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Pharmacology Key Concepts
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1
Question
What does bioavailability measure in pharmacology?
Answer
The fraction of drug reaching systemic circulation unchanged.
2
Question
In which scenario is bioavailability 100%?
Answer
When drugs are administered via IV route.
3
Question
What is the primary factor influencing maximum plasma concentration (Cmax)?
Answer
Lipid solubility of the drug.
4
Question
How does first pass metabolism affect bioavailability?
Answer
It decreases bioavailability due to hepatic processing before reaching systemic circulation.
5
Question
What role does lipid solubility play in drug absorption?
Answer
It enhances absorption and Cmax.
6
Question
What is the significance of Tmax in pharmacokinetics?
Answer
It indicates the rate of absorption.
7
Question
Which plasma protein does an acidic drug primarily bind to?
Answer
Albumin.
8
Question
How does high plasma protein binding influence volume of distribution?
Answer
It results in a low Vd.
9
Question
What is the primary purpose of drug metabolism?
Answer
To make drugs water-soluble for excretion.
10
Question
Which enzyme pathway is involved in oxidation during phase I reactions?
Answer
CYP450 enzymes.
11
Question
What is the main function of phase II reactions?
Answer
Conjugation to increase water solubility.
12
Question
Which process is responsible for drug excretion via the kidneys?
Answer
Glomerular filtration, tubular reabsorption, and secretion.
13
Question
What is the effect of plasma protein binding on drug filtration?
Answer
High protein binding reduces filtration.
14
Question
How does the half-life (t½) relate to drug elimination?
Answer
It is the time for plasma concentration to reduce by 50%.
15
Question
What type of pharmacokinetic order do most drugs follow?
Answer
First order kinetics.
16
Question
In zero order kinetics, what remains constant?
Answer
Amount of drug eliminated per unit time.
17
Question
What does the Lineweaver-Burk plot analyze?
Answer
Enzyme kinetics and inhibition types.
18
Question
What characterizes non-competitive inhibition on enzyme activity?
Answer
Vmax decreases, Km remains same.
19
Question
Which receptor type facilitates rapid responses via ion channels?
Answer
Ionotropic receptors.
20
Question
What is a key feature of enzymatic receptors?
Answer
Drug binds on the membrane, enzyme activates inside.
21
Question
How do G-protein coupled receptors (GPCRs) work?
Answer
By altering cAMP, Ca2+, or opening ion channels.
22
Question
More efficacy in a drug means?
Answer
Greater maximum effect regardless of dose.
23
Question
What is the significance of potency?
Answer
Less drug needed for effect.
24
Question
What does a sigmoidal dose-response curve indicate?
Answer
Gradual increase in response with dose.
25
Question
Which phase of clinical trials is conducted on healthy volunteers for pharmacokinetics?
Answer
Phase 0.
26
Question
What is the median effective dose (ED50)?
Answer
Dose at which 50% respond.
27
Question
Which schedule of drugs in India requires prescription by a registered medical practitioner?
Answer
Schedule H.
28
Question
What is the main difference between enzyme inducers and inhibitors?
Answer
Inducers increase enzyme activity; inhibitors decrease it.
29
Question
What is the therapeutic index, and what does it indicate?
Answer
LD50/ED50; safety margin of the drug.
30
Question
What is a spurious drug?
Answer
Fake or imitation drug designed to deceive.