FMGE 2025 - Pharmacology Practice Questions

Q: A 75 kg person is administered a drug with a half-life of 3 hours. What is the approximate clearance of the drug?

23 mL/min. ⚠️ **Note:** This question cannot be solved using standard pharmacokinetic formulas without the volume of distribution (Vd). The answer relies on estimation principles rather than exact calculation. ***23 mL/min*** - This represents a **low to moderate clearance** value, typical for drugs that undergo hepatic metabolism with low-to-intermediate extraction ratios - For context: Normal **creatinine clearance** (marker of GFR) is approximately 90-120 mL/min in adults [1], so 23 mL/min represents roughly 20-25% of renal clearance capacity - This is a plausible value for drugs with **predominantly hepatic metabolism** with low hepatic extraction ratio - Using the relationship $Cl = \frac{0.693 \times Vd}{t_{1/2}}$, this would correspond to a Vd of approximately 6 liters (if t½ = 3 hours) [2] *210 mL/min* - This represents **moderate to high clearance**, suggesting efficient elimination - Comparable to **renal plasma flow** (approximately 600-700 mL/min × filtration fraction) - Would require a Vd of approximately 54 liters with the given half-life - Typical for drugs with good renal excretion or intermediate hepatic extraction *1670 mL/min* - This is extremely high clearance, approaching **total hepatic blood flow** (1500 mL/min) - Would require Vd of approximately 433 liters, which exceeds total body water (42L in a 70kg person) - Only seen with high extraction ratio drugs (>0.7) with extensive first-pass metabolism - Physiologically implausible for most drugs *6770 mL/min* - This clearance is **physiologically impossible** as it exceeds cardiac output (5-6 L/min = 5000-6000 mL/min) [3] - Clearance cannot exceed the blood flow to the eliminating organ [3] - Clearly a distracter option with no pharmacokinetic validity

Q: Which medication can be administered to reduce the frequency of future headache episodes in a 26-year-old female patient who experiences one-sided pulsating headaches accompanied by nausea, vomiting, and sensitivity to light and finds relief in a dimly lit environment?

Propranolol. ***Propranolol***- This is a non-selective **beta-blocker** and is considered a first-line prophylactic agent for the reduction of frequency and severity in patients with **episodic migraine** [1].- The patient's symptoms (unilateral, pulsating headache, **nausea, vomiting, and photophobia**) [2] are classic features of migraine, making **Propranolol** an appropriate choice for maintenance therapy [3].*Alprazolam*- This medication is a **short-acting benzodiazepine** primarily indicated for the acute management of anxiety and panic disorders [3].- It has **no established role** in the long-term prophylactic management of migraine and carries risks of sedation and dependence.*Diazepam*- This is a **long-acting benzodiazepine** commonly used as a muscle relaxant, anxiolytic, and for acute seizure management.- Similar to Alprazolam, it is **not recommended** for headache prophylaxis due to lack of efficacy and significant abuse potential [3].*Fluoxetine*- This drug is a selective serotonin reuptake inhibitor (**SSRI**) primarily used to treat **major depressive disorder** and anxiety [3].- While some antidepressants (like TCAs) are used for migraine prophylaxis, **Fluoxetine** is generally not considered a standard or preferred first-line agent for preventing migraine attacks.

Q: A patient with a history of peptic ulcer disease presents with arthritis and develops carditis. Which of the following is the most appropriate anti-inflammatory drug?

Celecoxib. ***Celecoxib***- Celecoxib is a **selective COX-2 inhibitor**, meaning it primarily blocks the enzyme responsible for inflammation while largely preserving **COX-1** activity, which is crucial for gastric mucosal protection [2].- This selectivity significantly reduces the risk of **peptic ulcers** and gastrointestinal bleeding, making it the safest NSAID choice for patients with a history of **Peptic Ulcer Disease** (PUD) requiring treatment for arthritis and carditis [1].- **Note**: While COX-2 inhibitors carry cardiovascular risk warnings, in this clinical scenario (likely **rheumatic carditis** requiring anti-inflammatory therapy), celecoxib offers the best **risk-benefit profile** among NSAIDs by minimizing GI complications in a PUD patient [3]. Close cardiac monitoring is advised.*Ibuprofen*- Ibuprofen is a **non-selective NSAID** that inhibits both COX-1 and COX-2, leading to effective anti-inflammatory effects but also significant risk of **gastrointestinal (GI) toxicity**.- Inhibition of **COX-1** impairs the synthesis of protective mucosal prostaglandins, posing a high risk of ulcer recurrence or bleeding in patients with a PUD history [4].*Diclofenac*- Diclofenac is also a **non-selective NSAID** which carries a considerable risk of GI side effects by inhibiting **COX-1**, making it generally unsuitable for patients with pre-existing PUD.- Although sometimes exhibiting relative COX-2 preference compared to agents like naproxen, the GI risk remains high enough to warrant the use of a true COX-2 selective inhibitor like celecoxib in this high-risk patient [2].*Naloxone*- Naloxone is an **opioid receptor antagonist** used primarily to reverse the effects of opioid overdose; it has no **anti-inflammatory** properties.- This medication is completely irrelevant to the underlying inflammatory condition (arthritis and carditis) and the need for **pain and inflammation control**.

