Pharmacokinetics Flashcards
Learn terms
Volume of distribution
Ratio of amount of drug in the body to the drug concentration in the plasma or blood(liters)
Clearance
Ratio of rate of elimination of a drug to the concentration of the drug in blood or plasma(volume/time) or mL/min
Half life(time)
Time required for the amount of drug in the body or blood to fall by 50 pc,drugs eliminated by first order kinetics this number is constant.
Bioavailability
Fraction of drugs reaching the systemic circulation
Minimum effective concentration
Plasma drug conc below which the person’s response is too small for clinical benefit
First pass effect
The elimination of drug occurring after it’s administered but before it’s passage into systemic circulation(gut wall,portal circulation and liver)
Steady state
The condition in which avg total amount of drug doesn’t change over multiple dosing cycles.
Rate of drug elimination=rate of administration
Biodisposition
The process of drug absorption,distribution and elimination(synonym of pharmacokinetics)
Amount of drug in the body ///
Plasma drug concentration
Apparent volume of distribution
Alternating factors
- Vd of drugs bound to albumin can be altered by liver or kidney disease
- drug bound in peripheral tissues, drug’s concentration may drop to very low values even though the total amount in the body is large.
Rate of elimination to the plasma concentrations
Same for first order kinetics
Drug
Blood flow
Conditions of organ of elimination
Half life constant for drugs that follow first order monsters
T1/2=0.693×__Vd_
CL
Disease age and other variables alter the clearance much more than Vd
Bioavailability
Fraction of the administered dose that reaches the systemic circulation
Unity for IV route but even this occurs in varying periods of time depending on drug formulation.
Expulsion of drugs by intestinal transport,first pass metabolism,and distribution into other tissues that occurs .
