NEET-PG 2013 - Pharmacology Practice Questions

Q: Which drug is primarily used in the treatment of breast cancer?

Tamoxifen. ***Tamoxifen*** - **Tamoxifen** is a **selective estrogen receptor modulator (SERM)** primarily used to treat and prevent **estrogen receptor (ER)-positive breast cancer**. - It works by blocking estrogen from binding to receptors in breast cancer cells, thereby inhibiting their growth. *Cyproterone* - **Cyproterone** is an **anti-androgen** and **progestogen** primarily used to treat conditions like **prostate cancer**, **acne**, and **hirsutism** in women. - Its main mechanism involves blocking androgen receptors and reducing androgen production, which is not the primary pathway for breast cancer. *Testosterone* - **Testosterone** is an **androgen** (male sex hormone) and is **not used** in the primary treatment of breast cancer. - In certain rare cases of severe metastatic breast cancer, androgens like high-dose testosterone have been historically used for palliation, but this is not standard therapy. *Chlorambucil* - **Chlorambucil** is an **alkylating agent** used primarily in the treatment of **chronic lymphocytic leukemia (CLL)** and certain **lymphomas**. - It works by interfering with DNA replication and transcription, but it is not a first-line or primary agent for breast cancer.

Q: What is the mechanism of action of Warfarin?

Inhibition of Vitamin K epoxide reductase. ***Inhibition of Vitamin K epoxide reductase*** - Warfarin blocks **Vitamin K epoxide reductase (VKORC1)** [1, 2, 3], an enzyme essential for recycling oxidized vitamin K into its active reduced form [1, 3]. - This reduction prevents the activation of **vitamin K-dependent clotting factors** (II, VII, IX, X), leading to anticoagulation [1, 3]. *Inhibition of gamma glutamyl carboxylase* - **Gamma-glutamyl carboxylase** uses reduced vitamin K as a cofactor to carboxylate specific glutamic acid residues on clotting factors [1, 3]. - While essential for clotting factor activation, this enzyme itself is **not directly inhibited by warfarin** [1, 3]. *Activation of Vitamin K epoxide reductase* - Activating **VKORC1** would increase the production of reduced vitamin K, thereby **promoting coagulation** rather than inhibiting it [1, 2]. - This is the opposite of warfarin's intended therapeutic effect. *Activation of gamma glutamyl carboxylase* - Activating **gamma-glutamyl carboxylase** would enhance the carboxylation and activation of **clotting factors**, leading to procoagulant effects [1, 3]. - This mechanism contradicts warfarin's role as an **anticoagulant**.

Q: Drug of choice for familial hypercholesterolemia?

Lovastatin. ***Lovastatin*** - **Statins** (HMG-CoA reductase inhibitors) are the **first-line therapy** for familial hypercholesterolemia as they effectively lower **LDL cholesterol** levels by inhibiting cholesterol synthesis [1]. - While other agents can be used adjunctively, statins like lovastatin are the cornerstone for managing this genetic condition [2]. *Nicotinic acid* - **Nicotinic acid** (niacin) primarily lowers **triglycerides** and increases **HDL cholesterol**, but it is less potent than statins for reducing LDL-C, especially in familial hypercholesterolemia [1]. - Its use is often limited by significant **side effects** like flushing. *Cholestyramine* - **Cholestyramine** is a **bile acid sequestrant** that binds to bile acids in the intestine, preventing their reabsorption and mildly lowering LDL cholesterol. - It is less effective than statins and often causes **gastrointestinal side effects** such as constipation and bloating. *Gemfibrozil* - **Gemfibrozil** is a **fibrate**, primarily used to lower **triglyceride levels** and increase HDL cholesterol. - It has minimal impact on LDL cholesterol compared to statins and is not the primary treatment for familial hypercholesterolemia [2].

Q: What is Hydroxyethyl starch?

