Analgesics and Anti-inflammatory Drugs — MCQs

Analgesics and Anti-inflammatory Drugs Indian Medical PG Practice Questions and MCQs

Question 151: Which of the following represents the mechanism of action of Etanercept?

A. Blocking tumor necrosis factor (Correct Answer)
B. Blocking bradykinin synthesis
C. Blocking cyclo-oxygenase-2
D. Blocking lipoxygenase

Explanation: **Explanation:** **Mechanism of Action (Correct Answer):** Etanercept is a biological Disease-Modifying Antirheumatic Drug (bDMARD). It is a **soluble TNF-receptor fusion protein** (specifically, a recombinant human TNF-receptor p75 Fc fusion protein). It acts as a **decoy receptor** that binds to circulating Tumor Necrosis Factor (TNF-α and TNF-β), preventing them from interacting with cell surface receptors. This neutralizes the pro-inflammatory cascade responsible for joint destruction in conditions like Rheumatoid Arthritis. **Analysis of Incorrect Options:** * **Option B (Bradykinin synthesis):** Bradykinin is a potent vasodilator and mediator of pain/inflammation. Drugs like Icatibant (a bradykinin B2 receptor antagonist) target this pathway, primarily for Hereditary Angioedema, not Etanercept. * **Option C (COX-2):** This is the mechanism of Selective COX-2 inhibitors (e.g., Celecoxib) and traditional NSAIDs. They inhibit prostaglandin synthesis rather than cytokine signaling. * **Option D (Lipoxygenase):** This pathway leads to leukotriene production. Drugs like Zileuton (LOX inhibitor) or Montelukast (receptor antagonist) target this pathway, primarily for asthma management. **High-Yield Clinical Pearls for NEET-PG:** * **Structure Mnemonic:** Etanercept **"Intercepts"** the TNF molecule (Decoy receptor). * **Indications:** Rheumatoid arthritis, Psoriatic arthritis, and Ankylosing spondylitis. * **Pre-treatment Screening:** Always screen for **Latent Tuberculosis** (using TST or IGRA) before starting Etanercept, as TNF-alpha is essential for maintaining granulomas. * **Comparison:** Unlike Infliximab or Adalimumab (which are monoclonal antibodies), Etanercept is a fusion protein.

Question 152: Aspirin is useful in all the following conditions EXCEPT?

A. Fever
B. Post myocardial infarction
C. Venous thrombosis
D. Gout (Correct Answer)

Explanation: **Explanation:** The correct answer is **Gout (Option D)**. Aspirin is generally contraindicated in patients with gout because it exhibits a **bimodal effect** on uric acid excretion. At low doses (the most common clinical dosage), aspirin inhibits the organic anion transporters (OAT) in the renal tubules, leading to decreased uric acid secretion [1]. This results in **hyperuricemia**, which can precipitate or worsen an acute gouty attack. While high doses (>5g/day) are uricosuric [3], such doses are clinically intolerable due to toxicity (salicylism) [4]. **Why other options are incorrect:** * **Fever (A):** Aspirin is a classic antipyretic [3]. It inhibits COX enzymes in the hypothalamus, reducing Prostaglandin E2 (PGE2) levels, which resets the thermoregulatory center to normal. (Note: Avoid in children with viral fever due to Reye’s syndrome risk) [5]. * **Post Myocardial Infarction (B):** Low-dose aspirin (75–150 mg) irreversibly inhibits COX-1 in platelets [2], preventing the formation of Thromboxane A2 (TXA2). This provides a potent antiplatelet effect, reducing the risk of recurrent MI and stroke. * **Venous Thrombosis (C):** While anticoagulants (like Heparin/Warfarin) are preferred for DVT, aspirin is used for the prophylaxis of thromboembolic events, especially in post-operative settings or when anticoagulants are contraindicated. **High-Yield Clinical Pearls for NEET-PG:** 1. **Analgesic Asthma:** Aspirin can trigger bronchospasm in sensitive individuals by shifting arachidonic acid metabolism toward the leukotriene pathway (Samter’s Triad). 2. **Zero-Order Kinetics:** At therapeutic/toxic doses, aspirin metabolism shifts from first-order to zero-order kinetics. 3. **Reye’s Syndrome:** Characterized by fulminant hepatic failure and encephalopathy in children using aspirin during viral infections (Varicella/Influenza) [4], [5].

