Pharmacology Exam I part 2

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Pharmacology Exam I part 2
2013-09-16 00:14:46

part 2
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  1. KOW
    octanl; water partitioning coefficent that tels you how lipid soluble a chemical is, the drug is added to water and octanol and is then measured to see how much is in the water or octanol phase
  2. octanol
    a surrogate for fat
  3. Log KOW is 1
    drug is water soluble
  4. Log KOW is 10
    the drug is lipid soluble
  5. Most drugs have a KOW of?
    log KOW of 1-4; most drugs are not lipid soluble because if it was lipid soluble then it would go to the fat which is distributed to the whole body
  6. Ibuprofen with a pH 1 has a log KOW of? ph 7?
    • pH 1 log KOW: 3-4
    • pH 7 log KOW: <1
  7. charge equates the
    lipid solubility fo the drugs
  8. Bioavailable drug
    the amount of drugs that reaches blood stream; ex. propanolol ~20% Bioavailable dose of propanol
  9. Passive diffusion
    route that most drugs take; some drugs are so small they can diffuse through nuclear pores such as ethanol
  10. Henderson-Hasselbalch equations
  11. Benzoic acid
    pH 1 then 99.9% of it is neutral/nonionized form so it will absorb easily in acidic environment (stomach)
  12. Absorption in lungs (asthma)
    does not take long because doesn't need to diffuse 100% of what is inhaled goes into the body
  13. Absorption through the skin
    most drugs can't penetrate into the blood by the skin
  14. Factors affecting absorption
    EDTA or co-solvents can increase absorption
  15. 3 factors limiting absorption
    GI motility (are you eating? is your stomach active?), blood flow, and gastric emptying
  16. GI motility example
    you take a drug and then you eat something, the food will push the drug to the small intestine therefore the drug won't work
  17. Surface area can also limit absorption because
    the intestines contain many folds (everyone has different number of folds in the intestine)
  18. Why do people have to sometimes take food siwth drugs?
    to prevent ulcers
  19. Volume of distribution (VOD)
    measure of how widely distributed a drug is in the body. this measure tells us where the drug goes
  20. VOD equation
    dose/[] in plasma ; we usually don't want a drug to distribute all over the body
  21. Drugs can be stored in:
    plasma proteins (esp. albumin protein), liver and kidney, bone, fat and hydrophobic components
  22. Drugs bound to albumin
    increases the residence time in plasma
  23. Drugs unbound to albumin
    goes to the liver and tissues
  24. Cmax depends on
    absorption, distribution, metabolism, and excretion
  25. Kidney
    recieves 25% of CO and some drugs can be actively secreted into glomerulus into tubules
  26. Feces
    biliary excretion
  27. First-pass metabolism
    when the drug goes from the large intestine back to the liver through the portal vein
  28. Enterohepatic circulation
    drug being reabsorbed in liver (ex. birth control drug); we are not able to control it but it is important to be aware of it
  29. What is a good VOD?
    the smaller the VOD the better. usually durgs are less than or equal to 3 are good. if the VOD value is closer to the value fo the plasma concentration the drug is more effective
  30. Drugs that have a VOD less than or equal to 3
    heparin and insulin
  31. Drugs that have a VOD greater than 20
    diazepam (valium) and ethanol (vod of 40-50)
  32. Why does ethanol distribute so well?
    it is so small so it has the ability to travel through pores
  33. Distribution
    blood flow and solubility
  34. Most profused organs
    brain, liver, kidneys, lungs and heart
  35. Metabolism
    generally happens int he liver but many other tissues are also metabolic
  36. Liver metabolism
    detoxification and bioactivation
  37. The two stages of metabolism
    Phase I and Phase II
  38. Phase I of metabolism
    oxidation, reduction, hydrolysis; most drugs go through this phase to make it more reactive
  39. Phase II of metabolism
    conjugation enzymes; phase II is to make drugs more water soluble to be eliminated easily
  40. Phase I enzymes
    alcohol dehydrogenase
  41. Cytochrom P450
    superfamily (there are subgroups such as CYP450 1 and CYP450 2) of heme containing proteins; contained in the endoplasmic reticulum
  42. Induction causes enzymatic activity to increase or decrease?
  43. Scenario: if drug A induces CYP450 1 and drug B is metabolized by CYP450 1 then what effect will this cause?
    if they are taken together drug B will be metabolized faster so the therapeutic affects of it are shorter
  44. Inhibition causes enzymatic activity to increase or decrease?
  45. Scenario: if drug A inhibits CYP450 1 and drug B is metabolized by CYP450 1 then what effect will this cause?
    if they are taken together then drug B cannot be metabolized which increases half life of body