Pharmacology Exam 1

  1. Routes of Drug administration
    • Intravenous
    • Intramuscular
    • Dermal
    • Subcutaneous
    • Oral
    • Sublingual
    • Inhalation
  2. Advantages of Intravenous route
    • Fast
    • Bypasses absorption barriers
    • May give a larger volume of drug over a longer period of time
  3. Disadvantages of the Intravenous route
    • May not recall drug from circulation after administration
    • Drug may precipitate
    • Fast administration of the drug may cause an embolism
  4. Advantages of the intramuscular route
    • High blood supply to muscles
    • fast delivery of large quantities of drug
    • control of absorption
    • cold = slows absorption
    • oily vehicle slows absorption
    • enhanced absorption by rubbing area to increase blood flow
  5. Disadvantages of the Intramuscular route
    • Irritation
    • Damage from drug
  6. Advantages of the Dermal Route
    • May be removed easily
    • avoid GI tract
  7. Disadvantages
    • Poor absorption due to layers of skin
    • Skin irritation
    • Drug must be lipid soluble
  8. Advantages of the Subcutaneous route
    • Better blood supply than dermal = better absorption
    • enhanced absorption by dissolving subcutaneous connective tissue
  9. Advantages of the Oral route
    • most economic
    • convenient
    • no skilled health care provider to administer
  10. Disadvantages of the oral route
    • irritation to stomach
    • subject to 1st pass effect
  11. First Pass Effect
    Metabolism by the liver before circulation to the rest of the body
  12. Two major sites involved in Drug absorption
    • Stomach
    • Small Intestines
  13. Site of most absorption
    • Small Intestines
    • Larger surface area
    • more blood supply due to surface area
    • bile acids and salts secreted increase absorption of lipid soluble drugs
  14. Advantages of the sublingual route
    • high absorption due to blood supply
    • no first pass effect
  15. Disadvantages of sublingual route
    dosage form must be small
  16. Advantages of the inhalation route
    good absorption for gas or volatile drugs due to high surgace area and blood supply of alveoli
  17. Components of Biological Membranes
    • Lipid
    • Protein
    • Aqueous Channels/pores
  18. Mechanisms of crossing biological membranes
    • Passive Transfer
    • Specialized Transfer
  19. Passive Transfer
    • Simple diffusion
    • Filtration
  20. Specialized transport mechanisms
    • Facilitated Diffusion
    • Active Transport
  21. Simple diffusion of weak acids
    • May give up a proton
    • Unionized form may move into the cell
  22. Factors effecting the weak acid drug reaching equilibrium across a membrane
    • pH of side 1 and side 2
    • Ability of the drug to ionize
    • lipid solubility of the unionized form
  23. Henderson - Hasselbach Equation
  24. How can we make ionized drug unionized to cross the membrane?
    • Increase the reactants to increase the products A-+H+ <=> AH
    • Increase [H+] = decrease the pH
    • Manipulate the opposite side
    • Reduce [H+] on side 1 = increase the pH
    • AH on side 1 dissociates to compensate by releasing H+
    • AH is pulled from side 2 to make up for the loss, resulting in more AH formed on side 2 from A- and H+
  25. Facilitated Diffusion and Active Transport
    Utilize carrier proteins
  26. Carrier-Mediated Transport Mechanisms
    • Carriers are finite in number and may reach saturation
    • Carriers have specificity
  27. Facilitated Diffusion
    Carries drug down its concentration gradient
  28. Active Transport
    • Carries drug against its concentration gradient
    • Requires energy
  29. Full stomach when taking a medication
    food acts as a barrier to drug absorption
  30. Fatty meals with medication
    • prolonged gastric emptying time
    • food and drug stay in the stomach for a longer time
    • bile acids and salts are conducive to absorption of lipid soluble drugs
  31. Fiber and various metals
    • Contain positive and negative charges which may bind drug
    • forms chelate with drug
    • drug is not absorbed
  32. Liquids
    good for making tablets into a solution
  33. Effects of Aging on drug absorption
    • decreased GI secretions
    • decreased GI motility
    • decrease in blood flow to GI tract
    • decreased surface area of GI tract
    • decreased enterocytes
Card Set
Pharmacology Exam 1