Pharm exam 1

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Pharm exam 1
2012-02-01 02:22:53
Pharm exam

Pharm exam 1
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  1. what is frist pass metabolism
    loosing some of the drug due the metabolism that takes place in the liver as there are vessels from the GI tract going directly to the hepatic portal system
  2. a durg has a first pass metabolism of 60:40 what does it mean
    1- that if 100g of the drug is given orally only 40g of it will actually be available to exert an effect

    2- seems high so might want another way to administer the drug than orally
  3. what's the benefit of administering a drug sublingual?
    protects from hepatic first pass meatbolism
  4. whats the advantage of administering a drug rectally
    • 1- decreased hepatic first pass metabolism
    • 2- good for patients that are unconscious or vomitting
  5. what are the disadvantage of administering a drug rectally
    • 1- absorption is irregular and incomplete
    • 2- irritation of the rectal mucosa
    • 3- diarrhea
  6. what are the 5 parenteral administration
    • 1- intravenous
    • 2- subcutaneous
    • 3- intramuscular
    • 4- intra -arterial
    • 5- intrathecal
  7. intramuscular injection is given mostly to
    the deltoid
  8. which of the route of administration has the fastest absorption
    intramuscular injection
  9. ice increases the absoption of a drug given intramuscularly
    • FALSE - it slows it down
    • exercise or hot bath increases absorption
  10. advantages of intramuscular absorption
    • 1- rapid absorption
    • 2- slow constant absorption
  11. disadvantage of intramuscular absorption
    • 1- big volumes
    • 2- irritation, paraesthesia (burning)
    • 3- accidental intravenous
    • 4- cost - trained people
  12. advantage of intravenous administration
    • 1- bioavailability
    • 2- drug delivery is controled, accurate and immediate
    • 3- big volumes - wont' irritate like it can when given intramuscularly
  13. disadvantages of intravenous administration
    • 1- unfavorable reaction - high concentration of drug is rapidly attained in the plasma
    • 2- bolus injection - smaller administration is advisable
    • 3- requires close monitoring of patients response - done at hospital
    • 4- once drug is injected there is no retreat - no going back
  14. vaccines are usually given subcutaneously
  15. advantage of subcutaneous administration
    • 1- slow and constant absorption
    • 2- control the period over which the drug is absorbed
  16. disadvantage of subcutaneous administration
    • 1- irritation, pain, necrosis
    • 2- small volume can be given - 2mL
  17. advantages of an inhaled administration
    • 1- instantaneous absorption
    • 2- avoides heptaic first pass loss
    • 3- pulmonary disease - local applicaiton
  18. disadvantage of inhalation of drugs
    1- local and systemic reactions to allergens
  19. why will topical applicaiton into the eye results in higher absorbance?
    increases blood supply
  20. advnantage of topical applicaiton (transdermal, mucous membrane - eye, ear)
    • 1- rapid absorbance b/c of increased blood supply
    • 2- local and systemic effects
  21. disadvantages of topical applicaiton
    • 1- intact skin forms a lipid barrier - ability to be absorbed through the skin depends on the drug
    • 2- absorbance depends on blood flow
  22. pharmacokinetics involves
    absorption - distribution/ metabolization - excretion

    the properties of the drug (size, solubiliyt, charge) molecule will affect all of these
  23. glycocalyx
    hydrosoluble - top part of the membrane
  24. what does an oil water partition coefficient of 1 mean? and what does a high oil water partition coefficient mean?
    that the drug will cross membrane easily - probably from high conc to lower

