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WorksheetsPDPK Final Exam
Total questions: 74
Worksheet time: 4hrs 38mins
The rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action is known as:
Bioavailabilty
Metabolism
Distribution
Rate of elimination
What formula would you use to determine bioavailability?
=1/2(C1+C2)(t2-t1)
=total drug concentration x fu
The movement of drug from site of administration/absorption to the rest of the body is known as:
Bioavailabilty
Metabolism
Distribution
Rate of elimination
What formula would you use to determine the volume of distribution (proportionally related to the amount of drug in body to concentration)?
=1/2(C1+C2)(t2-t1)
=total drug concentration x fu
Which of the following are true for rate of elimination?
The the absolute amount of drug that leaves the body per time
Rate of elimination (mg/hr) ≠ Rate constant of elimination (K)
Rate of elimination (mg/hr) ≠ Clearance (CL)
Units: R (mg/hr)
First order elimination
Linear graph paper
Concentration-time
Semi-log graph paper
Ln (concentration)-time
First order elimination
Linear graph paper
Concentration-time
Semi-log graph paper
Ln (concentration)-time
First order elimination
Linear graph paper
Concentration-time
Semi-log graph paper
Ln (concentration)-time
Zero order elimination
Linear graph paper
Drug concentration-time
Semi-log graph paper
Ln (concentration)-time
Which of the following are true for first-order elimination rates?
A constant fraction of drug in the body leaves the body per hour
Drug elimination rate is proportional to drug concentration
Drug elimination follows linear kinetics
A constant amount of drug in the body leaves the body per hour
No relevant half-life
Which of the following are true for zero-order elimination rates?
A constant fraction of drug in the body leaves the body per hour
Drug elimination rate is independent to drug concentration
Drug elimination follows linear kinetics
A constant amount of drug in the body leaves the body per hour
No relevant half-life
Blood facilitates Drug Distribution. Multiple equilibria will determine how much drug will be free and totally present in plasma or tissue. At equilibrium, free levels in tissue and plasma will be identical while tissue and plasma
bound drug might differ.
True
False
What formula would you use to determine the free drug concentration?
=1/2(C1+C2)(t2-t1)
=total drug concentration x fu = (1-%protein binding)*total drug
[(total drug-unbound drug)/total drug]*100 = (1-fu)*100
Which of the following are true regarding perfusion?
Limited distribution
Cell membrane between blood and tissue shows very high permeability for drug
Slow blood flow = slow uptake into tissues
Fast blood flow = fast uptake, until tissue free drug levels in blood and tissues are the same
Which of the following are true regarding permeability?
Drug enters tissue very slowly
Blood flow is not important for rate of uptake
Uptake is determined by FICK’s Law (Surface area of membrane, membrane thickness , Concentration gradient,
Partition coefficient, Ionization)
It’s not any more the number of vehicles (buses) driving by, but
how fast alumni is being pushed out (remember they are slow
leaving the bus).
Protein binding is especially important if:
The drug shows a narrow therapeutic window
The drug shows a high degree of protein binding (small differences in protein binding will affect the unbound fraction significantly)
The drug shows a wide therapeutic window
The drug shows a low degree of protein binding (large differences in protein binding will affect the unbound fraction significantly)
A pharmacist receives a call from a provider asking for assistance with two patients in the clinic. Both patients have a seizure disorder and are taking phenytoin. Patient A is seizure free but is experiencing symptoms of toxicity. Patient B has a higher phenytoin level and is doing fine. Both patients have normal renal function. Which of
the following statements is/are true for this scenario?
Patient B’s corrected phenytoin level will be lower than the total level reported
Patient A’s corrected phenytoin level will be lower than the total level reported
Patient A’s corrected phenytoin level will be higher than the total level reported
Patient A has a greater percentage of bound phenytoin
Patient A has a greater percentage of free phenytoin
Due to the nature of biological membranes, drugs with with the following properties are more likely to cross most membrane barriers?
Ionized
Lipophilic
Nonionized
Hydrophilic
Which of the following formulas are a first-order elimination equation?
=1/2(C1+C2)(t2-t1)
=total drug concentration x fu
C2=C1 * e-KΔt
Which of the following are half-life of compartmental analysis?
T1/2 = 0.693/k or Ln(2)/k
T1/2 = 0.693/λz or Ln(2)/λz
Which of the following are half-life of non-compartmental analysis?
T1/2 = 0.693/k or Ln(2)/k
T1/2 = 0.693/λz or Ln(2)/λz
Consider a lipophilic, protein bound, low extraction drug. What effects would an increase in plasma protein binding have on CLH?
Increase CLH
No effect
Decrease CLH
Consider a lipophilic, protein bound, low extraction drug. What effects would an increase in liver blood flow have on CLH?
