FOUNDATION – PHARMACOLOGY

Foundation

FOUNDATION – Pharmacology

Compiled Topical Questions of Foundation – Pharmacology

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“When a drug binds to a receptor and causes a specific effect — like lowering blood pressure or relieving pain — what term best describes this interaction?”

1 / 45

Tags: 2016

What is the effect of drugs on the body called?

Pharmacokinetics

Pharmacogenomics

None of these

Pharmacogenesis

Pharmacodynamics

Focus on the process that involves the movement of a drug into, through, and out of the body. Consider which option describes the body’s handling of a drug rather than the drug’s effects on the body.

2 / 45

Tags: 2021

What is meant by the term pharmacokinetics?

Methods of new drug development

Absorption, metabolism and excretion of drugs

Study of identification of drugs

Effect of drug on body

Biological and therapeutic effects of drug

💡Hint:

“When a drug reaches its target—its mechanism of action, therapeutic effects, and side effects—is studied under this branch. Think ‘drug mechanism’ .

3 / 45

Tags: 2021

Pharmacodynamics is the study of which of the following?

Absorption of drugs

Action of drugs on body

Excretion of drugs

Metabolism of drugs

Assimilation of drugs

Bioavailability is often expressed as a percentage and takes into account not only how much of the drug reaches circulation but also how much of it remains in its active form.

4 / 45

Tags: 2017

Which of the following statements best describes bioavailability?

The fraction of administered drug that reaches the systemic circulation in unchanged form

The rate of absorption of the administered drug into the systemic circulation

The frequency at which the administered drug reaches the systemic circulation

The speed at which the administered drug reaches the systemic circulation

The amount of administered drug that reaches the systemic circulation

Bioavailability refers to the proportion of a drug that enters the systemic circulation unchanged after it is administered. It reflects how much of the drug reaches the bloodstream and is available for therapeutic action. Let’s go through each option:

The speed at which the administered drug reaches the systemic circulation:

This describes the rate of absorption or the onset of action of the drug, but it is not bioavailability. Bioavailability involves how much of the drug reaches circulation, not how quickly it does so. Therefore, this option is incorrect.

The frequency at which the administered drug reaches the systemic circulation:

This option is unclear and does not accurately describe bioavailability. Bioavailability is not about how often a drug reaches circulation but rather about the amount and extent of the drug that reaches the bloodstream. Therefore, this option is incorrect.

The amount of administered drug that reaches the systemic circulation:

This statement is partially correct but lacks precision. Bioavailability specifically refers to the fraction or percentage of the drug that reaches the systemic circulation in an unchanged form, not just the amount. The total amount is important, but the form (unchanged) is essential for bioavailability. Therefore, this option is not fully correct.

The rate of absorption of the administered drug into the systemic circulation:

This describes how quickly the drug is absorbed into circulation, but bioavailability encompasses both how much and in what form the drug reaches circulation. The rate of absorption alone does not define bioavailability. Therefore, this option is incorrect.

The fraction of administered drug that reaches the systemic circulation in unchanged form:

This is the most accurate definition of bioavailability. It refers to the proportion of the drug that enters the bloodstream in its active, unchanged form, which is essential for its therapeutic effect. This is the correct answer.

When you need to get a drug into the bloodstream as quickly as possible, think about a method that bypasses the digestive system and goes straight into the circulatory system. Which route does that?

5 / 45

Tags: 2018

A 3-year-old boy has ingested some toxins that may kill him. Which of the following routes of administering the antidote will have the most rapid effect?

Rectal

Subcutaneous

Oral

Sublingual

Intravenous (IV)

The question asks about the route of administration for an antidote that will have the most rapid effect on a 3-year-old boy who has ingested toxins. When it comes to drug absorption, the route of administration plays a crucial role in how quickly the medication reaches the bloodstream and takes effect. The question aims to determine which route will provide the fastest therapeutic action.

Breakdown of the Answer Choices:

Rectal:
- Explanation: Rectal administration involves inserting a medication into the rectum, where it is absorbed into the bloodstream through the mucosal lining. It can be faster than oral administration but generally slower than intravenous (IV) or sublingual routes. Rectal administration is often used when a person cannot take medicine orally, but it may not be the quickest option.
- Why it’s incorrect: While rectal can be relatively fast, it is still slower than intravenous (IV) or sublingual administration.
Oral:
- Explanation: Oral administration involves swallowing the medication, which then has to pass through the digestive system before it is absorbed into the bloodstream. This is the most common route, but it is slower because it requires digestion and absorption in the intestines.
- Why it’s incorrect: Oral is the slowest route among the choices listed because the drug must first be digested and absorbed in the gastrointestinal tract.
Sublingual:
- Explanation: Sublingual administration involves placing the medication under the tongue, where it is absorbed directly into the bloodstream through the mucous membranes in the mouth. This route bypasses the digestive system and liver metabolism, leading to faster absorption compared to oral or rectal administration.
- Why it’s correct: Sublingual is faster than oral and rectal routes because it allows direct absorption into the bloodstream through the mucous membranes under the tongue. This makes it one of the quickest methods of drug absorption.
Intravenous (IV) (Correct Answer):
- Explanation: Intravenous (IV) administration involves injecting the medication directly into the vein, allowing it to enter the bloodstream immediately. This is the fastest route for administering a drug because it bypasses all absorption processes and delivers the drug directly to the circulatory system.
- Why it’s correct: IV is the fastest route of drug administration. Since the antidote is directly injected into the bloodstream, it will reach the target tissues and organs almost immediately, making it the most rapid route in urgent situations like poisoning.
Subcutaneous:
- Explanation: Subcutaneous (SC) administration involves injecting the medication into the layer of tissue just under the skin. This route is slower than IV because the drug must first diffuse into the bloodstream. Subcutaneous injection is commonly used for slower-release drugs or when IV access is not available.
- Why it’s incorrect: Subcutaneous administration is slower than both IV and sublingual routes because it requires absorption into the capillaries from the tissue.

