Exam 1 Study Questions Flashcards
What happens to oral dose after admin?
ADME
A- Drug is dissolved in GIT, enters blood
D- Drug reaches various tissues from systemic circulation
E - After X time, body gets drug through elimination
Pharmacokinetics definition
What the body does to the drug
biopharmaceutics definiton
influence of physiochemical properties of drugs, dosage forms and physiological factors affecting plasma conc through absorption and distribution.
disposition defintion
Interchangeable with Pharmacokinetics
events that occur after drug absoprtion
Encompasses distribution and elimination phases
pharmacodynamics definiton
What the drug does to body
Distinguish Pharmacokinetic vs Pharmacodynamic variability?
PK: due to variations in drug clearance, 500mg given to 2 ppl but plasma conc different after 2 hrs
PD: plasma conc can be same in 2 ppl but therapeutic response is different
What is most important assumption for pharmacokinetic monitoring in patients?
Dose of drugs determined assuming normal functioning of major metabolizing and excretion organs
under normal circumstances, dosage of drug does not change from person to person
reduced clearance of a drug may result in drug accumulation and adverse effects
faster clearance may render the drug ineffective
Therapeutic range defintion
Range between minimum effective conc and minimum toxic conc
Onset defintion
time for action to start
Duration of effect definition
How long drug effect remains, time its above the minimum effective concentration
Why do we measure plasma concentration?
to circumvent pharmacokinetic variability and to monitor individualized dosage regimens
What are limitations of pharmacokinetics?
lack of clear relation between plasma conc and therapeutic effect
some drugs have wide therapeutic window making plasma conc monitoring unnecessary
Most common models in Pharmacokinetics?
one and two compartment model
What is 1st pass metabolism?
Drug loss before its entry into systemic circulation
How does different route of admin effect bioavailability?
different routes of admin have different onset times, and bioavailability due to either undergoing or missing the 1st pass effect, type of tissue they go through
Difference between rate and rate constant?
Rate: depends on conc of reactant
Rate constant: independent of conc of reactant
What are the differences between the first and zero-order kinetics when the amount (or concentration)-time data are plotted on linear and semilog graphs?
1st: Normal graph curved, semi log is straight
Zero: Normal is straight, semi log is curved down
How is the rate of the process dependent on the amount (or concentration) for zero and first-order processes?
Zero: constant, doesn’t change. flow is same
First: changes with time, faster and first and then gets slower. variable flow
What are the assumptions of compartmentalization models?
Drug conc is homogenous
Drug elimination starts immediately after IV bolus injection
Druc conc represent plasma conc
Drug amount represents drug amount in body
Vole equals about/conc in compartment
What is apparent volume of distribution?
its not a real volume
Alleged or supposed, its hypothetical
What is the significance and application of V?
can show if drug is mostly in plasma (low distribution ~3, <5) or in fat (way higher, 100s+…no upper limit)
What are the different routes of drug elimination?
Renal excretion Metabolism (Primarily Liver) ~~~~~~~~~~~~ 90% ~~~~~~~~~~~~ < 10% excretion into bile some into sweat and exhaled-air
What is the appropriate length of urine collection time in order to estimate the total amount excreted in the urine?
4 half-lives
What is renal clearance?
efficacy of the kidneys in excreting the drug