Increase CLH
No effect
Decrease CLH
Consider a lipophilic, protein bound, low extraction drug. What effects would a decrease in metabolic liver enzymes have on CLH?
Increase CLH
No effect
Decrease CLH
Which of the following statements are true?
The larger CL, the larger k or the shorter t1/2
The larger Vd, the smaller k or the longer t1/2
Change in dose will not impact k, t1/2, or CL
The larger CL, the smaller k or the longer t1/2
The larger Vd, the larger k or the shorter t1/2
AUC is dependent on dose and CL. Choose the true statements about AUC.
The larger the dose, the larger the AUC
The larger the CL, the smaller the AUC
The larger the dose, the smaller the AUC
The larger the CL, the larger the AUC
Which of the following are true for the PK process after IV infusion?
In a constant IV infusion, drug solution is infused at a
constant or zero-order rate, K0.
During the IV infusion, the drug concentration increases in the plasma and the rate of drug elimination increases because rate of elimination is concentration dependent (first-order elimination).
Cp keeps increasing until steady state is reached at which time the rate of drug input (IV infusion rate) equals rate of drug output (elimination rate).
After the cessation of infusion, the remaining drug in body
continues to be eliminated at a first-order rate.
Which of the following are true for IV bolus and IV infusion?
Adding an iv bolus at the start of the infusion will result in achieving steady state condition immediately
The total concentration Ctot at t hours after the start of infusion would be equal to Cbol + Cinf
Adding an iv bolus at the start of the infusion will result in reaching steady state conditions significantly slower
The total concentration Ctot at t hours after the start of infusion would be equal to Cbol * Cinf
Which of the following statements are true regarding single dose oral medications?
tmax: After oral drug administration, the maximum plasma concentration (Cmax) is reached at time tmax when the rate of change of drug in the body is zero (i.e., Rate In = Rate Out).
Tmax is independent of dose and fraction absorbed
The smaller ka, the later tmax, the lower Cmax
The larger ka, the shorter tmax, the higher Cmax
AUC for oral single dose meds are independent of ka, and directly related to dose and bioavailability.
True
False
What are the steps for designing dosage regimens?
Step 1. Calculate K, Vd and Clearance
Step 2. Select Cavg and f based on therapeutic concentration range.
Step 3. Choose Div and τ – restricted by the size of the
available doses and convenient dosing interval (i.e., τ = 4,
6, 8, 12, 24 hours for best compliance by the patient).
Step 4. Check Cmax,ss and Cmin,ss to confirm that the dosage regimen is suitable.
eGFR - Estimated glomerular filtration rate is the test to measure your level of kidney function and determine your stage of kidney disease.
Which of the following are true regarding fe and 1-fe?
“fe” tells us about need to adjust in renal or liver disease
fe cutoff for dosage reduction in renal or hepatic disease: >0.25
fe > 0.25 –reduce dose in renal disease
1-fe >0.25 – reduce in liver disease
Which of the following are true regarding mean residence time (MRT)?
Statistical moment analogy to half-life.
Provides a useful estimate of the persistence of drug in the body
Represents the time for 63.2% of an iv bolus dose to be
eliminated
Function of both distribution and elimination parameters
Measure of the average time a drug molecule remains in the body
Which of the following are advantages of NCA vs. compartmental models?
No assumptions of compartments
Simple calculation
Do not require sophisticated software
Less variations among analysts
Intensive sampling
Which of the following are disadvantages of NCA vs. compartmental models?
No assumptions of compartments
No model for visualization or prediction
Some information may be lost (V1, K10, micro rate constants after IV dosing).
Less variations among analysts
Intensive sampling
Which of the following are associated with linear dose-independent PK?
ADME all obey first-order kinetics
PK parameters (CL, Vd, F, K and t1/2) is dose independent
AUC is proportional to dose
At least one of the ADME processes is saturable
At least one PK parameters is dose dependent
Which of the following are associated with nonlinear dose-dependent PK?
ADME all obey first-order kinetics
PK parameters (CL, Vd, F, K and t1/2) is dose independent
AUC is disproportional to dose
At least one of the ADME processes is saturable
At least one PK parameters is dose dependent
For nonlinear PK, what form of the Michaelis-Menen equation would be used when Cp is very small (Km>>Cp)
v= (Vm/Km) * Cp (first order)
v=Vm (zero order)
v=Vm/2 (Km=concentration associated with Vmax/2)
For nonlinear PK, what form of the Michaelis-Menen equation would be used when Cp is very large (Cp>>Km)
v= (Vm/Km) * Cp (first order)
v=Vm (zero order)
v=Vm/2 (Km=concentration associated with Vmax/2)
For nonlinear PK, what form of the Michaelis-Menen equation would be used when Cp = Km ?
v= (Vm/Km) * Cp (first order)
v=Vm (zero order)
v=Vm/2 (Km=concentration associated with Vmax/2)
Which of the following are true for nonlinear kinetic characteristics?