Think about situations where time is critical — like a patient in cardiac arrest or status epilepticus. Which drug route would deliver medication fast enough to potentially save their life?

6 / 45

Tags: 2018

Which of the following states the advantage of parenteral drug administration?

It is too slow to be used in an emergency

It has slow-onset and long duration of action

It cannot be used in unconscious patients

It can provide an immediate effect

Its dosage cannot be monitored

Parenteral drug administration refers to any route of drug delivery that bypasses the gastrointestinal (GI) tract, such as intravenous (IV), intramuscular (IM), and subcutaneous (SC) routes. Among these, IV administration is especially known for providing an immediate and rapid effect because the drug is delivered directly into the systemic circulation. This makes parenteral routes ideal in emergency situations where fast drug action is crucial, like in cardiac arrest, anaphylaxis, or shock.

For example:

IV adrenaline (epinephrine) in anaphylactic shock
IV diazepam for status epilepticus
IV antibiotics for severe infections

Why the other options are incorrect:

“It cannot be used in unconscious patients” — Incorrect
Parenteral administration is actually the preferred route for unconscious patients because they can’t swallow oral medications. This makes IV, IM, and SC routes very useful when a patient is comatose, sedated, or under general anesthesia.
“Its dosage cannot be monitored” — Incorrect
Dosage in parenteral administration can be closely monitored, especially with IV drugs. IV infusion allows precise control over drug levels, and titration of dosage can be done by adjusting the infusion rate. In emergencies, bolus doses can be given rapidly, and the effect can be immediately observed and adjusted.
“It is too slow to be used in an emergency” — Incorrect
Parenteral routes — especially IV administration — are the fastest way to deliver drugs in emergencies. Drugs administered IV start working within seconds to minutes, making them ideal for life-threatening situations.
“It has slow-onset and long duration of action” — Incorrect
This statement applies more to some oral medications and certain intramuscular or subcutaneous drugs, but not parenteral administration overall. IV drugs have rapid onset and short duration, while IM drugs might have a moderate onset and longer action depending on the formulation.

Imagine drug metabolism as a two-step process. Phase I is like preparing the drug for disposal, and Phase II is like packaging it up for removal. Which of these options sounds like it belongs in the “packaging” stage?

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Tags: 2022

Which of the following is not a phase 1 reaction in the process of drug metabolism?

Reduction

Dehydrogenation

Hydrolysis

Conjugation

Oxidation

Think about the difference between a sudden, immediate loss of drug effect and a gradual decrease over time.

8 / 45

Tags: 2019

What is the rapid reduction in the response of a drug after a single administration defined as?

Supersensitivity

Tachyphylaxis

Tolerance

Anaphylaxis

Hypersensitivity

“Once a drug binds to a receptor, what determines whether it can trigger a response or not?”

9 / 45

Tags: 2021

What is the ability of the drug to elicit a response after binding to a receptor called?

Efficacy

Elimination

Potency

Pharmacology

Intrinsic activity

Consider how a drug spreads throughout the body. If a drug is mostly confined to the bloodstream, its distribution is minimal. However, if it moves extensively into tissues, only a small amount remains in plasma. How might this relationship be expressed in terms of a ratio involving the administered amount and its detectable concentration in the plasma?

10 / 45

Tags: 2020

What is the formula for the calculation of the volume distribution of drugs?

Vd = Plasma concentration / dose

Vd = administered dose / plasma concentration

Vd= plasma concentration + dose

Vd = 2 x plasma concentration / dose

Vd = plasma concentration × dose

Option	Why It’s Incorrect or Correct	Correct?
Vd = plasma concentration + dose	Invalid concept; addition not meaningful	❌ No
Vd = 2 × plasma concentration / dose	Arbitrary; doesn’t fit pharmacokinetic principle	❌ No
Vd = plasma concentration × dose	Units don’t match; not consistent with Vd definition	❌ No
Vd = plasma concentration / dose	Inverse of correct formula	❌ No
Vd = administered dose / plasma concentration	✅ Matches definition and units of volume of distribution	✅ Yes

“Which route bypasses the digestive system and ensures a higher percentage of the drug reaches the bloodstream directly?”

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Tags: 2021

What is the advantage of the parenteral route?

