FMGE 2025 - Pharmacology PYQs Practice Questions

Q: Which anti-epileptic drug is commonly associated with gum hypertrophy and dizziness as side effects?

Phenytoin. ***Phenytoin*** - It is classically associated with **gingival hyperplasia** (gum hypertrophy) due to increased stimulation of **fibroblast activity** and **collagen synthesis** in the gingiva, which is a major distinction from other AEDs. - Dose-dependent **dizziness** and **ataxia** are very common CNS side effects, reflecting its non-linear kinetics and narrow therapeutic index. *Carbamazepine* - Its most characteristic serious side effects include **aplastic anemia** and agranulocytosis, requiring baseline and periodic complete blood counts (CBCs). - It is a potent inducer of **CYP450 enzymes** and frequently causes **hyponatremia** (via Syndrome of Inappropriate Antidiuretic Hormone secretion, SIADH). *Levetiracetam* - This drug is generally well-tolerated but is notably associated with significant **behavioral side effects** such as irritability, aggression, and mood instability. - It does not cause **gum hypertrophy** or significant liver enzyme induction, unlike Phenytoin or Carbamazepine. *Topiramate* - Commonly causes side effects related to cognition, often called **"Dopamax"**, leading to cognitive slowing, difficulty concentrating, and language problems. - Other unique side effects include **weight loss** and the formation of **kidney stones** (nephrolithiasis) due to inhibition of carbonic anhydrase. [Practice more Pharmacology PYQs on OnCourse]

Q: Which anti-tubercular drug is associated with mutations in the katG gene?

Isoniazid. ***Isoniazid*** - It is a **prodrug** that requires activation by the **catalase-peroxidase enzyme** complex, which is encoded by the **katG gene** in *Mycobacterium tuberculosis*. - Mutations or deletions in the **katG gene** are the most common cause of high-level Isoniazid resistance, preventing the drug from converting into its active form (isonicotinic acyl radical). *Rifampicin* - Resistance is predominantly caused by mutations in the **rpoB gene**, which encodes the **beta-subunit of RNA polymerase**. - Mutations in **rpoB** prevent Rifampicin from binding to the RNA polymerase, thereby inhibiting its primary mechanism of blocking transcription. *Moxifloxacin* - This drug belongs to the fluoroquinolone class and targets **DNA gyrase** (encoded by *gyrA* and *gyrB*) and **topoisomerase IV**. - Resistance is typically mediated by point mutations within the **Quinolone Resistance Determining Regions (QRDRs)** of these target genes. *Ethambutol* - Resistance to Ethambutol is most frequently associated with mutations in the **embB gene**. - The **embB gene** encodes the **arabinosyl transferase** enzyme, which is crucial for synthesizing the **arabinogalactan layer** of the mycobacterial cell wall. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following conditions is not reversed with the administration of atropine?

Muscle weakness due to neuromuscular blockade. ***Muscle weakness due to neuromuscular blockade*** - Atropine is a **muscarinic receptor antagonist** and therefore has no direct effect on the **nicotinic receptors** responsible for neuromuscular transmission and muscle strength. - The reversal of **non-depolarizing neuromuscular blockade** requires increasing acetylcholine via a **cholinesterase inhibitor** (e.g., neostigmine), which acts at the **neuromuscular junction**. *Bradycardia* - Atropine blocks **M2 receptors** on the heart's sinoatrial (SA) node, inhibiting **vagal tone** and increasing the heart rate, thereby reversing bradycardia. - It is the primary drug used to treat hemodynamically significant **bradyarrhythmias**. *Excessive salivation* - Atropine is an anticholinergic agent that blocks **M3 receptors** on exocrine glands, effectively reducing all secretions, including **saliva**. - This is why it is often used as a pre-anesthetic agent to dry secretions and reduce the risk of **aspiration**. *Bronchoconstriction* - Atropine blocks **M3 receptors** in the bronchial smooth muscle, leading to relaxation and **bronchodilation**. - While effective, related synthetic compounds like **ipratropium** are often preferred for treating bronchoconstriction due to fewer systemic anticholinergic side effects. [Practice more Pharmacology PYQs on OnCourse]

Q: Which adverse effect of Bleomycin is exacerbated by radiation exposure?