Plasma expander. ***Plasma expander*** - **Hydroxyethyl starch** is a **colloid solution** used intravenously to increase plasma volume and maintain oncotic pressure. - It is often used in situations of **hypovolemia** or shock to support circulation. *Vasodilator* - A **vasodilator** is a medication that widens blood vessels, typically used to lower blood pressure or improve blood flow. - Hydroxyethyl starch does not directly cause **vasodilation** as its primary mechanism of action. *Inotrope* - An **inotrope** is an agent that alters the force or energy of muscular contractions, mainly affecting the heart's contractility. - Hydroxyethyl starch has no direct effect on **myocardial contractility**. *Diuretic* - A **diuretic** is a substance that promotes increased production of urine, thereby increasing the excretion of water from the body. - While fluid administration can temporarily increase urine output, hydroxyethyl starch is not classified as a **diuretic agent** itself.

Q: Which of the following is NOT a beta-2 agonist?

Ketotifen. ***Ketotifen*** - **Ketotifen** is an **oral anti-allergic drug** that acts as a **mast cell stabilizer** and **H1-antihistamine**, not a beta-2 agonist. - It is used for **prophylactic treatment** of asthma and allergic conditions, working through different mechanisms than bronchodilators. *Terbutaline* - **Terbutaline** is a **short-acting beta-2 agonist (SABA)** used for bronchodilation in asthma and COPD [2]. - Available in **oral, inhaled, and injectable forms** for rapid relief of bronchospasm. *Salbutamol* - **Salbutamol** (also known as albuterol) is a **short-acting beta-2 agonist (SABA)** and the most widely used rescue inhaler for asthma [1], [2]. - Provides **rapid bronchodilation** by stimulating beta-2 receptors in airway smooth muscles [3]. *Bambuterol* - **Bambuterol** is a **long-acting beta-2 agonist (LABA)** that is a prodrug of **terbutaline**. - It is slowly converted to the active form in the body, providing **sustained bronchodilation** for maintenance therapy.

Q: Which of the following is a benzylisoquinoline muscle relaxant?

Doxacurium. ***Doxacurium*** - **Doxacurium** is a long-acting, non-depolarizing neuromuscular blocker classified as a **benzylisoquinoline** compound [1]. - These agents are known for their minimal cardiovascular effects and lack of histamine release in therapeutic doses [1]. *Vecuronium* - **Vecuronium** is an **aminosteroid** non-depolarizing neuromuscular blocker [2]. - It is known for its intermediate duration of action and minimal cardiovascular effects [1]. *Rocuronium* - **Rocuronium** is also an **aminosteroid** non-depolarizing neuromuscular blocker [2]. - It has a rapid onset of action, making it suitable for rapid sequence intubation, and can be reversed by **sugammadex**. *Pancuronium* - **Pancuronium** is an **aminosteroid** non-depolarizing neuromuscular blocker with a long duration of action [1]. - It is associated with a vagolytic effect that can cause an increase in **heart rate** and **blood pressure** [1].

Q: Which of the following drugs has not been withdrawn from the Indian market for safety reasons?

Cotrimoxazole. ### Cotrimoxazole - Cotrimoxazole, a combination of **trimethoprim and sulfamethoxazole**, remains a widely used and available antibiotic in India [1], [2]. - It treats various bacterial infections, including **urinary tract infections** and respiratory infections, and has not been withdrawn for safety reasons [1]. ### Gatifloxacin - **Gatifloxacin** was withdrawn from the Indian market due to concerns about **severe glycemic disturbances**, including both hypo- and hyperglycemia. - These side effects posed significant risks, especially in patients with diabetes or those predisposed to blood sugar fluctuations. ### Rofecoxib - **Rofecoxib**, an NSAID, was withdrawn globally, including from India, due to an increased risk of **cardiovascular events** such as heart attack and stroke. - Its selective inhibition of COX-2 was found to disturb the balance of prostaglandins, leading to adverse cardiovascular outcomes. ### Phenformin - **Phenformin**, an oral antidiabetic drug, was withdrawn from the Indian market due to its association with a high incidence of **lactic acidosis**, a severe and often fatal metabolic complication. - This serious side effect made its risk-benefit profile unacceptable for continued use.

Q: Peripheral neuropathy as a side effect is caused by which of the following anticancer drugs?

