FMGE 2019 - Pharmacology PYQs Practice Questions

Q: Allopurinol inhibits which enzyme?

Xanthine oxidase. ***Xanthine oxidase*** - Allopurinol is a **purine analog** that acts as a **competitive inhibitor** of the enzyme **xanthine oxidase**. - By inhibiting xanthine oxidase, allopurinol prevents the conversion of **hypoxanthine to xanthine** and subsequently to **uric acid**, thereby lowering serum uric acid levels. *Lysyl oxidase* - **Lysyl oxidase** is an enzyme involved in the **cross-linking of collagen and elastin**, crucial for the stability of connective tissues. - Its inhibition would not directly affect **uric acid metabolism** or be a mechanism of allopurinol's action. *Cyclooxygenase* - **Cyclooxygenase (COX)** is a key enzyme in the synthesis of **prostaglandins and thromboxanes** from arachidonic acid, mediating inflammation and pain. - **NSAIDs** are inhibitors of cyclooxygenase, not allopurinol. *Kinase* - **Kinases** are a broad class of enzymes that **catalyze the transfer of phosphate groups** from high-energy molecules (like ATP) to specific substrates. - While essential for many cellular processes, kinases are not the specific target of **allopurinol** in uric acid reduction. [Practice more Pharmacology PYQs on OnCourse]

Q: All of the following can result in gynecomastia except:

Aromatase inhibitors. ***Aromatase inhibitors*** - **Aromatase inhibitors** block the conversion of androgens to estrogens, thereby **decreasing estrogen levels** which would prevent rather than cause gynecomastia. - They are used in estrogen-sensitive breast cancers to reduce estrogen-dependent growth. *Spironolactone* - **Spironolactone** is an aldosterone antagonist that also possesses anti-androgenic effects and can inhibit androgen synthesis, leading to an **increased estrogen-to-androgen ratio** and gynecomastia. - It can also directly stimulate the estrogen receptor in male breast tissue. *Sulphonamides* - Certain **sulphonamides**, particularly sulfasalazine, have been associated with gynecomastia, possibly due to direct toxic effects on testicular function leading to a **relative increase in estrogen activity**. - While less common than with some other drugs, it can alter the estrogen-androgen balance. *Digoxin* - **Digoxin** can cause gynecomastia by mimicking estrogen physiologically or by inhibiting androgen production, leading to an **alteration in the estrogen-to-androgen ratio**. - The risk of gynecomastia is especially noted with prolonged use and higher doses of digoxin. [Practice more Pharmacology PYQs on OnCourse]

Q: Mechanism of action of atropine in treatment of organophosphate poisoning is?

It has antimuscarinic activity. ***It has antimuscarinic activity*** - **Organophosphate poisoning** leads to **excessive acetylcholine** at muscarinic receptors, causing symptoms like miosis, bradycardia, and increased secretions. - **Atropine** is a **competitive antagonist** at these muscarinic receptors, thereby blocking the effects of excess acetylcholine. *It inhibits secretion of acetylcholine* - Atropine does not directly inhibit the secretion of **acetylcholine** from nerve terminals. - Its action is postsynaptic, specifically at the **receptor level**. *It is reactivator of acetylcholine esterase enzyme* - **Pralidoxime (2-PAM)** and other **oximes** are the drugs that reactivate **acetylcholinesterase**. - Atropine does not reactivate the enzyme; it only blocks the effects of acetylcholine. *It is agonist of acetylcholine receptors* - An **agonist** would mimic the effects of acetylcholine, which would worsen the symptoms of organophosphate poisoning. - Atropine is an **antagonist**, meaning it blocks the receptors. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following is the shortest-acting corticosteroid?

