Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 141: Which drug is used to treat patent ductus arteriosus (PDA)?

A. Oxaceprol
B. Indomethacin (Correct Answer)
C. Dopamine
D. Medical treatment is ineffective

Explanation: **Explanation:** **1. Why Indomethacin is correct:** In fetal life, the **Ductus Arteriosus (DA)** remains open due to high levels of circulating **Prostaglandin E2 (PGE2)**, which acts as a vasodilator. After birth, if the DA fails to close (Patent Ductus Arteriosus), pharmacological intervention is required. **Indomethacin** (and Ibuprofen) are non-selective COX inhibitors. By inhibiting the cyclooxygenase enzyme, they decrease the synthesis of PGE2, leading to the constriction and functional closure of the ductus. **2. Analysis of Incorrect Options:** * **Oxaceprol:** This is an atypical anti-inflammatory drug used primarily in osteoarthritis. It works by inhibiting leukocyte adhesion and has no role in PDA management. * **Dopamine:** This is an inotropic and vasopressor agent used to treat cardiogenic shock or hypotension. It does not affect prostaglandin synthesis or ductal closure. * **Medical treatment is ineffective:** This is incorrect because medical management with NSAIDs is the first-line treatment for PDA in preterm infants, often avoiding the need for surgical ligation. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** While Indomethacin was traditionally the gold standard, **Ibuprofen** (IV) is now often preferred due to a lower risk of renal side effects and necrotizing enterocolitis. **Paracetamol** (IV) is also emerging as an effective alternative with fewer contraindications. * **To Keep the Duct Open:** In cyanotic heart diseases (e.g., Transposition of Great Arteries), we need to keep the ductus open. The drug used for this is **Alprostadil (PGE1 analog)**. * **Contraindication:** NSAIDs should be avoided in the third trimester of pregnancy to prevent premature closure of the ductus arteriosus in utero.

Question 142: What is the plasma half-life of aspirin?

A. Independent of dose
B. Longer for anti-inflammatory doses compared to analgesic doses (Correct Answer)
C. Shorter for anti-inflammatory doses compared to analgesic doses
D. Can be increased by alkalinizing the urine

Explanation: The plasma half-life of aspirin is unique because it exhibits **dose-dependent (capacity-limited) elimination kinetics** [3], also known as Michaelis-Menten or Zero-order kinetics at high doses. ### 1. Why the Correct Answer is Right Aspirin is rapidly hydrolyzed to **salicylic acid**. At low (analgesic) doses, salicylic acid is conjugated with glycine and glucuronic acid in the liver—a process that follows first-order kinetics with a half-life of about **2–3 hours** [2]. However, at high (anti-inflammatory) doses, the hepatic metabolic enzymes become **saturated**. Once saturation occurs, the elimination shifts to zero-order kinetics, where a constant amount of the drug is cleared per unit of time rather than a constant fraction. This significantly prolongs the plasma half-life to **15–30 hours** [2]. Therefore, the half-life is longer for anti-inflammatory doses than for analgesic doses. ### 2. Why Other Options are Wrong * **Option A:** Incorrect. Because of enzyme saturation, the half-life is highly dependent on the dose administered [2]. * **Option C:** Incorrect. Higher doses saturate metabolic pathways, leading to slower clearance and a longer half-life, not a shorter one [3]. * **Option D:** Incorrect. Salicylates are acidic drugs. **Alkalinizing the urine** (e.g., with Sodium Bicarbonate) increases the ionization of salicylic acid, preventing its reabsorption in the renal tubules. This **increases excretion** and actually **decreases** the plasma half-life [1]. ### 3. NEET-PG High-Yield Pearls * **Zero-order kinetics mnemonic:** "7-**W**A**TT**" (**W**arfarin (at high doses), **A**lcohol, **T**heophylline, **T**olbutamide, **P**henytoin, **P**ropanol, **S**alicylates). * **Therapeutic Window:** Low dose (75–150 mg) for antiplatelet effect; Medium dose (300–600 mg) for analgesia/antipyresis; High dose (3–5 g) for anti-inflammatory effect [1]. * **Toxicity:** Salicylism (tinnitus, vertigo) is an early sign of toxicity. Alkalinization of urine is a standard treatment for aspirin poisoning [1].

