General Pharmacology Practice Questions

Q: Drugs used for rare diseases are known as:

Orphan drugs. **Explanation:** **1. Why "Orphan Drugs" is correct:** Orphan drugs are biological products or medicines intended for the diagnosis, prevention, or treatment of **rare diseases** (e.g., Cystic Fibrosis, Gaucher’s disease, Thalidomide for Leprosy). These diseases affect a very small percentage of the population. Because the market for these drugs is limited, pharmaceutical companies find them commercially non-viable to develop under normal conditions. To encourage their production, governments provide incentives like tax credits, patent extensions, and simplified marketing authorization. **2. Why other options are incorrect:** * **Rare drugs:** This is a distractor term. While the diseases are rare, the pharmacological classification for the treatment is "Orphan drug," not "rare drug." * **Over-the-counter (OTC) drugs:** These are non-prescription drugs that can be sold directly to a consumer without a doctor's note (e.g., Paracetamol, Antacids). They are used for common, self-limiting conditions, the opposite of rare diseases. * **Emergency drugs:** These are life-saving medications required for immediate administration in acute conditions (e.g., Adrenaline in anaphylaxis, Atropine in organophosphate poisoning). Their classification is based on the urgency of use, not the prevalence of the disease. **3. High-Yield Clinical Pearls for NEET-PG:** * **Definition Criteria:** In the USA, a rare disease is defined as one affecting fewer than **200,000 people**. * **Examples of Orphan Drugs:** * **Digoxin Immune Fab:** For Digoxin toxicity. * **Fomepizole:** For Methanol poisoning. * **Amphotericin B:** For Visceral Leishmaniasis (Kala-azar). * **Thalidomide:** For Type 2 Lepra reaction (ENL) [1]. * **Regulatory Act:** The Orphan Drug Act was first passed in the USA in 1983.

Q: Which of the following is NOT an example of chronic adverse drug reactions?

Nitrate induced headache. ### Explanation Adverse Drug Reactions (ADRs) are classified using the **Rawlins and Thompson classification**. To answer this question, one must distinguish between **Type A (Augmented)** and **Type C (Chronic)** reactions. **1. Why "Nitrate induced headache" is the correct answer:** Nitrate-induced headache is a **Type A (Augmented)** reaction. It is a predictable, dose-dependent extension of the drug’s primary pharmacological action (vasodilation). It occurs acutely shortly after administration. Because it is an immediate effect rather than a result of long-term cumulative exposure, it is NOT classified as a chronic ADR. **2. Analysis of Incorrect Options (Chronic ADRs):** Type C reactions are associated with **long-term drug use** and involve cumulative dose effects. * **Glucocorticoid-induced osteoporosis:** This occurs due to the cumulative suppression of osteoblast activity and calcium resorption over months or years of therapy. * **Chloroquine-induced retinopathy:** This is a classic example of cumulative toxicity where the drug deposits in the retinal pigment epithelium over a long duration (typically seen with high cumulative doses >1000g). * **Amiodarone deposition in cornea:** Also known as *cornea verticillata*, this occurs due to the long-term accumulation of the drug in lysosomal compartments (phospholipidosis). **3. High-Yield Clinical Pearls for NEET-PG:** * **Type A (Augmented):** Common, predictable, low mortality (e.g., Gastritis by NSAIDs, Hypoglycemia by Insulin). * **Type B (Bizarre):** Unpredictable, idiosyncratic, high mortality (e.g., Anaphylaxis, SJS/TEN). * **Type C (Chronic):** Related to cumulative dose (e.g., Analgesic nephropathy). * **Type D (Delayed):** Occurs years after treatment (e.g., Teratogenicity, Carcinogenicity). * **Type E (End of use):** Withdrawal symptoms (e.g., Opioid withdrawal, Rebound hypertension with Clonidine).

Q: What is the duration of Phase IV in clinical trials?

Indefinite duration. ### Explanation **Correct Answer: D. Indefinite duration** **1. Why "Indefinite duration" is correct:** Phase IV clinical trials, also known as **Post-Marketing Surveillance (PMS)**, begin after a drug has been approved by regulatory authorities (like the FDA or CDSCO) and is available on the market. Unlike Phases I, II, and III, which have specific protocols and fixed timelines to establish safety and efficacy for approval, Phase IV has no fixed endpoint. Its primary purpose is the continuous monitoring of the drug’s performance in the general population to detect **rare adverse effects**, long-term complications, and drug-drug interactions that may not have surfaced in the controlled, smaller cohorts of Phase III. As long as the drug remains on the market, Phase IV monitoring continues. **2. Why other options are incorrect:** * **Options A, B, and C:** These represent finite timeframes. While individual Phase IV *studies* might last 1–5 years, the **phase itself** is ongoing. Fixed durations are more characteristic of pre-marketing phases: * **Phase I:** Days to weeks. * **Phase II:** Months to ~2 years. * **Phase III:** 1 to 4 years. **3. High-Yield Clinical Pearls for NEET-PG:** * **Primary Goal:** To detect **Rare Adverse Events** (e.g., incidence < 1 in 10,000). * **Population:** Open-ended; includes special groups (elderly, children, pregnant women) usually excluded from earlier phases. * **Pharmacovigilance:** This is the core activity of Phase IV. It can lead to "Black Box Warnings" or the withdrawal of a drug (e.g., Rofecoxib due to cardiovascular risks). * **Phase V:** Sometimes used to describe translational research or population-level effectiveness studies, though not a standard regulatory term.

