Drugs & Toxicology

Chapters 9 & 10

Drugs

• Are natural or synthetic substances designed to affect the subject psychologically or physiologically

Narcotic Drugs

• Are analgesics, meaning they relieve pain by a depressing action on the central nervous system– Effects blood pressure, pulse rate, and

breathing rate

• Regular use can lead to physical dependence

• Most common narcotic drugs are the opiates

Heroin

• Morphine is readily extracted from opium and is used to synthesize heroin

• Addicts frequently dissolve heroin in water by heating it in a spoon and then injecting in the skin

• Heroin produces a “high” that is accompanied by drowsiness and a sense of well being that generally lasts 3-4 hours

Codeine

• Also present in opium, but it is usually prepared synthetically from morphine

Oxycontin

• Is not derived from opium or morphine

• It does have the same physiological effects on the body as do opium narcotics

• Is prescribed to a million patients for treatment with chronic pain

Methadone

• Is a well known synthetic opiate

• Is pharmacologically related to heroin

• Eliminates the addict’s desire for heroin while producing minimal side effects

Hallucinogens

• Marijuana is the most well known member of the class

• Cause marked changes in normal thought processes, perceptions, and moods

• Marijuana is the most controversial drug in this class because its long term effects on health are still largely unknown

Marijuana

• Refers to the preparation derived from the plant Cannabis

• The chemical substance largely responsible for the hallucinogenic properties of marijuana is tetrahydrocannabinol, or THC

• THC content varies in different parts of the plant, generally decreasing in the following sequence: resin, flowers, leaves, with little THC in the stem, roots, or seeds

Marijuana

• The THC rich resin is known as hashish

• Marijuana does not cause physical dependency, but the risk of harm is in heavy, long term use

Other Hallucinogens

• Include LSD, mescaline, PCP, psilocybin, and MDMA (ecstasy)

LSD

• Is synthesized form lysergic acid, and can cause hallucinations that can last for 12 hours

PCP

• AKA phencyclidine• Is often synthesized in clandestine laboratories

and is often smoked, ingested, or sniffed• Is often mixed with other drugs such as LSD or

amphetamine and is sold as a powder (angel dust), capsule, or tablet

• Oral intake of PCP first leads to feelings of strength and invulnerability, which may turn to depression, tendencies toward violence, and suicide

Depressants

• Are another class of drugs• Are substances used to depress the functions of

the central nervous system• Calm irritability and anxiety and may induce sleep• Include alcohol (ethanol), barbiturates,

tranquilizers, and various substances that can be sniffed, such as airplane glue, model cement, or aerosol gas propellants such as freon

Alcohol

• Enters the body’s bloodstream and quickly travels to the brain where it acts to suppress the brain’s control of though processes and muscle coordination

Barbiturates

• AKA downers

• Are normally taken orally

• Create a feeling of well being, relax the body, and produce sleep

Tranquilizers

• Produce a relaxing tranquility without impairment of high thinking faculties or inducing sleep

Sniffing

• Has immediate effects such as exhilaration, but impairs judgment and may cause liver, heart, and brain damage or even death

Stimulants

• Are substances taken to increase alertness or activity, followed by a decrease in fatigue and a loss of appetite

• Includes amphetamines, sometimes known as “uppers” or “speed”, and cocaine, which in its free base form is known as crack

Amphetamines

• Amphetamines and methamphetamines often are injected intravenously

• Cause an initial rush followed by an intense feeling of pleasure that is followed by a period of exhaustion and a prolonged period of depression

Cocaine

• Is extracted from the leaves of Erythroxylin coca

• Causes increased alertness and vigor, accompanied by the suppression of hunger, fatigue, and boredom

Crack

• Is cocaine mixed with baking soda and water, then heated

• Is often smoked in glass pipes, and like cocaine, stimulates the brain’s pleasure center

Club Drugs

• Refers to synthetic drugs that are used at nightclubs, bars, and raves

• Substances that are often used as club drugs include, but are not limited to, MDMA (ectasy), GHB (gamma hydroxybutyrate), Rohypnol (Roofies), ketamine, and methamphetamine

