NEET-PG 2015 - Pharmacology Practice Questions

Q: In primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?

Longitudinal fibres of the ciliary muscle. ***Longitudinal fibres of the ciliary muscle***- Pilocarpine is a **muscarinic agonist** that contracts the **longitudinal fibers of the ciliary muscle** [1, 3].- This contraction pulls on the **scleral spur**, separating the **trabecular meshwork** sheets, which increases conventional **aqueous humor outflow** [2, 3].*Trabecular meshwork*- While the **trabecular meshwork** is the site where aqueous humor exits the eye, pilocarpine primarily acts on the ciliary muscle to **indirectly affect** the meshwork's outflow facility [2, 3].- Pilocarpine does not directly alter the structure or function of the trabecular meshwork cells.*Ciliary epithelium*- The **ciliary epithelium** is responsible for **aqueous humor production** [1, 2].- Pilocarpine primarily affects **outflow**, not production, through its action on the ciliary muscle [1, 2].*All of the options*- Pilocarpine does not act on **all** these structures; its primary mechanism is through the ciliary muscle to enhance outflow.- It has no direct significant effect on **ciliary epithelium** or direct action on the **trabecular meshwork** itself.

Q: From which part of the Papaver somniferum plant does the latex, commonly referred to as 'milk', exude?

Unripe capsule of the plant. ***Unripe capsule of the plant*** - The **latex** (or 'milk') containing **opioid alkaloids** like morphine and codeine is primarily harvested by incising the **unripe seed capsules** of the *Papaver somniferum* plant. - This milky sap is then collected and dried to produce **crude opium**. *Leaf of the plant* - The leaves of *Papaver somniferum* do not contain significant amounts of the latex and are not the primary source of **opium alkaloids**. - While some **alkaloids** might be present in trace amounts, they are not extracted commercially from the leaves. *Root of the plant* - The roots of the poppy plant are not known to exude latex or to be a significant source of medically relevant **opioid alkaloids**. - Their primary function is absorption of water and nutrients, and anchoring the plant. *Seeds of the plant* - While the dried seeds are used for culinary purposes (poppy seeds), they contain very low levels of **opioid alkaloids** compared to the latex. - The latex is produced within the **capsule** before the seeds fully mature.

Q: All of the following are medical uses of erythropoietin except?

Megaloblastic Anemia. ***Megaloblastic Anemia*** - Megaloblastic anemia is caused by **vitamin B12 or folate deficiency**, which impairs DNA synthesis and leads to the production of large, immature red blood cells. - Treatment involves supplementing the deficient vitamin (B12 or folate), as erythropoietin does not address the underlying cause of impaired red blood cell maturation. *Treatment of anaemia associated with renal disease* - **Erythropoietin** is primarily produced by the kidneys, and chronic kidney disease often leads to decreased erythropoietin production, resulting in anemia. - Administering exogenous erythropoietin stimulates red blood cell production, making it a critical treatment for **anemia of chronic kidney disease**. *Chemotherapy induced anemia* - Chemotherapy can suppress bone marrow function, leading to **decreased red blood cell production** and subsequent anemia. - Erythropoietin-stimulating agents can be used to mitigate this side effect by **stimulating erythropoiesis** in the bone marrow. *Specific cases of anemia associated with Crohn's disease.* - Anemia in Crohn's disease can have multiple causes, including iron deficiency from blood loss, malabsorption of vitamins, and **anemia of chronic disease**. - Erythropoietin may be considered in cases where the anemia is primarily due to **inflammation-induced suppression of erythropoiesis** or decreased erythropoietin response, particularly if other treatments are ineffective.

Q: What is the progestogen of choice in emergency contraception?

Levonorgestrel. ***Correct Option: Levonorgestrel*** - **Levonorgestrel** is the **progestogen of choice** for **emergency contraception** (Plan B, morning-after pill) - It works by **inhibiting or delaying ovulation**, preventing fertilization - Also alters **cervical mucus** to prevent sperm penetration and may affect endometrial receptivity - WHO-recommended as **single dose (1.5 mg)** or two doses (0.75 mg each, 12 hours apart) - Most effective when taken **within 72 hours** of unprotected intercourse, preferably within 24 hours *Incorrect Option: Norethisterone* - **Norethisterone** is a progestogen used in **oral contraceptive pills** and for managing gynecological conditions (menorrhagia, endometriosis, dysmenorrhea) - While it has progestational effects, it is **not the first-line choice** for emergency contraception - Less effective than levonorgestrel for post-coital contraception *Incorrect Option: Medroxyprogesterone* - **Medroxyprogesterone acetate** is used as a **long-acting depot contraceptive** (Depo-Provera injection every 3 months) - Also used for hormone replacement therapy and treating endometrial hyperplasia - **Not suitable for emergency contraception** due to its formulation and mechanism of action *Incorrect Option: Oxytocin* - **Oxytocin** is a posterior pituitary hormone that causes **uterine contractions** during labor and **milk ejection** during breastfeeding - It has **no role in contraception** or preventing pregnancy - Used therapeutically for labor induction, postpartum hemorrhage prevention, and augmentation of labor

Q: Which of the following drugs can lead to pemphigus?

