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2014-01-29 15:00:05
Vet Med

Module 4 - Infectious Agents - Pharmacokinetics
Show Answers:

  1. How do you work out the volume of distribution?
    Vd = total amount of drug / concentration of drug in plasma
  2. What is the approximate volume of distribution for a drug that is distributed in a) plasma b) ECF c) total body water d) more than total body water
    • a) 0.005l/kg
    • b) 0.2 l/kg
    • c) 0.55 l/kg
    • d) >1l/kg
  3. How do we work out a loading dose?
    Loding dose = Vd x Ceff
  4. What are some of the factors affecting volume of distribution?
    • Species
    • Age
    • Disease
  5. What are the two core metabolic processes?
    • Phase 1 reactions - functionalisation
    • Phase 2 reactions - conjugation
  6. What is the main function of metabolism?
    To increase the water solubility of a molecules to make it easier for them to be excreted.
  7. Some drugs can induce the synthesis of microsomal enzymes.  What are the results of this?
    • Increased metabolism
    • Can increase or decrease toxicity
  8. What are some of the factors that can affect metabolism?
    • Previous drug therapy
    • Age
    • Disease
    • Species
    • Inter-individual variation
  9. What is clearance?
    The efficiency of the irreversible elimination of a drug from the systemic circulation Or the volume of blood cleared of a drug per unit time
  10. What is zero order kinetics?
    When the concentration of a drug declines linearly over time
  11. What is first order kinetics?
    When the concentration of a drug declines exponentially with time
  12. What is Kabs?
    The rate constant for absorption
  13. What is Kexc?
    The rate constant for excretion
  14. What is Kmet?
    The rate constant for metabolism
  15. What is C(t)?
    The concentration at time 't'
  16. What is Cls?
    Total clearance of the drug
  17. What is half life?
    The amount of time required for a quantity to fall to half its value as measured at the beginning of the time period