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57 Cards in this Set
- Front
- Back
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What is pharmacokinteics?
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the study of drug movement throughout the body or what the body does to a drug
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What is a drugs greastest barrier when trying to reach its target cells?
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the mucous membrane
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Oral drugs must cross what to enter the bloodstream?
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the plasma membranes of the mucosal cells of the GI tract and the capillary endothelial cells
a lot of the drug can be lost before the drug enters the bloodstream |
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Oral drugs must cross what to leave the bloodstream?
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cross capillary cells, travel through interstitial fluid and may also need to enter target cells which also have a cell membrane
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How can drugs given by the enteral route be broken down?
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stomach acid and digestive enzymes
enzymes in the liver and other organs phagocytes may attempt to remove the drug or trigger an immune response if the body views the drug as foreign |
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What is the ADME process?
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absorption
distribution metabolism excretion |
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How does the ability of a drug to cross plasma membranes effect how the body moves meds throughout it?
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meds that bind to proteins are less likely to move across membranes b/c they are so large
lipid soluble meds will quickly pass through the plasma membranes |
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What are the 2 processes drugs use to cross the plasma membrane?
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diffusion or passive transport- movemnt of a chemical from an area of higher concentration to an area of lower concentration
active transport- movement of a chemical against a concentration or electrochemical gradient |
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What is absorption?
How can drugs be absorbed? |
a process involving the movement of a substance from its site of administration, across body membranes, to circulating fluids
primary pharmacokinetic factor determining the length of time it takes a drug to produce its effect the more rapid the absorption the faster the onset of action across the skin and mucous membranes lining of the GI or respiratory tracts |
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How to get absoprtion faster?
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high doeses of meds are generally absorbed faster w/ a more rapid onset of action than those given in low concentrations
IV has the most rapid onset elixir or syrups are absorbed faster than tabs or caps |
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basic drugs are absorbed in environments and acidic drugs are absorbed in environments
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alkaline
acidic |
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What is distribution?
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involves the transport of pharmacologic agents throughout the body and is mostly influenced by the amount of blood flow to body tissues
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Which organs receive the most blood?
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heart, liver, kindeys and brain
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What is affinity and what are some tissues that would be affected?
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the ability to accumulate and store drugs after absorption
bone marrow, teeth, eyes and adipose tissue |
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What are drug-protein complexes?
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when drugs bind reversibly to plasma proteins (albumin)
too large to cross capillary membranes thus the drug is not available for distribution to body tissues drugs that are highly protein bound need to be administered more b/c they are to large to cross membranes |
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What does the blood-brain barrier and the fetal-placental barrier do?
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inhibit many chemicals and meds from entering
sedatives, anti anxiety agents and anti convulsants redily cross the blood-brain barrier to produce their actions on the CNS. most anti tumor drugs do not easily cross, making brain cancers difficult to treat fetal-placental barrier protects the unborn baby from harmful substances that could pass from the mother's bloodstream, potentially harming it |
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What is metabolism?
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biotransformation
is the process of chemically converting a drug to a form that is USUALLY more easily removed from the body |
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What is the primary site of metabolism?
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the liver though the kidneys and cells of the intestinal tract also have high metabolic rates
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What are conjugates?
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addition of side chains during metabolization that makes drugs more water soluble and more easily excreted by the kidneys
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What does the hepatic microsomal enzyme system do?
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inactivates drugs and accelerates their excretion
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What are prodrugs?
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drugs that have no pharmacological activity unless they are 1st metabolized to their active form by the body
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What is enzyme induction?
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ability to increase metabolic activity in the liver
a drug increases the rate of its own meabolism, requiring higher doese of meds to achieve optimal therapeutic effect |
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Enzyme induction is reduced in who?
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infants and the elderly
making these clients more sensitive to drug therapy than middle-aged clients |
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Which routes bypass the first-pass effects?
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sublingual, rectal, buccal or parenteral
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What is excretion?