Question 153: Aspirin causes mucosal injury by which mechanism?

A. Ion trapping (Correct Answer)
B. Ionization in the stomach
C. Biotransformation
D. Increased H+ secretion

Explanation: ### Explanation Aspirin (Acetylsalicylic acid) causes gastric mucosal injury through both systemic and local mechanisms. The local mechanism is primarily driven by **Ion Trapping**. **1. Why "Ion Trapping" is correct:** Aspirin is a weak acid ($pK_a \approx 3.5$). In the highly acidic environment of the stomach ($pH \approx 1-2$), aspirin remains in its **non-ionized (lipid-soluble)** form. This allows it to easily diffuse across the lipid membranes of gastric mucosal cells. Once inside the cell, where the $pH$ is neutral ($\approx 7.4$), aspirin dissociates into its **ionized (water-soluble)** form. Because ionized molecules cannot easily cross back through the lipid membrane, aspirin becomes "trapped" inside the mucosal cells. This high intracellular concentration leads to direct cellular toxicity, oxidative stress, and mitochondrial damage. **2. Analysis of Incorrect Options:** * **B. Ionization in the stomach:** If aspirin ionized in the stomach, it would become lipid-insoluble and could not enter the cells to cause damage. It is the *lack* of ionization in the stomach that facilitates entry. * **C. Biotransformation:** While aspirin is metabolized (deacetylated) to salicylic acid, the acute mucosal injury is a physical-chemical property of the drug's diffusion, not a result of metabolic activation. * **D. Increased $H^+$ secretion:** Aspirin does not significantly increase acid secretion; rather, it weakens the **mucosal barrier** (by inhibiting $PGE_2$ and $PGI_2$ which normally stimulate mucus and bicarbonate secretion), making the stomach more vulnerable to existing acid. **High-Yield NEET-PG Pearls:** * **Dual Mechanism:** Aspirin causes damage via **Local effect** (Ion trapping) and **Systemic effect** (COX-1 inhibition leading to decreased protective prostaglandins). * **Prostaglandins ($PGE_2$):** These are cytoprotective; they increase mucus/bicarbonate secretion and maintain mucosal blood flow. * **Prevention:** To reduce local injury, aspirin is often formulated as **enteric-coated** tablets, which dissolve in the alkaline $pH$ of the small intestine rather than the stomach.

Question 154: Which of the following causes Metabolic syndrome EXCEPT?

A. Clozapine
B. Olanzapine
C. Risperidone
D. Ziprasidone (Correct Answer)

Explanation: **Explanation:** The question focuses on the metabolic side-effect profiles of **Atypical Antipsychotics (Second-Generation Antipsychotics)**. Metabolic syndrome in this context is characterized by significant weight gain, hyperlipidemia, and hyperglycemia (Type 2 Diabetes mellitus). **Why Ziprasidone is the Correct Answer:** Among the atypical antipsychotics, **Ziprasidone** and **Aripiprazole** are considered **"metabolic neutral."** [1], [2] They have the lowest propensity for causing weight gain or alterations in glucose and lipid metabolism. [2] Ziprasidone’s primary clinical concern is actually **QTc interval prolongation**, [3] rather than metabolic dysfunction. **Analysis of Incorrect Options:** * **Clozapine & Olanzapine (Options A & B):** These are the worst offenders. They have the **highest risk** of causing profound weight gain and metabolic syndrome. [1], [2] Clozapine is also associated with agranulocytosis and seizures, while Olanzapine is notorious for rapid-onset insulin resistance. * **Risperidone (Option C):** This drug carries a **moderate risk** for metabolic syndrome. [2] While less severe than Olanzapine, it frequently causes weight gain and is highly associated with **hyperprolactinemia** (leading to gynecomastia or galactorrhea). **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Weight Gain:** "COQ" (Clozapine, Olanzapine, Quetiapine) are the high-risk metabolic drugs. * **Safest Metabolic Profile:** Ziprasidone, Aripiprazole, and Lurasidone. * **Monitoring:** Patients on Atypical Antipsychotics require baseline and periodic monitoring of BMI, waist circumference, fasting blood glucose, and lipid profile. [3], [4] * **Ziprasidone Pearl:** Always perform an ECG before prescribing due to the risk of Torsades de Pointes (QTc prolongation). [3]

Question 155: Hallucinations, psychosis, hypertension, and tachycardia are adverse effects typically associated with which of the following narcotics?

