Problems related to Vd & LD

  Problem 01. A drug has a volume of distribution of 300 L in a 500 Kg horse.

  1. What is its Vd in L/Kg?

Problem 02. A drug has a volume of distribution of 0.3 L/Kg. [Student Question]

  1. What is the total Vd in a 15 Kg Beagle?
  2. What is the total Vd in a 40 pound Beagle?

Problem 03. A drug was given IV to a 70 Kg calf at a dose of 2.5 mg/Kg. Concentrations of drug in plasma were found to be the as follows (mg/L): 2 hr = 7.07; 4 hr = 5.00; 6 hr = 3.54; 8 hr = 2.50.

  1. What is the total dose?
  2. What is the Cp(0)?
  3. What is the Vd/Kg?
  4. What is the whole animal Vd?

 Problem 04. A drug was given IV to a 3 Kg cat at a dose of 5 mg/Kg. The resulting Cp(0) was 20 mg/L. The same dose of drug was given to the cat 1 month later by mouth and the animal had no significant change in weight or hydration status. The resulting Cp(0) was 17 mg/L. Assume both of these values were "correct." [Student Question]

  1. What is the approximate F?
  2. What formula did you use to calculate F?
  3. How does it compare to the approach described in class?

Problem 05. A drug was given IV to an animal that had an estimated Vd of 0.9 L/Kg. The dose was 4 mg/Kg.

  1. What is the estimated Cp(0)?
  2. What is the estimate of F?
  3. How does this Cp(0) correspond to the "A" in the one-compartment pharmacokinetic model?

Problem 06. A drug was given PO to an animal that had an estimated Vd of 0.6 L/Kg. The dose was 3 mg/Kg and the literature states the F for this drug give PO is 0.8.

Problem 07. You are treating a 25 pound terrier with a drug that has a Vd of 0.4 L/Kg and you want the concentration to be in the range of 15 mg/L.

Problem 08. You are treating a 15 Kg dog with a drug that has a Vd of 0.3 L/Kg, a PO F=0.6, and you want a Cp(0) of 10 mg/L.

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Last modified: 05 Sep 1996 18:39 glc