Question 143: Which of the following is a TNF-alpha inhibitor?

A. Etanercept (Correct Answer)
B. Abatacept
C. Daclizumab
D. Toclizumab

Explanation: **Explanation:** **Etanercept** is a TNF-alpha inhibitor. It is a genetically engineered fusion protein consisting of two identical chains of the recombinant human TNF-receptor (p75) bound to the Fc fraction of human IgG1. It acts as a **"decoy receptor,"** binding to circulating TNF-alpha and TNF-beta, thereby preventing them from interacting with cell surface receptors and reducing the pro-inflammatory cascade. **Analysis of Incorrect Options:** * **Abatacept (Option B):** This is a **T-cell costimulation modulator**. It consists of CTLA-4 fused to IgG1, which binds to CD80/86 on antigen-presenting cells, preventing the "second signal" required for T-cell activation. * **Daclizumab (Option C):** This is a monoclonal antibody against the **IL-2 receptor (CD25)**. It was primarily used in multiple sclerosis and transplant rejection (though largely withdrawn from markets due to hepatic toxicity). * **Tocilizumab (Option D):** This is a monoclonal antibody that targets the **IL-6 receptor**. It is commonly used in Rheumatoid Arthritis and Giant Cell Arteritis. **High-Yield Clinical Pearls for NEET-PG:** 1. **TNF-alpha Inhibitors Classification:** * **Fusion Protein:** Etanercept. * **Monoclonal Antibodies:** Infliximab (chimeric), Adalimumab (fully human), Certolizumab, and Golimumab. 2. **Pre-treatment Screening:** Before starting any TNF-alpha inhibitor, patients must be screened for **Latent Tuberculosis** (using PPD or IGRA) and Hepatitis B, as these drugs can cause reactivation. 3. **Drug of Choice:** While Methotrexate remains the first-line DMARD for Rheumatoid Arthritis, TNF inhibitors are added when the response to non-biological DMARDs is inadequate.

Question 144: Which of the following is NOT characteristic of aspirin-sensitive asthma?

A. Nasal polyposis
B. Treatment with inhaled corticosteroids
C. Rhinosinusitis
D. Increased prostaglandins (Correct Answer)

Explanation: **Explanation:** Aspirin-sensitive asthma, also known as **Aspirin-Exacerbated Respiratory Disease (AERD)** or **Samter’s Triad**, is a non-allergic hypersensitivity reaction. **Why "Increased Prostaglandins" is the correct answer:** The underlying mechanism of AERD is the **inhibition of the Cyclooxygenase-1 (COX-1) enzyme** by aspirin and other NSAIDs. This inhibition leads to a "shunting" of arachidonic acid metabolism away from the prostaglandin pathway and toward the **Lipoxygenase (LOX) pathway**. This results in: 1. **Decreased** protective prostaglandins (especially PGE2, which normally inhibits inflammation). 2. **Increased** production of **Cysteinyl Leukotrienes** (LTC4, LTD4, LTE4), which are potent bronchoconstrictors and mediators of inflammation. Therefore, prostaglandins are decreased, not increased. **Analysis of Incorrect Options:** * **A & C (Nasal polyposis and Rhinosinusitis):** These are classic components of Samter’s Triad. Patients typically present with chronic rhinosinusitis and bilateral nasal polyps before developing asthma and aspirin sensitivity. * **B (Treatment with inhaled corticosteroids):** Inhaled corticosteroids (ICS) are the mainstay of long-term management for the underlying asthma component of AERD, as they help reduce airway inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Samter’s Triad:** Asthma + Nasal Polyposis + Aspirin Sensitivity. * **Drug of Choice for Management:** Leukotriene Receptor Antagonists (e.g., **Montelukast, Zafirlukast**) are highly effective because they block the effects of the excess leukotrienes. * **Avoidance:** Patients must avoid all COX-1 inhibiting NSAIDs; however, selective **COX-2 inhibitors** (like Celecoxib) are generally well-tolerated.