Q: A patient requires ceftriaxone 180 mg. You have a 2 mL syringe with 10 divisions per mL. The vial contains 500 mg/5 mL of ceftriaxone. How many divisions in the 2 mL syringe will you fill to give 180 mg ceftriaxone?

18. ### Explanation This question tests the ability to perform **pharmaceutical calculations**, a vital skill for clinical practice and a high-yield area in General Pharmacology. **1. Why Option A is Correct:** To find the number of divisions, we follow a two-step calculation: * **Step 1: Calculate the volume required.** The vial concentration is $500\text{ mg}$ in $5\text{ mL}$, which simplifies to $100\text{ mg/mL}$. Using the formula: $\text{Volume} = \frac{\text{Desired Dose}}{\text{Concentration on Hand}}$ $\text{Volume} = \frac{180\text{ mg}}{100\text{ mg/mL}} = \mathbf{1.8\text{ mL}}$ * **Step 2: Convert volume into syringe divisions.** The syringe has $10\text{ divisions per mL}$. Total divisions = $\text{Volume (mL)} \times \text{Divisions per mL}$ Total divisions = $1.8\text{ mL} \times 10 = \mathbf{18\text{ divisions}}$ **2. Why the Other Options are Incorrect:** * **Option B (1.8):** This represents the volume in **milliliters (mL)**, not the number of divisions. * **Option C (20):** This would be the total capacity of the $2\text{ mL}$ syringe ($2 \times 10 = 20$), delivering $200\text{ mg}$. * **Option D (2):** This is a mathematical error, likely from miscalculating the concentration or the division factor. **3. Clinical Pearls & High-Yield Facts:** * **Ceftriaxone Specifics:** It is a third-generation cephalosporin. **High-yield fact:** Avoid diluting Ceftriaxone with **Calcium-containing solutions** (like Ringer’s Lactate) as it can form fatal precipitates, especially in neonates. * **Calculation Tip:** Always double-check the "units" requested (mL vs. mg vs. divisions). In NEET-PG, "divisions" usually refers to the smallest markings on a syringe (often $0.1\text{ mL}$ in a $2\text{ mL}$ or $5\text{ mL}$ syringe). * **Pediatric Dosing:** Most errors occur during the conversion from stock concentration to the final volume; always use the $C_1V_1 = C_2V_2$ or the "Desired/Have" formula.

Q: In sub-acute toxicity studies, for what duration is the drug given to animals?

2-12 weeks. **Explanation:** Toxicity studies are a fundamental part of preclinical drug development, categorized based on the duration of drug administration to determine the safety profile of a new chemical entity. **1. Why Option B is Correct:** **Sub-acute toxicity studies** (also known as repeated-dose or short-term toxicity studies) involve the daily administration of a drug for a period typically ranging from **2 to 12 weeks** (commonly 4 weeks/28 days). The primary objective is to identify target organ toxicity and establish the "No Observed Adverse Effect Level" (NOAEL) before proceeding to human clinical trials. **2. Analysis of Incorrect Options:** * **Option A (Single dose):** This refers to **Acute Toxicity studies**. The drug is administered in a single dose (or multiple doses within 24 hours) to determine the Median Lethal Dose ($LD_{50}$) and immediate toxic effects. * **Option C (6-12 months):** This refers to **Chronic Toxicity studies**. These are conducted to evaluate the effects of long-term exposure, including cumulative toxicity and potential carcinogenic effects. In most species, this lasts 6 months, though it can extend to 12. * **Option D (1-3 years):** This duration is typically reserved for **Carcinogenicity studies** in rodents (usually 2 years) or long-term observation in specific longitudinal safety models. **High-Yield Clinical Pearls for NEET-PG:** * **Acute Toxicity:** Single dose; determines $LD_{50}$. * **Sub-acute Toxicity:** 2–12 weeks; identifies target organs of toxicity. * **Chronic Toxicity:** >6 months; evaluates cumulative effects. * **Therapeutic Index (TI):** Calculated as $LD_{50} / ED_{50}$. A higher TI indicates a safer drug. * **Pre-clinical requirement:** Toxicity must be tested in at least two mammalian species (one rodent and one non-rodent) before Phase I trials.

