Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 291: Rasburicase is used in the management of hyperuricemia. By what mechanism does it act?

A. Decreasing urate synthesis
B. Increasing urate oxidation (Correct Answer)
C. Decreasing intestinal absorption of uric acid
D. Increasing renal excretion of uric acid

Explanation: **Mechanism of Action: Rasburicase** **Explanation of the Correct Answer:** Rasburicase is a recombinant form of the enzyme **urate oxidase**. In most mammals, this enzyme converts uric acid into **allantoin**. However, humans lack a functional urate oxidase gene. Rasburicase works by catalyzing the **oxidation** of poorly soluble uric acid into allantoin, which is 5 to 10 times more soluble and easily excreted by the kidneys. This rapidly lowers serum uric acid levels, making it highly effective in preventing and treating Tumor Lysis Syndrome (TLS). **Analysis of Incorrect Options:** * **Option A (Decreasing urate synthesis):** This is the mechanism of **Xanthine Oxidase inhibitors** like Allopurinol and Febuxostat. They prevent the formation of uric acid but do not clear existing uric acid. * **Option C (Decreasing intestinal absorption):** Uric acid is primarily an endogenous metabolic byproduct of purine degradation; intestinal absorption is not a significant target for pharmacological management of hyperuricemia. * **Option D (Increasing renal excretion):** This is the mechanism of **Uricosuric drugs** like Probenecid, Sulfinpyrazone, and Lesinurad, which inhibit the URAT1 transporter in the proximal tubule. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Primarily used for the management of hyperuricemia in pediatric and adult patients with leukemia, lymphoma, and solid tumors receiving anti-cancer therapy (Tumor Lysis Syndrome). * **Contraindication:** It is strictly contraindicated in **G6PD deficiency**. The oxidation of uric acid produces **hydrogen peroxide** ($H_2O_2$) as a byproduct, which can trigger severe hemolysis in these patients. * **Pegloticase:** A similar recombinant urate oxidase enzyme, but "pegylated" to increase half-life and decrease immunogenicity; used for refractory chronic gout.

Question 292: All of the following effects are produced by inhibitors of prostaglandin synthesis EXCEPT:

A. Prolongation of bleeding time
B. Prolongation of prothrombin time (Correct Answer)
C. Prolongation of labour
D. Gastric mucosal damage

Explanation: Inhibitors of prostaglandin synthesis, primarily **Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)**, act by inhibiting the enzyme Cyclooxygenase (COX). ### **Why Option B is Correct** **Prolongation of prothrombin time (PT):** Prothrombin time is a measure of the extrinsic and common pathways of the coagulation cascade (clotting factors like II, VII, IX, and X). NSAIDs inhibit **platelet aggregation**, not the synthesis or function of clotting factors. Therefore, they do not affect PT. *Note: High-dose salicylates can occasionally interfere with Vitamin K metabolism, but this is not a general property of prostaglandin synthesis inhibitors.* ### **Why Other Options are Incorrect** * **A. Prolongation of bleeding time:** NSAIDs inhibit COX-1 in platelets, preventing the synthesis of **Thromboxane A2 (TXA2)**, a potent platelet aggregator. This leads to impaired primary hemostasis and an increased bleeding time. * **C. Prolongation of labour:** Prostaglandins (PGE2 and PGF2α) are essential for uterine contractions and cervical ripening. By inhibiting their synthesis, NSAIDs can delay the onset of labor and increase its duration. * **D. Gastric mucosal damage:** Prostaglandins (PGE2 and PGI2) are cytoprotective in the stomach; they inhibit acid secretion and stimulate mucus/bicarbonate production. Inhibiting them leads to peptic ulcers and mucosal erosions. ### **High-Yield Clinical Pearls for NEET-PG** * **Aspirin** is an **irreversible** inhibitor of COX, whereas other NSAIDs are reversible. * **Closure of PDA:** Prostaglandin inhibitors (Indomethacin/Ibuprofen) are used to close a Patent Ductus Arteriosus, as PGE2 keeps the ductus open. * **Analgesic Nephropathy:** Chronic use of NSAIDs can lead to papillary necrosis due to decreased renal blood flow (mediated by PGE2/PGI2). * **Triple Whammy:** Avoid combining NSAIDs + ACE inhibitors + Diuretics, as this combination significantly increases the risk of acute kidney injury.

