria Clostridium botulinum,
botulism paralyzes muscles.
• It causes irreversible damage to nerve endings.
• Very small amounts are extremely deadly.
• Botulism is the most poisonous biological
substance.
Pesticides and Heavy Metals
• Pesticides mostly are used to protect plants
or food crops.
• Metal compounds are very poisonous.
• Metal compounds can damage many organs in the
body.
Bioterrorism Agents
Ricin
 is a poisonous protein in the castor bean.
 is lethal in extremely small amounts.
 can enter the body in various ways:
– inhaled as a mist or a powder.
– ingested as food or drink.
– injected into the body.
 can cause death within a few hours.
Anthrax
• is caused by the bacteria Bacillus anthracis, which
forms spores.
• can be spread to humans from infected animals.
• can enter the human body through:
– inhalation; causing breathing problems that
usually result in death.
– ingestion; becoming fatal in 25% to 60% of
cases.
– absorption via the skin; leading to death in
about 20% of untreated cases.