Pulmonary toxicity. ***Pulmonary toxicity*** - Bleomycin is well-known for causing dose-dependent **pulmonary fibrosis**. It damages **type I pneumocytes**, leading to inflammation, proliferation of **type II pneumocytes**, and eventual fibrosis, impairing gas exchange. - The risk of pulmonary toxicity is significantly increased by concurrent or prior **chest radiation therapy** and administration of high concentrations of supplemental **oxygen**, as both are also injurious to lung tissue. *Gastric toxicity* - Bleomycin is not typically associated with significant gastric toxicity. Common side effects are milder and include **mucositis** and **stomatitis** rather than severe gastric damage. - There is no evidence of a synergistic toxic effect on the gastric mucosa when Bleomycin is combined with radiation therapy. *Neural toxicity* - Neurotoxicity is not a characteristic side effect of Bleomycin. Chemotherapeutic agents like **vincristine** and **cisplatin** are more commonly associated with peripheral neuropathy. - While radiation can cause nerve damage, this is not a known interaction that is specifically exacerbated by Bleomycin administration. *Hepatotoxicity* - Severe liver damage (**hepatotoxicity**) is a rare side effect of Bleomycin. Mild and transient elevations of liver enzymes may occur but are not clinically significant. - Unlike the lungs, the liver is not a primary site for synergistic toxicity between Bleomycin and radiation therapy. [Practice more Pharmacology PYQs on OnCourse]

Question 1

Which anti-epileptic drug is commonly associated with gum hypertrophy and dizziness as side effects?

Accepted Answer

Phenytoin

Answer

Carbamazepine

Answer

Topiramate

Answer

Levetiracetam

Question 2

Which anti-tubercular drug is associated with mutations in the katG gene?

Accepted Answer

Isoniazid

Answer

Moxifloxacin

Answer

Ethambutol

Answer

Rifampicin

Question 3

Which of the following conditions is not reversed with the administration of atropine?

Accepted Answer

Muscle weakness due to neuromuscular blockade

Answer

Bradycardia

Answer

Bronchoconstriction

Answer

Excessive salivation

Question 4

Which adverse effect of Bleomycin is exacerbated by radiation exposure?

Accepted Answer

Pulmonary toxicity

Answer

Neural toxicity

Answer

Hepatotoxicity

Answer

Gastric toxicity

Question 5

What is the key difference between Cisplatin and Carboplatin?

Accepted Answer

Cisplatin has more nephrotoxic side effects compared to Carboplatin

Answer

Cisplatin is less neurotoxic than Carboplatin

Answer

Carboplatin is more neurotoxic than Cisplatin

Answer

Cisplatin causes fewer gastric issues compared to Carboplatin

Question 6

A 25-year-old woman presents to the emergency department 6 hours after ingesting a large quantity of paracetamol tablets. What is the most likely progression of paracetamol poisoning in this case?

Accepted Answer

Increase in liver enzymes starting around 24 hours

Answer

Recovery within 72 hours

Answer

Paracetamol achieves peak concentration within 4 hours

Answer

Liver failure within 24 hours

Question 7

A patient with rheumatoid arthritis is taking indomethacin and an ACE inhibitor for hypertension. What potential side effect is likely to be seen?

Accepted Answer

Hyperkalemia

Answer

Hypercalcemia

Answer

Hypernatremia

Answer

Hyperphosphatemia

Question 8

A patient with penicillin allergy presents with fever, burning micturition, and hearing problems accompanied by dizziness. Which drug is the most appropriate for the management?

Accepted Answer

Ciprofloxacin

Answer

Ampicillin-Clavulanic acid

Answer

Amikacin

Answer

Azithromycin

Question 9

A 35-year-old male experiences headache, nausea, and shortness of breath while trekking. The physician prescribes a drug to alleviate his symptoms. The drug administered primarily acts on which part of the nephron?

Accepted Answer

Proximal convoluted tubule (PCT)

Answer

Loop of Henle

Answer

Collecting duct (CD)

Answer

Distal convoluted tubule (DCT)

Question 10

Which of the following drug dosages is incorrect for the treatment of leprosy in adults?

Accepted Answer

Rifampicin 450 mg

Answer

Clofazimine 50 mg

Answer

Dapsone 100 mg

Answer

Clofazimine 300 mg

FMGE 2025 — Pharmacology