A. Morphine
B. Meperidine
C. Pentazocine (Correct Answer)
D. Buprenorphine

Explanation: ### Explanation **Correct Answer: C. Pentazocine** **Why it is correct:** Pentazocine is a **mixed agonist-antagonist** opioid. It acts as an agonist at **kappa (κ)** receptors and a weak antagonist or partial agonist at **mu (μ)** receptors. The specific adverse effects mentioned—hallucinations, nightmares, and psychosis (dysphoria)—are attributed to its activation of **kappa receptors** and its interaction with **sigma (σ) receptors**. Furthermore, unlike pure mu-agonists (which cause bradycardia and hypotension), pentazocine increases plasma catecholamine levels. This leads to **sympathetic stimulation**, resulting in an increase in heart rate (**tachycardia**) and blood pressure (**hypertension**). This makes it contraindicated in patients with myocardial infarction. **Why other options are incorrect:** * **A. Morphine:** A prototype pure mu-agonist. It typically causes sedation, respiratory depression, and miosis. It causes peripheral vasodilation (via histamine release), leading to **hypotension**, not hypertension. * **B. Meperidine (Pethidine):** While it can cause tachycardia (due to its atropine-like structure), its hallmark toxicity is **seizures** caused by its metabolite, *normeperidine*. It does not typically cause the psychotomimetic effects seen with pentazocine. * **D. Buprenorphine:** A partial mu-agonist and kappa-antagonist. Because it **antagonizes** kappa receptors, it is notably free from the dysphoric and hallucinogenic effects associated with pentazocine. **High-Yield Clinical Pearls for NEET-PG:** * **Kappa Agonism:** Responsible for spinal analgesia, dysphoria, and psychotomimetic effects. * **Ceiling Effect:** Pentazocine exhibits a "ceiling effect" for respiratory depression, unlike morphine. * **Precipitated Withdrawal:** Giving pentazocine to a morphine addict can precipitate sudden withdrawal symptoms due to its mu-antagonist properties. * **Avoid in MI:** Due to increased cardiac workload (tachycardia/hypertension), pentazocine is avoided in cardiac pain; Morphine remains the drug of choice.

Question 156: What is the drug of choice for acute gout?

A. Febuxostat
B. Probenecid
C. Rofecoxib
D. Naproxen (Correct Answer)

Explanation: ### Explanation **1. Why Naproxen is the Correct Answer:** In the management of **acute gout**, the primary goal is to control intense inflammation and pain [1, 2]. **NSAIDs** (Non-Steroidal Anti-inflammatory Drugs) are considered the **first-line treatment** [1]. Naproxen, along with Indomethacin and Ibuprofen, is highly effective in inhibiting prostaglandin synthesis, thereby rapidly reducing joint swelling and pain [1]. While Indomethacin was traditionally the drug of choice, Naproxen is now often preferred due to its better tolerability profile. **2. Analysis of Incorrect Options:** * **Febuxostat (Option A):** This is a xanthine oxidase inhibitor used for **chronic gout** (prophylaxis) to lower serum uric acid levels [1]. Starting it during an acute attack can worsen symptoms by causing rapid mobilization of urate crystals from tissues. * **Probenecid (Option B):** This is a **uricosuric agent** used for chronic management [2]. Like Febuxostat, it has no anti-inflammatory properties and is contraindicated during an acute flare. * **Rofecoxib (Option C):** While selective COX-2 inhibitors (like Celecoxib) can be used for gout, Rofecoxib was withdrawn from the global market due to significant cardiovascular risks (increased risk of MI and stroke). **3. NEET-PG High-Yield Clinical Pearls:** * **Order of preference for Acute Gout:** NSAIDs (1st line) > Colchicine (if NSAIDs are contraindicated) > Corticosteroids (if both are contraindicated or for polyarticular gout) [1]. * **Colchicine:** Acts by inhibiting **microtubule assembly** (binding to tubulin) and preventing neutrophil chemotaxis [1]. Its dose-limiting side effect is **diarrhea**. * **Aspirin:** Is **contraindicated** in gout because low doses (1–2g/day) inhibit uric acid excretion in the renal tubules, potentially worsening hyperuricemia. * **Rule of Thumb:** Never start or stop urate-lowering therapy (Allopurinol/Febuxostat) during an acute attack.