Question 293: Which of the following is a selective cyclo-oxygenase-2 inhibitor?

A. Ketorolac
B. Tolmetin
C. Nabumetone (Correct Answer)
D. Oxaprozin

Explanation: **Explanation:** The correct answer is **Nabumetone**. **1. Why Nabumetone is correct:** NSAIDs are classified based on their selectivity for COX enzymes. While most traditional NSAIDs are non-selective, **Nabumetone** is a unique **preferential COX-2 inhibitor**. It is a prodrug converted in the liver to its active metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA). Because it is a non-acidic prodrug and shows greater selectivity for the COX-2 isoform over COX-1, it is associated with a lower incidence of gastrointestinal side effects (like peptic ulcers) compared to traditional NSAIDs. **2. Why other options are incorrect:** * **Ketorolac:** A potent non-selective NSAID with a high affinity for **COX-1**. It is primarily used for short-term management of severe pain due to its high risk of GI toxicity and renal impairment. * **Tolmetin:** An acetic acid derivative and a **non-selective** COX inhibitor used in the treatment of rheumatoid arthritis and osteoarthritis. * **Oxaprozin:** A propionic acid derivative (similar to Ibuprofen) that acts as a **non-selective** COX inhibitor with a long half-life. **3. NEET-PG High-Yield Pearls:** * **Selective COX-2 Inhibitors:** Celecoxib, Etoricoxib, Parecoxib (the "Coxibs"). * **Preferential COX-2 Inhibitors:** Nabumetone, Meloxicam, Etodolac, Nimesulide. * **Clinical Note:** While COX-2 inhibitors spare the GI mucosa, they carry an increased risk of **cardiovascular thrombotic events** (except low-dose aspirin) because they inhibit PGI2 (vasodilator/anti-aggregatory) without affecting TXA2 (vasoconstrictor/pro-aggregatory). * **Nabumetone** is the only non-acidic NSAID in clinical use.

Question 294: Which of the following is a new oral drug approved for Rheumatoid arthritis?

A. UPADACITINIB (Correct Answer)
B. FEDRATINIB
C. ENTRECTINIB
D. TALAZOPARIB

Explanation: **Explanation:** **Upadacitinib** is the correct answer as it is a second-generation, oral, selective **Janus Kinase 1 (JAK1) inhibitor** approved for the treatment of moderate-to-severe Rheumatoid Arthritis (RA) in patients who have had an inadequate response to Methotrexate. ### Why Upadacitinib is Correct: In RA, the JAK-STAT signaling pathway plays a crucial role in the release of pro-inflammatory cytokines (like IL-6 and Interferons). While first-generation JAK inhibitors like Tofacitinib target multiple JAK enzymes (JAK1, JAK2, and JAK3), **Upadacitinib** is engineered for greater selectivity toward **JAK1**. This selectivity potentially reduces side effects associated with JAK2 inhibition, such as anemia and thrombocytopenia. ### Analysis of Incorrect Options: * **B. Fedratinib:** This is a selective **JAK2 inhibitor** primarily used in the treatment of **Myelofibrosis**, not RA. * **C. Entrectinib:** This is a tyrosine kinase inhibitor (TKI) targeting **NTRK and ROS1**, used as an anti-cancer agent for solid tumors and non-small cell lung cancer (NSCLC). * **D. Talazoparib:** This is a **PARP inhibitor** used in the treatment of BRCA-mutated HER2-negative breast cancer. ### High-Yield Clinical Pearls for NEET-PG: * **JAK Inhibitor Suffix:** Drugs ending in **"-tinib"** are generally tyrosine kinase inhibitors. * **Other JAK Inhibitors in RA:** Tofacitinib (Pan-JAK), Baricitinib (JAK1/2), and Filgotinib (JAK1). * **Route of Administration:** Unlike biological DMARDs (e.g., Adalimumab, Etanercept) which are injectable, JAK inhibitors are **orally administered**. * **Pre-treatment Screening:** Always screen for **Latent Tuberculosis** and Hepatitis B/C before starting JAK inhibitors, as they can cause reactivation.

