1S Q3 Flashcards
T or F:
Plasma protein binding to the organ is the main determinant of drug delivery, but blood flow and blood cell partitioning may also be important for extensively bound drugs that are highly extracted.
False
Smaller volumes than IM
Subcutaneous
Prolonged duration of action
Transdermal
T or F:
The ratio of the rate of elimination of the drug compared to the plasma drug concentration defines volume of distribution.
False; …. defines clearance
Calculated from the dose divided by the AUC
Clearance
The factor that predicts the rate of elimination in relation to the drug concentration
Clearance
T or F:
Suppositories tend to move upward in the rectum into a region where veins that lead to the liver predominate, thus only about 50% of a rectal dose can be assumed to bypass the liver.”
True
5 to <100% Bioavailability
PO or Inhalation
T or F:
Volume of distribution measures the apparent space in the body available to contain the drug.
True
T or F:
“The standard dose of a drug is based on trials in healthy volunteers and patients with average ability to absorb, distribute, and eliminate the drug.”
True
Drug effects that are directly related to plasma concentrations
Immediate effects
Type of effect seen for almost all drugs.
Delayed
T or F:
At concentrations that are high relative to the Km, the elimination rate is almost independent of concentration, a state of first order elimination
False; pseudo-zero order elimination
Also known as Michaelis-Menten elimination.
Capacity Limited Elimination
T or F:
“Pharmacokinetics governs the concentration-effect part of the interaction, whereas pharmacodynamics deals with the dose-concentration part.”
False
Determined by the site of administration and the drug formulation
Rate of Absorption
Target Concentration Design for Dosage Regimen
a. Maintenance dose
b. Loading dose
c. both
d. None of the above
c
At steady state, the dosing rate ( rate in ) must equal the rate of elimination ( rate out )
Maintenance dose
Hepatic elimination on bioavailability
First Pass Effect
Most convenient
Oral
Usually very slow absorption
Transdermal
Also known as nonlinear elimination
Capacity-limited
Reflect the time required for the drug to distribute from plasma to the site of action
Delayed
May be Painful
IM and SC
T or F:
The standard dose of a drug will be suitable for all patients
False
T or F:
Drugs absorbed from suppositories in the lower rectum enter vessels that drain into the inferior vena cava, thus bypassing the liver
True
At concentrations that are high relative to the Km, the elimination rate is almost independent of concentration, a state of pseudo-zero order elimination
True
“Blood flow to the organ is the main determinant of drug delivery, but plasma protein binding and blood cell partitioning may also be important for extensively bound drugs that are highly extracted.”
True
Just enough drug is given in each dose to replace the drug eliminated since the preceding dose.
Maintenance dose
Drugs are cleared very readily by the organ of elimination.
Flow limited elimination
80 to <100% Bioavailability.
Transdermal
T or F:
Volume distribution is the ratio of the amount of the drug in the body compared to the plasma concentration.
True
The volume of distribution is the most important proportionality factor.
Loading dose
Greater when administered as a constant infusion than with intermittent dosing.
Cumulative Effects
Due to the slow turnover of a physiologic substance that is involved in the expression of the drug effect.
Delayed effects
T or F:
Systemic clearance is affected by bioavailability
False
Also known as concentration-dependent elimination.
Capacity limited elimination
75 to <100% Bioavailability
SC and IM
Less first-pass effect than oral.
Rectal (PR)
Most rapid onset
Intravenous (IV)
Also known as mixed-order elimination
Capacity limited elimination
T or F:
Effective drug concentration is the drug that reaches the systemic circulation
True
T or F:
“The pharmacokinetic processes of absorption, distribution, and elimination determine how rapidly and for how long the drug will appear at the target organ.”
False
Drug elimination pathways when blood flow to an organ does not limit elimination.
Capacity limited elimination
Capacity limited elimination
The hepatic first-pass effect can be avoided to a great extent by, EXCEPT
Oral tablets
T or F:
“A drug that completely binds to proteins in the blood, diffuses freely in between cellular spaces.”
False
Time it takes for the amount of the drug falls to half of the earlier measurement is known as
Half-life
T or F:
The pharmacokinetic concepts of maximum response and sensitivity determine the magnitude of the effect at a particular concentration
False
“Some drugs bind tightly to receptors, and it is the half-life of dissociation that determines the effect”
Delayed effects
T or F:
A drug that is avidly bound to molecules in the peripheral tissues, requires a larger total dose to achieve measurable plasma concentration
True
T or F:
At concentrations that are high relative to the Km, the elimination rate is almost dependent of concentration a state of pseudo-zero order elimination
False
T or F:
The lung may also serve as a site of first-pass loss by excretion and possibly metabolism for drugs administered by nongastrointestinal routes
True
Major organs of drug elimination
Liver, Small Intestines, Kidney, Skin, and Lungs
T or F:
Systemic clearance is not affected by bioavailability.
True
Often very rapid onset
Inhalation
Fraction of the administered dose of the drug that reaches the systemic circulation
Bioavailability
T or F:
The goal of therapeutics is to achieve a desired beneficial effect with adverse effects.
False
30 to <100% Bioavailability
Rectal (PR)
Most of the drug in the blood perfusing the organ is eliminated on the first pass of the drug through it.
Flow limited elimination
The elimination depend primarily on the rate of drug delivery to the organ of elimination
Flow limited elimination
T or F:
Clearance and volume of distribution are two basic parameters of pharmacokinetics of a particular drug
True
Used for drugs with long half-lives
Loading dose
Bioavailability is dependent on the following factors EXCEPT
Elimination
The measure of the ability of the drug to eliminate the drug
Clearance
Which provides direct access to systemic veins
Sublingual absorption, transdermal route
Pharmacodynamic variables
a. maintenance dose
b. loading dose
c. both
d. neither
d
