1.05 - Pharmacokinetics 3 and 4 Flashcards
Biotransformation occurs mostly in the ___
Liver
Biodegradation can make drugs more ___ (polar or non-polar), thus, more readily excreted
Polar
Differentiate active and inactive compounds based on polarity, solubility, and ionization
Active compounds are less polar, less ionized, and lipid soluble
Phase of biotransformation where drugs are oxidized or reduced to a more polar, less pharmacologically active form via oxidative, hydrolytic, and reductive reactions
Phase I or non-synthetic phase
Phase of biotransformation where drugs are conjugated with acetate, glucoronate, sulfate, or glycine
Phase II or synthetic phase
___ is the most common conjugation reaction
Glucoronidation (e.g. glucoronosyl transferase)
In general, asians are __ (slow or rapid) acetylators
Rapid
Metabolism of Theophylline is induced by ___
Benzo (a) pyrene
Metabolism of Barbiturates, chloramphenicol, anticoagulants, digitoxin, doxorubicin is induced by ___
Phenobarbital and other barbiturates
Metabolism of cortisol, dexamethasone, digitoxin, theophylline is induced by ___
Phenytoin
Metabolism of Coumarin anticoagulants, digitoxin, glucocorticoids, propranolol is induced by ___
Rifampicin
Metabolism of warfarin is induced by ___
Griseofulvin
___ decreases metabolism of probenecid
Allopurinol, chloramphenicol, isoniazid
___ decreases metabolism of phenytoin
Dicumarol
___ decreases metabolism of warfarin
Cimetidine
___ decreases metabolism of theophylline
Erythromycin
___ decreases metabolism of terfenadine
Ketoconazole
____ (polar or nonpolar) substances has shorter retention time, easily excreted, and difficult to be absorbed
Polar
The ___ (zero or first) order kinetics is where a constant fraction or percentage of the drug is handled per unit time; dependent on drug concentration; linear, non-saturable
First order kinetics
The __ (zero or first) order kinetics is non-linear, saturable, where a constant amount of drug is handled per unit time; dependent on rate constant of the process
Zero order kinetics
Enumerate the 5 well-studied drugs that follow zero order kinetics
Mnemonic: Pro-PADE Probenecid Phenytoin Aspirin Dicoumarol Ethanol
Enumerate the three most important pharmacokinetic parameters
Bioavailability
Volume of distribution
Clearance
___ is the fraction of the drug that remains unchanged once it reaches the circulation
Bioavailability
What does a low volume of distribution (Vd) mean?
The drug remains within the vascular component (may be due to high degree of protein binding, very low lipid water partition coefficient, low permeability to membranes)
What does a high volume of distribution mean?
The drug has been widely absorbed by the tissues (may be due to increased solubility of the drug)
___ is a measure of how efficient the system is in removing the drug
Clearance
The half-life concept is only applicable to drugs with (first or zero) ___ order kinetics
First order kinetics
Aspirin has a half-life of __ hours
4 hours
Digitoxin has a half-life of ___ days
7 days
If the graph of therapeutic range is steep, the therapeutic window is ____
Narrow therapeutic window
If the graph of therapeutic range is more slanted/diagonal, the therapeutic window is ____
Wide therapeutic window (therefore, relatively safe)
Ibuprofen has a ___ (narrow or wide) therapeutic window
Wide therapeutic window
Theophylline has a ___ (narrow or wide) therapeutic window
Narrow therapeutic window
