Exam 1

Medical Definition of a Drug

Medical Definition of a Drug

Any substance that may prevent or cure disease or enhance physical or mental welfare

Pharmacological Definition of a Drug

Any chemical agent that alters biochemical processes of tissues or organisms

Common use definition of a Drug

Psychoactive drugs, used non-medically as well as medically

Drug classifications

By origin (plants, etc.)

By therapeutic use (stimulant, painkiller, etc.)

By site of drug action (e.g., CNS)

By chemical structure

By mechanism of action (how it produces its drug effects)

By street name (e.g., “speed,” “uppers,” “downers”)

Drug classification by origin

Plants, etc (Ex: opiates)

Drug classification by theraputic use

Stimulant, painkillers (Ex: Antidepressants)

Drug classification by site of drug action

CNS, etc

Drug classification by Chemical sturcture

barbituates

Drug classification by mechanism of action

how it produces its drug effects

Drug classification by street name

speed, uppers, downers

Drug classification by legality (illicit)

Illegal drugs (heroin, cocaine, marij)

Drug classification by legality (licit)

Legal drugs (alcohol, caffeine, nicotine)

Schedule 1 drug

the drug or substance has a high potential for harmful use. it has NO currently accepted medical use in treatment in the US. lack of accepted safety for use under medical supervision.

Schedule 2 Drug

the drug or other substance has a High potential for misuse. It HAS a currently ACCEPTED medical use or use with SEVERE restrictions. Misuse of the drug may lead to severe psychological or physical Dependence.

Schedule 3 Drug

the drug or other substance has a potential for misuse less than the drugs or other substances in Schedule 1 or 2. HAS an accepted medical use. Misuse may lead to Moderate or Low physical dependence or High psychological dependence.

Schedule 4 Drug

the drug or other substance has a Low potential for misuse relative to schedule 3 drugs. HASan accepted medical use. Misuse of the drug may lead to Limited physical dependence or psychological dependence relative to Schedule 3 drugs

Schedule 5 Drug

the drug or other substance has a LOw potential for misuse compared to schedule 4 drugs. HAS an accepted medical use. misuse may lead to Limited physical dependence or psycological dependence compared to Schedule 4 drugs

Pharmacology

How drugs act on biological systems, how the body responds

Psychopharmacology

The effects of drugs on behavior

National Survey on Drug Use and Health

1)Conducted annually by Substance Abuse and Mental Health Services Administration (SAMHSA):

•ongoing since 1971 for those 12 and older

•Data on overall prevalence of use in last year and last month and lifetime use

•Includes alcohol and tobacco as well as marijuana, cocaine, heroin, opioid

Monitoring the Future

Conducted annually by the University of Michigan, funded by NIDA)

§ongoing for 12^th graders since 1975

§added 8^th, 10^th graders in 1991

Past year illicit drug use (18-25)

38.0

Past year Marijuana Use (18-25)

35.4

•Estimated cost of alcohol abuse

$249 billion

•Estimated cost of tobacco and illicit drugs

$493 billion

International Comparisons of Drug Use

•17 countries, 54,069 respondents

•Americas, Europe, Japan, New Zealand reported more alcohol and cannabis use than Middle Eastern countries, Africa, China

•U.S. had highest lifetime use of cocaine of all countries responding

•Several similarities with NSDUH survey:

•More males used all drugs than females in all countries

•Younger adults are more likely to use all drugs than older adults

Any mental illnesses (18-25)

33.7

Serious mental illnesses (18-25)

11.4

Three sets of factors in the drug experience

1. Pharmacological (pharmacokinetics & pharmacodynamics)

2. Characteristics of the drug user (set)

3. Setting in which the drug is used (setting)

Pharmacokinetics

“What the body does to the drug”

Absorption, distribution, metabolism, and excretion (ADME)

•Absorption and distribution = how much drug reaches sites of action

•Metabolism and excretion = two routes of drug elimination

•Required to learn a drug’s effect after it enters the body

Pharmacodynamics

Study of “biochemical and physiological effects of drugs and their mechanisms of action” (What the drug does to the body)

•Language used by pharmacologists to describe drug effects and ways to depict them

•Biological bases of observed drug effects

Standards followed in describing and representing drug effects

Absorption and distribution

how much drug reaches sites of action

Metabolism and excretion

two routes of drug elimination

•Administration

How does the drug enter the body?

Absorption

How does the drug move from site of administration into the body’s circulatory system

•Distribution

How does the drug move to various areas of body?

Activation

How and where does the drug produce its effects?

•Biotransformation/elimination

How is the drug inactivated and excreted from body

Drug Dose

Pharmacologists compute drug dose according to a person’s body weight

•Volume of body fluid correlates positively with body weight

•The greater the drug concentration at a site, the greater the drug effect

Determine the desired dose, expressed in milligrams of drug per kilogram (mg/kg) of body weight

routes of admininstration

may be either the site where a drug is taken or how a drug is taken; route of administration can strongly influence drug effects

Main routes of administration

Oral

•Injection 

•Subcutaneous

•Intramuscular

•Intravenous

•Inhalation

•Intranasal (sniffing)

•Sublingual (under the tongue)

Transdermal (through the skin

oral administration

usually the safest, most ecnonomical way to take a drug, causes slower absorption than other routes, and Outcome: diminished drug effect

Injection administration

bypasses the difestive process entirely and delivers the drug more directly into the bloodstream

