chapter 20 - forensic toxicology

how toxicology, pharmacology, and forensic toxicology are the same/different

toxicology: study of harmful effects of drugs and poisons on living things

pharmacology: study of drugs and their harmful or BENEFICIAL effects on living things

forensic toxicology: legal application of toxicology to criminal and civil cases

methods of drug intake

swallowing a powder or pill

dissolving powder in liquid and drinking it

IV injection

Intramuscular, subcutaneous, or intravenous injection

absorption

enters blood stream

if inhaled, enters through alveoli of lungs

intramuscular or subcutaneous injections enter bloodstream through capillaries present in muscles or skin

drugs taken orally can be absorbed into the bloodstream in the stomach, small intestine, or both

oral injections give control over the rate of absorption: empty stomach = fast absorption, full stomach = slower absorption

circulation

higher concentrations of blood, more pronounced the effects are

certain effects may not appear at low drug concentrations

some drugs tend to build up and collect in fatty tissues, which can make them dangerous over time

mercury, lead, and pesticides are examples of drugs that may collect in the body

elimination

exhaled in breath if drug is volatile

sweated out if drug is water soluble

through urine as drug itself or metabolite

person has no control over rate at which this happens

process is entirely under control of liver and kidneys

synergism

magnified effects from a combination of drugs

sum of two effects of drugs is greater than two parts of an individual drug

tolerance

increasing doses of a drug are required to keep the same level of effects on the person

reverse tolerance occurs when users get more heightened effects over time from use of the drugs

how does the body eliminate ethanol

liver metabolizes alcohol by changing it to acetaldehyde and then acetic acid

metabolites: acetaldehyde and acetic acid

metabolites are dissolved in urine

may be eliminated through breath and perspiration (smell of a person drinking, breathalyzers)

field sobriety tests

walk and turn

stand on one foot

horizontal gaze nystagmus

results of tests are admissible in court as evidence of impairment

addiction

physical effects of a drug, manifested by an extreme craving for the drug

enteric dosage form

form of a drug that is made to be released overtime in the bloodstream

forensic toxicology

legal application of toxicology

half-life

the time it takes for the concentration of a drug in the body to be reduced by 50%

metabolite

the action of the liver on a drug to change it into a different substance that is generally less harmful and easier to eliminate from the body

proof (alcohol)

a measure of alcohol concentration in hard liquors. it is equal to twice the percentage of alcohol in the drink

toxicology

the study of harmful effects of drugs and poisons on living things

BAC

Blood Alcohol Concentration