BASIC PHARMACOLOGY NBME CBSE FINAL EXAM LATEST
2024/2025 QUESTIONS AND VERIFIED CORRECT ANSWERS/
ALREADY GRADED A++
Define Km in MM kinetics: - ANSWER The concentration of substrate [S] at
which 1/2 Vmax is reached
Km is _________ related to affinity of the enzyme for its substrate -
ANSWER inversely
Vmax is directly proportional to what? - ANSWER to the enzyme
concentration
What characterizes MM kinetics? - ANSWER a hyperbolic curve when
Vmax is plotted against [S]. Most enzymes follow MM kinetics.
Enzymatic reactions demonstrated a sigmoid curve usually denote: -
ANSWER cooperative binding / kinetics, ie hemoglobin
In the lineweaver-burk plot, how is the y-intercept related to Vmax? What
does the slope of the line equal? The y-intercept? The x-intercept? -
ANSWER They're inversely related. The slope of the line is equal to
Km/Vmax while the y-intercept is equal to 1/Vmax. The x-intercept is equal
to 1/-Km.
In the L-B plot, if the x-intercept is closer to 0, what does that mean? -
ANSWER x-intercept = 1/-Km. So if it is closer to 0, Km is greater and
affinity is lower
In the L-B plot, how are competitive and non-competitive inhibitors
expressed with respect to one another? - ANSWER competitive inhibitors'
lines cross eachother competitively whereas non-competitive do not.
What are some key differences between competitive and non-competitve
inhibitors? - ANSWER competitive=reversible or irreversible. non-
competitive=irreversible. competitive may be overcome by a higher [S]
whereas noncompetitive or irreversible competitive may not be overcome.
Noncompetitive inhibitors do not resemble substrate, and they do not bind
the active site like the other two. Reversible competitive has no effect on
,Vmax whereas the other two lower it. Conversely, reversible competitive
increases the Km whereas the other two have no effect on Km.
pharmacodynamically, reversible competitive inhibitors lower potency
whereas the other two lower efficacy.
Define pharmacokinetics: - ANSWER The effects of the body on the drug.
ADME.
Define pharmacodynamics: - ANSWER Effects of the drug on the body.
Includes receptor binding, drug efficacy, drug potency and drug toxicity
Define Bioavailability (F): - ANSWER The fraction of the administered drug
which reaches systemic circulation unchanged. For an IV dose, the
F=100%. Orally it is typically less because of incomplete absorption and /
or FPHM.
Define Volume of Distribution (Vd): - ANSWER The theoretical volume
occupied by the total absorbed drug amount at the plasma concentration.
Apparent Vd of plasma protein: - ANSWER bound drugs can be altered by
liver and kidney disease (low protein binding, high Vd). Vd=amount of drug
in body / plasma concentration of drug
Where is Vd low? - ANSWER In blood. 4-8L. Drug types: large / charged
molecules, plasma protein bound.
Where is Vd medium? - ANSWER ECF. Small hydrophilic molecules.
Where is Vd high? - ANSWER All tissues including fat. Small lipophilic
molecules, especially if bound to tissue protein.
What is the equation for half-life? - ANSWER T1/2= .693 x Vd / CL.
T1/2 is a property of _______ order elimination - ANSWER first
How many half lives does it take for a drug administered as a constant
infusion to reach steady state? - ANSWER 4-5
How many half lives does it take for a drug administered as a constant
infusion to reach 90% of steady state? - ANSWER 3.3
,Define clearance (CL): - ANSWER The volume of plasma cleared of a drug
during a given time unit.
Under what circumstances may clearance be impaired? - ANSWER
cardiac, hepatic or renal defects
What is the equation for clearance? - ANSWER CL=rate of elimination of
drug / plasma drug concentration. This is = Vd x Ke (elimination constant)
How do you calculate loading dose? - ANSWER = Cp x Vd / F (where
Cp=target plasma concentration at steady state)
How do you calculate maintenance dose? - ANSWER = Cp x CL x T / F
(T=tau=dose interval, or time between doses, if it is not administered
continuously)
What happens to loading and maintenance doses during renal and liver
disease? - ANSWER maintenance dose is lowered whereas loading dose
remains unchanged
Time to steady state depends primarily on _____ and is _____ of dose and
dosing frequency - ANSWER T1/2 ; independent
Zero order elimination: Definition and examples of drugs that follow -
ANSWER Rate of elimination is constant regardless of Cp. (constant
AMOUNT of drug). Cp decreases linearly with time. Phenytoin, ethanol,
aspirin (at high or toxic concentrations). **Capacity-limited elimination**
First-order elimination: - ANSWER rate of elim directly proportional to the
drug concentration. (constant FRACTION of drug per unit time). Cp lowers
exponentially with time. **flow-dependent elimination**
What forms of drugs are trapped in urine and cleared quickly? - ANSWER
ionized species
What forms of drugs may be reabsorbed? - ANSWER neutral species
What are some examples of drugs that are weak acids? What are the
implications of a drug being a weak acid on its elimination via urine? How
, can you treat an overdose of these drugs? - ANSWER phenobarbital, mtx,
aspirin. These are trapped in basic environments. Treat overdose with
bicarbonate.
