37 Questions
Which of the following is true about pharmacokinetics?
Pharmacokinetics is the study of how drugs move within the body.
What is the purpose of calculating pharmacokinetic properties?
To model how drugs move within the body.
What is the one compartment model in pharmacokinetics?
A model of the body as a single, homogenous vessel.
What is the rate of drug elimination in first order kinetics?
The rate of drug elimination is directly proportional to the concentration of drug.
What is the difference between first order and zero order kinetics?
In first order kinetics, the rate of metabolism is proportional to drug concentration, while in zero order kinetics, the rate of metabolism becomes independent of drug concentration.
What can happen in zero order kinetics?
Drug concentration can increase in the body, leading to potential toxic side effects.
What can be determined using the one compartment model in pharmacokinetics?
The volume of distribution of a drug.
Which one of these equations correctly represents the volume of distribution (Vd)?
Vd = amount drug body / [drug] plasma
What is the relationship between plasma concentration (Cp) and volume of distribution (Vd)?
High Vd - Accumulated in peripheral tissues, low plasma concentration
What is the equation to calculate the dose of a drug (D)?
Dose = Vd * [drug] plasma
What is the equation to calculate the volume of distribution (Vd)?
Vd = Dose / [drug] plasma
What is the equation to calculate the half-life (t1/2) of a drug?
t1/2 = 0.693 / k
What is the equation to calculate the half-life (t1/2) of a drug from a concentration-time graph?
t1/2 = (t2 - t1) / 0.693
What is the equation to calculate the initial concentration of drug in plasma (C0)?
C0 = Dose / Vd
Which formula can be used to calculate the half-life of a drug if the elimination rate constant (Kel) is known?
t1/2 = 0.693/Kel
What is the pharmacokinetic parameter that most significantly limits the time course of action of a drug?
Clearance
What is the formula to calculate the total clearance (Cl total) of a drug?
Cl total = Cl renal + Cl liver + Cl lungs
How can the clearance (Cl) of a drug be calculated using the elimination half-life (t1/2) and volume of distribution (Vd)?
Cl = (0.693/ t1/2 ) x Vd
What is the equilibrium point called where the amount of drug administered exactly replaces the amount of drug excreted?
Steady state
How can the steady state concentration (Css) be calculated?
Css = Bioavailability x Dose / Interval x Clearance
What is the loading dose formula to achieve a desired steady state plasma concentration (Css)?
Loading dose = Vd x desired Css
What is the formula to calculate the volume of distribution (Vd) of a drug if the dose (Dose) and initial plasma concentration (C0) are known?
Vd = Dose / C0
What is the relationship between the drug's half-life and the time required to reach steady state?
The shorter the half-life, the more rapidly steady state is reached
Which process in pharmacokinetics involves the transfer of the drug from its site of administration to the general circulation?
Absorption
What is the primary route of drug elimination in pharmacokinetics?
Urine
What is the equation to calculate the volume of distribution (Vd) of a drug?
Vd = Cl / Css
Which pharmacokinetic parameter most significantly limits the time course of action of a drug?
Half-life
What is the equation to calculate the loading dose of a drug to achieve a desired steady state plasma concentration (Css)?
Loading dose = Css x Vd
What is the difference between drugs with long and short half-lives?
Drugs with long half-lives have longer duration of action.
What is the equation to calculate the half-life (t1/2) of a drug from a concentration-time graph?
t1/2 = 0.693 / Kel
Which one of the following best describes the typical concentration-time curve for a drug with first order kinetics?
The concentration of the drug decreases exponentially over time.
What is the importance of zero order (saturation) kinetics?
Zero order kinetics allows for a constant rate of drug elimination.
How is volume of distribution defined in pharmacology?
Volume of distribution is the theoretical volume in which the drug is uniformly distributed.
What is clearance in pharmacology?
Clearance is the rate at which a drug is eliminated from the body.
How is half-life defined in pharmacology?
Half-life is the time it takes for the drug concentration to decrease by half.
What are the factors that determine the choice of dose, route, and frequency of drug administration?
Pharmacokinetic factors
What is the rationale for loading doses?
Loading doses are used to quickly achieve therapeutic drug levels.
Test your knowledge on volume of distribution, clearance, and half-life with this quiz. Learn about the relationship between drug concentration, dose, and the amount of drug in the body.
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