Tetracycline injection causes palsy of which nerve?
What is the primary indication for the use of Erlotinib?
Which anticancer drug is known to inhibit spindle formation during cell division?
Which of the following statements is FALSE regarding vincristine?
What is the drug of choice for most forms of interstitial lung disease?
Drug of choice for open angle glaucoma:
Which prostaglandin inhibitor is used in the treatment of patent ductus arteriosus (PDA)?
Which drug is used to keep the patent ductus arteriosus (PDA) open?
XDR-TB is defined as resistance to which of the following drug combinations?
What is the drug of choice for the treatment of kala-azar?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 111: Tetracycline injection causes palsy of which nerve?
- A. Radial (Correct Answer)
- B. Median
- C. Ulnar
- D. Superficial peroneal
Explanation: ***Radial*** - Tetracycline injections, especially when given in the deltoid region, can inadvertently injure the **radial nerve** due to its superficial course. - Damage to the radial nerve typically results in **wrist drop** and sensory deficits over the dorsum of the hand. *Ulnar* - The **ulnar nerve** is commonly injured at the elbow (cubital tunnel syndrome) or wrist (Guyon's canal). - Injury typically results in weakness of intrinsic hand muscles and sensory loss in the little finger and ulnar half of the ring finger, which is not characteristic of an injection injury in the deltoid region. *Median* - The **median nerve** is more frequently injured at the wrist (carpal tunnel syndrome) or elbow. - Injury causes difficulty with thumb opposition and sensation in the first three and a half digits on the palmar side. *Superficial peroneal* - The **superficial peroneal nerve** is found in the lower leg and foot, innervating the lateral compartment muscles and providing sensation to the dorsum of the foot. - It would not be affected by an injection in the upper arm or shoulder region.
Question 112: What is the primary indication for the use of Erlotinib?
- A. Colon cancer
- B. Gall bladder cancer
- C. Pancreatic cancer
- D. NSCLC (Correct Answer)
Explanation: ***NSCLC (Non-Small Cell Lung Cancer)*** - **Erlotinib** is primarily indicated for patients with advanced **non-small cell lung cancer (NSCLC)**, particularly those with activating mutations in the **epidermal growth factor receptor (EGFR)**. - It functions as an **EGFR tyrosine kinase inhibitor**, blocking the signaling pathways essential for cancer cell growth and survival. - This is the **FDA-approved primary indication** and where Erlotinib shows the most significant clinical benefit. *Pancreatic cancer* - While Erlotinib has been used in combination with gemcitabine for **locally advanced, unresectable or metastatic pancreatic cancer**, it is not its primary or most prominent indication. - Its efficacy in pancreatic cancer is generally modest and overshadowed by its dramatic impact in EGFR-mutated NSCLC. *Colon cancer* - **Erlotinib** is **not a primary treatment** for **colon cancer**. - Other targeted therapies (such as anti-EGFR monoclonal antibodies like cetuximab) or chemotherapy regimens are typically used for colorectal cancer. *Gall bladder cancer* - **Erlotinib** is generally **not indicated** for the treatment of **gallbladder cancer**. - Treatment often involves surgery, chemotherapy, or radiation, with targeted therapies being less established for this malignancy.
Question 113: Which anticancer drug is known to inhibit spindle formation during cell division?
- A. Busulfan
- B. Vinca alkaloids (Correct Answer)
- C. 5-FU
- D. Methotrexate
Explanation: ***Vinca alkaloids*** - **Vinca alkaloids**, such as **vincristine** and **vinblastine**, bind to **tubulin** and prevent its polymerization into microtubules. - This action effectively **inhibits the formation of the mitotic spindle**, leading to metaphase arrest and ultimately cell death. *Busulfan* - **Busulfan** is an **alkylating agent** that **cross-links DNA**, thereby interfering with DNA replication and transcription. - Its primary mechanism is **DNA damage**, not direct inhibition of spindle formation. *5-FU* - **5-fluorouracil (5-FU)** is an **antimetabolite** that inhibits **thymidylate synthase**, thereby impairing DNA synthesis and repair. - It acts by **mimicking pyrimidine bases** and incorporating into DNA and RNA, leading to cellular dysfunction. *Methotrexate* - **Methotrexate** is an **antifolate** drug that inhibits **dihydrofolate reductase**, an enzyme crucial for the synthesis of purines and pyrimidines. - This enzyme inhibition leads to **impaired DNA and RNA synthesis**, impacting rapidly dividing cells.
Question 114: Which of the following statements is FALSE regarding vincristine?
- A. Its use is associated with neurotoxicity.
- B. It is an alkaloid.
- C. It is a useful drug for induction of remission in acute lymphoblastic leukemia.