What are some examples of drugs that are weak bases? What are the
implications for elimination? How do you treat an overdose? - ANSWER
amphetamines. These are trapped in acidic environments. Treat with
ammonium chloride.
Phase I of drug metabolism: - ANSWER redox, hydrolysis with cytp450
yielding SLIGHTLY polar, water-soluble metabolites (still active usually)
What patients first lose phase I? - ANSWER geriatric patients
Phase II of drug metabolism: - ANSWER CONJUGATION (glucuronidation,
acetylation, sulfation) usually yielding VERY POLAR, INACTIVE
metabolites (renally excreted). Geriatric patients have phase II.
What happens in patients who are slow acetylators? - ANSWER greater
side effects from drugs because of lowered rate of metabolism of drugs.
Define efficacy: - ANSWER the maximal effect a drug can produce
What drugs have high efficacy? - ANSWER analgesics, abx,
antihistamines, decongestants.
Do partial or full agonists have greater efficacy? - ANSWER full agonists
have more efficacy than partial agonists
Define potency: - ANSWER The amount of drug needed for a given effect.
High potency means high affinity for receptor. A lower EC50 indicates
higher potency.
High potency drug classes: - ANSWER chemotherapeutics,
antihypertensives and lipid lowering drugs (cholesterol drugs)
Effect of a competitive antagonist in terms of potency, efficacy: - ANSWER
shifts the curve to the right (thus raising the EC50 and thus lowering
potency) while it does not have an effect on the efficacy (thus the max
2024/2025 QUESTIONS AND VERIFIED CORRECT ANSWERS/
ALREADY GRADED A++
Define Km in MM kinetics: - ANSWER The concentration of substrate [S] at
which 1/2 Vmax is reached
Km is _________ related to affinity of the enzyme for its substrate -
ANSWER inversely
Vmax is directly proportional to what? - ANSWER to the enzyme
concentration
What characterizes MM kinetics? - ANSWER a hyperbolic curve when
Vmax is plotted against [S]. Most enzymes follow MM kinetics.
Enzymatic reactions demonstrated a sigmoid curve usually denote: -
ANSWER cooperative binding / kinetics, ie hemoglobin
In the lineweaver-burk plot, how is the y-intercept related to Vmax? What
does the slope of the line equal? The y-intercept? The x-intercept? -
ANSWER They're inversely related. The slope of the line is equal to
Km/Vmax while the y-intercept is equal to 1/Vmax. The x-intercept is equal
to 1/-Km.
In the L-B plot, if the x-intercept is closer to 0, what does that mean? -
ANSWER x-intercept = 1/-Km. So if it is closer to 0, Km is greater and
affinity is lower
In the L-B plot, how are competitive and non-competitive inhibitors
expressed with respect to one another? - ANSWER competitive inhibitors'
lines cross eachother competitively whereas non-competitive do not.
What are some key differences between competitive and non-competitve
inhibitors? - ANSWER competitive=reversible or irreversible. non-
competitive=irreversible. competitive may be overcome by a higher [S]
whereas noncompetitive or irreversible competitive may not be overcome.
Noncompetitive inhibitors do not resemble substrate, and they do not bind
the active site like the other two. Reversible competitive has no effect on
,Vmax whereas the other two lower it. Conversely, reversible competitive
increases the Km whereas the other two have no effect on Km.
pharmacodynamically, reversible competitive inhibitors lower potency
whereas the other two lower efficacy.
Define pharmacokinetics: - ANSWER The effects of the body on the drug.
ADME.
Define pharmacodynamics: - ANSWER Effects of the drug on the body.