Cannot be used in emergency

Takes time to reach the site of action

Delayed access to systematic circulation

Cannot be given to unconscious patients

Greater absorption than oral route

Think about how we assess drug safety: What ratio involves comparing the dose that causes harmful effects in 50% of people to the dose that causes therapeutic effects in 50% of people?

12 / 45

Tags: 2017

How can the therapeutic index be calculated?

TD₅₀/ED₅₀

Pharmacokinetics/pharmacodynamics

Efficacy/potency

[E]/[Eₘ‎ₐₓ]

PT/INR

The therapeutic index (TI) is a measure of the safety of a drug. It compares the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity. The higher the therapeutic index, the safer the drug, as it indicates a greater margin between effective and toxic doses.

1. Pharmacokinetics/pharmacodynamics:

Pharmacokinetics refers to the absorption, distribution, metabolism, and excretion of a drug, while pharmacodynamics refers to the effects of the drug on the body. While both of these are important in understanding a drug’s action, the therapeutic index itself is specifically calculated using toxic and effective dose measurements (TD₅₀/ED₅₀), not through pharmacokinetic or pharmacodynamic principles. Therefore, this is not the correct answer.

2. TD₅₀/ED₅₀:

The therapeutic index is calculated as the ratio of the toxic dose (TD₅₀, the dose that causes toxicity in 50% of individuals) to the effective dose (ED₅₀, the dose that produces a therapeutic effect in 50% of individuals). Thus, the formula for the therapeutic index is:

\text{Therapeutic Index} = \frac{TD_{50}}{ED_{50}}

This ratio provides a quantitative measure of the safety margin of a drug. A higher TI means there is a greater difference between the therapeutic and toxic doses, indicating a safer drug. Option 2 is the correct answer.

Efficacy/potency:

Efficacy refers to the maximum effect a drug can produce, while potency refers to the amount of drug required to produce a given effect. While both concepts are important in pharmacology, they are not directly related to the calculation of the therapeutic index. The TI involves the ratio of toxic dose to effective dose, not efficacy and potency. Therefore, this option is not correct.

PT/INR:

PT (Prothrombin Time) and INR (International Normalized Ratio) are used to measure the clotting ability of blood and are not related to the therapeutic index. These are typically used to monitor anticoagulant therapy, particularly with drugs like warfarin. Therefore, this option is not correct.

[E]/[Eₘ‎ₐₓ]:

This expression likely refers to the fractional response (E/Eₘ‎ₐₓ), where E is the observed effect and Eₘ‎ₐₓ is the maximum possible effect of the drug. While this is related to the potency and efficacy of a drug, it is not used to calculate the therapeutic index. Thus, this option is incorrect.

Which drug, once used as a sedative during pregnancy, became notorious for causing severe congenital limb deformities and led to a major shift in the way medications are tested for safety in pregnancy?

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Tags: 2018

A couple has a baby delivered with shortened limbs. Upon investigation, it was found that, during pregnancy, the mother was using tranquilizers. Which of the following contraindicated drug was used?

Thalidomide

Insulin

Tetracycline

Aspirin

Warfarin

Think about where drugs need to go to be eliminated from the body. Are the kidneys and urine more “watery” or “oily”?

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Tags: 2019

Which of the following is true regarding biotransformation?

It decreases lipid solubility of a drug

It causes hydrolysis of a drug

It decreases ionization of a drug

It increases lipid solubility of a drug

It increases ionization of a drug

Think about how two drugs can produce opposite effects on the same tissue without directly interacting with each other. What type of antagonism involves different receptors or pathways?

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Tags: 2020

Two drugs act on the same organ or tissue and activate different receptors that produce different responses. Which type of antagonism is this?

Competitive

Physiological

Dispositional

Pharmacological

Chemical

The question describes a scenario where two drugs act on the same organ or tissue but activate different receptors, leading to different responses. This situation is an example of **physiological antagonism**. Let’s break down why this is the correct answer and why the other options are incorrect.

Correct Option: Physiological AntagonismPhysiological antagonism occurs when two drugs act on the same tissue or organ but produce opposite effects by acting on different receptors or pathways. The drugs do not directly interact with each other; instead, their effects counteract each other at the level of the tissue or organ.

– Example: Histamine and adrenaline (epinephrine) act on the bronchial smooth muscle. Histamine binds to H1 receptors, causing bronchoconstriction, while adrenaline binds to β2-adrenergic receptors, causing bronchodilation. These opposing effects are physiological antagonism.

Why the Other Options Are Incorrect:Pharmacological antagonismThis refers to a situation where one drug blocks the effect of another drug by acting on the same receptor. For example, naloxone is a pharmacological antagonist of morphine because it binds to opioid receptors and blocks morphine’s effects. This is not the case in the question, as the drugs act on different receptors.

Chemical antagonism:
– This occurs when two drugs chemically interact with each other to neutralize their effects. For example, protamine sulfate binds to heparin to form an inactive complex. This is not relevant to the question, as there is no chemical interaction between the drugs.

Dispositional antagonism:
– This refers to a situation where one drug reduces the concentration of another drug at its site of action, often by altering absorption, distribution, metabolism, or excretion. For example, a drug that induces liver enzymes might increase the metabolism of another drug, reducing its effectiveness. This is not the case in the question.