Q: Which of the following immunosuppressive agents acts selectively by inhibiting helper T-cells?

Cyclosporine. **Explanation** **Correct Option: C. Cyclosporine** Cyclosporine is a **calcineurin inhibitor**. Its primary mechanism of action involves binding to an intracellular protein called **cyclophilin**. This complex inhibits calcineurin, a phosphatase required for the dephosphorylation and activation of the **Nuclear Factor of Activated T-cells (NFAT)**. Without active NFAT, the transcription of **Interleukin-2 (IL-2)** is blocked. Since IL-2 is the primary cytokine responsible for the proliferation and differentiation of **Helper T-cells (CD4+)**, cyclosporine acts selectively on this cell population without significantly affecting B-cells or causing bone marrow suppression. **Incorrect Options:** * **A. Cyclophosphamide:** An alkylating agent that cross-links DNA. It is non-selective and cytotoxic to all rapidly dividing cells, including B-cells and T-cells, often causing significant myelosuppression. * **B. Azathioprine:** A purine antimetabolite (prodrug of 6-mercaptopurine) that inhibits DNA synthesis. It affects both T and B lymphocyte proliferation non-selectively. * **D. Cytosine arabinoside (Cytarabine):** A pyrimidine antimetabolite used primarily in chemotherapy (AML). It inhibits DNA polymerase and is not used as a selective immunosuppressant for T-cells. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** Cyclosporine is a cornerstone for preventing graft-versus-host disease (GVHD) in organ transplants. * **Side Effects:** Remember the "6 H's": **H**ypertension, **H**irsutism, **H**yperplasia of gums, **H**yperlipidemia, **H**yperkalemia, and **H**epatotoxicity. * **Nephrotoxicity:** This is the most important dose-limiting toxicity. * **Metabolism:** It is metabolized by **CYP3A4**; therefore, grapefruit juice (inhibitor) increases its toxicity.

Q: Which of the following is a recently approved drug for the treatment of neovascular age-related macular degeneration?

Brolucizumab. **Explanation:** **Brolucizumab** is the correct answer. It is a humanized single-chain antibody fragment (scFv) that inhibits all isoforms of **Vascular Endothelial Growth Factor-A (VEGF-A)**. Approved recently for neovascular (wet) Age-Related Macular Degeneration (nAMD), its primary advantage is its small molecular weight (26 kDa), which allows for better retinal penetration and a longer duration of action, enabling 12-week dosing intervals. **Analysis of Incorrect Options:** * **Istradefylline:** An adenosine A2A receptor antagonist used as an add-on treatment to levodopa/carbidopa in patients with **Parkinson’s disease** experiencing "off" episodes. * **Lefamulin:** A pleuromutilin antibiotic used for the treatment of **community-acquired bacterial pneumonia (CABP)**. * **Upadacitinib:** A selective Janus kinase (JAK) inhibitor used primarily in **Rheumatoid Arthritis** and other inflammatory conditions like atopic dermatitis. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of nAMD:** Characterized by Choroidal Neovascularization (CNV). VEGF is the primary mediator of this leakage and vessel growth. * **Other Anti-VEGF agents:** Ranibizumab (Fab fragment), Bevacizumab (Full-length mAb - off-label), and Aflibercept (VEGF Trap). * **Faricimab:** Another recent approval; it is a bispecific antibody targeting both **VEGF and Angiopoietin-2 (Ang-2)**. * **Side Effect Alert:** Brolucizumab has been associated with a higher risk of **retinal vasculitis** and intraocular inflammation compared to other anti-VEGFs.

Q: All are true regarding protease-activated receptors, except:

They are a family of three seven-transmembrane proteins.. **Explanation:** Protease-activated receptors (PARs) are a unique subfamily of **G-protein-coupled receptors (GPCRs)**. The mechanism of activation is distinct: a protease (like thrombin) cleaves a specific segment of the receptor's extracellular N-terminus, creating a "tethered ligand" that then binds to the receptor itself to initiate signaling. **1. Why Option A is the Correct Answer (The Exception):** PARs are a family of **four** seven-transmembrane proteins (**PAR-1 to PAR-4**), not three. * **PAR-1, PAR-3, and PAR-4** are primarily activated by **thrombin**. * **PAR-2** is primarily activated by **trypsin** or mast cell tryptase. **2. Analysis of Other Options:** * **Option B (Activated by Thrombin):** This is a true statement. Thrombin is the principal activator of PAR-1 (the main thrombin receptor on platelets), PAR-3, and PAR-4. This is a critical step in platelet aggregation and clot formation. * **Option C (Release PGE2):** This is true. Activation of PARs (especially in the gastric mucosa and airways) triggers the release of cytoprotective mediators like **Prostaglandin E2 (PGE2)** and nitric oxide. * **Option D (Protect epithelial cells):** This is true. In the gastrointestinal tract, PAR activation (specifically PAR-2) promotes epithelial cell survival, mucus secretion, and mucosal repair, serving a protective "sensor" function against luminal proteases. **High-Yield Clinical Pearls for NEET-PG:** * **Vorapaxar:** A competitive antagonist of **PAR-1**. It is used clinically as an antiplatelet drug to reduce thrombotic cardiovascular events in patients with a history of MI or peripheral arterial disease. * **Irreversibility:** Because the receptor is activated by proteolytic cleavage (a covalent change), a single receptor molecule can only be activated once, making the mechanism effectively irreversible until a new receptor is synthesized.