Question 295: Which of the following drugs is used in myocardial infarction?

A. Cocaine
B. Pethidine
C. Morphine (Correct Answer)
D. Butorphanol

Explanation: **Explanation:** **Morphine** is the opioid of choice in the management of acute myocardial infarction (MI), particularly when chest pain is unresponsive to nitrates. [3] Its therapeutic benefit is twofold: 1. **Analgesia:** It provides potent relief from intense ischemic pain and reduces the associated sympathetic surge. 2. **Hemodynamic Effects:** Morphine acts as a **venodilator**, reducing venous return (preload) and decreasing the oxygen demand of the myocardium. [3] It also helps relieve pulmonary congestion in patients with associated left ventricular failure. [3] **Analysis of Incorrect Options:** * **A. Cocaine:** Cocaine is a potent vasoconstrictor and sympathomimetic. It is strictly **contraindicated** in MI as it increases myocardial oxygen demand and can cause coronary artery vasospasm, potentially worsening or even causing an MI. * **B. Pethidine (Meperidine):** While an analgesic, pethidine is generally avoided in MI because it has **anticholinergic (atropine-like) effects**, which can cause tachycardia, thereby increasing myocardial oxygen consumption. [3] * **D. Butorphanol:** This is an opioid agonist-antagonist. It can increase pulmonary artery pressure and cardiac workload, making it less ideal than pure mu-agonists like Morphine in a cardiac setting. **High-Yield Pearls for NEET-PG:** * **M.O.N.A. Regimen:** The classic initial management for ACS includes **M**orphine, **O**xygen, **N**itroglycerin, and **A**spirin. [1] [2] * **Caution:** Morphine should be used cautiously in **Inferior Wall MI** involving the Right Ventricle, as these patients are preload-dependent and morphine-induced venodilation can lead to severe hypotension. * **Antidote:** In case of respiratory depression due to morphine, **Naloxone** is the specific antagonist.

Question 296: What is the recommended dose of methotrexate for the treatment of rheumatoid arthritis?

A. 7.5 - 15 mg per week (Correct Answer)
B. 2.5 - 5 mg per week
C. 7.5 - 15 mg per month
D. 2.5 - 5 mg per month

Explanation: **Explanation:** Methotrexate (MTX) is the "anchor drug" and the first-line Disease-Modifying Antirheumatic Drug (DMARD) for Rheumatoid Arthritis (RA). In RA, it acts primarily by inhibiting **aminoimidazolecarboxamide ribonucleotide (AICAR) transformylase**, leading to increased extracellular adenosine, which has potent anti-inflammatory effects. **Why Option A is Correct:** The standard starting dose for RA is **7.5 to 15 mg administered once weekly**. This dose is significantly lower than those used in cancer chemotherapy because the goal is immunomodulation rather than cytotoxicity. The dose can be escalated up to 25 mg/week based on patient response and tolerance. **Why Other Options are Incorrect:** * **Options B & D (2.5 - 5 mg):** These doses are sub-therapeutic for RA and would fail to achieve adequate disease control. * **Options C & D (Monthly dosing):** Methotrexate has a relatively short half-life; monthly administration would not maintain the steady-state concentration required to suppress chronic synovial inflammation. **Weekly dosing** is the gold standard to balance efficacy with safety. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism (Low dose):** Increases adenosine (anti-inflammatory). * **Mechanism (High dose/Onco):** Inhibits **Dihydrofolate Reductase (DHFR)**, preventing DNA synthesis. * **Supplementation:** Always co-prescribe **Folic acid (5 mg)** to reduce GI side effects, mucosal ulcers, and hepatotoxicity without compromising efficacy. * **Monitoring:** Regular Liver Function Tests (LFTs) and CBC are mandatory due to risks of hepatotoxicity and bone marrow suppression. * **Contraindication:** It is highly **teratogenic** (Category X); it must be stopped at least 3 months before conception in both males and females.

