1What is pharmacokinetics? *important*
the study of drug movement throughout the body
includes drug metabolism and drug excretion
2What are the passage ways of drugs across membranes? (3)
1. Pass through channels or pores
2. Pass with the help or transport
3. Penetrate the membrane
3What is p-glycoprotein?
"uber driver"
transmembrane protein that transports a wide variety of drug out of cells
4How do drugs pass across membranes?
movement throughout the body is dependent on the drug's ability to penetrate membranes directly
most drugs are too large to pass through channels or pores
5What is a general rule in chemistry?
"like dissolves like"
a drug must be lipid soluble
6What is acid? *important*
a proton donor: tends to ionize in basic (alkaline) media
may change the drug
7What is base? *important*
a proton acceptor: tends to ionize in acidic media
8What is absorption? *important*
movement of a drug from its site of administration into the blood ***
rate of absoprtion determines how soon effects will begin
amount of absorption helps determine how intense the effects will be
9What are factors that affect drug absorption? (5)
rate of dissolution
surface area
blood flow
lipid solubility
pH partitioning
10Intravenous *important*
barriers to absorption -> none
absorption pattern -> intant absorption
advantages -> rapid onset
disadvantage -> can't take it back, irreversible, must be water soluble
11Intramuscular (1 inch-1 1/2 inch) *important*
barriers to absorption -> capillaries easy to pass
absorption pattern -> rapid w water soluble, slow w non-water soluble
advantages -> quicker, good for poorly soluble drugs
disadvantages -> needle fears, it hurts
12Subcutaneous (5/8ths) *important*
no significant barriers to absorption
13Oral *important*
barriers to absorption -> GI tract
absorption pattern -> slow
drug movement after absorption
advantages -> easy
disadvantages -> lot longer to work, NPO or can't swallow pills well
14Types of oral administrations
tablets -> chalky feeling, fast acting
enteric-coated preparations -> shiny outside, helps w/ stomach acid chemical issues
sustained-release preparations -> multi-colored balls inside, work at different times
15Additional routes of administrations *important*
topical -> creams
transdermal -> nicotine patches, nitroglycern
inhaled -> inhaler, flonaxe
rectal/ vaginal -> suppository
16What is distribution? **important**
movement of drugs throughout the body
17What is distribution determined by? (3)
blood flow to tissues
exiting the vascular system
entering cells
18How do drugs get to the tissues?
drugs are carried by the blood to tissues and organs of the body
blood flow determines the rate of delivery
19What do abscesses and tumors do to tissues?
low regional blood flow affects therapy
pus-filled pockets rather than internal blood vessels
solid tumors have a limited blood supply
20What is typical for capillary beds?
drugs pass between capillary cells rather than through them
capillarys are thin
21What is the blood-brain barrier?
tight junctions between the cells that comprise the walls of most capillaries in the central nervous system
drugs must be able to pass through the cells of the capillary wall
only drugs that are lipid soluble or that have a transport system can cross the blood-brain barrier to a significant degree
22What is placental drug transfer?
membranes of the placenta do NOT constitute an absolute barrier to the passage of drugs
movement is determined in the same way as it is for other membranes
23What are the risks with drug transfer?
birth defects: mental retardation, gross malformations, low birth weight
mother's use of habitual opioids: birth of drug-dependent baby
24Protein binding
drugs can form reversible bonds with various proteins
plasma albumin is the most abundant and important protein
large molecule that always remains in the blood stream
affects drug distribution
25Entering cells
some drugs must enter cells to reach the site of action
most drugs must enter cells to undergo metabolism and excretion
many drugs produce thera effects by binding with receptors on the external surface of the cell membrane
these do not need to cross the cell membrane to act
26What is drug metabolism?
also known as biotransformation
defined as the enzymatic alteration of drug structure
27Where does drug metabolism most often take place?
in the liver
may impact what meds you can take
28What should be considered with drug metabolism?
heptatic drug-metabolism enzymes (large group of enzymes to help w/ metabolism)
therapeutic consequences of drug metabolism
special considerations in drug metabolism
29What is the P450 system?
12 enzymes that are invovled with drug metabolism in the liver
most drug metabolism that takes place in the liver is performed by the hepatic microsomal enzyme system
metabolism does not always result in a smaller molecule
30What are the therapeutic consequences of drug metabolism?
accelerated renal drug excretion
drug inactivation
increased therapeutic action
activation of prodrugs
increased or decreased toxicity
31What are special considerations in drug metabolism?
age -> always have to think about
induction of drug-metabolizing enzymes
first-pass effect
nutritional status -> may need to eat b4 certain meds, can impact drug response
competition among drugs
32What is excretion? *important*
defined as the removal of drugs from the body
33What are factors that modify renal drug excretion?
pH-dependent ionization
competition for active tubular transport
age
34What are nonrenal routes of drug excretion?
breast milk
bile
enterohepatic recirculation
lungs
sweat/ saliva
35What is drug half-life? **important**
time required for the amount of the drug in the body to be decreased by 50% (generalization different for each person)
ex: morphine have 1/ 2 life 3 hours, 3 mg at 8am by 11 am 50% of morphine been decreased
36What is the therapeutic range? **important**
objective of drug dosing is to maintain plasma drug levels within the therapeutic range
need to monitor plasma ranges to know how much drug is in system