Competitive antagonism:
– This occurs when two drugs compete for the same receptor site. The antagonist binds reversibly to the receptor, preventing the agonist from binding and producing its effect. For example, atropine competitively antagonizes acetylcholine at muscarinic receptors. This is not the case in the question, as the drugs act on different receptors.

Think about the speed at which the body adapts to a drug. Which term describes a rapid decrease in drug effectiveness after just one or a few doses?

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Tags: 2020

What is the rapid reduction in the response of a drug after a single administration defined as?

Anaphylaxis

Tolerance

Hypersensitivity

Tachyphylaxis

Supersensitivity

When thinking of how a drug produces its effects on the body, like reducing pain, lowering blood pressure, or inhibiting an enzyme.

17 / 45

Tags: 2018

What is the action of a drug on the body known as?

Pharmacokinetics

Drug clearance

Solubility

Pharmacodynamics

Bioavailability

Consider the pharmacokinetics of insulin—why would a diabetic patient need steady drug levels over several hours rather than an immediate spike?”

18 / 45

Tags: 2017

The subcutaneous route is used due to which of the following advantages?

Immediate action

Fast absorption

Slow absorption

Avoids usage of injections

Prevention of shock

“A drug can bind perfectly to a receptor — but what really matters is what happens next. Does it cause a strong effect, a weak one, or none at all? This term captures the strength of the signal after the connection.”

19 / 45

Tags: 2016

What is the ability of the drug to elicit a response after binding to a receptor called?

Potency

Efficacy

Pharmacology

Elimination

Intrinsic activity

Think about which route involves the drug passing through the liver before reaching the rest of the body. The liver plays a key role in metabolizing substances before they can take effect systemically — but not all administration routes take the drug there first.

20 / 45

Tags: 2018

Drug administration through which of the following routes is most likely to go through first pass metabolism?

Intravenous

Buccal

Intramuscular

Oral

Subcutaneous

When a drug is administered orally, it is absorbed through the gastrointestinal (GI) tract — specifically from the stomach and small intestine. From there, the drug enters the portal circulation and travels directly to the liver before it reaches the systemic bloodstream. In the liver, the drug undergoes first-pass metabolism (also called pre-systemic metabolism), where a significant portion of the drug can be metabolized and inactivated before it has a chance to reach the rest of the body.

This process can greatly reduce the bioavailability (the fraction of the administered dose that reaches systemic circulation in an active form) of certain drugs. Drugs like propranolol and morphine undergo extensive first-pass metabolism, which is why their oral doses are much higher compared to their intravenous doses.

Why the Other Options Are Incorrect:

Intravenous (IV):
Drugs administered through IV bypass the GI tract and enter the systemic circulation directly. This completely avoids first-pass metabolism because the liver is not involved before the drug reaches the rest of the body. That’s why IV drugs usually have 100% bioavailability.
Intramuscular (IM):
IM injections deliver the drug into the muscle tissue, where it is absorbed into the systemic circulation without passing through the liver first. This also bypasses first-pass metabolism. However, absorption rate can vary depending on the blood flow to the muscle.
Subcutaneous (SC):
Like IM, subcutaneous drugs are absorbed into the systemic circulation directly from the fatty tissue under the skin. There is no first-pass effect here either, but the absorption can be slower compared to IM due to lower blood supply in the subcutaneous tissue.
Buccal:
Buccal administration (placing the drug inside the cheek) allows the drug to be absorbed through the oral mucosa directly into the systemic circulation, bypassing the liver. This route avoids first-pass metabolism and allows for faster onset of action for certain drugs.

Which drug, often used to help the baby’s lungs mature in cases of expected premature birth, might also impact fetal circulatory structures like the ductus arteriosus if overused or misused?

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Tags: 2018

A case of premature closure of the ductus arteriosus is seen. Which drug was the fetus exposed to?

Corticosteroids

Insulin

Tranquillizer

Retinoic acid

Tetracycline

Consider how the body responds to a drug when it “overreacts” in a way that can cause serious symptoms like difficulty breathing, swelling, or even shock. What term would describe this dangerous immune response that happens very quickly after exposure to the drug?

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Tags: 2018

What is the immune-mediated response activated in a patient in response to a certain drug called?

Idiosyncrasy

Tolerance

Supersensitivity

Tachyphylaxis

Anaphylaxis

The question asks about the immune-mediated response triggered in a patient when they are exposed to a certain drug. To answer correctly, we need to understand the various terms and how they relate to immune responses.