Penicillamine. ***Penicillamine*** - **Penicillamine** is a well-known drug that can induce **pemphigus**, often through mechanisms involving alterations in **desmosome structure** or function. - The drug's sulfhydryl groups are thought to interfere with the integrity of **desmoglein proteins**, leading to blister formation. *Isoniazid* - **Isoniazid** is a first-line antituberculosis drug primarily associated with **hepatotoxicity** and **peripheral neuropathy**. - It is not typically implicated in the development of **pemphigus**. *Carbamazepine* - **Carbamazepine** is an anticonvulsant that can cause various cutaneous reactions, most notably **Stevens-Johnson syndrome (SJS)** and **toxic epidermal necrolysis (TEN)**. - While it can cause severe skin reactions, **pemphigus** is not a common side effect of carbamazepine. *Furosemide* - **Furosemide** is a loop diuretic that can cause **photosensitivity**, rashes, and rarely, severe skin reactions like **erythema multiforme**. - It is not recognized as a drug that induces **pemphigus**.

Q: What is the primary treatment indication of folic acid?

Treatment of megaloblastic anemia. ***Treatment of megaloblastic anemia*** - Folic acid is essential for **DNA synthesis** and cell division, and its deficiency leads to impaired red blood cell maturation, causing **megaloblastic anemia**. - Supplementation with folic acid effectively reverses the hematological abnormalities in **folate-deficient megaloblastic anemia**. *Prevention of neural tube defects in pregnancy* - While folic acid is crucial for preventing **neural tube defects** (NTDs), this is a **prophylactic** rather than a primary therapeutic use. - The focus of this question is on the *primary therapeutic* use, implying treatment of an existing condition. *Management of hemoglobinopathies* - Hemoglobinopathies like **sickle cell anemia** or **thalassemia** are genetic disorders affecting hemoglobin structure or production, not primarily due to folic acid deficiency. - Folic acid may be given to these patients to support increased red blood cell turnover, but it does not address the underlying genetic defect. *None of the above* - This option is incorrect because folic acid has a clear primary therapeutic role in treating **megaloblastic anemia**.

Q: Which of the following is a long-acting local anesthetic?

Dibucaine. ***Dibucaine*** - **Dibucaine** is a **long-acting amide local anesthetic** with a duration of action up to 10 hours. - Its high **lipid solubility** contributes to its prolonged effect and greater potency compared to other local anesthetics. *Prilocaine* - **Prilocaine** is considered an **intermediate-duration amide local anesthetic**, with a duration of action typically 1-2 hours. - It carries a risk of **methemoglobinemia** at higher doses, which differentiates it from longer-acting agents. *Procaine* - **Procaine** is a **short-acting ester local anesthetic**, with a duration of action usually less than 1 hour. - It is known for its relatively **high allergenicity** due to its metabolism to para-aminobenzoic acid (PABA). *Lignocaine* - **Lignocaine (Lidocaine)** is an **intermediate-acting amide local anesthetic**, with a duration of action around 1-3 hours. - It is one of the most commonly used local anesthetics, but its duration is not as long as that of dibucaine.

Q: Suxamethonium primarily acts on which type of receptors?

Nicotinic acetylcholine receptors. ***Nicotinic acetylcholine receptors*** - **Suxamethonium** is a depolarizing muscle relaxant that acts as an **agonist at nicotinic acetylcholine receptors** at the neuromuscular junction. - This initial activation leads to muscle fasciculations followed by prolonged depolarization, causing **flaccid paralysis**. *Potassium channels* - While some drugs may affect potassium channels to alter neuronal excitability, suxamethonium's primary mechanism of action is not on these channels. - Blocking potassium channels is characteristic of drugs like **certain antiarrhythmics** or **sulfonylureas**. *Calcium channels* - **Calcium channels** play a role in muscle contraction, but they are not the primary target of suxamethonium. - Drugs like **dihydropyridines** (e.g., nifedipine) target calcium channels for their antihypertensive effects. *Chloride channels* - Chloride channels are involved in maintaining resting membrane potential and inhibitory neurotransmission. - Drugs such as **benzodiazepines** indirectly enhance GABA-mediated chloride influx, which is distinct from suxamethonium's action.

Q: What is the drug of choice (DOC) for the treatment of subacute sclerosing panencephalitis (SSPE)?