Ecstasy

• AKA methylenedioxymethamphetamine• Is a synthetic mind altering drug that exhibits

many hallucinogenic and amphetamine-like effects

• Enhances self awareness and decreases inhibitions• Seizures, muscle breakdown, stroke, kidney

failure, and cardiovascular system failure often accompany chronic abuse

GHB & Rohypnol

• Are central nervous system depressants that are often connected with drug facilitated sexual assault, rape, and robbery

Ketamine

• Is primarily used as a veterinary animal anesthetic that in humans causes euphoria and hallucinogens

• Can also cause impaired motor functions, high blood pressure, amnesia, and mild respiratory depression

Anabolic Steroids

• Are synthetic compounds that are chemically related to the male sex hormone testosterone

• Are often abused by individuals who are interested in accelerating muscle growth

• Side effects include unpredictable effects on mood and personality, depression, diminished sex drive, halting bone growth, and liver cancer

Toxicology

• Is the study of the adverse effects of chemicals or physical agents on living organisms

Toxicologists

• Toxicologists are charged with the responsibility for detecting and identifying the presence of drugs and poisons in body fluids, tissues, and organs

• Work in crime labs and medical examiners offices, but may also reach into hospital labs and health care facilities to identify a drug overdose or monitor the intake of drugs

Toxicology

• Toxic substances may– Be a cause of death– Continue to death– Cause impairment– Explain behavior

Aspects of Toxicology

• Dosage• The chemical or physical form of the substance• The mode of entry into the body• Body weight and physiological conditions of the

victim, including age and sex• The time period of exposure• The presence of other chemicals in the body or in

the dose

Lethal Dose

• LD50

• Refers to the dose of a substance that kills half the test population, usually within 4 hours

• Expressed in milligrams of substance per kilogram of body weight

Symptoms of Poisoning

Type of Poison Symptom/Evidence

Caustic poison (lye) Burns around the lips and mouth

Carbon monoxide Red or pink patches on chest & thighs

Sulfuric acid Black vomit

Hydrochloric acid Greenish-brown vomit

Nitric acid Yellow vomit

Phosphorus Coffee brown vomit, onion or garlic odor

Cyanide Burnt almond odor

Arsenic, mercury Pronounced diarrhea

Methyl (wood) or isopropyl alcohol Nausea, vomiting, unconsciousness, blindness

To Prove a Case

• Prove a crime was committed

• Motive

• Intent

• Access to poison

• Access to victim

• Death was caused by poison

• Death was homicidal

Forensic Autopsy

• Look for– Irritated tissues– Characteristic odors– Mees line

• Single transverse white bands on nails

• Order toxicological screens– Postmortem concentrations should be done at the scene

for comparison– No realistic calculation of dose can be made from a

single measurement

Human Specimens for Analysis

• Blood• Urine• Vitreous humor of eye• Bile• Gastric contents• Liver tissue• Brain tissue• Kidney tissue• Hair• Nails

Toxicology of Alcohol

• Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage

• It is the most abused drug• Like any depressant, alcohol principally effects the

central nervous system, particularly the brain • 40% of all traffic deaths are alcohol related• About 5% is excreted unchanged in breath,

perspiration, and urine• 90% is detoxified by the liver

Toxicology of Alcohol

• Alcohol appears in the blood within minutes after it has been taken by mouth and slowly increases in concentration while it is being absorbed from the stomach and the small intestine into the bloodstream– It takes 30 –90 minutes for full absorption

Rate of Absorption

• Depends on – Time taken to consume the drink– The alcohol content– The amount of alcohol consumed– Food present in the stomach– Physiology of the consumer

Blood Alcohol Content

• The extent to which the individual may be under the influence of alcohol is usually determined by either measuring the quantity of alcohol present in the blood system or by measuring the alcohol content in the breath

• Is expressed as percent weight per volume of blood

• Legal limits in all states is 0.08%

Blood Alcohol Content

• Parameters affecting BAC– Body weight– Alcoholic content– Number of beverages consumed– Time between consumption

Blood Alcohol Content

• Burn off rate of 0.015% per hour but can vary– Male

• BAC Male= 0.071 x (# oz) x (% alcohol)/ body weight

– Female • BAC Female= 0.085 x (# oz) x (% alcohol)/body weight

Field Tests

• Preliminary tests– Used to determine the degree of suspect’s

physical impairment and whether or not another test is justified

• Psychophysical tests– 3 basic tests exist

• Horizontal gaze nystagmus (HGN)• Nine step walk and turn (WAT)• One leg stand (OLS)

