Pharmacology & Pathophysiology: 150+ Q&A Study Guide
PHARMACOLOGY QUESTIONS & ANSWERS
Drug Absorption, Distribution, Metabolism, and Excretion (ADME)
1. Q: What is bioavailability? A: Bioavailability is the fraction of an
administered dose that reaches systemic circulation in unchanged form.
It's expressed as a percentage, with IV administration having 100%
bioavailability.
2. Q: What factors affect drug absorption in the GI tract? A: pH, gastric
emptying time, intestinal motility, blood flow, food presence, drug
formulation, and first-pass metabolism.
3. Q: What is the first-pass effect? A: The first-pass effect is the
metabolism of orally administered drugs by the liver before reaching
systemic circulation, reducing bioavailability.
4. Q: How does protein binding affect drug distribution? A: Only
unbound (free) drug is pharmacologically active. High protein binding
reduces free drug concentration and may cause drug interactions
through displacement.
5. Q: What are the major routes of drug elimination? A: Hepatic
metabolism (Phase I and II reactions) and renal excretion are the
primary routes, with biliary excretion and pulmonary elimination as
secondary routes.
6. Q: What is clearance in pharmacokinetics? A: Clearance is the
volume of plasma from which a drug is completely removed per unit
time, measured in L/hr or mL/min.
,7. Q: What is the half-life of a drug? A: Half-life is the time required for
the plasma concentration to decrease by 50%. It takes approximately 5
half-lives to reach steady state.
8. Q: What are Phase I drug metabolism reactions? A: Phase I reactions
include oxidation, reduction, and hydrolysis, primarily mediated by
cytochrome P450 enzymes in the liver.
9. Q: What are Phase II drug metabolism reactions? A: Phase II
reactions involve conjugation with glucuronic acid, sulfate, acetate, or
amino acids, making drugs more water-soluble for excretion.
10. Q: What is zero-order kinetics? A: Zero-order kinetics occurs when
elimination mechanisms are saturated, resulting in constant amount of
drug eliminated per unit time (e.g., alcohol metabolism).
Pharmacodynamics
11. Q: What is the difference between agonists and antagonists? A:
Agonists bind to receptors and produce a biological response, while
antagonists bind to receptors but block the action of agonists without
producing a response.
12. Q: What is receptor affinity? A: Receptor affinity is the strength of
binding between a drug and its receptor, determined by the dissociation
constant (Kd).
13. Q: What is intrinsic activity? A: Intrinsic activity is the ability of a
drug to produce a maximum response once bound to a receptor. Full
agonists have intrinsic activity of 1, partial agonists have values
between 0 and 1.
, 14. Q: What is competitive inhibition? A: Competitive inhibition occurs
when an antagonist competes with an agonist for the same receptor
binding site, which can be overcome by increasing agonist
concentration.
15. Q: What is non-competitive inhibition? A: Non-competitive
inhibition occurs when an antagonist binds to a different site than the
agonist, changing receptor conformation and reducing maximum
response.
16. Q: What is the therapeutic index? A: Therapeutic index (TI) is the
ratio of toxic dose to effective dose (TD50/ED50). A higher TI indicates a
safer drug with a wider margin of safety.
17. Q: What is potency? A: Potency refers to the amount of drug
needed to produce a given effect. It's determined by the EC50
(concentration producing 50% maximum response).
18. Q: What is efficacy? A: Efficacy is the maximum response a drug can
produce, regardless of dose. It's the ceiling effect or Emax.
19. Q: What are partial agonists? A: Partial agonists bind to receptors
and produce a submaximal response even at full receptor occupancy.
They can act as functional antagonists in the presence of full agonists.
20. Q: What is tachyphylaxis? A: Tachyphylaxis is rapidly developing
tolerance to a drug, often occurring within minutes to hours of
repeated administration.
Autonomic Pharmacology
PHARMACOLOGY QUESTIONS & ANSWERS
Drug Absorption, Distribution, Metabolism, and Excretion (ADME)
1. Q: What is bioavailability? A: Bioavailability is the fraction of an
administered dose that reaches systemic circulation in unchanged form.
It's expressed as a percentage, with IV administration having 100%
bioavailability.
2. Q: What factors affect drug absorption in the GI tract? A: pH, gastric
emptying time, intestinal motility, blood flow, food presence, drug
formulation, and first-pass metabolism.
3. Q: What is the first-pass effect? A: The first-pass effect is the
metabolism of orally administered drugs by the liver before reaching
systemic circulation, reducing bioavailability.
4. Q: How does protein binding affect drug distribution? A: Only
unbound (free) drug is pharmacologically active. High protein binding
reduces free drug concentration and may cause drug interactions
through displacement.
5. Q: What are the major routes of drug elimination? A: Hepatic
metabolism (Phase I and II reactions) and renal excretion are the
primary routes, with biliary excretion and pulmonary elimination as
secondary routes.
6. Q: What is clearance in pharmacokinetics? A: Clearance is the
volume of plasma from which a drug is completely removed per unit
time, measured in L/hr or mL/min.
,7. Q: What is the half-life of a drug? A: Half-life is the time required for
the plasma concentration to decrease by 50%. It takes approximately 5
half-lives to reach steady state.
8. Q: What are Phase I drug metabolism reactions? A: Phase I reactions
include oxidation, reduction, and hydrolysis, primarily mediated by
cytochrome P450 enzymes in the liver.
9. Q: What are Phase II drug metabolism reactions? A: Phase II
reactions involve conjugation with glucuronic acid, sulfate, acetate, or
amino acids, making drugs more water-soluble for excretion.
10. Q: What is zero-order kinetics? A: Zero-order kinetics occurs when
elimination mechanisms are saturated, resulting in constant amount of
drug eliminated per unit time (e.g., alcohol metabolism).
Pharmacodynamics
11. Q: What is the difference between agonists and antagonists? A:
Agonists bind to receptors and produce a biological response, while
antagonists bind to receptors but block the action of agonists without
producing a response.
12. Q: What is receptor affinity? A: Receptor affinity is the strength of
binding between a drug and its receptor, determined by the dissociation
constant (Kd).
13. Q: What is intrinsic activity? A: Intrinsic activity is the ability of a
drug to produce a maximum response once bound to a receptor. Full
agonists have intrinsic activity of 1, partial agonists have values
between 0 and 1.
, 14. Q: What is competitive inhibition? A: Competitive inhibition occurs
when an antagonist competes with an agonist for the same receptor
binding site, which can be overcome by increasing agonist
concentration.
15. Q: What is non-competitive inhibition? A: Non-competitive
inhibition occurs when an antagonist binds to a different site than the
agonist, changing receptor conformation and reducing maximum
response.
16. Q: What is the therapeutic index? A: Therapeutic index (TI) is the
ratio of toxic dose to effective dose (TD50/ED50). A higher TI indicates a
safer drug with a wider margin of safety.
17. Q: What is potency? A: Potency refers to the amount of drug
needed to produce a given effect. It's determined by the EC50
(concentration producing 50% maximum response).
18. Q: What is efficacy? A: Efficacy is the maximum response a drug can
produce, regardless of dose. It's the ceiling effect or Emax.
19. Q: What are partial agonists? A: Partial agonists bind to receptors
and produce a submaximal response even at full receptor occupancy.
They can act as functional antagonists in the presence of full agonists.
20. Q: What is tachyphylaxis? A: Tachyphylaxis is rapidly developing
tolerance to a drug, often occurring within minutes to hours of
repeated administration.
Autonomic Pharmacology