Question 297: Which drug possesses both analgesic and moderate anti-inflammatory properties?

A. Paracetamol
B. Nimesulide
C. Ketorolac (Correct Answer)
D. Diflunisal

Explanation: **Explanation:** **Ketorolac** is a potent NSAID primarily used for its superior analgesic efficacy, often compared to morphine for postoperative pain. Unlike most other potent analgesics (like opioids), it also possesses **moderate anti-inflammatory** activity. It acts by non-selectively inhibiting COX-1 and COX-2 enzymes, thereby decreasing prostaglandin synthesis. In clinical practice, it is favored for short-term management of acute severe pain where an anti-inflammatory component is also beneficial. **Analysis of Incorrect Options:** * **A. Paracetamol (Acetaminophen):** While a first-line analgesic and antipyretic, it has **negligible anti-inflammatory** activity because it is inactivated by peroxides at sites of inflammation. * **B. Nimesulide:** This is a preferential COX-2 inhibitor. While it has anti-inflammatory properties, it is primarily classified as an anti-inflammatory drug with analgesic effects, rather than being the specific answer for "moderate" anti-inflammatory activity in this comparative context. * **D. Diflunisal:** A salicylic acid derivative. While it has a long half-life and anti-inflammatory properties, its analgesic potency is significantly lower than that of Ketorolac. **High-Yield NEET-PG Pearls:** * **Ketorolac** should not be used for more than **5 days** due to the high risk of gastrointestinal mucosal lesions and renal toxicity. * It is the most common NSAID used **parenterally** (IV/IM) for post-operative analgesia. * **Topical Ketorolac** is frequently used in ophthalmology to prevent miosis during ocular surgery and to treat seasonal allergic conjunctivitis.

Question 298: Which of the following medications can be safely administered to a patient with congestive heart failure?

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

Explanation: **Explanation:** The correct answer is **Paracetamol (Acetaminophen)**. **Why Paracetamol is the correct choice:** In patients with Congestive Heart Failure (CHF), maintaining optimal renal perfusion and fluid balance is critical. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) inhibit the enzyme Cyclooxygenase (COX), which leads to a decrease in the synthesis of vasodilatory prostaglandins (PGE2 and PGI2). In CHF, these prostaglandins are essential to counteract the vasoconstrictive effects of the Renin-Angiotensin-Aldosterone System (RAAS). **Paracetamol** is a weak peripheral prostaglandin inhibitor and primarily acts centrally. Therefore, it does not interfere with renal blood flow, does not cause sodium/water retention, and does not exacerbate heart failure, making it the safest analgesic for these patients. **Why the other options are incorrect:** * **Aspirin, Diclofenac, and Ibuprofen:** These are traditional NSAIDs. By inhibiting renal prostaglandins, they cause afferent arteriolar vasoconstriction, leading to decreased glomerular filtration rate (GFR). This results in **sodium and water retention**, which increases preload and afterload, potentially triggering an acute decompensation of heart failure. * Furthermore, NSAIDs can blunt the efficacy of life-saving CHF medications like ACE inhibitors and Diuretics. **Clinical Pearls for NEET-PG:** * **NSAIDs and CHF:** The risk of heart failure hospitalization doubles with the use of NSAIDs. * **Cardiovascular Risk:** Among NSAIDs, **Naproxen** is considered to have the safest cardiovascular profile, while **Diclofenac** and **Selective COX-2 inhibitors (Coxibs)** carry the highest risk of thrombotic events (MI/Stroke). * **Drug of Choice:** Paracetamol remains the first-line analgesic for patients with cardiovascular comorbidities.