Field Tests

• Horizontal gaze nystagmus (HGN– Follow a pen or small flashlight, tracking left to right

with one’s eyes– Wavering at 45 degrees indicates BAC of 0.10

• Nine step walk and turn (WAT)– Comprehend and execute two or more simple

instructions at a time

• One leg stand (OLS)– Maintain balance, comprehend and execute two or

more simple instructions at one time

The Breathalyzer

• More practical in the field• Collects and measures alcohol content of

alveolar breath• Breath sample mixes with 3 ml of 0.025%

potassium dichromate in sulfuric acid and water– Measures light absorption of potassium

dichromate before and after the reaction with alcohol

Controlled Substances

• Are drugs that are restricted by law

• Law was enacted in 1970 listing illegal drugs, their category and their penalty for possession, sale or use– Called Controlled Substances Act– Was created to prevent and control drug use

Controlled Substances Act

• Established 5 schedules of classification for controlled dangerous substances on the basis of a drug’s– Potential for abuse– Potential for physical and psychological

dependence– Medical value

Schedule I Drugs

• High potential for abuse

• No currently acceptable medical use in the US

• A lack of accepted safety for use under medical supervision

• Includes marijuana, heroin, ecstasy, and LSD

Schedule II Drugs

• High potential for abuse

• A currently accepted medical use with severe restrictions

• Abuse may lead to severe psychological or physical dependence

• Include cocaine, PCP, morphine, amphetamines, methamphetamines, ritalin

Schedule III Drugs

• Lower potential for abuse than the drugs in I or II

• A currently accepted medical use in the US• Abuse may lead to moderate physical

dependence or high psychological dependence

• Include all barbiturate prescriptions not covered under II, codeine, and anabolic steroids

Schedule IV Drugs

• Low potential for abuse relative to drugs in III

• A currently accepted medical use in the US• Abuse may lead to limited physical or

psychological dependence relative to drugs in III

• Include darvon, phenobarbital, and some tranquilizers such as diazepam (valium) and chlordiazepoxide (librium)

Schedule V Drugs

• Low potential for abuse relative to drugs in IV• Currently accepted medical use in the US• Abuse may lead to limited physical or

psychological dependence relative to drugs in IV• Include opiate drug mixtures that contain

nonnarcotic medicinal ingredients– Codeine found in cough medicine

Drug Identification

• The challenge or difficulty of forensic drug identification comes in selecting analytical procedures that will ensure a specific identification of a drug

• 3 ways to identify drugs– PDR- Physician’s Desk Reference– Field Tests- presumptive tests– Laboratory Tests- conclusive tests

What Can be Tested for Drugs

• Blood• Urine• Hair• Gastric contents• Bile• Liver tissue• Brain tissue• Kidney tissue• Spleen tissue• Vitreous humor of the eye

PDR

• Is used to identify manufactured pills, tablets, and capsules

• Is updated each year• Can be a quick and an easy identifier of the legally

made drugs that may be found at a scene• Reference book gives a picture of a drug, whether

it is a prescription, over the counter, or a controlled substance, as well as more detailed information about the drug

Presumptive Tests

• Include – Spot or color tests– Microcrystalline test

• A reagent is added that produces a crystalline precipitate which is unique for a certain drug

– Chromatography

Spot or Color Tests• 5 types

– Marquis• Turns purple in the presence of most opium derivatives and orange-

brown with amphetamine

– Dillie-Koppanyl• Turns violet-blue in the presence of barbiturates

– Duquenois-Levine• Turns a purple color in the presence of marijuana

– Van Urk• Turns blue-purple in the presence of LSD

– Scott test• Turns blue in the presence of cocaine

Confirmatory Tests

• Include – Spectrophotometry

• Ultraviolet (UV)

• Visible

• Infrared (IR)

– Mass spectrometry

Spectroscopy

• The interaction of electromagnetic radiation with matter

• Measured using a spectrophotometer– An instrument used to measure and record the

absorption spectrum of a chemical substance

Mass Spectrometry

• In a mass spectrometer, an electron beam is directed at sample molecules in a vacuum chamber

• The electrons break apart the sample molecules into many positive charged fragments– Are sorted and collected according to their

mass to charge ratio by an oscillating electric or a magnetic field