Q: Which of the following is a correct triple drug regimen for the treatment of Helicobacter pylori infection?

Omeprazole + Clarithromycin + Metronidazole. ***Omeprazole + Clarithromycin + Metronidazole*** - This is a **standard triple therapy regimen** containing **1 PPI (Omeprazole) + 2 antibiotics (Clarithromycin + Metronidazole)** - Also known as **PCM regimen**, recommended as first-line therapy for H. pylori eradication - Given for **14 days** with cure rates of 70-85% - Particularly useful in **penicillin-allergic patients** *Metronidazole + Omeprazole + Amoxicillin* - This is actually a **valid triple therapy** (PPI + Amoxicillin + Metronidazole = PAM regimen) - However, this combination is **less preferred** than clarithromycin-based regimens due to lower efficacy in areas with metronidazole resistance - Used as alternative when clarithromycin resistance is high *Omeprazole + Amoxicillin + Metronidazole* - Same as option A (PAM regimen), just reordered - Valid but **less preferred** than clarithromycin-based triple therapy *Metronidazole + Ciprofloxacin + Amoxicillin* - **Missing the PPI component** - incomplete triple therapy - Standard H. pylori triple therapy MUST include a **proton pump inhibitor** - Ciprofloxacin is not a first-line agent for H. pylori

Q: A patient developed Achilles tendonitis and leg swelling after taking a certain antibiotic. This adverse effect is commonly associated with fluoroquinolones. What is the most likely mechanism of action of the drug involved?

Inhibition of bacterial DNA gyrase and topoisomerase IV. ***Inhibition of bacterial DNA gyrase and topoisomerase IV*** - This is the characteristic mechanism of action for **fluoroquinolones** (e.g., ciprofloxacin, levofloxacin), which disrupts bacterial DNA replication and repair, leading to cell death. - This class of antibiotics is well-known for causing **tendinopathy** and **tendon rupture**, with the **Achilles tendon** being the most commonly affected site, as described in the clinical scenario. *Inhibition of bacterial protein synthesis at 50S subunit* - This mechanism is characteristic of antibiotic classes like **macrolides** (e.g., erythromycin, azithromycin) and **lincosamides** (e.g., clindamycin). - Their common adverse effects include **gastrointestinal distress** and **QT interval prolongation** (macrolides), not tendonitis. *Inhibition of bacterial folic acid synthesis* - This is the mechanism of action for **sulfonamides** (inhibiting dihydropteroate synthase) and **trimethoprim** (inhibiting dihydrofolate reductase). - These drugs are associated with adverse effects like **hypersensitivity reactions** (including Stevens-Johnson syndrome), **photosensitivity**, and **crystalluria**, not tendon-related issues. *Inhibition of bacterial cell wall synthesis* - This mechanism is used by a broad range of antibiotics, including **beta-lactams** (penicillins, cephalosporins) and **glycopeptides** (vancomycin). - Common adverse effects associated with these drugs are **hypersensitivity reactions** (beta-lactams) and **Red Man Syndrome** or **nephrotoxicity** (vancomycin).

Q: A patient took a drug for migraine treatment, following which there was numbness, and his hand appeared as below. What is the possible drug that was taken?

Dihydroergotamine. ***Dihydroergotamine*** - Dihydroergotamine is an **ergot alkaloid** that causes potent, non-selective **vasoconstriction** of both arteries and veins. This can lead to severe peripheral ischemia, a condition known as **ergotism**. - The clinical presentation of numbness, tingling, and cold extremities, as suggested by the patient's symptoms and the appearance of the hand, is a classic manifestation of ergotamine-induced vasospasm. *Sumatriptan* - Sumatriptan is a **triptan**, which is a selective **5-HT1B/1D receptor agonist**. While it does cause vasoconstriction, its effects are more selective for **cranial arteries**. - Though it can cause paresthesias (tingling/numbness), severe peripheral ischemia leading to the signs seen in the image is a much rarer side effect compared to ergot alkaloids. *Butorphanol* - Butorphanol is an **opioid agonist-antagonist** used for pain relief. Its mechanism of action does not involve vasoconstriction. - Common side effects are related to the central nervous system, such as sedation, dizziness, and nausea, not peripheral vascular symptoms. *Aspirin* - Aspirin is a **nonsteroidal anti-inflammatory drug (NSAID)** that inhibits **cyclooxygenase (COX)** and has antiplatelet effects. It does not cause vasoconstriction. - Its primary side effects include **gastrointestinal irritation** and an increased risk of **bleeding**, which are unrelated to the patient's presentation.