Question 299: Nausea and vomiting associated with the administration of opioid analgesics are the result of stimulation of which of the following?

A. Limbic system
B. Emetic system
C. Chemoreceptor trigger zone (CTZ) (Correct Answer)
D. Opioid receptors in the gastrointestinal tract

Explanation: ### Explanation **Correct Option: C. Chemoreceptor Trigger Zone (CTZ)** Opioid-induced nausea and vomiting (OINV) primarily occur due to the direct stimulation of **mu (μ) and kappa (κ) receptors** located in the **Chemoreceptor Trigger Zone (CTZ)**. The CTZ is situated in the **area postrema** on the floor of the fourth ventricle. Because this area lies outside the blood-brain barrier, it can be directly stimulated by circulating drugs like morphine. Additionally, opioids increase the sensitivity of the vestibular apparatus, which further contributes to motion-induced nausea. **Analysis of Incorrect Options:** * **A. Limbic system:** While the limbic system is involved in the emotional and affective components of pain and reward (addiction), it is not the primary center for triggering the emetic reflex. * **B. Emetic system:** The "emetic center" (Vomiting Center) in the medulla coordinates the physical act of vomiting. While the CTZ sends signals to the emetic center, opioids act initially on the CTZ to trigger this pathway, rather than stimulating the emetic center directly. * **D. Opioid receptors in the GI tract:** Stimulation of peripheral mu-receptors in the gastrointestinal tract leads to **decreased motility and constipation** (Opioid-induced constipation), not nausea and vomiting. **High-Yield Clinical Pearls for NEET-PG:** * **Tolerance:** While patients develop tolerance to the emetic effects of opioids over time, they **never** develop tolerance to **miosis (pin-point pupil)** and **constipation**. * **Management:** Opioid-induced vomiting can be managed with dopamine antagonists (e.g., Metoclopramide) or 5-HT3 antagonists (e.g., Ondansetron). * **Dual Mechanism:** Opioids have a "biphase" effect; at low doses, they stimulate the CTZ (emetic), but at very high doses, they may actually depress the vomiting center.

Question 300: Which of the following is an irreversible inhibitor of cyclooxygenase?

A. Aspirin (Correct Answer)
B. Phenylbutazone
C. Indomethacin
D. Piroxicam

Explanation: **Explanation:** **1. Why Aspirin is the Correct Answer:** Aspirin (Acetylsalicylic acid) is unique among Non-Steroidal Anti-inflammatory Drugs (NSAIDs) because it causes **irreversible inhibition** of the cyclooxygenase (COX-1 and COX-2) enzymes. It achieves this by **covalently acetylating** a specific serine residue (Serine 529 in COX-1) near the active site of the enzyme. Since platelets cannot synthesize new proteins (as they lack a nucleus), the COX inhibition lasts for the entire lifespan of the platelet (approx. 8–11 days). This is the pharmacological basis for its use as an antiplatelet agent. **2. Why Other Options are Incorrect:** * **B, C, and D (Phenylbutazone, Indomethacin, Piroxicam):** These are traditional NSAIDs that act via **reversible, competitive inhibition** of the COX enzymes. They bind non-covalently to the active site, and their inhibitory effect lasts only as long as the drug concentration is maintained in the plasma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Low-dose Aspirin (75–150 mg):** Selectively inhibits COX-1 in platelets, leading to decreased Thromboxane A2 (TXA2) production (anti-thrombotic effect). * **Zero-order Kinetics:** Aspirin follows first-order kinetics at low doses but shifts to **zero-order (saturation) kinetics** at anti-inflammatory or toxic doses. * **Reye’s Syndrome:** Aspirin is contraindicated in children with viral infections (e.g., Influenza, Varicella) due to the risk of fulminant hepatic failure and encephalopathy. * **Analgesic Triad (Samter’s Triad):** Aspirin sensitivity, Asthma, and Nasal polyps. * **Toxicity:** Salicylism (tinnitus, vertigo) and metabolic acidosis with respiratory alkalosis are classic signs of overdose.

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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