- D. It does not cause alopecia. (Correct Answer)
Explanation: ***It does not cause alopecia.*** - This statement is **false** because vincristine, like many chemotherapeutic agents, commonly causes **alopecia** (hair loss) due to its impact on rapidly dividing cells, including hair follicle cells. - While it may be considered less myelosuppressive than some other anticancer drugs, its effect on hair follicles is well-documented. *It is an alkaloid.* - This statement is **true** because vincristine is a **vinca alkaloid**, derived from the Madagascar periwinkle plant (*Catharanthus roseus*). - Vinca alkaloids are a class of antineoplastic agents that target microtubules. *Its use is associated with neurotoxicity.* - This statement is **true** as **neurotoxicity** is a prominent and dose-limiting side effect of vincristine, manifesting as peripheral neuropathy (e.g., paresthesias, foot drop, constipation due to autonomic neuropathy). - This adverse effect arises from its mechanism of action, which involves disrupting microtubules critical for axonal transport. *It is a useful drug for induction of remission in acute lymphoblastic leukemia.* - This statement is **true**; **vincristine** is a cornerstone of combination chemotherapy regimens for **acute lymphoblastic leukemia (ALL)**, particularly during the induction phase. - Its efficacy in ALL is attributed to its ability to arrest cell division in metaphase.
Question 115: What is the drug of choice for most forms of interstitial lung disease?
- A. Antibiotics
- B. Bronchodilators
- C. Aspirin
- D. Corticosteroids (Correct Answer)
Explanation: ***Corticosteroids*** - **Corticosteroids** are the **drug of choice** for many forms of **interstitial lung disease (ILD)** due to their potent **anti-inflammatory** and **immunosuppressive properties**, which help reduce lung inflammation and prevent fibrosis. - They are particularly effective in inflammatory ILDs such as **sarcoidosis**, **hypersensitivity pneumonitis**, and some **connective tissue disease-associated ILDs**. *Antibiotics* - **Antibiotics** are primarily used to treat bacterial and other microbial infections and are **not effective** against the **inflammatory and fibrotic processes** characteristic of most ILDs. - They might be used if there's a **secondary bacterial infection** complicating ILD, but not as primary treatment for the ILD itself. *Bronchodilators* - **Bronchodilators** work by relaxing the muscles around the airways, making them wider and easier to breathe through, which is beneficial in conditions like **asthma** or **COPD**. - They are **not primarily used** in ILD as the main problem is **inflammation and scarring of the lung tissue**, not reversible airway constriction. *Aspirin* - **Aspirin** is an **NSAID** with **anti-inflammatory**, **anti-platelet**, and **analgesic properties**, commonly used for pain relief, fever reduction, and cardiovascular protection. - It has **no established role** in the primary treatment of **interstitial lung disease**, as its anti-inflammatory effects are typically insufficient for the severe inflammation seen in ILD.
Question 116: Drug of choice for open angle glaucoma:
- A. Acetazolamide
- B. Latanoprost (Correct Answer)
- C. Brimonidine
- D. Timolol
Explanation: ***Latanoprost*** - **Prostaglandin F2α analogs** like latanoprost are generally considered **first-line therapy** for open-angle glaucoma due to their efficacy and once-daily dosing. - They work by **increasing uveoscleral outflow** of aqueous humor, thereby lowering intraocular pressure (IOP). *Acetazolamide* - **Acetazolamide** is a **carbonic anhydrase inhibitor** that reduces aqueous humor production. - It is typically used for **acute angle-closure glaucoma** or when initial treatments fail, often due to systemic side effects with long-term use. *Timolol* - **Timolol** is a **non-selective beta-blocker** that reduces aqueous humor production. - While effective, it is often a second-line agent or used in combination due to potential systemic side effects like **bronchospasm** and **bradycardia**. *Brimonidine* - **Brimonidine** is an **alpha-2 adrenergic agonist** that reduces aqueous humor production and increases uveoscleral outflow. - It is typically used as a second-line agent or in combination therapy due to potential side effects like **ocular pruritus** and **allergic conjunctivitis**.
Question 117: Which prostaglandin inhibitor is used in the treatment of patent ductus arteriosus (PDA)?
- A. PGE-2
- B. Misoprostol
- C. Indomethacin (Correct Answer)
- D. Dinoprostone
Explanation: ***Indomethacin*** - **Indomethacin** is a non-steroidal anti-inflammatory drug (**NSAID**) that inhibits **prostaglandin synthesis**, particularly **prostaglandin E2 (PGE2)**. - **PGE2** helps keep the **ductus arteriosus** open in utero; by inhibiting its production, indomethacin facilitates the closure of a **patent ductus arteriosus (PDA)** in neonates. *Misoprostol* - **Misoprostol** is a **prostaglandin E1 (PGE1) analog** and is used to induce labor, treat gastric ulcers, and for medical abortions. - It would work to **maintain** rather than close the **ductus arteriosus** if used in a neonate with a heart defect requiring patency. *Dinoprostone* - **Dinoprostone** is a **prostaglandin E2 analog** used for cervical ripening and labor induction. - It is not used for closing a **PDA**; its prostaglandin agonistic action would likely keep the **ductus arteriosus open**. *PGE-2* - **Prostaglandin E2 (PGE2)** is a naturally occurring prostaglandin that helps maintain the patency of the **ductus arteriosus** in the fetus. - Administering **PGE2** would keep the **ductus arteriosus open**, which is the opposite of the desired effect when treating a **PDA**.