Question 157: In which of the following conditions can a high dose of morphine be used without significant danger?

A. Gall bladder surgery
B. Labour
C. Myocardial infarction (Correct Answer)
D. Head injury

Explanation: **Explanation:** **Correct Option: C (Myocardial Infarction)** Morphine is the drug of choice for pain management in ST-elevation myocardial infarction (STEMI). At high doses, it provides profound analgesia and reduces anxiety (anxiolysis), which decreases sympathetic overactivity. Crucially, morphine acts as a **venodilator**, reducing preload and myocardial oxygen demand. In the controlled environment of a Cardiac Care Unit (CCU) with hemodynamic monitoring and ventilatory support available, high doses can be administered safely to manage cardiogenic pulmonary edema and severe ischemic pain. **Why other options are incorrect:** * **A. Gall bladder surgery:** Morphine causes contraction of the **Sphincter of Oddi**, increasing intrabiliary pressure. This can worsen biliary colic or complicate post-operative recovery in biliary surgeries. * **B. Labour:** Morphine readily crosses the placental barrier. High doses during labor can cause **neonatal respiratory depression** and may also prolong labor by decreasing uterine contractions. * **C. Head injury:** Morphine is strictly contraindicated in head injuries for two reasons: 1) It causes respiratory depression, leading to CO2 retention and subsequent cerebral vasodilation, which **increases intracranial pressure (ICP)**. 2) It causes miosis and sedation, which masks pupillary signs and neurological monitoring essential for assessing the patient's status. **High-Yield Clinical Pearls for NEET-PG:** * **Specific Antagonist:** Naloxone is the drug of choice for morphine overdose. * **Triad of Morphine Poisoning:** Coma, Pin-point pupil (miosis), and Depressed respiration. * **Tolerance:** Develops to most effects except **miosis** and **constipation**. * **Alternative in Biliary Colic:** Pethidine (Meperidine) is preferred as it has less effect on the Sphincter of Oddi and possesses atropine-like antispasmodic properties.

Question 158: Which drug is known to cause Reye syndrome?

A. Celecoxib
B. Aspirin (Correct Answer)
C. Diclofenac
D. Paracetamol

Explanation: **Explanation:** **Aspirin (Acetylsalicylic acid)** is the correct answer because of its strong clinical association with **Reye Syndrome**, a rare but potentially fatal condition characterized by acute encephalopathy and fatty liver degeneration (microvesicular steatosis). This syndrome typically occurs in children and adolescents recovering from viral infections, particularly **Influenza B** or **Varicella (Chickenpox)**, who have been treated with salicylates. The underlying mechanism involves mitochondrial injury, leading to impaired fatty acid oxidation and hyperammonemia. **Analysis of Incorrect Options:** * **Celecoxib:** A selective COX-2 inhibitor. While it carries risks of cardiovascular events and sulfa-allergy reactions, it is not associated with Reye syndrome. * **Diclofenac:** A potent non-selective NSAID commonly used for musculoskeletal pain. It is known for causing hepatotoxicity in rare cases but does not trigger Reye syndrome. * **Paracetamol (Acetaminophen):** This is the **drug of choice** for fever and pain in children with viral infections precisely because it does not cause Reye syndrome. Its primary toxicity is centrilobular hepatic necrosis due to NAPQI accumulation in overdose. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindication:** Aspirin is strictly contraindicated in children under 16 years of age for viral fevers. * **Exception:** Aspirin is still used in children for **Kawasaki Disease** (to prevent coronary artery aneurysms) and Juvenile Idiopathic Arthritis, under strict supervision. * **Pathology:** Look for "microvesicular steatosis" and "mitochondrial swelling" in biopsy descriptions related to Reye syndrome. * **Clinical Presentation:** Persistent vomiting, altered mental status, and hepatomegaly without jaundice.

Question 159: What is the preferred treatment for fungal infections of the brain in the post-operative period?