    a high oil water partition coefficient means that little drug will pass the cell membrnae b/c won't be soluble in the hydrophilic part
  25. facilitated diffusion is a form of active process
    • FALSE its a form of a passive process
    • a carrier mediated transport process where there is NO INPUT OF ENERGY! - ion channel for ex
  26. what is the most common membrane transport mechanism
    passive diffusion
  27. most of the drugs are weak acids
  28. what form of the drug is able to cross the membrane
    the non dissociated form HA
  29. Where do you expect to see more of the CHARGED form of a weak acid durg in a neurtral, acidic adn basic environments
    • neutral - same
    • acidic - intracellul
    • basic - extracellul
  30. where would you expec to see more of the NONCHARGED form of a weak acid drug in an nerutral, acidic, basic environment
    • neutral - same
    • acidic - extracellular
    • basic - intracellular
  31. where is the rate of absorbance for an acidic drug the greates
    stomach - in an acidic environment - more of the drug will be in the noncharged form
  32. where is the rate of absorbance greatest for basic drugs
  33. the slower the drug absrobance the shorter the drug works
    FALSE - the slower the drug is absorbed teh longer it has to work
  34. in the stomach the absorption of
    a drug in teh acidic form of the weak acid will be
    a drug in the basic form of the weak base will be
    • intracellulary
    • extracellulary
  35. pinocytosis
    a form of facilitated diffusion (no energy!)
  36. ionized from is the most common type of drug action
  37. Drugs that use active diffusion are
    those that mainly work on the CNS
  38. absorption is influenced most importatbly by the 3
    • 1- size of particle
    • 2- oil/water partition oefficient
    • 3- pH of environment
  39. distributuion of a drug depends on
    • 1- the drug phsiochemical properties
    • 2- caridac output and regional blood flow (location of affect)
    • 3- capillary permeability
    • 4- tissue volume
  40. why does a basic drug have more residual affect than an acidic drug
    bc in comparign tissue vs blood - the blood is more basic so the basic drug will tend to stay in teh tissue - just a bit

    an acidic drug will have a slight higher concentration in the blood
  41. absorption vs. distribution are dependent on what pH levels
    • absorption - stomach vs gastri pH
    • distribution - blood vs tissue pH
  42. ampicillin has a 30% affinity for plamsa protein, if I administer 100g of the drug how much of the drug is free drug
  43. I take penicillin which has 70% affinity for plasma protiens and now I start taking diclofenac which has a 90% affinity to plasma protiens - should I modify the dosage of penicillin
    yes, b/c more of it will be available now that a higher affinity bond with the plasma proteins will be made with diclofenac
  44. when a drug binds to tissues it decreases its
    elimination as it won't get metabolized
  45. what kind of drug is needed to cross the CNS
    very liposoluble b/c of the myelin but also capable of reaching the membrnae that is hydrophilic
  46. why does ion trapping of basic drugs occurs in fetus plasma
    b/c it's more acidic!
  47. 4 drugs toxic to the fetus
    • 1- thalidomide - teratogen
    • 2- anticoagulants - bleeding
    • 3- tetracycline - stian
    • 4- sulfonamide - neonatal jaundice
  48. excretion of a lipid soluble drug involves
    • 1- inactivating the drug
    • 2- making it more hydrosoluble so will get exreted in urine
  49. elderly and elimination of drugs
    kidney works only 50% of it's capacity so less fluid will be filtrated which compromise the elimination of drugs
  50. eliminatin of a drug is dependent on ___ of the urine
    • pH
    • most acidic drugs get eliminated in basic urine
    • taking a drug that makes the urine too basic will lead to faster elimination
    • taking drug/food that makes the urine more acidic teh acidic drug will get eliminated less
  51. what is the active ingredient in aspirin
    salicylate - very acidic!
  52. if there is an overdoes of aspirin what shall you do
    administer sodium bicarbonate to make the urine basic and facilitate excretion!
  53. which substances are exreted biliary
    • fecal!
    • 1- unabsorbed orally ingested
    • 2- metabolites excreted in bile
    • 3- drug metabolites secreted direcly into the intestinal tract and did not get reabsorbed
    • 4- high molecular weight substances >500
    • - some drugs aren't design to be absrobed - cholesterol drugs
  54. the concetnration of some drugs in saliva is related to drug levels in the plamsa
  55. what's impo when breast feeding
    caution when taking basic drugs b/c breast milk is more acidic than plamsa and might ahve more basic compunds concentrated