Drugs Chapter 7
Drugs • Hallucinogens – mostly naturally occurring substances that can change normal thought processes, perceptions, and moods. • Stimulants – act on the nervous system to make the user feel better and increase his/her energy/alertness.
Drugs • Narcotics/analgesics – substances affecting the central nervous system to relieve pain. • Depressants – a drug that reduces excitability and calms a person.
Poisons • Toxicology – the study of the adverse effects of chemicals or physical agents on living organisms.
Poison Effectiveness • The chemical form of the substance (pure arsenic versus arsenic trioxide). • Method of entry (oral versus injection). • Condition of victim (weight, age, general health).
Poison Effectiveness Time period of exposure • chronic exposure – continuing exposure over long periods of time • acute exposure – large dosage at one time
Poison Effectiveness Presence of other chemicals. • synergism – combined effect of substances that exceeds the sum of their individual effects. • antagonism – combined effect of substances that decrease their individual effects.
Counteracting Poisons • Chelating agent – an organic compound that combines with a metal to form a ring compound.
Alcohol • Alcohol is the most abused depressant in the United States. • The chemical name for alcohol is ethanol or ethyl alcohol. • Ethanol, like all alcohols, is toxic. • Ethanol effects the central nervous system. • Alcohol circulates in the blood stream immediately after consumption.
Alcohol and the Law • The law is concerned with the level of blood alcohol content (BAC). • BAC is expressed as a percent weight per volume. • Federal and Kansas BAC limits are both 0.08 percent. • This means that there is 0.08 grams of pure alcohol for every 100 mL of blood.
Alcohol Laws • DUI – driving under the influence • DWI – driving while intoxicated • OUI – operating under the influence • OWI – operating while intoxicated • MIP – minor in possession
Alcohol Processing • The average person removes 0.015 percent per hour. • About 5% of ethanol leaves the body through respiration, perspiration, and urine. • About 90% of alcohol is chemically processed (metabolized) by the liver. • It is changed first to acetaldehyde (a poison). • Then it is changed to acetic acid and finally to carbon dioxide and water.
CH3CH2OH→HCH3COO HCH3COO→CO2 + H2O
BAC Affects • 0.02 divided attention, slowed reaction time • 0.04 Eye movement control • 0.05 Coordination • 0.06 Judgment • 0.08 Concentrated attention, speed control
Breathalyzer Tests • Henry’s Law - At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. • According to Henry’s Law the concentration of alcohol in the breath is proportional to the concentration of alcohol in the blood.
The Chemistry of Breathalyzers • An orange dichromate ion is reduced to a green chromium (III) ion. 8H++Cr2O72- +3C2H5OH→ 2Cr3++3C2H4O+7H2O