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how drugs are removed from the body
the rate at which meds are excreted determines their concentration in the bloodstream and tissues which determines their duration of action |
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Which pts would have a increased duration of action?
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liver disease
renal disease/failure |
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What is the primary site of excretion?
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kidneys!
filter 180 L of blood/day free drugs, water-soluble agents, and small molecules are easily filtered at the glomerulus proteins (blood cells), and drug-protein complexes are not filtered due to their large size |
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What is the minimum effective concentration?
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the amount of drug required to produce a therapeutic range
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What is the toxic concentration?
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or the level of drug that will result in serious adverse effects
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What is the therapeutic range of a drug?
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the plasma drug concentration between the minimum effective concentration and the toxic concentration
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The most common description of a drug's duration of action is its..
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half life
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What is half life?
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the lenght of tiem required for the plasma concentration of a med to decrease in half after administration
the greater the half life the longer it takes a med to be excreted the shorter the half life the more often the drug must be taken |
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When is a plateau reached?
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when the level of drug is maintained continuously whithin the therapeutic range, resulting in equilibrium
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When does the amount of drug administered reach equilibrium?
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when repeated doses result in the accumulation of a drug that is equal to the amount of drug eliminated
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Theoretically it takes how many half lives to reach equilibrium?
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4 doses
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How can you reach a pleatu faster?
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by administering a loading dose
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What is a loading dose?
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is a higher amount of drug often given only once or twice that is administered to prime the bloodstream with a level sufficient to quickly induce a therapeutic response
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What are intermittent maintenance doses?
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given to keep the plasma drug concentration in the therapeutic range
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How are serum drug levels monitored?
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by drawing a lab specimen and measuring the level of drug in the serum
especially important for certain amnioglycoside antibiotics, digoxin and warfarin (blood thinner) |
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What is the trough level?
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point when the drug is at its lowest concentration and is drawn within the 30 min window before the next dose of drug
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What is the peak level?
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the highest plasma concentration and should be measured when the absoprtion of a dose is complete
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What is pharmacodynamics?
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the process by which drugs alter cell physiology and affect the body
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What is a frequency distribution curve?
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a graphical representation of the number of clients responding to a drug action at different doses
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What is a drug's median effective dose?
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the dose required to produce a specific therapeutic response in 50% of a group of patients
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What is the median lethal dose?
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is the dose of drug that will be lethal in 50% of a group of animals
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What is the therapeutic index?
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a ratio of a drugs median effective dose and its median lethal dose
the larger the index the greater the therapeutic index a measure of a drug's safety margin |
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What is the median toxicity dose?
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is the dose that will produce a given toxicity in 50% of a group of patients
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What is the graded-dose response relationship?
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measures a client's response to a drug at different dosages
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How can you compare drugs within the same therapeutic and pharmacologic class?
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potency and efficacy
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A drug that is more will produce a therapeutic effect at a lower dose, compared with a drug in the same class
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potent
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What is efficacy?
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the magnitude of maximal response that can be produced from a particular drug
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What are cellular receptors?
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cellular macromolecules to which medications bind to initiate its effect
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What are the types of drug-receptor interactions?
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agonist- a drug that produces the same type of response as the endogenous substance, sometimes prodcuing a greater maximal response than the endogenous chemical
partial-agonist- a drug that produces a weaker response than an agonist antagonist- a drug that will occupy a receptor and prevent the endogenous chemical from acting |
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What are adverse drug effects?
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undesirable effects other than the intended therapeutic effect
some are predictable and tolerable and some can be sever, warranting discontinuation of the drug |
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What is an idiosyncratic effect?
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any unusual response to a drug that may manifest itself by over-response, under response, or even opposite the expected response
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What is an antagonistic effect?
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the combined effect of 2 or more drugs acting simultaneously to produce an effect that is less than that of each drug alone
don't work well together |
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What is a synergistic effect?
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the combined effect of 2 or more drugs acting simultaneously to produce an effect that is greater than that of each drug alone
work better together |