Breakdown of the Terms:

Let’s analyze each of the options provided:

Tachyphylaxis:
- Definition: Tachyphylaxis refers to a rapid decrease in the response to a drug after its administration. This is often observed in cases where the body quickly becomes less responsive to the drug with repeated doses. It is not an immune-mediated response but rather a pharmacological phenomenon where the drug’s effectiveness diminishes over time.
- Why it’s incorrect: Tachyphylaxis is about drug tolerance at a receptor or cellular level and does not involve an immune response.
Supersensitivity:
- Definition: Supersensitivity occurs when the body becomes overly sensitive to a drug or substance, often due to alterations in receptor sensitivity or number. This can be a result of previous drug exposure, but it is more of a pharmacodynamic phenomenon than an immune-mediated one.
- Why it’s incorrect: Supersensitivity refers to altered physiological responses and does not involve the immune system’s direct involvement in the reaction.
Tolerance:
- Definition: Tolerance refers to the diminishing effect of a drug over time as the body becomes accustomed to its presence. This can occur due to pharmacokinetic or pharmacodynamic adaptations but, like tachyphylaxis, is not an immune response.
- Why it’s incorrect: Tolerance involves a decreased drug effect over time and does not involve immune-mediated reactions.
Idiosyncrasy:
- Definition: Idiosyncrasy refers to an unusual or abnormal reaction to a drug that is genetically determined and is not typically immune-mediated. It can lead to severe drug reactions in certain individuals, but it is not caused by an immune response.
- Why it’s incorrect: While idiosyncratic reactions can be unpredictable and severe, they are not primarily immune-mediated but are more related to individual genetic differences in drug metabolism.
Anaphylaxis (Correct Answer):
- Definition: Anaphylaxis is a severe, systemic allergic reaction triggered by the body’s immune system in response to a drug (or other allergens). It is a classic type I hypersensitivity reaction mediated by IgE antibodies and involves the release of histamines and other inflammatory mediators that cause symptoms like swelling, difficulty breathing, and hypotension.
- Why it’s correct: Anaphylaxis is the immune-mediated response that is specifically triggered by drugs (or other substances) in hypersensitive individuals. It involves an immediate, potentially life-threatening response by the immune system, making it the best answer for this question.

Think about a situation where a person requires progressively higher doses of a drug over time to achieve the same effect. This phenomenon is common in pain management and addiction medicine.

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Tags: 2021

Which of the following refers to the gradual decrease in responsiveness due to repeated administration of the drug?

Tachyphylaxis

Placebo effect

Hypersensitivity

Tolerance

Idiosyncrasy

This type of antagonism neutralizes toxins by direct binding, rather than working through receptor mechanisms.

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Tags: 2023

A patient is given drug X to decrease the toxicity of heavy metal by directly binding to it and not allowing it to bind to tissues. Which of the following is an example of this kind of antagonism?

Chemical

Functional

Pharmacokinetic

Allosteric

Irreversible

Think about how protein levels affect drug binding

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Tags: 2019

Which statement correctly describes the situation of the administration of a drug to a malnourished child?

Less drug will remain free in blood due to increased level of plasma proteins

There will be decreased drug excretion due to decreased renal activity

There will be increased drug excretion due to increased renal activity

More drug will remain free in blood due to decreased level of plasma proteins

There will be fast absorption of drug in gastrointestinal tract leading to increased drug effect

Think about the purpose of drug metabolism in the body. What property of drugs needs to be altered to ensure they can be excreted efficiently?

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Tags: 2020

What is the effect of biotransformation on drugs?

Less lipid soluble

More pharmacologically active

Less readily eliminated

Less ionized

More lipid soluble

What is Biotransformation?

Biotransformation, also known as drug metabolism, is the chemical modification of drugs by the body — mainly occurring in the liver through specialized enzymes, primarily from the cytochrome P450 family.

Purpose of Biotransformation:

The body’s goal is to convert lipid-soluble drugs (which can cross cell membranes easily and accumulate) into water-soluble, ionized forms that can be eliminated through urine or bile.
This process usually deactivates the drug but may sometimes activate a prodrug or generate toxic metabolites.

Phases of Biotransformation:

Phase I (Functionalization): Adds or exposes functional groups (-OH, -NH₂) via oxidation, reduction, hydrolysis.
Phase II (Conjugation): Adds large polar groups (like glucuronide, sulfate) making the compound highly water-soluble.

✅ Why “Less Lipid Soluble” is Correct:

After biotransformation, the drug becomes less lipid-soluble and more polar (water-soluble).
This change helps the kidneys eliminate the drug more easily since lipid-soluble substances are reabsorbed in the renal tubules while water-soluble substances are excreted.

❌ Why the Other Options Are Incorrect:

❌ Less ionized:

Incorrect because: Biotransformation generally makes the drug more ionized (polar), enhancing water solubility for elimination.
Key Principle: Ionized drugs don’t cross membranes easily and are better excreted.

❌ More pharmacologically active:

Partially true in special cases: Some prodrugs become active after metabolism, but this is not the general effect.
Overall: Biotransformation usually reduces activity or prepares the drug for elimination.

❌ Less readily eliminated:

Completely opposite of the goal: Biotransformation is specifically designed to enhance elimination by making the drug water-soluble.

❌ More lipid soluble:

Incorrect because: If the drug became more lipid-soluble, it would stay in fat stores and membranes longer — defeating the body’s goal of excretion.

“Drugs don’t last forever in the body. What is the process that breaks them down?”

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Tags: 2019

Which of the following refers to the process that makes the drugs less effective?

Phosphorylation

Hydrogenation

Glycosylation

Oxidation

Biotransformation

Think of how small, lipid-soluble molecules easily slip through cell membranes without needing energy. That’s the simplest and most common absorption method.