Includes receptor binding, drug efficacy, drug potency and drug toxicity
Define Bioavailability (F): - ANSWER The fraction of the administered drug
which reaches systemic circulation unchanged. For an IV dose, the
F=100%. Orally it is typically less because of incomplete absorption and /
or FPHM.
Define Volume of Distribution (Vd): - ANSWER The theoretical volume
occupied by the total absorbed drug amount at the plasma concentration.
Apparent Vd of plasma protein: - ANSWER bound drugs can be altered by
liver and kidney disease (low protein binding, high Vd). Vd=amount of drug
in body / plasma concentration of drug
Where is Vd low? - ANSWER In blood. 4-8L. Drug types: large / charged
molecules, plasma protein bound.
Where is Vd medium? - ANSWER ECF. Small hydrophilic molecules.
Where is Vd high? - ANSWER All tissues including fat. Small lipophilic
molecules, especially if bound to tissue protein.
What is the equation for half-life? - ANSWER T1/2= .693 x Vd / CL.
T1/2 is a property of _______ order elimination - ANSWER first
How many half lives does it take for a drug administered as a constant
infusion to reach steady state? - ANSWER 4-5
How many half lives does it take for a drug administered as a constant
infusion to reach 90% of steady state? - ANSWER 3.3
,Define clearance (CL): - ANSWER The volume of plasma cleared of a drug
during a given time unit.
Under what circumstances may clearance be impaired? - ANSWER
cardiac, hepatic or renal defects
What is the equation for clearance? - ANSWER CL=rate of elimination of
drug / plasma drug concentration. This is = Vd x Ke (elimination constant)
How do you calculate loading dose? - ANSWER = Cp x Vd / F (where
Cp=target plasma concentration at steady state)
How do you calculate maintenance dose? - ANSWER = Cp x CL x T / F
(T=tau=dose interval, or time between doses, if it is not administered
continuously)
What happens to loading and maintenance doses during renal and liver
disease? - ANSWER maintenance dose is lowered whereas loading dose
remains unchanged
Time to steady state depends primarily on _____ and is _____ of dose and
dosing frequency - ANSWER T1/2 ; independent
Zero order elimination: Definition and examples of drugs that follow -
ANSWER Rate of elimination is constant regardless of Cp. (constant
AMOUNT of drug). Cp decreases linearly with time. Phenytoin, ethanol,
aspirin (at high or toxic concentrations). **Capacity-limited elimination**
First-order elimination: - ANSWER rate of elim directly proportional to the
drug concentration. (constant FRACTION of drug per unit time). Cp lowers
exponentially with time. **flow-dependent elimination**
What forms of drugs are trapped in urine and cleared quickly? - ANSWER
ionized species
What forms of drugs may be reabsorbed? - ANSWER neutral species
What are some examples of drugs that are weak acids? What are the
implications of a drug being a weak acid on its elimination via urine? How
, can you treat an overdose of these drugs? - ANSWER phenobarbital, mtx,
aspirin. These are trapped in basic environments. Treat overdose with
bicarbonate.
What are some examples of drugs that are weak bases? What are the
implications for elimination? How do you treat an overdose? - ANSWER
amphetamines. These are trapped in acidic environments. Treat with
ammonium chloride.
Phase I of drug metabolism: - ANSWER redox, hydrolysis with cytp450
yielding SLIGHTLY polar, water-soluble metabolites (still active usually)
What patients first lose phase I? - ANSWER geriatric patients
Phase II of drug metabolism: - ANSWER CONJUGATION (glucuronidation,
acetylation, sulfation) usually yielding VERY POLAR, INACTIVE
metabolites (renally excreted). Geriatric patients have phase II.
What happens in patients who are slow acetylators? - ANSWER greater
side effects from drugs because of lowered rate of metabolism of drugs.
Define efficacy: - ANSWER the maximal effect a drug can produce
What drugs have high efficacy? - ANSWER analgesics, abx,
antihistamines, decongestants.
Do partial or full agonists have greater efficacy? - ANSWER full agonists
have more efficacy than partial agonists
Define potency: - ANSWER The amount of drug needed for a given effect.
High potency means high affinity for receptor. A lower EC50 indicates
higher potency.
High potency drug classes: - ANSWER chemotherapeutics,
antihypertensives and lipid lowering drugs (cholesterol drugs)
Effect of a competitive antagonist in terms of potency, efficacy: - ANSWER
shifts the curve to the right (thus raising the EC50 and thus lowering
potency) while it does not have an effect on the efficacy (thus the max
