Which of the following antiretroviral drugs is not associated with peripheral neuropathy?
Which of the following is a topical sulfonamide ?
Tetracycline injection causes palsy of which nerve?
What is the primary indication for the use of Erlotinib?
Which of the following antiglaucoma medications can cause drowsiness?
Drug of choice for open angle glaucoma:
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?
Which of the following drugs is useful in acute attack of gout ?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 111: Which of the following antiretroviral drugs is not associated with peripheral neuropathy?
- A. Stavudine
- B. Zalcitabine
- C. Didanosine
- D. Indinavir (Correct Answer)
Explanation: ***Indinavir*** - **Indinavir** is a **protease inhibitor** that can cause side effects such as **nephrolithiasis** (kidney stones) and **hyperbilirubinemia**, but it is generally *not associated with peripheral neuropathy*. - It works by blocking the viral protease enzyme, preventing the cleavage of viral polyproteins into functional proteins, which disrupts viral replication. *Stavudine* - **Stavudine** is a **nucleoside reverse transcriptase inhibitor (NRTI)** notorious for causing dose-dependent **peripheral neuropathy**. - This toxicity is due to its interference with **mitochondrial DNA synthesis**, leading to nerve damage. *Zalcitabine* - **Zalcitabine** (ddC) is another **NRTI** strongly associated with a high incidence of **peripheral neuropathy**. - Its mechanism of action and side effect profile are similar to those of stavudine in causing **mitochondrial toxicity**. *Didanosine* - **Didanosine** (ddI) is an **NRTI** known to cause several adverse effects, including **peripheral neuropathy**, particularly at higher doses. - Like other dideoxynucleoside analogs, its toxicity is linked to **mitochondrial dysfunction**.
Question 112: Which of the following is a topical sulfonamide ?
- A. Sulfadoxine
- B. Sulfamethopyrazine
- C. Sulfisoxazole
- D. Mafenide (Correct Answer)
Explanation: ***Mafenide*** - **Mafenide** is a **sulfonamide antibiotic** primarily used **topically** as a cream for preventing and treating **wound infections**, particularly in **burn patients**. - It works by inhibiting bacterial growth and has good penetrative capabilities in **necrotic tissue** and **eschar**. - It is **water-soluble** and can penetrate burn eschar effectively. *Sulfadoxine* - **Sulfadoxine** is a **long-acting oral sulfonamide** frequently used in combination with **pyrimethamine** for conditions like **malaria** and **toxoplasmosis**. - It is administered **systemically**, not topically. *Sulfamethopyrazine* - **Sulfamethopyrazine** (also known as sulfalene) is another **long-acting sulfonamide** primarily used **orally** for conditions such as **malaria** and **urinary tract infections**. - Its clinical application is **systemic**, not topical. *Sulfisoxazole* - **Sulfisoxazole** is a **short-acting oral sulfonamide** used systemically for **urinary tract infections** and other bacterial infections. - It is **rapidly absorbed** and excreted, making it suitable for systemic use, not topical application.
Question 113: 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 114: 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 115: Which of the following antiglaucoma medications can cause drowsiness?
- A. Brimonidine (Correct Answer)
- B. Latanoprost
- C. Dorzolamide
- D. Timolol
Explanation: ***Brimonidine*** - **Brimonidine** is an **alpha-2 adrenergic agonist** [1] that can cause central nervous system depression, leading to side effects such as **drowsiness** and fatigue. - This systemic side effect is more common with the topical ophthalmic formulation due to systemic absorption. *Latanoprost* - **Latanoprost** is a **prostaglandin analog** that primarily works by increasing uveoscleral outflow, and its side effects are mainly localized to the eye (e.g., iris color change, eyelash growth). - It does not typically cause systemic side effects like drowsiness because its systemic absorption is minimal. *Dorzolamide* - **Dorzolamide** is a **topical carbonic anhydrase inhibitor** [1] that reduces aqueous humor production, and its most common side effects include local ocular irritation and a bitter taste. - While systemic carbonic anhydrase inhibitors can cause fatigue and drowsiness, the topical formulation has very limited systemic absorption, making drowsiness uncommon. *Timolol* - **Timolol** is a **non-selective beta-blocker** [1] that reduces aqueous humor production and can cause systemic side effects such as bradycardia, bronchospasm, and hypotension. - While some beta-blockers can cause fatigue, **drowsiness** as a prominent side effect is less common compared to alpha-2 agonists.
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 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 118: 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 119: 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.
Question 120: Which of the following drugs is useful in acute attack of gout ?
- A. Furosemide
- B. Sulfinpyrazone
- C. Allopurinol
- D. Piroxicam (Correct Answer)
Explanation: ***Piroxicam*** - **Piroxicam** is a **non-steroidal anti-inflammatory drug (NSAID)**, which are the first-line treatment for acute gout attacks. - NSAIDs work by inhibiting **prostaglandin synthesis**, thereby reducing inflammation and pain associated with the acute crystal-induced arthritis. *Furosemide* - **Furosemide** is a loop diuretic that can **raise uric acid levels** by increasing reabsorption in the renal tubules. - Therefore, it would exacerbate **gout** and is contraindicated during an acute attack. *Sulfinpyrazone* - **Sulfinpyrazone** is a **uricosuric agent** used for chronic gout management to increase uric acid excretion. - It is **not used for acute attacks** as it can precipitate or worsen an attack by mobilizing uric acid crystals. *Allopurinol* - **Allopurinol** is a **xanthine oxidase inhibitor** used for long-term management of hyperuricemia and chronic gout. - Starting allopurinol during an **acute attack** can worsen or prolong the attack by causing rapid changes in serum uric acid levels.