Question 145: Which of the following is a preferential COX-2 inhibitor?

A. Nimesulide
B. Diclofenac
C. Aceclofenac
D. All of the above (Correct Answer)

Explanation: **Explanation:** The classification of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) based on their selectivity for Cyclooxygenase (COX) enzymes is a high-yield topic for NEET-PG. While traditional NSAIDs (like Aspirin or Ibuprofen) are non-selective, certain drugs exhibit a higher affinity for the **COX-2 isoform**, which is induced during inflammation, while sparing the constitutive **COX-1 isoform** (responsible for gastric protection and platelet function). **Why "All of the above" is correct:** NSAIDs are categorized into three main groups regarding COX-2: 1. **Selective COX-2 Inhibitors:** The "Coxibs" (e.g., Celecoxib, Etoricoxib). 2. **Preferential COX-2 Inhibitors:** These drugs inhibit COX-2 more than COX-1 at therapeutic doses, offering a better gastric safety profile than non-selective agents. * **Nimesulide:** A classic preferential inhibitor often used for acute pain. * **Diclofenac:** Though often grouped with non-selective drugs, it shows significant preferential COX-2 activity. * **Aceclofenac:** A prodrug of diclofenac with similar preferential selectivity. * *Other examples include Meloxicam and Etodolac.* **Clinical Pearls for NEET-PG:** * **Gastric Safety:** Preferential and Selective COX-2 inhibitors have a lower risk of peptic ulcers and GI bleeding compared to non-selective NSAIDs. * **Cardiovascular Risk:** Selective and preferential COX-2 inhibition can shift the balance toward Thromboxane A2 (COX-1 mediated), increasing the risk of thrombotic events (MI/Stroke). * **Nimesulide Warning:** It is associated with rare but severe **hepatotoxicity**; its use is banned in children in many countries and restricted in adults. * **Etoricoxib:** Currently the most COX-2 selective agent available.

Question 146: Which of the following drug classes is essential in the management of dry socket?

A. Antibiotics
B. Anti-inflammatory agents
C. Analgesics (Correct Answer)
D. Antipyretics

Explanation: **Explanation:** **Dry Socket (Alveolar Osteitis)** is a painful dental condition that occurs after tooth extraction when the blood clot fails to form or dislodges, exposing the underlying bone and nerves. **1. Why Analgesics are Correct:** The primary clinical feature of dry socket is **severe, radiating pain** that typically begins 3–5 days post-extraction. Since the condition is self-limiting and the underlying pathology is the exposure of nerve endings rather than a systemic infection, the cornerstone of management is **pain control**. Treatment involves irrigation of the socket and the placement of a medicated dressing (e.g., Zinc Oxide Eugenol), which acts as a local analgesic and protective barrier. **2. Why Other Options are Incorrect:** * **Antibiotics:** Dry socket is not primarily an infectious process; it is a failure of clot formation/retention. Routine use of systemic antibiotics is not indicated unless there are signs of systemic involvement (fever, lymphadenopathy). * **Anti-inflammatory agents:** While NSAIDs (which have both analgesic and anti-inflammatory properties) are used, the specific goal in dry socket is the relief of acute neurological pain rather than reducing tissue edema or chronic inflammation. * **Antipyretics:** These are used to reduce fever. Fever is not a characteristic feature of an uncomplicated dry socket. **3. High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** Smoking (most common), oral contraceptives, traumatic extraction, and prior history of dry socket. * **Most Common Site:** Mandibular third molars (wisdom teeth). * **Management Gold Standard:** Local debridement and **Zinc Oxide Eugenol (ZOE)** dressing. * **Pharmacology Link:** Eugenol (derived from clove oil) provides potent local anesthetic and obtundent (pain-dulling) effects on the exposed bone.

Question 147: Anaphylactic reactions caused by NSAIDs are true for all statements below EXCEPT?

