Pharmacokinetics

__________: 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