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76 Cards in this Set
- Front
- Back
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The study of drug movement throughout the body involving four processes: Metabolism, excretion, distribution & absorbtion.
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Pharmokinetics
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Defined as the movement of a drug from its site of administration into the blood.
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Absorption
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Defined as drug movement of drugs throughout the body, from the blood to
the "INTERSTIAL" space of tissues & from there into the cells. |
Distribution
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Defined as "ENZYMATICALLY" mediated alterations of drug structure (AKA biotransformation) most of which takes place in the liver.
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Metabolism
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Defined as the movment of drugs & their metablolites from out of the body.
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Excretion
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The combined definition of both metabolism & excretion.
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Elmination
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Channels or Pores, a transport system, or direct penetration are one of three ways that do what to a cell membrane?
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Cross a cell membrane
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Compounds with the capacity to cross membranes via channels would include these two small ions.
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Sodium & Potasium
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Carries that can move drugs from one side of the cell membrane to the other. Examples would be certain oral drugs, plus renal excreation would be slow w/out them.
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Transport Systems
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A.K.A. Multidrug transporter protein, which is a transmembrane protein that transports a wide variety of drugs "OUT" of cells.
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P-Glycoprotein
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This requires that a drug to be lipid soluble in order to cross the cell membrane.
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Direct Penetration
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Molecules with an uneven distribution of electric charge (i.e. they have no "NET" charge). This is due to the fact that they have an equal number of protons & electrons, resulting in positive & negative charges that balance each other out.
They are not lipid soluble and can't penetrate the cell membrane. |
Polar Molecules
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Molecules that "DO" bear a net charge that's either positive or negative; but are unable to cross membranes.
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Ions
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Molecules that contain at least one atom of nitrogen & carry a positive charge at all times.
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Quanternary Ammonium Compounds
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Defined as a compound that gives up a hydrogen ion (i.e. proton donor).
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Acid
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The conversion of an acid to a base or vice versa is known as this...
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Ionization
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Whether a weak acid or base carries a charge is determined by the pH of the surrounding media. The ionization of drugs depends on this.
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pH Dependant Ionization
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The process whereby a drug "accumulates" on the side of a membrane where the pH most favors its ionization is referred to as this.
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Ion Trapping
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The characteristic of absorption that determines how "SOON" effects will begin.
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Rate
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The characteristic of absorption that determines how "INTENSE" effects will be.
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Amount
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This is the rate at which a drug helps determine the rate of absorption.
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Rate of Dissolution
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A major determinant of the rate of absorption. The larger this is, the faster absorption will be.
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Surface Area
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Drugs are absorbed most rapidly from sites where this is high.
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Blood Flow
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Drugs of this nature that effect absorption are drugs that can readily cross the membrane which seperates them from the blood.
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Lipid Solubility
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Absorption will be enhancesd when the difference between the pH of plasma & the pH at the site of administration is such that drug molecules will have a greater tendency to be ionized in the plasma.
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pH Partitioning
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The literal definition is "Outside the GI tract". The term in of itself is used to mean injection.
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Injection
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Route of Administration that's both instantaneous & complete. Has no barriers to absorption, resulting in rapid onset of action. Permits precise control over the amount of the drug, which enables the use of large volumes of fluid. Because of the irritant properties of some drugs, the route must be used.
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IV
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The only barrier to this route of absorption is the capillary wall. Rate of absorption is determined by water solubility & blood flow at site of injection. Advantage is for use of parenteral administration of poorly soluble drugs. Disadvantage are discomfort & inconvenience.
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IM
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This route of absorption generally has the same advantages & disadvantages of IM injections.
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subQ
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The literal translation is, "Outside the GI-tract", commonly used to mean by injection.
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Parenteral
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With regards to distribution, the rate at which drugs are delivered to a particular tissue is determined by this.
Abscesses don't have this & solid tumors have a limited supply of this, whereby being resistant to drug therapy. |
Blood Flow to tissues.
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After a drug has been delivered by via the blood, the next step is to exit this system, which is necessary for drugs to undergo metabolism & excretion. Drugs exit this system via the capillary beds.
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Vascular System
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Drugs ****between capillaries, rather than through them.
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Pass
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Only drugs that have these two attributes can cross the blood brain barrier.
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Lipid Soluble & Transport system.
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Drug preparations are considered this if they contain the same amount of chemical compound
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Chemically Equivalant
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Preparations are considered equal if the drug they contain, is absorbed at the same rate & to the same extent.
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Bioavailability
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This is a mixture of a drug plus binders & fillers, all of which have been compressed together.
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Tablet
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Preparatons that consist of drugs that have been covered with a material designed to dissolve in the intestinge but not the stomach. Protects the drug from pepsin & gastric discomfort.
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Enteric Coating
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Preparations involving capsules that are filled with tiny spheres that contain the actual drug, which dissolve at various rates. They also permit reduction in the number of daily doses.
