Kinetics and Dynamics

pharmacokinetics

what body does to drug

pharmacodynamics

what drug does to body

absorption

what happens to a drug from when it is introduced to body and until it reaches circulating fluids and tissues

distribution

the way the drug moves thru the bloodstream to its target organs

metabolism

breakdown of drug molecules

elimination

kidneys remove drug byproducts from the body

oral route

most frequently used

subcutaneous

injection into fat tissue

intramuscular

injections into muscle

intravenous

directly into blood stream (quickest effect)

first pass effect

inactivation of drugs in liver and intestines; drug concentration reduced before reaching circulation

parenteral injection

subcutaneous, intramuscular, intravenous

inhaled medication

allows for rapid absorption of drugs in gaseous, vaporized, or aerosol forms

protein binding

drugs bind to proteins in blood to get carried thru circulation to tissues; the more bound to the protein, the more difficult it is to get to the tissue

tightly bound drugs

released slowly and have longer duration

loosely bound drugs

act faster and are excreted quicker

blood brain barrier

protects brain and keeps harmful substances away from brain including drugs

lipid soluble drugs

more likely to pass through blood brain barrier and reach cns

not lipid soluble drugs

not able to pass through blood brain barrier

drug half life

time it takes for half of the medication to be eliminated from body

liver

most important site for metabolism

first pass effect

breakdown of oral drugs in the liver immediately after absorption

liver

breaks down the drugs and a portion of drug is destroyed and not transported into blood stream

hepatic enzyme P450

essential for metabolism of many medications

if drugs inhibit P450

other drugs may not metabolize and could build up to toxic levels

drug food interactions

drugs are best taken on an empty stomach

mechanism of action definition

how a medication functions within the body

ways of mechanism of action

replace missing chemicals, increase cellular activities, slow cellular activities, interfere with foreign cells

receptor sites

areas on cell membranes that react to certain drugs to cause an effect within the cell

agonist drugs

mimic ligan receptor activation responses

antagonist drugs

block the receptor’s activation response

drug drug interactions

can occur any time two or more drugs are taken together; increases client risk

potency

amount of drug required to produce therapeutic response

therapeutic response

intended response

side effects/adverse reaction

anticipated effects other than intended

serious adverse effects

unintended effect that causes harm, often requires discontinuation of medication