Q: A patient with hypertension, tachycardia and early renal involvement is prescribed an ARB (telmisartan). What is the most likely mechanism by which the drug helps improve heart rate and blood pressure?

By decreasing peripheral vascular resistance. ***By decreasing peripheral vascular resistance*** - ARBs (Angiotensin Receptor Blockers) like **telmisartan** selectively block AT1 receptors, preventing angiotensin II from binding - This blockade leads to **vasodilation** (reduced vasoconstriction) → decreased peripheral vascular resistance (afterload reduction) - Lower afterload reduces **blood pressure** and decreases cardiac workload, which secondarily **improves heart rate** - ARBs also provide **renoprotection** by reducing intraglomerular pressure, making them ideal for hypertension with early renal involvement *By decreasing cardiac output directly* - ARBs do not have direct negative inotropic effects on the heart - Any reduction in cardiac output is secondary to decreased afterload, not a primary mechanism *By directly blocking beta-1 receptors* - This describes the mechanism of **beta-blockers** (e.g., metoprolol, atenolol), not ARBs - Beta-blockers directly reduce heart rate and contractility; ARBs work via peripheral vasodilation *By increasing sodium excretion via loop diuretics* - This describes the mechanism of **loop diuretics** (e.g., furosemide), not ARBs - While ARBs may have mild diuretic effects, their primary mechanism is reducing peripheral vascular resistance through AT1 receptor blockade

Q: What is the preferred preoperative drug for managing blood pressure in a patient with pheochromocytoma?

Phenoxybenzamine. ***Phenoxybenzamine***- It is the standard first-line agent, administered 10–14 days preoperatively, because it is a **non-selective**, **irreversible alpha-adrenergic blocker**.- This irreversible blockade prevents the high concentrations of circulating **catecholamines** (epinephrine and norepinephrine) resulting in severe **hypertensive crisis** during surgical tumor manipulation.*Propranolol*- Propranolol and other pure **beta-blockers** should only be initiated *after* adequate **alpha-blockade** is established, typically to control tachycardia.- Giving a beta-blocker alone leaves the **alpha-1 receptors** unopposed, leading to unchecked systemic **vasoconstriction** and severe, potentially fatal, hypertension.*Prazosin*- Although Prazosin is an **alpha-1 selective blocker**, it is generally less preferred because it is a *reversible* antagonist.- **Phenoxybenzamine** is favored because its irreversible action provides superior, more stable, and prolonged protection against massive **catecholamine surges** during surgery.*Labetalol*- Labetalol is generally avoided for initial control because its **beta-blocking action** significantly outweighs its alpha-blocking action (high beta:alpha ratio).- This dominant beta blockade can induce **unopposed alpha vasoconstriction**, similar to pure beta-blockers, resulting in paradoxical and severe **hypertension**.

Q: A woman taking cetirizine for allergic rhinitis complains of excessive sleepiness. Which of the following is the best alternative with minimal sedative effect?

Fexofenadine. ***Fexofenadine***- It is a second-generation H1 antihistamine that has the **lowest lipophilicity** and is actively transported out of the central nervous system (CNS) by the **P-glycoprotein** pump.- This mechanism results in **minimal to virtually no sedative effects**, making it the best non-sedating alternative to cetirizine.*Hydroxyzine*- This is a first-generation H1 antihistamine that easily crosses the **blood-brain barrier** (BBB).- It is known for its significant **sedative** and **anxiolytic properties**, and would worsen the patient's complaint of excessive sleepiness.*Diphenhydramine*- As a highly lipophilic, first-generation antihistamine, it exhibits profound CNS penetration and causes profound **drowsiness** and cognitive impairment.- It also possesses potent **anticholinergic effects**, which contribute significantly to various side effects but not lack of sedation.*Promethazine*- This drug is a first-generation antihistamine known for its **strong antiemetic** and highly **sedative** properties.- It is structurally related to phenothiazine antipsychotics and would likely cause **more severe sleepiness** than cetirizine.