A. Amphotericin-B (Correct Answer)
B. Gentian violet
C. 2% salicylic acid
D. Gentamycin

Explanation: **Explanation:** **Why Amphotericin-B is correct:** Amphotericin-B is a potent polyene antifungal that remains the "gold standard" for treating severe, systemic, and deep-seated fungal infections, including those involving the Central Nervous System (CNS). In the post-operative period, patients may develop life-threatening fungal meningitis or abscesses (often due to *Candida* or *Aspergillus*). Amphotericin-B works by binding to ergosterol in the fungal cell membrane, creating pores that lead to cell death. For CNS infections, the **Liposomal Amphotericin-B** formulation is preferred as it achieves better CNS penetration and carries a lower risk of nephrotoxicity compared to the conventional deoxycholate form. **Why the other options are incorrect:** * **Gentian violet:** This is a topical antifungal and antibacterial dye used primarily for superficial infections like oral thrush or intertrigo. It has no systemic application or CNS penetration. * **2% Salicylic acid:** This is a keratolytic agent used topically to treat skin conditions like acne, warts, or psoriasis. It has no role in treating systemic fungal infections. * **Gentamycin:** This is an Aminoglycoside antibiotic effective against Gram-negative bacteria. It has no antifungal activity and poor CNS penetration unless administered intrathecally. **NEET-PG High-Yield Pearls:** * **Mechanism of Action:** Binds to ergosterol and forms transmembrane pores (Ionophores). * **Side Effects:** Nephrotoxicity (most common/dose-limiting), infusion-related reactions ("shake and bake" chills/fever), and hypokalemia. * **Drug of Choice:** It is the DOC for Mucormycosis (Zygomycosis) and severe Cryptococcal meningitis (often combined with Flucytosine). * **Liposomal Form:** Preferred in clinical practice to reduce the "Amphotericin-Terrible" side effect profile.

Question 160: Rofecoxib was withdrawn due to which of the following reasons?

A. Ischemic heart disease (Correct Answer)
B. Renal complication
C. Liver adenoma
D. Gastric ulcer

Explanation: **Explanation:** **Rofecoxib**, a selective COX-2 inhibitor, was voluntarily withdrawn from the global market in 2004 following the **APPROVe trial**, which demonstrated a significantly increased risk of **Ischemic Heart Disease (IHD)** and myocardial infarction. **Why Option A is correct:** The underlying mechanism involves an imbalance between prostanoids. COX-2 is the primary enzyme responsible for producing **Prostacyclin (PGI2)** in the vascular endothelium, which is a potent vasodilator and inhibitor of platelet aggregation. Selective COX-2 inhibitors suppress PGI2 without affecting **Thromboxane A2 (TXA2)** (produced by COX-1 in platelets), which is a vasoconstrictor and pro-aggregatory agent. This shift toward a pro-thrombotic state leads to increased cardiovascular events like MI and stroke. **Why other options are incorrect:** * **B. Renal complications:** While COX-2 inhibitors can cause fluid retention and worsen hypertension (similar to non-selective NSAIDs), this was not the primary reason for withdrawal. * **C. Liver adenoma:** This is not a recognized side effect of Rofecoxib; hepatic toxicity is more commonly associated with drugs like high-dose Paracetamol or Nimesulide. * **D. Gastric ulcer:** Selective COX-2 inhibitors were actually developed to *reduce* the risk of gastric ulcers compared to traditional NSAIDs. **High-Yield NEET-PG Pearls:** * **VIGOR Trial:** First major study to highlight the GI benefits but also the CV risks of Rofecoxib. * **Valdecoxib** was also withdrawn for similar CV risks and serious skin reactions (Stevens-Johnson Syndrome). * **Celecoxib** remains on the market but carries a "black box warning" for cardiovascular and gastrointestinal risks. * **Contraindication:** Avoid selective COX-2 inhibitors in patients with established ischemic heart disease or stroke.

Practice by Chapter

NSAIDs: Classification and Mechanism

Practice Questions

COX-2 Selective Inhibitors

Practice Questions

Acetaminophen (Paracetamol)

Practice Questions

Opioid Analgesics and Antagonists

Practice Questions

Drugs Used in Gout and Hyperuricemia

Practice Questions

Drugs Used in Rheumatoid Arthritis

Practice Questions

Disease-Modifying Antirheumatic Drugs

Practice Questions

Glucocorticoids as Anti-inflammatory Agents

Practice Questions

Migraine Therapeutics

Practice Questions

Neuropathic Pain Management

Practice Questions

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