Analgesics and Anti-inflammatory Drugs Practice Questions

Q: All of the following effects are produced by mu opioid receptor activation, except?

Tachycardia. **Explanation:** The correct answer is **A. Tachycardia**. Opioids act primarily through three types of G-protein coupled receptors: **Mu (μ)**, **Kappa (κ)**, and **Delta (δ)**. Activation of the Mu receptor (the primary mediator of opioid effects) typically results in **Bradycardia**, not tachycardia. This occurs because opioids increase vagal (parasympathetic) tone and decrease sympathetic outflow from the vasomotor center. **Why other options are incorrect:** * **Miosis (B):** Mu and Kappa receptor activation stimulates the **Edinger-Westphal nucleus** of the oculomotor nerve, leading to pupillary constriction (pinpoint pupils). This is a classic sign of opioid overdose and, unlike many other effects, tolerance does not develop to miosis. * **Sedation (C):** Opioids produce a dose-dependent depression of the Central Nervous System (CNS), leading to drowsiness and mental clouding. * **Euphoria (D):** Mu receptor activation in the ventral tegmental area leads to dopamine release in the nucleus accumbens, producing a powerful sense of well-being and pleasure, which contributes to the high addiction potential of these drugs. **High-Yield Clinical Pearls for NEET-PG:** * **The "Miosis Exception":** Meperidine (Pethidine) is an opioid that causes **mydriasis** (dilation) rather than miosis due to its atropine-like (antimuscarinic) properties. * **Tolerance:** Tolerance develops to most opioid effects *except* **Miosis** and **Constipation**. * **Triad of Opioid Overdose:** Coma, Pinpoint pupils, and Respiratory depression. * **Antidote:** Naloxone is the competitive antagonist used to reverse Mu-receptor-mediated respiratory depression.

Q: What process is inhibited by COX-2?

Cell proliferation. **Explanation:** Cyclooxygenase-2 (COX-2) is an inducible enzyme primarily expressed during inflammation and neoplasia. While COX-1 is "constitutive" (maintaining homeostatic functions like gastric protection), COX-2 is upregulated by growth factors, cytokines, and tumor promoters. **Why Cell Proliferation is the correct answer:** COX-2 plays a pivotal role in the cell cycle. It catalyzes the synthesis of Prostaglandin E2 (PGE2), which activates signaling pathways (like Wnt/β-catenin and MAPK) that stimulate **cell proliferation** and inhibit apoptosis. Consequently, the inhibition of COX-2 leads to a decrease in cell division. This is the pharmacological basis for using NSAIDs (like Celecoxib or Aspirin) in the chemoprevention of colorectal adenomas and other malignancies where COX-2 is overexpressed. **Analysis of Incorrect Options:** * **A & C (Cell Adhesion and Migration):** While COX-2 can indirectly influence the metastatic potential of cancer cells, its primary and most direct regulatory effect is on the mitotic rate and survival of the cell itself. * **B (Cell Differentiation):** COX-2 activity is generally associated with maintaining an undifferentiated, proliferative state in stem cells and cancer cells. Inhibition usually promotes or restores differentiation rather than inhibiting it. **NEET-PG High-Yield Pearls:** * **Selective COX-2 Inhibitors (Coxibs):** These lack anti-platelet effects (as platelets only express COX-1) but increase cardiovascular risk due to an imbalance between Thromboxane A2 and Prostacyclin (PGI2). * **Clinical Application:** Celecoxib is FDA-approved for reducing the number of polyps in **Familial Adenomatous Polyposis (FAP)**. * **Expression:** COX-2 is constitutively expressed in only a few sites: the **Kidney, Brain, and Spinal Cord.**

Q: A 25-year-old woman develops a sore, red, hot, swollen left knee. She has no history of trauma and no familial history of joint disease. Aspirin is effective in relieving symptoms of acute inflammation in this patient because it inhibits which of the following enzymes?

