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Chapter 8

Toxicology: Drugs and Poisons “All substances are poisons. There is none which is not. The right dose differentiates a poison and remedy.” —Paracelsus (1495-1541). Swiss physician and chemist

Toxicology Definition—the study of the adverse effects of chemicals or physical agents on living organisms.

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Forensic Toxicology  Postmortem—medical examiner or coroner  Criminal—motor vehicle accidents (MVA)  Workplace—drug testing  Sports—human and animal  Environment—industrial, catastrophic, terrorism Chapter 8

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Toxicology Toxic substances may:  Be a cause of death  Contribute to death  Cause impairment  Explain behavior

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Drugs  A natural or synthetic substance designed to affect humans (or other animals)  Drugs can be classified by their potential for dependence: psychologically or physiologically Chapter 8

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Drugs  Physiological Dependence: -the body is exposed to a substance so frequently that it becomes reliant on the substance to function. (Ex.Heroin) - Experiences withdrawal symptoms such as 1. Sweating 2. Vomiting 3. Hallucinations 4. Seizures Chapter 8

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Drugs  Psychological Dependence: - Frequent use of a substance leads the mind to rely on the substance to function (Ex. Cocaine, marijuana) - Experiences withdrawal symptoms such as: 1. Depression 2. Irritability 3. Insomnia Chapter 8

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Drug Classification  Drugs are classified by their pharmacological effects (what they do to a person) A. Hallucinogens B. Stimulants C. Depressants D. Narcotics (Analgesics) Chapter 8

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Drug Classification A. Hallucinogens Mostly naturally occurring substances that can change normal thought processes, perceptions, and moods

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Hallucinogen Examples  Marijuana- from the cannabis plant; most widely used hallucinogen in the U.S -decreases concentration, slows reactions

 LSD (Acid)- chemically made from a fungus on grain plants -causes visual and auditory hallucinations Chapter 8

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Drug Classification B. Stimulants -Acts on the central nervous system -Increases energy, suppresses appetite -Causes anxiety and depression

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Stimulant Examples  Stimulants can range from coffee to cocaine  Cocaine- comes from the leaf of the coca plant; 500 pounds of leaves = 1 pound of cocaine - Causes insomnia, weight loss

 Nicotine – found in tobacco products Chapter 8

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Drug Classifications C. Depressants -slows brain activity -Examples include:  Anti-anxiety medications    Chapter 8

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Drug Classifications D. Narcotics (Analgesics) - Substances that affect the central nervous system to relieve pain - Narcotics are prescribed by doctors for pain but are often abused Chapter 8

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Narcotic Examples  Over the counter (OTC) - Aspirin, Tylenol, Motrin

 Codeine- found in medications

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Narcotic Examples  Opium- harvested from the poppy flower; Contains morphine  Heroine- made from morphine; injected intravenously

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Poisons  A substance that is capable of causing illness or death in humans and animals when ingested or absorbed.

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Poison Classification  Poisons are classified as:  1. Heavy metals  2. Corrosive  3. Pesticides  4. Toxins  5. Volatiles  6. Electrolytes Chapter 8

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Heavy Metal Poisons  Heavy Metal Poisons include:  Arsenic Poisoning-found in pesticides; causes brain and nerve damage  Lead Poisoning-found in old paint -typical in occupational exposure (automotive repair, road construction) - Drinking water from lead pipes Chapter 8

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Heavy Metal Poisons  Heavy Metal Poisoning Symptoms:  Vomiting, abdominal pain, diarrhea  Skin rashes

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Corrosive Poisons  Corrosive Poisons include:  Household Cleaners Bleach Drain cleaner Ammonia Acids (battery acid)

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Corrosive Poisons  Effects of corrosive poisons include: -Burns to the skin, mouth, and throat -Damage to the stomach lining

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Pesticides  Chemicals to control pest populations  Pesticide poisoning symptoms include: Convulsions Skin irritation Slow heart rate

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Toxins  A harmful substance produced by a living organism (plant or animal)  Examples:  Poison Arrow Dart Frog  Blue Ring Octopus  Poison Hemlock (plant)

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Volatiles  Gaseous substances that are harmful when inhaled  Examples include:  Ethanol- found in alcohol, gasoline

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Electrolyte Poisoning  An overabundance of minerals in the body causes adverse effects  Can cause dizziness, vomiting, and kidney failure  Electrolytes include: 1. Potassium 2. Sodium Chapter 8

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STOP HERE!  END OF DRUGS AND POISONS

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Detecting Poisons  Detecting poisons in a corpse is an important step in determining if the death was a homicide.

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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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Toxicity Classes LD50 (rat,oral)

Correlation to Ingestion by 150 lb Adult Human

Toxicity