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Tags: 2019

A person uses aspirin (pain killer) for headache relief. What is the most common method of absorption of drugs?

Carrier mediated transport

Osmosis

Endocytosis

Active transport

Passive diffusion

This reaction is associated with Phase II, not Phase I metabolism.

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Tags: 2017

Which of the following is not a phase I reaction?

Deamination

Reduction

Glucuronidation

Oxidation

Hydrolysis

When thinking of folic acid inhibitors, remember drugs that target bacterial enzymes in the folate pathway, like dihydrofolate reductase or dihydropteroate synthase

30 / 45

Tags: 2016

Which drug prevents the synthesis of folic acid?

Chloramphenicol

Probenecid

Isoniazid

Trimethoprim

Chloroquine

Drugs that are highly lipid-soluble or bind extensively to tissues they are stored in body compartments outside the bloodstream.

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Tags: 2023

A pharmacologist invents a new drug and experiments with it on a human volunteer. What is the earliest evidence that the drug is most likely being stored in tissue?

A large volume of distribution

Decreased rate of drug metabolism

Increased number of side effects

Increased plasma protein bounding

Decreased amount of free drug excreted in the urine

Think about the branch of pharmacology that focuses on the effects of drugs and their mechanisms of action. Which term describes what the drug does to the body, rather than what the body does to the drug?

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Tags: 2017

What is the action of a drug on the body known as?

Pharmacokinetics

Bioavailability

Drug clearance

Pharmacodynamics

Solubility

Some acne medications are strictly avoided during pregnancy due to their severe effects on fetal brain development. What key ingredient do they contain?

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Tags: 2018

A pregnant woman with chronic cough takes cough syrup during her gestation. Cough syrups cause mental retardation of the fetus. Which of the following components of the cough syrup are responsible for this?

Retinoic acid

Potassium iodide

Tetracycline

Thalidomide

Ethylene

Correct Answer: Retinoic Acid

✔ Retinoic acid (isotretinoin or vitamin A derivatives) is a potent teratogen that disrupts normal embryonic development.
✔ It is commonly found in acne medications (e.g., isotretinoin/Accutane) and some cough syrups that contain vitamin A derivatives.
✔ Teratogenic effects of retinoic acid:

Mental retardation & intellectual disabilities
Craniofacial abnormalities (e.g., microcephaly, cleft palate)
Cardiovascular defects
Thymic hypoplasia
Central nervous system malformations

Why it is in some cough syrups?

Some cough syrups contain vitamin A derivatives for their mucosal healing and immune-boosting properties.
Excess retinoic acid during pregnancy disrupts neural crest cell migration, leading to severe birth defects.

❌ Why the Other Options Are Incorrect?

1. Potassium Iodide ❌

Potassium iodide is sometimes used as an expectorant in cough syrups.
It can cause fetal hypothyroidism if taken in excess but does not cause mental retardation directly.
Effects of excess iodine in pregnancy:
- Goiter in fetus
- Hypothyroidism (Cretinism) → Can lead to intellectual disability, but only indirectly
Since the primary teratogen in the question directly causes mental retardation, potassium iodide is not the best answer.

2. Tetracycline ❌

Tetracycline is an antibiotic, not a common ingredient in cough syrups.
It is teratogenic but mainly affects bone and teeth development, not the brain.
Effects of tetracycline in pregnancy:
- Permanent yellow-gray tooth discoloration
- Inhibition of bone growth
Since mental retardation is not a primary effect, tetracycline is incorrect.

3. Ethylene ❌

Ethylene is an industrial chemical used in plastics and antifreeze, not a typical component of cough syrups.
High exposure can be toxic, but it is not a known teratogen associated with mental retardation.

4. Thalidomide ❌

Thalidomide is a well-known teratogen, but it is not found in cough syrups.
It was used in the 1950s-60s as a sedative and anti-nausea drug, leading to limb malformations (phocomelia).
Major effects of thalidomide exposure in pregnancy:
- Severe limb defects (“flipper limbs”)
- Ear and eye malformations
- Congenital heart defects
While it is a potent teratogen, it does not primarily cause mental retardation, making it an incorrect choice.

“Nature is the first pharmacy—think of the study that uncovers medicinal secrets hidden in plants, animals, and minerals!”

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Tags: 2021

What is the term used for the study of natural drugs and their physical and chemical properties?

Pharmacognosy

Pharmacodynamics

Pharmacy

Toxicology

Pharmacopoeia

Think about the barriers that drugs must overcome when administered orally. Which route bypasses these barriers entirely, ensuring faster and more reliable drug delivery?

35 / 45

Tags: 2020

What is the advantage of the parenteral route?

Takes time to reach the site of action

Cannot be given to unconscious patients

Greater absorption than oral route

Delayed access to systematic circulation

Cannot be used in emergency

The question is about the advantages and disadvantages of the parenteral route of drug administration, which is a key topic in pharmacology. The parenteral route refers to administering drugs by injection or infusion, bypassing the gastrointestinal tract. Let’s analyze each option to determine which one correctly describes an advantage of the parenteral route.