Cyclooxygenase. ### Explanation **Correct Option: A. Cyclooxygenase** Aspirin (Acetylsalicylic acid) is a Non-Steroidal Anti-Inflammatory Drug (NSAID) that exerts its anti-inflammatory, analgesic, and antipyretic effects by **irreversibly inhibiting the enzyme Cyclooxygenase (COX-1 and COX-2)**. This inhibition prevents the conversion of arachidonic acid into **prostaglandins (PGs)** and thromboxanes. Prostaglandins (specifically PGE2 and PGI2) are the primary mediators of the cardinal signs of inflammation—vasodilation (redness/heat), increased vascular permeability (swelling), and sensitization of pain receptors (soreness). **Why Incorrect Options are Wrong:** * **B. Myeloperoxidase:** This enzyme is found in neutrophil granules and is involved in the production of hypochlorous acid to kill bacteria; it is not the target of aspirin. * **C. Phospholipase A2:** This enzyme releases arachidonic acid from membrane phospholipids. It is inhibited by **Corticosteroids** (via lipocortin/annexin A1), not by NSAIDs. * **D. Superoxide dismutase:** This is an antioxidant enzyme that neutralizes superoxide radicals; it is not involved in the mechanism of action of common analgesics. **High-Yield NEET-PG Pearls:** * **Irreversible Binding:** Aspirin is unique among NSAIDs because it **acetylates** the serine residue of COX, leading to irreversible inhibition. Other NSAIDs (like Ibuprofen) are reversible inhibitors. * **Antiplatelet Effect:** At low doses (75–150 mg), aspirin selectively inhibits COX-1 in platelets, preventing Thromboxane A2 (TXA2) synthesis for the lifetime of the platelet (8–11 days). * **Zero-Order Kinetics:** At high/toxic doses, aspirin metabolism shifts from first-order to zero-order kinetics. * **Reye’s Syndrome:** Aspirin is contraindicated in children with viral infections (flu/chickenpox) due to the risk of fulminant hepatic failure and encephalopathy.

Q: All of the following are TNF alpha inhibitors except?

Omalizumab. **Explanation:** The question tests your ability to distinguish between different classes of monoclonal antibodies used in immunological disorders. **Why Omalizumab is the correct answer:** **Omalizumab** is a recombinant DNA-derived humanized monoclonal antibody that selectively binds to **free human Immunoglobulin E (IgE)**. By binding to IgE, it prevents the binding of IgE to the high-affinity receptor (FcεRI) on the surface of mast cells and basophils, thereby inhibiting the allergic cascade. It is clinically indicated for **moderate-to-severe persistent asthma** and chronic idiopathic urticaria, not for conditions requiring TNF-α inhibition. **Analysis of Incorrect Options (TNF-α Inhibitors):** * **Infliximab (Option A):** A chimeric monoclonal antibody that binds to both soluble and transmembrane forms of TNF-α. It is widely used in Crohn’s disease and Rheumatoid Arthritis (RA). * **Adalimumab (Option B):** A fully human monoclonal antibody against TNF-α. It has a lower risk of neutralizing antibody formation compared to Infliximab. * **Etanercept (Option D):** A soluble **decoy receptor** (fusion protein) that binds to TNF molecules in the circulation, preventing them from interacting with cell surface receptors. **High-Yield Clinical Pearls for NEET-PG:** * **Screening:** Before starting any TNF-α inhibitor, patients **must be screened for Latent Tuberculosis** (via TST or IGRA) because these drugs can cause reactivation of TB. * **Suffix Clues:** * *-ximab:* Chimeric (e.g., Infliximab) * *-zumab:* Humanized (e.g., Omalizumab) * *-mumab:* Fully Human (e.g., Adalimumab) * *-cept:* Receptor fusion protein (e.g., Etanercept) * **Other TNF Inhibitors:** Certolizumab (pegylated) and Golimumab.

Q: A 45-year-old male presented with severe pain in the knee and shoulder joints. A diagnosis of rheumatoid arthritis was made and the patient was started on methotrexate 15mg weekly. However, even after 6 months of treatment, recurrent episodes of arthritis continued. The physician wanted to add another disease-modifying antirheumatic drug (DMARD) that inhibits pyrimidine synthesis by inhibiting the dihydroorotate dehydrogenase enzyme. Which of the following drugs is the physician considering?

Leflunomide. ### Explanation **Correct Option: C. Leflunomide** **Mechanism of Action:** Leflunomide is a prodrug that is converted into its active metabolite, **A77 1726 (malononitrilamide)**. This metabolite acts as a potent inhibitor of the mitochondrial enzyme **dihydroorotate dehydrogenase (DHODH)**. This enzyme is critical for the **de novo synthesis of pyrimidines** (specifically UMP). Since activated T-lymphocytes require rapid pyrimidine synthesis to proliferate, Leflunomide effectively arrests the cell cycle in the G1 phase, thereby exerting its immunosuppressive effect in Rheumatoid Arthritis. **Analysis of Incorrect Options:** * **A. Sulfasalazine:** It is a DMARD used in RA, but its exact mechanism is unclear. It is thought to inhibit NF-κB and reduce cytokine production, but it does not inhibit pyrimidine synthesis. * **B. Infliximab:** This is a biological DMARD that acts as a **chimeric monoclonal antibody against TNF-α**. It does not interfere with metabolic pathways like pyrimidine synthesis. * **D. Abatacept:** This is a biological agent that inhibits T-cell costimulation by binding to **CD80 and CD86** on antigen-presenting cells, preventing their interaction with CD28 on T-cells. **High-Yield Clinical Pearls for NEET-PG:** * **Loading Dose:** Leflunomide has a very long half-life (approx. 2 weeks); hence, a loading dose is often used to reach steady state quickly. * **Side Effects:** Hepatotoxicity (monitor LFTs) and diarrhea are common. It is also highly **teratogenic**. * **Washout Procedure:** Due to its long half-life, if a patient needs to stop the drug (e.g., for pregnancy), **Cholestyramine** is administered to enhance biliary excretion and "wash out" the drug. * **Comparison:** While Methotrexate inhibits *purine* synthesis (via dihydrofolate reductase), Leflunomide inhibits *pyrimidine* synthesis.

