Pharmacokinetics Applied to the Treatment of Asthma (PKA)


Workshop Outline
This problem-solving exercise introduces students to pharmacokinetics, a branch of pharmacology that provides a quantitative description of drug disposition. Pharmacokinetics defines the relationship between the dose of a drug and its concentration in various body compartments over time. In contrast, pharmacodynamics is concerned with the relationship between the dose of a drug and its pharmacologic action(s). Selecting the appropriate dose to achieve and maintain a desired therapeutic concentration in a patient depends on an understanding of these concepts.

Learning Goals for the PKA Workshop

  1. Distinguish between graded and quantal dose-response curves, and derive desired therapeutic drug concentrations from such curves.
  2. Explain what is meant by describing the body as a single or a series of multiple kinetic compartments, and distinguish between first-order and zero-order (saturation) kinetics.
  3. Define the following pharmacokinetic terms: half-life (t1/2), volume of distribution (Vd), and clearance (Cl). Explain how these parameters are related to each other.
  4. Calculate correct loading and maintenance doses to achieve and maintain drug levels in plasma within the therapeutic range.
  5. Apply the plateau principle to compute concentrations of drug in plasma during approach to plateau or steady-state.
  6. Define bioavailability. State the consequences of slow or delayed absorption of a drug on peak and trough concentrations during a dosing interval.