A. Caused by all NSAIDs
B. COX-2 inhibitors are safe (Correct Answer)
C. Related to a hypersensitivity reaction
D. Not related to inhibition of COX

Explanation: ### Explanation **Concept Overview:** NSAID-induced hypersensitivity reactions are broadly categorized into two types: **Pharmacological (Pseudo-allergic)** and **Immunological (True Allergic)**. The question refers to the more common **Pseudo-allergic reactions**, which are not true IgE-mediated allergies but are caused by the **inhibition of the COX-1 enzyme**. When COX-1 is inhibited, arachidonic acid is shunted toward the lipoxygenase (LOX) pathway, leading to an overproduction of **leukotrienes** (LTC4, LTD4, LTE4). This causes bronchospasm, urticaria, and anaphylactoid symptoms. **Why Option B is the Correct Answer (The "Except"):** While selective COX-2 inhibitors (like Celecoxib) are generally safer for patients with "Aspirin-Exacerbated Respiratory Disease" (AERD), they are **not universally safe**. In patients with a **true IgE-mediated hypersensitivity** to a specific chemical class of NSAIDs, a COX-2 inhibitor can still trigger a life-threatening anaphylactic reaction. Therefore, stating they are "safe" in the context of all anaphylactic reactions is clinically inaccurate. **Analysis of Other Options:** * **Option A (Caused by all NSAIDs):** True for pseudo-allergic reactions. Since most traditional NSAIDs inhibit COX-1, any drug in this class can trigger the reaction via the leukotriene shunt. * **Option C (Related to a hypersensitivity reaction):** True. These are classified under Type I (IgE-mediated) or non-immunologic hypersensitivity. * **Option D (Not related to inhibition of COX):** This refers to **True Anaphylaxis** (IgE-mediated). Unlike the "shunting" mechanism, true anaphylaxis is triggered by the specific molecular structure of the drug, not its enzymatic potency against COX. **NEET-PG High-Yield Pearls:** * **Samter’s Triad:** Aspirin sensitivity, Bronchial Asthma, and Nasal Polyps. * **Drug of Choice:** For patients with NSAID-induced asthma, **Leukotriene receptor antagonists (Montelukast)** are used for management. * **Safe Alternative:** **Acetaminophen (Paracetamol)** is usually safe at low doses (<1000mg) because it is a weak peripheral COX-1 inhibitor.

Question 148: Which of the following NSAIDs is an anthranilic acid derivative?

A. Mefenamic acid (Correct Answer)
B. Sulindac
C. Nimesulide
D. Diclofenac

Explanation: **Explanation:** The classification of Non-Steroidal Anti-inflammatory Drugs (NSAIDs) based on their chemical structure is a high-yield topic for NEET-PG. **1. Why Mefenamic Acid is Correct:** Mefenamic acid belongs to the **Anthranilic acid derivative** class (also known as **Fenamates**). Chemically, these drugs are nitrogen-analogues of salicylic acid. Mefenamic acid acts by inhibiting both COX-1 and COX-2 enzymes and has an additional action of antagonizing certain prostaglandin receptors. Clinically, it is primarily used for dysmenorrhea and mild-to-moderate pain. **2. Analysis of Incorrect Options:** * **Sulindac:** This is an **Indene derivative** (Acetic acid derivative). It is unique because it is a **prodrug**; its sulfide metabolite is the active form that inhibits COX. * **Nimesulide:** This belongs to the **Sulfonanilide** class. It is a preferential COX-2 inhibitor and is notable for its potential hepatotoxicity, leading to its restricted use in many countries. * **Diclofenac:** This is a **Phenylacetic acid derivative**. It is one of the most commonly used NSAIDs and is known for its relatively higher potency and accumulation in synovial fluid, making it effective for rheumatoid arthritis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mefenamic Acid:** A common side effect to remember is **diarrhea** and hemolytic anemia. * **Shortest Half-life:** Aspirin (~15-20 mins). * **Longest Half-life:** Piroxicam (~50 hours), allowing for once-daily dosing. * **Ketorolac:** An acetic acid derivative used mainly for its potent analgesic effect (comparable to morphine) in postoperative settings, but limited to short-term use due to GI toxicity.

Question 149: Which of the following is true regarding the cyclo-oxygenase-1 (COX-1) isoenzyme?