Q: What is the primary effect of morphine on the chemoreceptor trigger zone (CTZ) of the medulla?

Stimulates the CTZ zone of the medulla. **Explanation:** **1. Why Option A is Correct:** Morphine and other opioids induce nausea and vomiting primarily by **direct stimulation of the Chemoreceptor Trigger Zone (CTZ)** located in the *area postrema* on the floor of the fourth ventricle [2]. The CTZ is rich in $\mu$ and $\kappa$ opioid receptors. Stimulation of these receptors triggers the vomiting center. Interestingly, while morphine stimulates the CTZ, it simultaneously **depresses the vomiting center** in the medulla. This is why, at higher or repeated doses, morphine may actually exert an anti-emetic effect. **2. Why Other Options are Incorrect:** * **Option B:** Morphine is a potent **respiratory depressant** [1]. It acts directly on the brainstem respiratory centers to reduce their responsiveness to carbon dioxide ($CO_2$) [3]. It does not stimulate the respiratory center; rather, respiratory depression is the most common cause of death in opioid overdose. * **Option C:** As established, the initial effect of morphine on the CTZ is excitatory (stimulation), not inhibitory (depression). Depression occurs at the level of the vomiting center, not the CTZ. **3. High-Yield Clinical Pearls for NEET-PG:** * **Vestibular Component:** Morphine also increases the sensitivity of the vestibular apparatus; hence, opioid-induced nausea is often worse in ambulatory patients than in those lying still [2]. * **Miosis:** Morphine causes "pinpoint pupils" via stimulation of the **Edinger-Westphal nucleus** (oculomotor nerve). This is a classic sign of opioid overdose where tolerance does not develop [1]. * **Biliary Colic:** Morphine causes constriction of the **Sphincter of Oddi**, leading to increased intrabiliary pressure. * **Antidote:** **Naloxone** is the drug of choice for reversing morphine-induced respiratory depression and CTZ stimulation.

Q: Which component of sulfasalazine is responsible for the therapeutic effect in rheumatoid arthritis?

Sulfapyridine. **Explanation:** Sulfasalazine is a prodrug composed of **Sulfapyridine** and **5-aminosalicylic acid (5-ASA)** linked by a covalent azo bond. This bond is cleaved by bacterial enzymes (azoreductases) in the colon. **1. Why Sulfapyridine is correct:** In **Rheumatoid Arthritis (RA)**, sulfasalazine acts as a Disease-Modifying Antirheumatic Drug (DMARD). The **sulfapyridine** moiety is absorbed systemically from the colon and is responsible for the anti-inflammatory and immunomodulatory effects in the joints. It inhibits the release of inflammatory cytokines (like IL-1 and TNF-α) and may suppress B-cell activity. **2. Why other options are incorrect:** * **5-aminosalicylic acid (5-ASA):** This component remains largely unabsorbed and stays in the colon. It is the active moiety for **Ulcerative Colitis** and Crohn’s disease due to its local anti-inflammatory effect on the bowel mucosa. It has no role in treating systemic joint disease. * **Intact sulfasalazine molecule:** The intact molecule is poorly absorbed from the gut and serves primarily as a vehicle to deliver the two active components to the distal bowel. **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effects:** Most side effects (nausea, rashes, agranulocytosis, and reversible oligospermia) are attributed to the **sulfapyridine** component. * **Monitoring:** Due to the risk of bone marrow suppression, CBC and LFTs should be monitored. * **Metabolism:** Sulfapyridine is metabolized via **acetylation** in the liver. "Slow acetylators" are at a higher risk of toxicity. * **Safe in Pregnancy:** Sulfasalazine is generally considered one of the safer DMARDs during pregnancy (Category B).

Q: Which NSAID is proposed to act by inhibition of COX-3?