Intravenous (IV) injection

drugs are administered directy into the bloodstream, FASTEST but MOST dangerous

Avoids most absorption problems, effects can be immediate

Most highly associated with complications: Large quantities of drug too quickly

Intramuscular (IM) Injection

Drugs are injected into muscle tissue, can be painful/irritating

absorption rates may differ by rat of blood flow to muscle and solution used

Subcutaneous (Sub-Q) injection

injecting drug just below the layers of skin, easiest injection route, only small volumes, slowest absorption rate of injections but constant absorption

Relatively slow but faster than oral administration

Inhatation administration

some drugs may be inhaled then absorbed through the LUNGS’ membrane

Fast and effective absorption

Tobacco smoke or freebase

Intranasal administration

snorting, sniffing (Cocaine, heroine, powdered tobacco snuff)

Rapid and effective way to absorb fat-soluble drugs

Sublingual administration

tablet dissolves in saliva under tongue, is absorbed through mouth’s mucous membranes (Nitroglycerin to treat heart pain)

Transdermal administration

through the skin- alternative to oral administration when a drug may cause unwanted gastrointestinal effects (Nicotine patches)

Absorption of a drug into the bloodstream

rate and extennt to which a drug leaves its site of administration; plays major role in the drug experience

factors that influence absoption

Drugs by all routes except IV must pass through at least 1 body membrane to reach the circulatory system

Drug distribution

body regions with the most bloor flow receive the most drug (heart, brain kidney and liver) areas recieving less bloodflow like muscles, viscera nad fat may take longer to recieve the drug

Diffusibility

the more diffusible tissues revieve the drug more rapidly

fat solubility

drugs more soluble in lipids penetrate body membranes, reach action site and brain more easily (Valium)

chemical binding of a drug to certain plasma proteins

the more “tightly” bound a drug, the slower its distrubution to action sites

bioavailability of a dryg

Route, absorption and diffusion all influence the ………

Liver enzymes

play a major role in drug metabolism; enxymes also in kidneys and GI tract

Kidney

Most important organ for ec=xcretion of drugs and their matabolites

First order Kinetics

amount of drug metabolized depends on amount in blood

Zero order kinetics

Rate of drug metabolism ia independent of its concentration in blood (Alcohol)

Half-life

time needed for amount of drug in the bodyto be cut in half

Set (characteristics of the user that effect drug effects)

Age (young vs old)

weght

gender (% body fat)

hormones

inherited differences in initial sensitivity and reactions to drugs and drug tolerance

Psycological state, personality abd expectations of an individual while using drugs

Setting

the physical and social environment in which drugs are used

Laws pertaining drug use

taking drugs alone vs with others influences the effects pf alcohol, marijuana, hallucinogenic drugs

immediate physical environment

Dose-effect curve

standard way to graphically represent the relationship between drug dose and the size of an effect.

Dose-effect curve Slope

steepness of a dose-effect curve reflects how much the drug dose changes before the effect gets larger

Dose-effect curve Efficacy

the peak of the dose-effect curve for a given effect

Dose-effect curve drug potency

minimum dose of a drug that yields its efficacy

Effective Dose (ED)

the dose at which a given percentage of individuals show a particular effect of a drug

Lethal Dose (LD)

the dose of a drug at which a given percentage of nonhuman subjects die withing a specified time

More

……… danger of accidental death whem difference between a drugs ED and LD is small

Theraputic index

a easure of a drugs saftey in medical care

Ratio= LD 50/ED 50 for a given drug

drug interactions

the effect of one drug alters the effect of the other

enhancing cobinations (Synergism)

the effects of taking teo drugs together are greater than the effects of taking either drug alone

diminishing combinations (Antagonism)

reduced effect of a drug in another drugs presence

neurons

basic building blocks of the nervous system; cells that can communicate with one another

Dendrites and axon

structures unique to the neruon- the provide for neural communication, WHICH IS BOTH ELECTRICAL AND CHEMICAL

electrical message

a nerve impulse or action potential is the ………… that is transmitted down

results form the mobement of ions in and out of the cell

the speed of nerve impulses ranges from approximately 1 m/s to 100 m/s

restng membrane potential

refers to the state of the neuron prior to the sending of a nerve impulse

the inside of the membrane is slightly negative with resct to the outside

hyperpolarization

apply small negative current tp increase negative membrane potential

depolarization

apply depolarizing current to decrease membrane potential towards neutrality

action potential

disproportionately large depolarization occurs when membrane reaches or exceeds the threshold of excitation- at this point the sodium channels open up

local anesthetic drugs

block sodium channels and therefore prevent action potentials from occuring

chemical communication

the synapse of the jucture between neurons

presynaptic neuron

the neuron that delivers ‘the message’ whoch is a chemical or neurotransmitter

postsynaptic neuron

the neuron that recieves ‘the message’- the chemical

synaptic cleft

the space in between across which the chemical travels

Neurotransmitters

are chemical substanes that a neuron uses to communicate information at the synapse

the “big 7” neuroteansmitters

Acetylcholine

Norepinephrine

Dopamine

Serotonin

GABA

Glutamate

endorphins

norepinephrine

discovered early- found outside as well as inside the brain

norepinephrine outside the brain

mediates the physical changes of emotional arousal

norepinephrine inside the brain

important in regular hunger, alertness and arousal

serotonin

important in regulating sleep

dopamine

regulates coordinated motor movements

monoamine dysregulation

is implicated in psychiatric disorders like depression and schizophrenia

endorphins

large molecules in the peptide family: functionally like morphine, heroine and other opitates, modulate pain relief

GABA (gamma aminobutyric acid)

among most abundant on known neurotransmitters on brain tissue and more significant inhibitory one: impedes neural firing

Glutamate

among most abundant of excitatory neurotransmitters; important in learning and memory processes

Anandamide

active chemicla in marijuana seems to mimic anandamide, a lipid