Chapter 5 - Toxicokinetic Theory Flashcards
Which of the following statements is true?
A. Renal clearance is equal to urine formation.
B. hepatic clearance cannot exceed hepatic blood flow.
C. A process that increases free drug conc will decrease hepatic clearance and increase renal clearance.
D. Total body clearance equals dose divided by half-life.
B. hepatic clearance cannot exceed hepatic blood flow.
Systemic availability of an orally administered toxicant is dependent on…
A. Gastrointestinal absorption
B. intestinal mucosa
C. First-pass liver metabolism
D. All of the above
D. All of the above
A classic example of a drug inducing its own metabolism is…
A. Warfarin
B. Lovastatin
C. Carbamazepine
D. Theophylline
C. Carbamazepine
An example of a thermodynmic parameter used in physiologic toxicokinetic models is…
A. Tissue partition coefficient
B. alveolar ventilation rate
C. Cardiac output
D. Liver volume
A. Tissue partition coefficient
Fick’s Law of diffusion…
A. Is a zero order process
B. is a first order process
C. Applies to active transport
D. Requires energy
B. is a first order process
The method of predicting the toxicokinetic behavior of chemicals and drugs across species is called…
A. Monte Carlo simulation
B. benchmark kinetics
C. Allometric scaling
D. Linear regression kinetics
C. Allometric scaling
Which of the following is not theoretically possible?
A. Volume of distribution greater than volume of human body
B. volume of distribution equal to blood volume
C. Total clearance equal to renal clearance
D. Bioavailability (F) greater than zero
D. Bioavailability (F) greater than zero
A compartment in which uptake of xenobiotic is dependent on membrane permeability and total membrane area is called…
A. Perfusion limited
B. diffusion limited
C. Blood flow limited
D. Ventilation limited
B. diffusion limited
The alpha phase of an intravenously administered drug classically represents the…
A. Absorption phase
B. elimination phase
C. Dissolution phase
D. Distribution phase
D. Distribution phase
An advantage of a physiologic toxicokinetic model over a classic model is…
A. It may be able to predict tissue concentrations
B. it has only two compartments
C. The mathmatics are less complicated
D. It can give a better estimation of bioavailability
A. It may be able to predict tissue concentrations
The hepatic clearance of a drug with high hepatic extraction ratio is largely dependent on…
A. Drug protein binding
B. hepatic blood flow
C. Drug-metabolizing enzyme activity
D. Intestinal blood flow
B. hepatic blood flow
All of the following is true of saturation kinetics with increasing dose except…
A. Clearance must decrease
B. Half-life can increase or decrease
C. Volume of distribution will decrease if there is saturation of serum protein binding
D. Volume of distribution will decrease if there is saturation of tissue binding
C. Volume of distribution will decrease if there is saturation of serum protein binding
All of the following are true of nonlinear kinetics except…
A. Ratio of metabolites will remain constant with change in dose
B. Clearance will change with change in dose
C. AUC will not be dose proportional
D. Decline of xenobiotic is nonexponential
A. Ratio of metabolites will remain constant with change in dose
All of the following are true of first-order kinetics except…
A. Steady state concentration is proportional to rate of intake
B. Rate of intake will not change time to steady state
C. Half-life is inversely proportional to clearance
D. A change in half-life will not change time to steady state.
D. A change in half-life will not change time to steady state.
All of the following are true of first-order kinetics except…
A. The elimination rate constant increases with increasing dose.
B. A semilogarithimic plot of plasma concentration versus time yields a single straight line
C. The conc. of xenobiotic in plasma decreases by a constant fraction of time
D. The volume of distribution is independent of dose.
A. The elimination rate constant increases with increasing dose.