Paracetamol. **Explanation:** **Correct Answer: B. Paracetamol** Paracetamol (Acetaminophen) is unique among common analgesics because it possesses potent analgesic and antipyretic properties but lacks significant peripheral anti-inflammatory activity. This clinical profile is attributed to its mechanism of action: it primarily inhibits prostaglandin synthesis in the **Central Nervous System (CNS)**. It is proposed that Paracetamol acts by inhibiting **COX-3**, a splice variant of the COX-1 enzyme found predominantly in the cerebral cortex and heart. By inhibiting COX-3, Paracetamol reduces pain and fever without affecting peripheral COX-1 or COX-2, which explains why it does not cause gastric ulcers or anti-platelet effects. **Analysis of Incorrect Options:** * **A. Nimesulide:** A **preferential COX-2 inhibitor**. It is known for its rapid onset of action but is associated with a risk of hepatotoxicity. * **C. Ketorolac:** A **non-selective COX inhibitor** with exceptionally potent analgesic activity. It is primarily used for short-term management of severe acute pain (e.g., post-operative) but has a high risk of GI side effects. * **D. Rofecoxib:** A **selective COX-2 inhibitor**. Most drugs in this class (Coxibs) were withdrawn or restricted due to an increased risk of cardiovascular events (thrombotic strokes and MI). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Paracetamol is the DOC for fever in children (to avoid Reye’s syndrome associated with Aspirin) and during pregnancy. * **Antidote:** In Paracetamol toxicity (NAPQI accumulation), the antidote is **N-acetylcysteine (NAC)**, which replenishes glutathione stores. * **Key Limitation:** Paracetamol is **not** an NSAID in the functional sense because it lacks anti-inflammatory activity at therapeutic doses.

Question 1

All of the following effects are produced by mu opioid receptor activation, except?

Accepted Answer

Tachycardia

Answer

Miosis

Answer

Sedation

Answer

Euphoria

Question 2

What process is inhibited by COX-2?

Accepted Answer

Cell proliferation

Answer

Cell adhesion

Answer

Cell differentiation

Answer

Cell migration

Question 3

A 25-year-old woman develops a sore, red, hot, swollen left knee. She has no history of trauma and no familial history of joint disease. Aspirin is effective in relieving symptoms of acute inflammation in this patient because it inhibits which of the following enzymes?

Accepted Answer

Cyclooxygenase

Answer

Myeloperoxidase

Answer

Phospholipase A2

Answer

Superoxide dismutase

Question 4

All of the following are TNF alpha inhibitors except?

Accepted Answer

Omalizumab

Answer

Infliximab

Answer

Adalimumab

Answer

Etanercept

Question 5

Which intra-articular steroid is least preferred in osteoarthritis?

Accepted Answer

Prednisolone

Answer

Triamcinolone

Answer

Hydrocortisone

Answer

Betamethasone

Question 6

A 45-year-old male presented with severe pain in the knee and shoulder joints. A diagnosis of rheumatoid arthritis was made and the patient was started on methotrexate 15mg weekly. However, even after 6 months of treatment, recurrent episodes of arthritis continued. The physician wanted to add another disease-modifying antirheumatic drug (DMARD) that inhibits pyrimidine synthesis by inhibiting the dihydroorotate dehydrogenase enzyme. Which of the following drugs is the physician considering?

Accepted Answer

Leflunomide

Answer

Sulfasalazine

Answer

Infliximab

Answer

Abatacept

Question 7

What is the primary effect of morphine on the chemoreceptor trigger zone (CTZ) of the medulla?

Accepted Answer

Stimulates the CTZ zone of the medulla

Answer

Stimulates the respiratory center of the medulla

Answer

Depresses the CTZ zone of the medulla

Answer

None of the above

Question 8

Which component of sulfasalazine is responsible for the therapeutic effect in rheumatoid arthritis?

Accepted Answer

Sulfapyridine

Answer

Intact sulfasalazine molecule

Answer

5-aminosalicylic acid

Answer

Both sulfapyridine and 5-aminosalicylic acid

Question 9

Which of the following analgesic combinations should be avoided?

Accepted Answer

Ibuprofen and Diclofenac

Answer

Aspirin and Codeine

Answer

Paracetamol and Dextropropoxyphene

Answer

Ibuprofen and Paracetamol

Question 10

Which NSAID is proposed to act by inhibition of COX-3?

Accepted Answer

Paracetamol

Answer

Nimesulide

Answer

Ketorolac

Answer

Rofecoxib

Analgesics and Anti-inflammatory Drugs — MCQs

Analgesics and Anti-inflammatory Drugs — MCQs

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