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58 Cards in this Set
- Front
- Back
________ describes how a drug gets to the site of action
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Pharmacokinetics
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the amount of drug in the body at any given time is determined by five processes:
(LADME) |
- L - liberation (release from pill)
- A - Absorptioin - D - Distribution - M - metabolism (biotransformation) - E - Elimination or Excretion |
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most drugs are absorbed through
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passive diffusion
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cell membranes act as a lipid barrier and allow ________ drugs to penetrate cell membranes more easily by diffusion. Drugs that are ________ do not diffuse easily in the lipid lyaer and either pass through aqueous pores or are prevented from entering the cell and thus are contained outside
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- lipid-soluble (lipophilic)
- water-soluble (hydrophilic) |
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Factors that affect absorption include:
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- blood flow
- lipid soluble - salt form of drug - food and other drugs |
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only _________ lipid soluble drugs will be absorbed acros cell membrane of tissues
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- nonionized (uncharged)
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How much of the drug changes to the ionized form will depend on the ______ of the drug and the _____ of the solution.
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- pKa
- pH |
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the _____ refers to the concentration of the H+ ions and the ____ of a drug is related to the equilibrium that the drug has with its ionized form and is the pH at which the drug is ____% ionized and is a constant value
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- ph
- pKa - 50% |
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Generally the pKa of a weak acid is ____ and weak bases is _____
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- 3-5
- 8-10 |
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If a local tissue pH is more alkaline and closer to pKa values of drugs, onset of action is
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faster
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Inflammation = ______ tissue environment
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acidic
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Drugs with extensive first pass metabolism and low bioavailability include
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- morphine
- lidocaine - Nitroglycerin |
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________ is the disappearance of active drug from bloodstream or body
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Elimination
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_________ is the elimination through kidneys and out of body in urine
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Excretion
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The most common excretion route
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kidney
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Two major routes of Elimination:
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- Excretion
- Biotransformation |
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the ______ is the primary site for biotransformation
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liver
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________ are drugs when orally administered they are inactive, but become active after biotransformation in the liver
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prodrugs
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Example of prodrugs include:
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- Levodopa (for parkinson's disease)
- Benazepril (Lotensin; antihypertensive drug) - Losartan (Cozar) |
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Biotransformation consist of ____ phases:
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- 2
- Phase I - involves enzymes in biotransformation (changes) of drugs - Phase II - Drug or metabolite from phase I is conjugated or linked with highly water soluble compounds such as glucuronic acid to make it more water soluble so that it can be excreted |
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_______ is the most common enzyme that metabolizes many drugs used in dentistry
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CYP3A4
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_______ enzyme metabolizes codeine, fluoxetine (prozac), and propanolol (heart medication)
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CYP2D6
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_______ enzyme metabolizes ibuprofen (advil)
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CYP2C9
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a _________ is the drug being metabolized
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substrate
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Clarithromycin (biaxin) is metabolized by
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CYP3A4
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some drugs are excreted in the bile by a process called
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biliary excretion
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__________ is the recycling of drugs and other substances by circulation of bile through intestine and liver
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enterohepatic recirculation
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______ is the time it takes for the concentration of the drug in the blood to fall to half (50%) of its original value
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Half-life (t 1/2)
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It takes about ____ half lives for a drug to be "considered" eliminated from the body
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4-5
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________ is the rate at which and the extent to which a drug is absorbed into the sytemic circulation
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bioavailability
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Most drug elimination follows ____ order of Kinetics
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first
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_______ means that the rate of drug elimination is equivalent to the drug concentration in the blood
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First order Kinetics
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__________ means that if drug elimination mechanisms become saturated a drug may exhibit zero order elimination because elimination of drug is at a constant rate and not dependent upon its concentration
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- zero order kinetics
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_______ is a large high dose of a drug given initially to rapidly establish a therapeutic plasma drug concentration
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Loading dose
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_________ is a lower dose used to maintain a desired drug level
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maintain dose
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________ is the concentration of the drug in the plasma between the MEC and the toxic concentration
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Therapeutic range
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_______ is the capacity of the body to remove a drug
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Drug clearance
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________ are the actions a drug has on the body and the mechanisms of action of the drug
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Pharmacodynamics
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Quantity of drug administerd is the
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drug dose
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_________ describes the response (what the drug does) and explains how the drug causes that response
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Drug response
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______ refers to the response of living matter to administered chemicals
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Drug action
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The site where such drug attachment takes place is termed the _______ and is regarded as being specific cell molecules
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receptor
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_______ will bind either a drug that is administered into the body or an endogenous substance
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receptor
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Receptors for hormones and neurotransmitters include
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- Adrenergic receptors
- muscarinic receptors - nicotinic receptors - insulin receptors - histamine receptors |
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Membrane transport proteins include
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- ion channels
- transporters for neurotransmitters |
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Enzyme receptors include
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- cyclooxygenase
- carbonic anhydrase - DNA polymers - human immunodeficiency virus (HIV) protease - Tyrosine kinase (for insulin) |
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a _______ is a drug that rapidly combines with a receptor to initiate a response an rapidly dissociates or releases from the receptor
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agonist
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most drugs used today are
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agonist
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a _____ is a drug that binds to the receptor but does no dissociate and has not positive response and no efficacy. It blocks the reaction of an agonist
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antagonist
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a _______ is a drug that slowly binds to the receptor and produces a mild therapeutic response when administered alone, but may inhibit the action of an agonist when given concurrently, acting like and antagonist
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partial agonist
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______ is the dose or amount of a drug required to produce a particular or specific biologic effect relative to a given or implied standard of reference
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Potency
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_____ is the ability of a drug to produce a therapeutic effect regardless of the dose.
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Efficacy
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_______ is observing and measuring the patient's response obtained at different doses of the drug
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Graded dose
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_______ is the drug dose that produces 50% of the maximum possible response
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Effective Dose (ED50)
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______ is the ratio of a drug's toxic dose to its therapeutic dose
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Therapeutic index (TI)
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_______ is the drug dose at which 50% of the animals die
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Lethal dose (LD50)
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TI = _________
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LD50
____ ED50 |
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True or False
A "safe" drug will have a high TI of generally at least 10 |
True
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