Hydrocortisone. ***Hydrocortisone***- **Hydrocortisone** is considered a **short-acting corticosteroid** with a biological half-life of 8-12 hours [1].- It is a naturally occurring glucocorticoid, acting as a direct replacement for cortisol.- Among the given options, it has the shortest duration of action.*Dexamethasone*- **Dexamethasone** is a **long-acting corticosteroid** with a biological half-life of 36-72 hours.- Its potent and prolonged action makes it suitable for conditions requiring sustained anti-inflammatory or immunosuppressive effects.*Triamcinolone*- **Triamcinolone** is an **intermediate-acting corticosteroid** with a biological half-life typically ranging from 18-36 hours.- It is commonly used for its anti-inflammatory effects in conditions like allergies, asthma, and skin disorders.*Deflazacort*- **Deflazacort** is an **intermediate-acting corticosteroid** with a duration of action of approximately 12-18 hours.- It is a prodrug that is metabolized to 21-desacetyl deflazacort, the active form, often used in conditions like Duchenne muscular dystrophy and inflammatory disorders. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following is a monoclonal antibody used in cancer treatment?

Rituximab. ***Rituximab*** - **Rituximab** is a **chimeric monoclonal antibody** that targets the **CD20 protein** found on the surface of normal and malignant **B lymphocytes**. - It is widely used in the treatment of various **lymphomas** and **leukemias**, as well as autoimmune diseases, by inducing the death of CD20-positive B cells. *Cisplatin* - **Cisplatin** is a **platinum-based chemotherapy drug** that works by forming **DNA adducts**, leading to DNA damage and apoptosis of cancer cells. - It is used in various solid tumors but is not a monoclonal antibody; it's a **cytotoxic agent**. *5-fluorouracil* - **5-fluorouracil (5-FU)** is an **antimetabolite chemotherapy drug** that interferes with DNA and RNA synthesis, thereby inhibiting cell division. - It is a **pyrimidine analog** and not a monoclonal antibody. *Methotrexate* - **Methotrexate** is a **folate analog antimetabolite** that inhibits **dihydrofolate reductase**, interfering with DNA synthesis and cell proliferation. - It's a conventional chemotherapy agent and immunosuppressant, not a monoclonal antibody. [Practice more Pharmacology PYQs on OnCourse]

Question 1

Allopurinol inhibits which enzyme?

Accepted Answer

Xanthine oxidase

Answer

Lysyl oxidase

Answer

Cyclooxygenase

Answer

Kinase

Question 2

All of the following can result in gynecomastia except:

Accepted Answer

Aromatase inhibitors

Answer

Spironolactone

Answer

Digoxin

Answer

Sulphonamides

Question 3

Mechanism of action of atropine in treatment of organophosphate poisoning is?

Accepted Answer

It has antimuscarinic activity

Answer

It inhibits secretion of acetylcholine

Answer

It is reactivator of acetylcholine esterase enzyme

Answer

It is agonist of acetylcholine receptors

Question 4

Which of the following is the shortest-acting corticosteroid?

Accepted Answer

Hydrocortisone

Answer

Dexamethasone

Answer

Triamcinolone

Answer

Deflazacort

Question 5

Which of the following is a monoclonal antibody used in cancer treatment?

Accepted Answer

Rituximab

Answer

Cisplatin

Answer

5-fluorouracil

Answer

Methotrexate

Question 6

Hydrochlorothiazide works by inhibiting

Accepted Answer

Na+ Cl pump in early DCT

Answer

Na+ Cl pump in late DCT

Answer

Na+ K+ 2Cl pump in descending limb of loop of Henle

Answer

Na+ K+ 2Cl pump in ascending limb of loop of Henle

Question 7

Which of the following is an oral direct thrombin inhibitor?

Accepted Answer

Dabigatran

Answer

Lepirudin

Answer

Rivaroxaban

Answer

Warfarin

Question 8

What is the dose of mifepristone in emergency contraception?

Accepted Answer

10 mg

Answer

25 mg

Answer

200 mcg

Answer

200 mg

Question 9

Which of the following is the chemoprophylaxis of choice in a person who is on a journey to endemic malarial region?

Accepted Answer

Atovaquone-proguanil

Answer

Doxycycline

Answer

Mefloquine

Answer

Chloroquine

Question 10

Therapeutic drug monitoring is done for:

Accepted Answer

Phenytoin

Answer

Aspirin

Answer

Heparin

Answer

Metformin

FMGE 2019 — Pharmacology