Q: Which of the following drugs acts by inhibiting the catechol-O-methyltransferase enzyme?

Tolcapone. ***Tolcapone***- **Tolcapone** is a potent inhibitor of **catechol-O-methyltransferase (COMT)**, an enzyme responsible for metabolizing dopamine and levodopa. - By inhibiting COMT, Tolcapone increases the bioavailability and half-life of **levodopa** in the brain, thereby improving motor symptoms in **Parkinson's disease**.*Amantadine*- Amantadine is thought to enhance the synthesis and release of **dopamine** from presynaptic nerve terminals. - It also acts as a non-competitive antagonist of the **N-methyl-D-aspartate (NMDA) receptor**, providing benefit primarily for **dyskinesia** associated with long-term levodopa use.*Rotigotine*- **Rotigotine** is classified as a non-ergot **dopamine agonist**, meaning it directly stimulates post-synaptic dopamine receptors (D2 and D3). - It is often administered as a **transdermal patch** for continuous dopamine stimulation, helping to manage motor fluctuations in Parkinson's disease.*Selegiline*- **Selegiline** is an inhibitor of **Monoamine Oxidase type B (MAO-B)**, an enzyme subgroup that preferentially metabolizes dopamine in the brain. - By selectively blocking MAO-B, it reduces the breakdown of dopamine, thereby potentiating the effects of endogenous and administered levodopa.

Question 1

A 75 kg person is administered a drug with a half-life of 3 hours. What is the approximate clearance of the drug?

Accepted Answer

23 mL/min

Answer

6770 mL/min

Answer

1670 mL/min

Answer

210 mL/min

Question 2

Which medication can be administered to reduce the frequency of future headache episodes in a 26-year-old female patient who experiences one-sided pulsating headaches accompanied by nausea, vomiting, and sensitivity to light and finds relief in a dimly lit environment?

Accepted Answer

Propranolol

Answer

Diazepam

Answer

Fluoxetine

Answer

Alprazolam

Question 3

A patient with a history of peptic ulcer disease presents with arthritis and develops carditis. Which of the following is the most appropriate anti-inflammatory drug?

Accepted Answer

Celecoxib

Answer

Diclofenac

Answer

Naloxone

Answer

Ibuprofen

Question 4

Which of the following is a correct triple drug regimen for the treatment of Helicobacter pylori infection?

Accepted Answer

Omeprazole + Clarithromycin + Metronidazole

Answer

Metronidazole + Omeprazole + Amoxicillin

Answer

Omeprazole + Amoxicillin + Metronidazole

Answer

Metronidazole + Ciprofloxacin + Amoxicillin

Question 5

A patient developed Achilles tendonitis and leg swelling after taking a certain antibiotic. This adverse effect is commonly associated with fluoroquinolones. What is the most likely mechanism of action of the drug involved?

Accepted Answer

Inhibition of bacterial DNA gyrase and topoisomerase IV

Answer

Inhibition of bacterial cell wall synthesis

Answer

Inhibition of bacterial folic acid synthesis

Answer

Inhibition of bacterial protein synthesis at 50S subunit

Question 6

A patient took a drug for migraine treatment, following which there was numbness, and his hand appeared as below. What is the possible drug that was taken?

Accepted Answer

Dihydroergotamine

Answer

Sumatriptan

Answer

Aspirin

Answer

Butorphanol

Question 7

A patient with hypertension, tachycardia and early renal involvement is prescribed an ARB (telmisartan). What is the most likely mechanism by which the drug helps improve heart rate and blood pressure?

Accepted Answer

By decreasing peripheral vascular resistance

Answer

By decreasing cardiac output directly

Answer

By directly blocking beta-1 receptors

Answer

By increasing sodium excretion via loop diuretics

Question 8

What is the preferred preoperative drug for managing blood pressure in a patient with pheochromocytoma?

Accepted Answer

Phenoxybenzamine

Answer

Prazosin

Answer

Propranolol

Answer

Labetalol

Question 9

A woman taking cetirizine for allergic rhinitis complains of excessive sleepiness. Which of the following is the best alternative with minimal sedative effect?

Accepted Answer

Fexofenadine

Answer

Promethazine

Answer

Diphenhydramine

Answer

Hydroxyzine

Question 10

Which of the following drugs acts by inhibiting the catechol-O-methyltransferase enzyme?

Accepted Answer

Tolcapone

Answer

Amantadine

Answer

Selegiline

Answer

Rotigotine

FMGE 2025 — Pharmacology