A. Is increased by inflammation
B. Is the predominant mode of action of Indomethacin (Correct Answer)
C. Is increased by lipopolysaccharide, a Gram-negative endotoxin
D. Is not involved in gastric mucosal protection

Explanation: ### Explanation **Correct Option: B. Is the predominant mode of action of Indomethacin** Cyclo-oxygenase (COX) exists in two main isoforms: **COX-1** and **COX-2**. * **COX-1** is a **constitutive** enzyme expressed in most tissues (stomach, kidneys, platelets). It maintains physiological functions like gastric mucosal integrity and platelet aggregation. * **COX-2** is an **inducible** enzyme, primarily expressed at sites of inflammation. **Indomethacin** is a potent, non-selective NSAID. While it inhibits both isoforms, its clinical efficacy and significant side-effect profile (especially GI toxicity) are attributed to its powerful inhibition of **COX-1**. Most traditional NSAIDs (like Ibuprofen and Naproxen) act predominantly by inhibiting COX-1 and COX-2 non-selectively, whereas "Coxibs" are selective for COX-2. --- ### Analysis of Incorrect Options: * **A & C: Is increased by inflammation / lipopolysaccharide:** These describe **COX-2**. COX-2 expression is induced by inflammatory mediators (cytokines, IL-1) and bacterial endotoxins (LPS). COX-1 levels remain relatively stable and are not significantly induced by these factors. * **D: Is not involved in gastric mucosal protection:** This is false. COX-1 is the primary enzyme responsible for synthesizing **PGE2 and PGI2** in the stomach, which inhibit acid secretion and promote protective mucus/bicarbonate production. This is why COX-1 inhibition leads to peptic ulcers. --- ### High-Yield Clinical Pearls for NEET-PG: 1. **Aspirin:** The only NSAID that **irreversibly** inhibits COX (via acetylation). At low doses (75-150mg), it is highly selective for platelet COX-1. 2. **COX-2 Selective Inhibitors (Celecoxib):** These spare the gastric mucosa but carry a higher risk of **cardiovascular thrombotic events** because they inhibit PGI2 (vasodilator/anti-aggregatory) without affecting Thromboxane A2 (vasoconstrictor/pro-aggregatory). 3. **Indomethacin:** The drug of choice for promoting the closure of **Patent Ductus Arteriosus (PDA)** in neonates.

Question 150: Which of the following statements is true about Dezocine?

A. It is slower acting than morphine.
B. It is less potent than morphine.
C. It acts on GABA receptors.
D. It does not increase histamine release. (Correct Answer)

Explanation: **Explanation:** **Dezocine** is a synthetic opioid analgesic with a unique pharmacological profile. It acts as a **mixed agonist-antagonist**, specifically serving as a partial agonist at $\mu$ (mu) receptors and an antagonist at $\kappa$ (kappa) receptors. **Why Option D is Correct:** Unlike morphine and other natural opiates, Dezocine **does not cause significant histamine release**. This makes it clinically advantageous for patients with reactive airway diseases (like asthma) or those prone to hypotension and pruritus, which are common side effects of histamine-releasing opioids. **Analysis of Incorrect Options:** * **Option A:** Dezocine has a **rapid onset of action**, typically within 15–30 minutes after intramuscular administration, making it comparable to or slightly faster than morphine in achieving peak effect. * **Option B:** It is **equipotent to morphine** (10 mg of Dezocine $\approx$ 10 mg of Morphine). It provides effective analgesia for moderate to severe pain. * **Option C:** Dezocine acts primarily on **Opioid receptors** ($\mu$ and $\kappa$), not GABA receptors. Its mechanism involves modulating pain pathways in the central nervous system. **High-Yield Clinical Pearls for NEET-PG:** * **Ceiling Effect:** Like other mixed agonist-antagonists, Dezocine exhibits a "ceiling effect" for respiratory depression, making it safer than pure $\mu$-agonists in overdose scenarios. * **Dependency:** It has a lower abuse potential compared to morphine. * **Contraindication:** Avoid in patients physically dependent on pure opioids, as its antagonist properties can precipitate **withdrawal symptoms**.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free