Drug concentration is high: close to zero order kinetics
Drug concentration is low: close to first order kinetics
K and half-life are drug concentrations dependent, which are NOT constants
AUC is disproportional to dose
Which of the following are FDA guidance on starting dose design?
Empirical approach: Dose by factor approach
The no observed adverse effect levels (NOAEL) of drug is scaled by making use of allometry to derive the maximum recommended starting dose (MRSD) for clinical studies.
NOAEL: the highest dose level that does not produce a
significant increase in adverse effects in comparison to the
control group.
Full send
Which of the following are true for applying a safety factor from HED to MRSD?
A safety factor provides a margin of safety for protection of human subjects receiving the initial clinical dose.
The MRSD for the clinical trial should be determined by dividing the HED by the safety factor (Default value is 10).
A safety factor of 10 may not be appropriate for all cases. It could be adjusted based on drug properties.
There are no safety factors
Which of the following are true for why SAD and MAD are conducted?
Phase I trial
Identify the pharmacokinetic and pharmacodynamics natures of the trial molecule
Emphasize on safety and tolerability of the subjects participating in Clinical Trials
Help in identifying the intolerable side effects of any drug molecule at a particular dose level
Define maximum tolerated dose
Which of the following are key measurements in bioequivalence studies?
AUC: the extent of absoption
Cmax: the rate of absorption
t1/2
CL
Which of the following are statistical analysis for AUC and Cmax in bioequivalence studies?
Geometric means
Arithmetic means
Geometric mean ratios
90 percent Confidence intervals (CI)
BE is generally determined if the 90% confidence intervals for Cmax and AUC fall within 80% to 125% of the reference listed drug.
True
False
How many half lives does it take to eliminate >95% of the drug is the body?
1
2
3
4
5
Which of the following are units for clearance?
mg/hr
L/hr
1/hr or hr-1
Which of the following are units for the rate constant of elimination (k)?
mg/hr
L/hr
1/hr or hr-1
The process of drug elimination from the body or from a single organ, which is defined as the Volume of fluid cleared of drug from the body per unit of time is known as:
Bioavailabilty
Clearance
Distribution
Rate of elimination
What parameters are the same for drugs C and D?
C0
K
t1/2
What parameters are the different for drugs C and D?
C0
K
t1/2
Amoxicillin shows a decrease in AUC and in increase in clearance in pregnant women. This concludes that amoxicillin is not appropriate to treat anthrax in pregnant women.
True
False
Which of following descriptions is NOT the advantage of noncompartmental analysis (NCA)?
Can be used for sparse sampling PK analysis
Less variations among analysts
Do not rely upon the assumptions of compartments
Fast and more cost- efficient than compartmental analysis
What is the drug concentration at which the rate of metabolism is ½ maximal?
Cmin
Cmax
Km
Vmax
Dosing strategies for aminoglycosides includes:
Traditional dosing
Extended interval dosing
Synergy dosing
Anergy dosing
Uses lower doses more frequently, two-three times daily if renal function is normal, or dose is reduced or dosing interval is extended in patients with decreased renal function describes:
Traditional dosing
Extended interval dosing
Synergy dosing
Uses higher doses (to attain higher peaks) less frequently, once daily if renal function is normal, or interval is extended past 24 h in renal disease patients describes:
Traditional dosing
Extended interval dosing
Synergy dosing
Utilization of a low dose of an aminoglycoside in conjunction with a beta-lactam or given every 8 to 24 h depending on infection describes:
Traditional dosing
Extended interval dosing
Synergy dosing
In traditional dosing, the dose is base off of:
Indication
Weight
Medication
Kidney function
In traditional dosing, the frequency is base off of:
Indication
Weight
Medication
Kidney function
Which of the following are true for ionization of acids?
Higher pH, more ionization, better solubility, low membrane permeability
Lower pH, less ionization, less solubility, high membrane permeability
Lower pH, more ionization, better solubility, low membrane permeability
Higher pH, less ionization, less solubility, high membrane permeability
Which of the following are true for ionization of bases?
Higher pH, more ionization, better solubility, low membrane permeability
Lower pH, less ionization, less solubility, high membrane permeability
Lower pH, more ionization, better solubility, low membrane permeability
Higher pH, less ionization, less solubility, high membrane permeability
What kind of interactions are present here?
Pharmacokinetic
Pharmacodynamic
Drug-drug
Drug-food
Penicillamine must be taken with an empty stomach. If this is not done what type of interactions can occur?
Pharmacokinetic
Pharmacodynamic
Drug-drug
Drug-food
Digoxin interacts with sucralfate and causes yellow vision. They form a chelate which is insoluble meaning it will not be abosrbed.
True
False