Vincristine. ***Vincristine*** - **Vincristine** is a **vinca alkaloid** that works by inhibiting **microtubule formation**, which is essential for cell division [1], [3]. - Its major dose-limiting toxicity is **peripheral neuropathy**, manifesting as paresthesias, weakness, and loss of reflexes due to damage to neuronal microtubules [1], [2]. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that forms cross-links in DNA, leading to cell death. - Its most common side effects include **myelosuppression**, hemorrhagic cystitis, and alopecia; **peripheral neuropathy** is generally not a prominent adverse effect. *Etoposide* - **Etoposide** is a **topoisomerase II inhibitor** that causes DNA strand breaks. - Key toxicities include **myelosuppression** and **gastrointestinal disturbances**, but it is not typically associated with significant peripheral neuropathy. *Irinotecan* - **Irinotecan** is a **topoisomerase I inhibitor** that causes DNA damage during replication. - Its primary dose-limiting toxicities are **diarrhea** and **myelosuppression**, not peripheral neuropathy.

Q: Which class of drugs does botulinum toxin mimic in its action?

Anticholinergics. ***Anticholinergics*** - **Botulinum toxin** inhibits the release of **acetylcholine** from **presynaptic nerve terminals** [2] by preventing vesicle fusion, leading to muscle paralysis [1]. - While the **mechanism differs** (botulinum acts presynaptically, anticholinergics act postsynaptically at receptors), the **functional outcome** is similar: reduced cholinergic neurotransmission. - In terms of **clinical effect** at the neuromuscular junction, both reduce acetylcholine's action, making anticholinergics the closest functional parallel among the given options. *Cholinergics* - **Cholinergics** enhance acetylcholine activity, either by increasing its release, mimicking its effects at receptors, or inhibiting its breakdown. - This is the **opposite** of botulinum toxin's action, which reduces acetylcholine's impact. *Adrenergics* - **Adrenergics** stimulate the **sympathetic nervous system** via **adrenergic receptors** (α and β receptors). - They act on **norepinephrine/epinephrine pathways**, not the cholinergic system where botulinum toxin acts. *Antiadrenergic* - **Antiadrenergic drugs** block **adrenergic receptors** or inhibit sympathetic activity. - These are unrelated to botulinum toxin's effect on **cholinergic neuromuscular transmission**.

Question 1

Which drug is primarily used in the treatment of breast cancer?

Accepted Answer

Tamoxifen

Answer

Cyproterone

Answer

Testosterone

Answer

Chlorambucil

Question 2

What is the mechanism of action of Warfarin?

Accepted Answer

Inhibition of Vitamin K epoxide reductase

Answer

Inhibition of gamma glutamyl carboxylase

Answer

Activation of Vitamin K epoxide reductase

Answer

Activation of gamma glutamyl carboxylase

Question 3

Drug of choice for familial hypercholesterolemia?

Accepted Answer

Lovastatin

Answer

Nicotinic acid

Answer

Cholestyramine

Answer

Gemfibrozil

Question 4

What is Hydroxyethyl starch?

Accepted Answer

Plasma expander

Answer

Vasodilator

Answer

Inotrope

Answer

Diuretic

Question 5

Which of the following is NOT a beta-2 agonist?

Accepted Answer

Ketotifen

Answer

Terbutaline

Answer

Salbutamol

Answer

Bambuterol

Question 6

Which of the following is a benzylisoquinoline muscle relaxant?

Accepted Answer

Doxacurium

Answer

Rocuronium

Answer

Pancuronium

Answer

Vecuronium

Question 7

Which of the following drugs has not been withdrawn from the Indian market for safety reasons?

Accepted Answer

Cotrimoxazole

Answer

Gatifloxacin

Answer

Phenformin

Answer

Rofecoxib

Question 8

Peripheral neuropathy as a side effect is caused by which of the following anticancer drugs?

Accepted Answer

Vincristine

Answer

Cyclophosphamide

Answer

Etoposide

Answer

Irinotecan

Question 9

Which of the following statements about hypolipidemic drugs is false?

Accepted Answer

Cholesterol reducing drugs are contraindicated in child less than 8 years

Answer

Gemfibrozil causes myopathy

Answer

Gemfibrozil can increase myopathy caused by statins

Answer

Lovastatin can cause hepatic dysfunction

Question 10

Which class of drugs does botulinum toxin mimic in its action?

Accepted Answer

Anticholinergics

Answer

Adrenergics

Answer

Antiadrenergic

Answer

Cholinergics

NEET-PG 2013 — Pharmacology