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Sustained Release
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Refers to the unique anatomy of capillaries in the CNS. Only drugs that are lipid soluble & have a transport system can pass through here.
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Blood Brain Barrier
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A transport molecule that that pumps a variety of drugs out of cells & back into the blood.
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P-glycoprotein
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Of all the proteins to which drugs can bind, this is the most important, being the most abundant in plasma.
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Plasma Albumin
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Binding between albumin & drugs is .... As a result, a drug may exist either bound or unbound.
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Reversible
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Regarding protein binding, drugs molecules that are this can leave the vascular system, whereas the other kind are too big to do so. Overall, this influences distribution.
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Unbound/Bound
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Mos drug metabolism takes place here in this organ, performed by the microsomal enzyme system.
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Liver.
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Another name for the microsomal enzyme system, which refers to cytochrome ...., consisting of a group of 12 closely related enzyme families.
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P450 system.
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The most important consequence of drug metabolism in which the kidney converts lipid-soluble drugs into more polar (ie. less soluble) compounds, making it possible for the kidneys to excrete many drugs.
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Accelerated Renal Drug Excreation
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The consequence where drug metabolism can convert pharmacologically active compounds to inactive forms.
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Drug Inactivation
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The consequence where metabolism can increase the effectiveness of some drugs.
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Increased Therapeutic Action
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A compound that is pharmocologically inactive as administered & then undergoes conversion to its active form within the body.
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Prodrug
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By converting drugs into inactive forms, metabolism can decrease this. Conversly, metabolism can increase this by converting safe compound to being potentiall harmful.
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Toxicity
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Due to this factor which influences drug metabolism, the drug-metabolizing capacity of infants is limited , because the liver doesn't develop its full capacity until about 1 year after birth.
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Age
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The process of stimulating enzyme synthesis during drug-metabolism, having two consequences. 1st, drug can increase rate of own metabolism, necessitating drug dosage increase. 2nd, can necessitate metabolism of other drugs used concerently.
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Induction
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Refers to the rapid hepatic inactivation of certain oral drugs. If the capacity of the liver to metabolize a is extemely high, the drug can be inactivate the first time through.
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First-Pass Effect
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The status influencing hepatic drug-metabolism enzymes, requiring a number of cofactors, that may be deficient in the malnourished.
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Nutritional Status
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When two drugs are metabolized by the same metabolic pathway & compete for metabolism, thereby decreasing the rate.
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Competition Between Drugs
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The step in excretion where renal excretion begins at the glomerulus of the kidney tubule. This process moves drugs from the blood into the tubular urine.
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Glomular Filtration
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The step in renal excretion where lipid-soluble drugs move back into the blood, whereas polar molecules remain in the urine.
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Passive Reabsorbtion
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Active transport systems within the kidney tubules that pump drugs from the blood vessles to the tubular urine. These tubular pumps for organic acids & bases move drugs from the blood to the urine.
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Active Tubular Secretions
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By manipulating urinary pH in such a way as to promote ionization of a drug, we can decrease passiver reabsorption back into the & thereby hasten the drug's elimination (i.e. useful in poisining)
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pH-Dependent Ionization
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An important route of excretion for certain drugs which is secreted into the small intestines & leaves the body in the feces.
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Bile
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Defined as the plasma drug level below with therapeutic effects will not occur.
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Minimum Effective Concentraion
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The plasma level at which toxic effects begin when toxic levels climb too high.
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Toxic Concentration
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The range of the plasma drug levels, falling between the MEC & the toxic concentration.
The objective of drug dosing is maintain plasma levels within this range. |
Therapeutic Range
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Defined as the "TIME" required for the amount of a drug in the body to decrease by 50% regardless of that amount in the body. 50% will leave the body at a specified time. It also determines the dosing interval.
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Half-Life
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This shows how plasma drug levels change over time after one dose. Drug levels simply go up & undergo absorption. They then come down & undergo excretion. (i.e. what time course)
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Single-Dose
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Administrating repeated doses will cause a drug to build up until a steady level is achieved, in which the amount of drug eliminated equals between the amount administered.
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Plateu
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When a drug is administered repeatedly in the same dose, plateau will be reached in this many half-lifes.
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Four
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The concentration where this must be kept below toxic concentration & the trough must be kept above the MEC.
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Peak
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The concentration where drug levels are at their lowest.
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Trough Concentration
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A technique used to reduce drug level fluctuations where plasma levels are kept nearly constant.
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Continuous Infusion
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A technique used to reduce drug level fluctuations, which releases the drug slowly & steadily.
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Depot Preparation
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A technique used to reduce drug level fluctuations, thats used to reduce both the size of each dose & the dosing ....., keeping the total daily dose constant.
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Interval
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A large initial dose that used when a plateau must be achieved mor quickly.
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Loading Dose
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The percentage of a drug in the body that will be eliminated over an interval equal to about four half-lives, when drug administration is discontinued.
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94%
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Drugs that have this type of therapeutic range, take longer to leave the body
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Narrow.
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