Correct Answer: Greater absorption than oral route

Why is this correct?
– The parenteral route (e.g., intravenous, intramuscular, subcutaneous) allows drugs to be directly absorbed into the bloodstream or tissues, bypassing the gastrointestinal tract.
– This results in greater and more predictable absorption compared to the oral route, where drugs may be subject to first-pass metabolism, degradation by stomach acid, or variability in gastrointestinal absorption.
– Parenteral administration is particularly useful for drugs that are poorly absorbed orally or for situations where rapid and precise drug delivery is required.

Incorrect Options:

Cannot be given to unconscious patients:
– This statement is incorrect. The parenteral route is often the preferred method for administering drugs to unconscious patients because it does not require the patient to swallow or cooperate.
– Why it’s wrong:The parenteral route is actually ideal for unconscious patients, as it ensures reliable drug delivery.

Cannot be used in emergency:
– This statement is incorrect. The parenteral route is **commonly used in emergencies** because it allows for rapid drug delivery and immediate effects.
– Why it’s wrong: Parenteral administration (e.g., intravenous injection) is the fastest way to deliver drugs in critical situations.

Takes time to reach the site of action:
– This statement is incorrect. The parenteral route, especially intravenous administration, delivers drugs directly into the bloodstream, allowing them to reach the site of action almost immediately.
– Why it’s wrong: Parenteral administration is known for its rapid onset of action, not delayed effects.

Delayed access to systemic circulation:
– This statement is incorrect. The parenteral route provides immediate access to systemic circulation, particularly with intravenous administration.
– Why it’s wrong:Parenteral administration is designed to bypass barriers to absorption, ensuring quick access to the bloodstream.

The reaction involves an immune system overreaction, often mediated by histamine release, and can lead to severe allergic symptoms like swelling, rash, or even shock.

36 / 45

Tags: 2017

What is the immune-mediated response activated in a patient in response to a certain drug called?

Tolerance

Anaphylaxis

Supersensitivity

Tachyphylaxis

Idiosyncrasy

Consider the purpose of each phase of biotransformation. What is the goal of phase 2 reactions, and how do they differ from phase 1 reactions? Think about the chemical modifications that make a drug more water-soluble and easier to excrete.

37 / 45

Tags: 2020

Which process occurs in phase 2 of biotransformation?

Hydrolysis

Acetylation

Phosphorylation

Oxidation

Reduction

Biotransformation is the process by which the body modifies chemical compounds, such as drugs or toxins, to make them more water-soluble and easier to excrete. It typically occurs in two phases: Phase 1 and Phase 2. The question specifically asks about Phase 2 of biotransformation. Let’s analyze each option to determine why the correct answer is Acetylation and why the others are incorrect.

Correct Answer: Acetylation

– Why it’s correct: Acetylation is a Phase 2 biotransformation reaction. In Phase 2, the products of Phase 1 reactions (or the original compound if it already has a functional group) are conjugated with endogenous molecules to increase their water solubility. Acetylation involves the addition of an acetyl group (CH₃CO-) to a compound, typically using acetyl-CoA as the donor. This process is catalyzed by enzymes such as N-acetyltransferases and is important for the metabolism of drugs like isoniazid and sulfonamides.

Incorrect Answers:

Reduction
– Why it’s wrong: Reduction is a Phase 1 reaction, not a Phase 2 reaction. In Phase 1, reduction involves the addition of electrons or hydrogen atoms to a molecule, often making it more reactive for subsequent Phase 2 conjugation. Examples include the reduction of nitro groups to amines or ketones to alcohols. Reduction does not involve conjugation with endogenous molecules, which is the hallmark of Phase 2 reactions.

Hydrolysis
– Why it’s wrong: Hydrolysis is also a Phase 1 reaction. It involves the breakdown of a compound by the addition of water, often resulting in the formation of smaller, more polar molecules. For example, esterases and amidases catalyze the hydrolysis of esters and amides, respectively. Like reduction, hydrolysis does not involve conjugation and is not part of Phase 2 biotransformation.

Oxidation
– Why it’s wrong: Oxidation is another Phase 1 reaction. It involves the loss of electrons or the addition of oxygen to a molecule, often catalyzed by cytochrome P450 enzymes. Oxidation reactions include hydroxylation, dealkylation, and deamination. While oxidation makes compounds more reactive for Phase 2 conjugation, it is not itself a Phase 2 process.

Phosphorylation
– Why it’s wrong: Phosphorylation is not a typical Phase 2 biotransformation reaction. It involves the addition of a phosphate group to a molecule and is more commonly associated with cellular signaling and energy metabolism (e.g., ATP production). Phosphorylation is not a standard mechanism for increasing the water solubility of drugs or toxins.

Think about the characteristics of the subcutaneous tissue and how it affects the absorption rate of drugs?

38 / 45

Tags: 2020

What is the advantage of administering drugs through the subcutaneous route?

Fast releasing drugs are given subcutaneously

Gives immediate drug action

Slow releasing drugs are given subcutaneously

Useful when patients are under anaphylactic shock

Gives a longer duration of action

Think about the process that occurs in the liver and involves enzymes modifying drugs to prepare them for excretion.

39 / 45

Tags: 2020

Which of the following refers to the process that makes the drugs less effective?