Q: Which of the following is FALSE regarding the sublingual route of drug administration?

All drugs can be administered via this route.. **Explanation** The sublingual route involves placing a drug under the tongue, where it dissolves and is absorbed through the highly vascularized oral mucosa directly into the systemic circulation. **Why Option B is False (The Correct Answer):** Not all drugs can be administered sublingually. To be effective via this route, a drug must be **lipid-soluble, non-irritating, and potent** (effective in small doses). Large, water-soluble molecules or drugs with an unpleasant taste are unsuitable. Furthermore, if a drug requires a large dose, the limited surface area of the sublingual mucosa makes absorption impractical. **Analysis of Other Options:** * **Option A (Bypasses first-pass metabolism):** This is **true**. Since the venous drainage from the mouth goes directly into the superior vena cava (bypassing the portal vein and liver), the drug avoids immediate hepatic degradation. * **Option C (Action can be terminated quickly):** This is **true**. If side effects occur or the desired effect is reached, the patient can simply spit out the remaining tablet, stopping further absorption. * **Option D (Rapid absorption):** This is **true**. Due to the thin epithelium and rich blood supply of the sublingual area, drugs reach the bloodstream quickly, making this route ideal for emergencies. **NEET-PG High-Yield Pearls:** * **Classic Examples:** Nitroglycerin (for Angina), Buprenorphine (opioid), and Nifedipine (though no longer preferred for hypertensive emergencies due to precipitous BP drops). * **Bioavailability:** Sublingual administration generally provides higher bioavailability compared to the oral route for drugs that undergo extensive first-pass metabolism. * **pH Influence:** The absorption is faster if the drug is in its **non-ionized form** (determined by the pKa of the drug and the pH of saliva).

Question 1

Drugs used for rare diseases are known as:

Accepted Answer

Orphan drugs

Answer

Rare drugs

Answer

Over-the-counter drugs

Answer

Emergency drugs

Question 2

Which of the following is NOT an example of chronic adverse drug reactions?

Accepted Answer

Nitrate induced headache

Answer

Glucocorticoid induced osteoporosis

Answer

Chloroquine induced retinopathy

Answer

Amiodarone deposition in cornea

Question 3

What is the duration of Phase IV in clinical trials?

Accepted Answer

Indefinite duration

Answer

3-5 years

Answer

1-3 years

Answer

1 year

Question 4

A patient requires ceftriaxone 180 mg. You have a 2 mL syringe with 10 divisions per mL. The vial contains 500 mg/5 mL of ceftriaxone. How many divisions in the 2 mL syringe will you fill to give 180 mg ceftriaxone?

Accepted Answer

18

Answer

1.8

Answer

20

Answer

2

Question 5

In sub-acute toxicity studies, for what duration is the drug given to animals?

Accepted Answer

2-12 weeks

Answer

A single dose

Answer

6-12 months

Answer

1-3 years

Question 6

Which of the following immunosuppressive agents acts selectively by inhibiting helper T-cells?

Accepted Answer

Cyclosporine

Answer

Cyclophosphamide

Answer

Azathioprine

Answer

Cytosine arabinoside

Question 7

Which of the following is a recently approved drug for the treatment of neovascular age-related macular degeneration?

Accepted Answer

Brolucizumab

Answer

Istradefylline

Answer

Lefamulin

Answer

Upadacitinib

Question 8

Which of the following is NOT a non-sedating antiallergic drug?

Accepted Answer

Triprolidine

Answer

Cetirizine

Answer

Astemizole

Answer

Terfenadine

Question 9

All are true regarding protease-activated receptors, except:

Accepted Answer

They are a family of three seven-transmembrane proteins.

Answer

They are activated by thrombin.

Answer

They release PGE2.

Answer

They protect epithelial cells.

Question 10

Which of the following is FALSE regarding the sublingual route of drug administration?

Accepted Answer

All drugs can be administered via this route.

Answer

It bypasses first-pass metabolism.

Answer

The drug's action can be terminated quickly if needed.

Answer

It allows for rapid absorption into the bloodstream.

General Pharmacology — MCQs

General Pharmacology — MCQs

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