Question 118: Which drug is used to keep the patent ductus arteriosus (PDA) open?
- A. PGE1 (Correct Answer)
- B. PGI2
- C. PGH2
- D. PGF2α
Explanation: ***PGE1*** - **Prostaglandin E1** (**PGE1**, alprostadil) is used to maintain the patency of the **ductus arteriosus** in neonates with certain congenital heart defects [1], [2]. - It acts as a **vasodilator** on the smooth muscle of the ductus, preventing its closure and allowing for adequate blood flow prior to surgical correction [1], [2]. *PGI2* - **Prostaglandin I2** (**PGI2**, prostacyclin) is a potent **vasodilator** and **platelet aggregation inhibitor** [1]. - While it has cardiovascular effects, it is primarily used for conditions like **pulmonary hypertension** and not for maintaining ductal patency [1]. *PGF2̑* - **Prostaglandin F2̑** (**PGF2̑**) is involved in processes such as **uterine contractions** and **bronchoconstriction** [1], [2]. - It does not play a role in maintaining the patency of the ductus arteriosus. *PGH2* - **Prostaglandin H2** (**PGH2**) is an immediate precursor in the synthesis of various other prostaglandins and thromboxanes. - It is not directly administered as a drug to maintain ductal patency but is an intermediate in their synthesis.
Question 119: XDR-TB is defined as resistance to which of the following drug combinations?
- A. INH plus rifampicin
- B. Fluoroquinolones plus INH plus amikacin
- C. Fluoroquinolones plus rifampicin plus kanamycin
- D. Fluoroquinolones plus INH plus rifampicin plus amikacin (Correct Answer)
Explanation: **Fluoroquinolones plus INH plus rifampicin plus amikacin** - **Extensively drug-resistant tuberculosis (XDR-TB)** is defined by resistance to the most effective anti-TB drugs: **isoniazid (INH)**, **rifampicin**, any **fluoroquinolone**, and at least one of the three injectable second-line drugs (**amikacin**, **kanamycin**, or **capreomycin**). - This combination signifies a substantial therapeutic challenge due to limited treatment options and a high risk of treatment failure. *INH plus rifampicin* - Resistance to **INH** and **rifampicin** defines **multidrug-resistant tuberculosis (MDR-TB)**, which is a precursor to XDR-TB but not XDR-TB itself. - While serious, MDR-TB is not as extensively resistant as XDR-TB, as it doesn't include resistance to fluoroquinolones and second-line injectables. *Fluoroquinolones plus INH plus amikacin* - This combination is incomplete for the definition of XDR-TB because it omits **rifampicin** from the core definition. - XDR-TB specifically requires resistance to both **INH** and **rifampicin** (defining MDR-TB), in addition to resistance to a fluoroquinolone and one of the injectable second-line drugs. *Fluoroquinolones plus rifampicin plus kanamycin* - This combination is also incomplete for the definition of XDR-TB as it omits **isoniazid (INH)**, which is one of the two most crucial first-line drugs that characterize MDR-TB. - XDR-TB builds upon MDR-TB's resistance to both INH and rifampicin.
Question 120: What is the drug of choice for the treatment of kala-azar?
- A. Amphotericin B
- B. Quinine
- C. Paromomycin
- D. Liposomal Amphotericin B (Correct Answer)
Explanation: ***Liposomal Amphotericin B*** - It is currently considered the **drug of choice** for treating **visceral leishmaniasis (kala-azar)** due to its high efficacy and better tolerability profile compared to conventional amphotericin B. - The **liposomal formulation** allows for targeted delivery to macrophages, where *Leishmania* parasites reside, reducing systemic toxicity. *Amphotericin B* - While effective against *Leishmania*, conventional **Amphotericin B deoxycholate** is associated with significant **nephrotoxicity** and other severe side effects. - It is generally reserved for cases where liposomal amphotericin B is unavailable or as an alternative in specific clinical situations. *Quinine* - **Quinine** is an **antimalarial drug** primarily used for the treatment of *Plasmodium falciparum* malaria. - It has no significant efficacy against *Leishmania* species, which are the causative agents of kala-azar. *Paromomycin* - **Paromomycin** is an **aminoglycoside antibiotic** that can be used as an alternative treatment for visceral leishmaniasis, especially in combination therapies. - Although effective, it is generally not considered the first-line **drug of choice** globally, and its efficacy can vary by region.