Inosine pranobex. ***Inosine pranobex*** - **Inosine pranobex (Isoprinosine)** is considered the **oral drug of choice** for treating **subacute sclerosing panencephalitis (SSPE)**, particularly in the early stages, as it has shown success in delaying disease progression. - This drug works by **modulating the immune system** and enhancing T-cell function, which helps control the persistent measles virus infection in the CNS. - **Note:** Best outcomes are achieved when inosine pranobex is combined with **intrathecal/intraventricular interferon-alpha**, but as a single oral agent, inosine pranobex is the primary choice. *Abacavir* - **Abacavir** is an **antiretroviral drug (NRTI)** used in the treatment of **HIV infection**. - It inhibits reverse transcriptase and has **no role** in treating measles virus-induced SSPE. *Glatiramer* - **Glatiramer acetate** is an **immunomodulatory drug** used in **multiple sclerosis (MS)**. - It works by mimicking **myelin basic protein** to reduce immune attacks on myelin, but is **not effective** against viral infections like SSPE. *Interferon* - **Interferon-alpha** (particularly **intrathecal/intraventricular** administration) has been used in **SSPE** as **combination therapy** with inosine pranobex, showing improved outcomes. - However, when given systemically alone, it has **significant side effects** and **variable efficacy**. - As a single answer option without specifying the route, **inosine pranobex** is preferred as the primary oral DOC.

Q: Which of the following medications is primarily used to decrease serum triglycerides?

Fibrates. ***Fibrates*** - Fibrates, such as **gemfibrozil** and **fenofibrate**, are primarily used to activate **PPAR-alpha**, leading to increased lipoprotein lipase activity and reduced hepatic triglyceride synthesis. - This effectively lowers **serum triglyceride levels** by 20-50% and can also increase HDL cholesterol. *Statin* - Statins primarily inhibit **HMG-CoA reductase**, the rate-limiting enzyme in cholesterol synthesis, which makes them highly effective at lowering **LDL cholesterol**. - While they can cause a modest reduction in triglycerides (10-30%), this is not their primary mechanism or indication. *Ezetimibe* - Ezetimibe works by inhibiting the absorption of **cholesterol** at the brush border of the small intestine, thereby lowering **LDL cholesterol**. - It has minimal effect on **triglyceride levels** and is not indicated for primary triglyceride reduction. *Niacin* - Niacin, or **nicotinic acid**, reduces the liver's production of VLDL (which contains triglycerides) and LDL, and also increases HDL cholesterol. - While it can significantly lower triglycerides, its use is often limited by bothersome side effects such as **flushing** and itchiness, making fibrates generally preferred for primary triglyceride lowering due to better tolerability.

Question 1

In primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?

Accepted Answer

Longitudinal fibres of the ciliary muscle

Answer

All of the options

Answer

Trabecular meshwork

Answer

Ciliary epithelium

Question 2

From which part of the Papaver somniferum plant does the latex, commonly referred to as 'milk', exude?

Accepted Answer

Unripe capsule of the plant

Answer

Leaf of the plant

Answer

Root of the plant

Answer

Seeds of the plant

Question 3

All of the following are medical uses of erythropoietin except?

Accepted Answer

Megaloblastic Anemia

Answer

Treatment of anaemia associated with renal disease

Answer

Chemotherapy induced anemia

Answer

Specific cases of anemia associated with Crohn's disease.

Question 4

What is the progestogen of choice in emergency contraception?

Accepted Answer

Levonorgestrel

Answer

Norethisterone

Answer

Medroxyprogesterone

Answer

Oxytocin

Question 5

Which of the following drugs can lead to pemphigus?

Accepted Answer

Penicillamine

Answer

Carbamazepine

Answer

Isoniazid

Answer

Furosemide

Question 6

What is the primary treatment indication of folic acid?

Accepted Answer

Treatment of megaloblastic anemia

Answer

Prevention of neural tube defects in pregnancy

Answer

Management of hemoglobinopathies

Answer

None of the above

Question 7

Which of the following is a long-acting local anesthetic?

Accepted Answer

Dibucaine

Answer

Prilocaine

Answer

Procaine

Answer

Lignocaine

Question 8

Suxamethonium primarily acts on which type of receptors?

Accepted Answer

Nicotinic acetylcholine receptors

Answer

Potassium channels

Answer

Calcium channels

Answer

Chloride channels

Question 9

What is the drug of choice (DOC) for the treatment of subacute sclerosing panencephalitis (SSPE)?

Accepted Answer

Inosine pranobex

Answer

Abacavir

Answer

Glatiramer

Answer

Interferon

Question 10

Which of the following medications is primarily used to decrease serum triglycerides?

Accepted Answer

Fibrates

Answer

Ezetimibe

Answer

Niacin

Answer

Statin

NEET-PG 2015 — Pharmacology