Pharm Block 1 (kinetics)

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Pharm Block 1 (kinetics)
2010-11-06 11:03:47
Pharm Block kinetics

Pharm Block 1 (kinetics
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  1. What is the formula for Loading dose?
    With will F be if it is an IV fluid?
    • Loading dose = (Vd)(Cp)
    • (F)

    - it is 100% absorbed into the blood stream so F=1

    • Vd= volume of distribution (amount in the body)
    • weight of man goes ontop
    • Cp= concentration in plasma (amount in the plasma)
    • PO= Loading dose
    • F= bioavaiability
  2. How many half lives for a drug to reach a steady state?

    What is the formula for Dosing rate?
    Formula for the Volume of distribution?
    Formula for therapeutic index?
    5 half lives

    Dosing rate = Css (plasma level) X CL (clearance) The amount in X the amount out

    Cd= dose / Cp

    TI= margin of safety= LD/ED
  3. What is Pka?
    What form crosses the Basement membran?
    it is the pH of a drug at which 1/2 is dissociated

  4. Clearance formula?

    What is formula for Infusion rate at steady state?
    CL= rate of elimination/ Cp

    Infustion rate= Cl X Cp
  5. Maintainance dose?

    Half life equation?
    Maintanance dose =Cp X CL X time / F

    T 1/2= .7/ Ke (elimination constant)

    Ke= CL/ Vd
  6. How much drug present at :

    1 half life?
    2 half lives?

    The time to reach steady state is dependent only on?
    • 50%
    • 75%

    Half life of drug
  7. Steady state equation?
    Css= Dose X F/ CL X Time
  8. what is the difference between zero order and 1st order kinetics?
    • Zero Order---
    • Constant Amount is eliminated per unit time
    • –When dose increases, the plasma concentration increases disproportionally
    • 1st order-
    • Constant % or fraction is eliminated per unit time
    • –When there is a high concentration of drug in the plasma, elimination is high
  9. Urine acidity effects on drug excretion
    –acidic urine: favors excretion of basic drugs

    –basic urine: favors excretion of acidic drugs
  10. the
    best predictor of intensity of drug activity ?