Glycosylation

Phosphorylation

Hydrogenation

Biotransformation

Oxidation

Think about the maximum effect a drug can produce, regardless of the dose. Which pharmacological term describes this concept?

40 / 45

Tags: 2020

What is the ability of a drug to produce a response called?

Bioavailibilty

Intrinsic activity

Potency

Efficacy

Kinematics

think of an enzyme that prevents DNA from tangling — and quinolones lock it up, stopping bacterial growth.

41 / 45

Tags: 2016

Quinolones inhibit the activity of which of the following enzymes?

RNA primer

Helicase

DNA polymerase

Topoisomerase 2

RNA polymerase

Think about medications like insulin. Why are they often given subcutaneously rather than intravenously? Is it to get a fast or slow, prolonged effect?

42 / 45

Tags: 2019

The subcutaneous route is used due to which property?

Slow absorption and prolonged effect

Fast absorption

Avoids usage of injections

Prevention of shock

Immediate effect

Consider which acne medication is known to be highly dangerous in pregnancy, requiring women to avoid pregnancy during and after treatment due to its ability to cause multiple organ system malformations, including the face, brain, and heart.

43 / 45

Tags: 2018

A mother gives birth to a baby with craniofacial defects as well as cardiovascular and central nervous system malformations. During history taking it is found that the mother used drugs for her acne during pregnancy. To which drug was the fetus exposed?

Corticosteroids

Angiotensin enzyme inhibitor

Retinoic acid

Antibiotics

Thyroxine

“A key fits into a lock, but some keys fit better than others.”

44 / 45

Tags: 2021

Which of the following refers to the affinity of the drug?

How tightly drug binds to plasma proteins

Measure of inhibiting potency of a drug

Measure of bioavailability of a drug

How drug binds to a receptor

Measure of rate at which it is eliminated

This drug administration route passes through the liver before entering systemic circulation, significantly reducing bioavailability.

45 / 45

Tags: 2023

A 45-year-old patient is being administered a drug through a route that offers the most first-pass metabolism. Through which route is the drug most likely being administered?

Inhalation

Oral

Sublingual

Intramuscular

Rectal

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FOUNDATION – PHARMACOLOGY

💡Hint:

Why the Other Options Are Incorrect

Breakdown of the Answer Choices:

Why the Other Options Are Wrong:

💊 What is Volume of Distribution (Vd)?

✅ Why This Formula is Correct:

❌ Why the Other Options Are Incorrect:

📌 Summary Table:

Why the Other Options Are Wrong:

❌ Why Other Options Are Incorrect:

❌ Why Other Options Are Incorrect:

Breakdown of the Terms:

Why the Other Options Are Incorrect

How Chemical Antagonism Works in Heavy Metal Toxicity:

Why not the other options?

What is Biotransformation?

Purpose of Biotransformation:

Phases of Biotransformation:

✅ Why “Less Lipid Soluble” is Correct:

❌ Why the Other Options Are Incorrect:

❌ Less ionized:

❌ More pharmacologically active:

❌ Less readily eliminated:

❌ More lipid soluble:

Why the Other Options Are Wrong:

Why is a Large Volume of Distribution (Vd) the Best Indicator of Tissue Storage?

Why not the other options?

Correct Answer: Retinoic Acid

❌ Why the Other Options Are Incorrect?

1. Potassium Iodide ❌

2. Tetracycline ❌

3. Ethylene ❌

4. Thalidomide ❌

Why the Other Options Are Wrong:

❌ Why Other Options Are Incorrect:

Why the Other Options Are Incorrect:

Why Does Oral Administration Have the Highest First-Pass Metabolism?

Why not the other options?

FOUNDATION – PHARMACOLOGY

Report a question

💡Hint:

Why the Other Options Are Incorrect

Breakdown of the Answer Choices:

Why the Other Options Are Wrong:

💊 What is Volume of Distribution (Vd)?

✅ Why This Formula is Correct:

❌ Why the Other Options Are Incorrect:

📌 Summary Table:

Why the Other Options Are Wrong:

❌ Why Other Options Are Incorrect:

❌ Why Other Options Are Incorrect:

Breakdown of the Terms:

Why the Other Options Are Incorrect

How Chemical Antagonism Works in Heavy Metal Toxicity:

Why not the other options?

What is Biotransformation?

Purpose of Biotransformation:

Phases of Biotransformation:

✅ Why “Less Lipid Soluble” is Correct:

❌ Why the Other Options Are Incorrect:

❌ Less ionized:

❌ More pharmacologically active:

❌ Less readily eliminated:

❌ More lipid soluble:

Why the Other Options Are Wrong:

Why is a Large Volume of Distribution (Vd) the Best Indicator of Tissue Storage?

Why not the other options?

Correct Answer: Retinoic Acid

❌ Why the Other Options Are Incorrect?

1. Potassium Iodide ❌

2. Tetracycline ❌

3. Ethylene ❌

4. Thalidomide ❌

Why the Other Options Are Wrong:

❌ Why Other Options Are Incorrect:

Why the Other Options Are Incorrect:

Why Does Oral Administration Have the Highest First-Pass Metabolism?

Why not the other options?