__________: the physiological movement of drugs within the body
Pharmacokinetics
Factors that influence blood levels of a drug (4)
Absorption, distribution, metabolism, excretion
Lypophilic means
loves fat
Hydrophilic means
loves water
__________: the random movement of drug molecules from an area of high concentration to an area of low concentration. (Requires no energy by the cell will continue until the concentrations in each area are equal)
Passive diffusion
3 drug characteristics with passive diffusion
small (CO2 O2..), lipophilic, non-ionic
__________: special "carrier molecule" in the cell membrane helps move certain drug molecules across the membrane (requires no energy by the cell, moves from high concentration to low until equilibrium)
Facilitated diffusion
__________: a special "carrier molecule" in the cell membrane that moves the drug across the membrane (require energy and can move drugs from areas of low concentrations to high and vice versa)
Active transport (goes against the concentration gradient)
__________: drug molecules are surrounded by part of the cell membrane and taken within the cell (requires energy and useful for large drug molecules proteins, insulin..)
Physical Transport
What are the two types of physical transport
Pinocytosis and phagocytosis
__________: type of physical transport that means cell drinking
Pinocytosis (smaller multiple drug molecules)
__________: type of physical transport that means cell eating
Phagocytosis (large drug molecule)
Name the fastest to slowest rate for type of drug distribution
Passive diffusion, facilitated diffusion and active transport, physical transport
Speed of drug movement across membranes depends on (5)
concentration gradient, molecule size (smaller=faster), how lipophilic molecule is (more lipophilic=faster), temperature (warmer=faster), thickness of membrane (thinner=faster)
ADME stands for
Absorption, distribution, metabolism (biotransformation), excretion
__________: movement of drug molecules from the site of administration to the bloodstream
Drug absorption
__________: amount of drug that actually reaches the bloodstream
Bioavailability
What way of administration can you get 100% absorption
IV (bioavailability=1, all other routes are <1)
What ways of administration do you get the lowest percent of absorption
Oral and SQ
4 types of drug movement across the membranes
Passive diffusion, facilitated diffusion, active transport, pinocytosis/phagocytosis (physical transport)
5 areas a drug can be absorbed
stomach, intestine, bloodstream, lung tissue, skin
__________: added to vaccines to make it stay in the injection spot longer (usually a mineral oil)
adjuvant
Extracellular fluid is primarily ...
water (drugs given SQ or IM must diffuse through the extracellular fluid to get to capillaries)
What type of drug must pass through cell membrane s of the GI tract to be absorbed?
Oral drugs
Lipophilic drugs are absorbed best ______
orally (hydrophilic drugs are poorly absorbed by GI tract)
Why are some hydrophilic drugs used orally on purpose?
Slower absorption in the intestineal lumen can be more effective
__________: have a net negative or positive charge, usually hydrophilic
Ionized (nonionized is usually lipophilic)
Each drug has a certain % that is ionized and non-ionized.... 1. charged= __________ and _________ 2. Uncharged = _________ and ________
1. ionized and hydrophilic
2. nonionized and lipophilic
__________: primarily nonionized in acidic environment and primarily ionized in alkaline enviroments
Acidic drugs ( AH= A- + H+.... acidic drugs want to give away their hydrogen ions)
__________: primarily nonionized in alkaline enivronment and primarily ionized in acidic environment
Alkaline (basic) drugs (B+H+= BH+)
__________: the pH where drug molecules are half ionized and half nonionized
pKA (each drug has a specific pKA)
Acidic drugs are primarily in __________ form at pH more acidic than its pKa
nonionized
Alkaline drugs are primarily ________ at pH more alkaline than its pKa
nonionized
__________: if the molecule changes to primarily hydrophilic form, it may not be able to cross a cell membrane
Ion trapping (important in drug excretion)
Different body compartments have different pH's. Inside cells and most fluids the pH is ______
7.4 (drugs can change from ionized to nonionized and vice versa with movement to a different compartment)
Blood has a more ________pH
alkaline
Absorption of drugs from fastest action to slowest ( options: SQ, IM, PO, IV)
IV, IM, SQ, PO
Onset of drug action depends on how fast the drug__________________
passes out of the stomach (lower gastric motility delays drug onset, while higher makes it speed up)
Amount of drug absorbed depends on how fast the drug moves through the __________
Intestines (more peristalsis =less absorption, less = more absorption)
__________: removes foreign substances and toxins from the blood
One liver function (all blood that leaves the intestines passes through the liver before it enters systemic circulation)
__________: extensive removal of the drug
first pass effect (liver's role)
__________: Body's ability to change the original drug into a form that can be eliminated, occurs primarily in the ________
Biotransformation, liver
__________: altered form of the drug after biotransformation
metabolite (usually inactive)
Good tissue perfusion (blood supply to a tissue) = _______
good absorption (more blood flow =good... exercised skeletal muscle)
Poor tissue perfusion= ____________
poor absorption (fat is poorest perfused tissue)
Cool temperature= vasoconstriction= __________
decreased absorption (lidocaine with epinephrine give SQ causes local vasoconstriction)
__________: the movement of a drug from the bloodstream into tissues (goal is to reach target tissues)
Drug distribution
Drug distribution depends on what 4 factors
Barriers, tissue perfusion, plasma protein binding, volume of distribution
Capillaries are ___ cell layer thick with ___ between them
one, gaps (except in the brain)
__________ (gaps in capillaries): Hydrophilic drugs move into the bloodstream by moving between capillary endothelial cells
Fenestrations (while lipophilic drugs pass through the cell membrane)
Blood brain barrier has ______ because of coating of _____ cells. Only _______ drugs may enter
Tight junctions, glial, lipophilic
Drugs move most rapidly and in greater concentrations to compartments with good tissue perfusion. Give 3 examples
Brain, liver, kidneys, exercised skeletal muscles
Drug delivery to poorly perfused tissue is delayed. Give 2 examples
Inactive skeletal muscle, adipose tissue
Some drugs like Albumin bind to large ______ in the bloodstream
proteins (others are free and able to pass out of the bloodstream into tissues )
Drugs that are bound to protein are_____
inactive
Highly protein bound drug=____ drug free to exert a therapeutic effect
less
Low plasma protein= ____ of the drug is free
more
What types of disease cause low plasma protien (3)
Liver, intestinal, and kidney disease ( dose of highly protein bound drugs should be reduced to avoid overdose.. barbiturates)
What two diseases cause high plasma protein
Neoplasm and corticosteroid excess