Drugs and Toxicology

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Drugs and Toxicology
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Introduction

• Forensic toxicology helps determine (a) the
  cause-and-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
• intentionallyby treating illness or relieving
  pain
• accidentallyby harmful combinations or overdoses
  
• deliberatelyby harming or killing others or by
  committing suicide

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PoisonMurder, 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.

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• Drug a natural or synthetic substance that is
  used to produce physiological or psychological
  effects in humans or other higher-order animals.

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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.

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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.

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• 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.

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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.

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• 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 plants
  flower, stem and seed. The plant secretes a
  sticky resin that is known as hashish.

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• 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.

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• 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.

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• 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.

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• Methylenedioxymethamphetamine, also know as MDMA
  or Ecstasy, has gained worldwide attention as the
  latest designer drug
• Ecstasy is a synthetic, mind-altering drug that
  exhibits many hallucinogenic and amphetamine-like
  effects.

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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!)

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• 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.

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• 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.

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• 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.

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• 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.

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• 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

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• 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.

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• 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.

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• Creates psychological dependence but not physical
  dependence.
• Exposure to these chemicals can be damaging to
  the liver, heart, and brain.

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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.

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• 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.

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• 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

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• 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.

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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.

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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.

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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.

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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.

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• 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.

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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.

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Pesticides and Heavy Metals

• Pesticides mostly are used to protect plants or
  food crops.
• Metal compounds are very poisonous.

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• Metal compounds can damage many organs in the
  body.

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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.

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• 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.