Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 81: Which one of the opioids has the maximum plasma protein binding capacity?

A. Morphine
B. Sufentanil (Correct Answer)
C. Fentanyl
D. Pethidine

Explanation: ### Explanation The correct answer is **Sufentanil**. The plasma protein binding of opioids is a critical pharmacokinetic parameter that determines their distribution and duration of action. Among the options provided, **Sufentanil** exhibits the highest plasma protein binding capacity, approximately **92–93%**, primarily binding to $\alpha_1$-acid glycoprotein. #### Analysis of Options: * **Sufentanil (93%):** It is a highly potent synthetic opioid (5–10 times more potent than fentanyl). Its high protein binding and high lipid solubility contribute to its rapid onset and specific redistribution profile. * **Fentanyl (~80–85%):** While highly lipid-soluble, its protein binding is lower than that of its derivative, sufentanil. * **Pethidine (Meperidine) (~60–70%):** It shows intermediate protein binding. It is notable for its metabolite, *normeperidine*, which can cause seizures. * **Morphine (~30–35%):** Morphine has the lowest protein binding among the listed options. It is relatively hydrophilic compared to synthetic opioids, leading to a slower onset of action when crossing the blood-brain barrier. #### High-Yield NEET-PG Pearls: 1. **Potency Hierarchy:** Sufentanil > Fentanyl > Remifentanil > Morphine > Pethidine. 2. **Protein Binding & pH:** Most opioids are weak bases. Changes in plasma pH can affect the fraction of free (active) drug. 3. **Remifentanil Fact:** It is unique because it is metabolized by **non-specific plasma and tissue esterases**, giving it an ultra-short half-life regardless of infusion duration. 4. **Clinical Correlation:** High protein binding (like in Sufentanil) means the drug can be displaced by other highly protein-bound drugs, potentially increasing the risk of toxicity in hypoproteinemic states.

Question 82: Which of the following statements about colchicine is false?

A. Used in acute gout
B. It is not an anti-inflammatory agent
C. It is antimitotic and causes telophase arrest (Correct Answer)
D. Can cause diarrhea

Explanation: ### Explanation **1. Why Option C is the Correct (False) Statement:** Colchicine is indeed an antimitotic drug, but it causes **Metaphase arrest**, not telophase arrest. It works by binding to tubulin dimers, preventing their polymerization into microtubules. This inhibits the formation of the mitotic spindle, which is essential for chromosome separation during metaphase. In the context of gout, this microtubule inhibition prevents the migration and phagocytic activity of neutrophils into the joint, thereby suppressing the inflammatory response to urate crystals. **2. Analysis of Other Options:** * **Option A (Used in acute gout):** This is **true**. Colchicine is a first-line agent for acute gouty arthritis, especially when NSAIDs are contraindicated (e.g., in patients with peptic ulcers or renal impairment). * **Option B (It is not an anti-inflammatory agent):** This is **true** in a pharmacological sense. Colchicine is not a general-purpose anti-inflammatory or analgesic (like NSAIDs). It does not inhibit the cyclooxygenase (COX) enzyme; its anti-inflammatory effect is specific to gout and certain other conditions (like Mediterranean fever) by targeting neutrophil activity. * **Option D (Can cause diarrhea):** This is **true**. Diarrhea is the most common and earliest sign of colchicine toxicity. It occurs because the drug inhibits the rapidly dividing cells of the gastrointestinal mucosa. **3. NEET-PG High-Yield Clinical Pearls:** * **Mechanism:** Binds to tubulin $\rightarrow$ inhibits microtubule polymerization $\rightarrow$ Metaphase arrest. * **Toxicity:** The "Gastrointestinal Warning"—treatment should be stopped immediately if diarrhea, nausea, or vomiting occurs. * **Other Uses:** Prophylaxis of gout, Familial Mediterranean Fever (FMF), Acute Pericarditis, and Behçet’s disease. * **Drug Interaction:** It is a substrate of P-glycoprotein and CYP3A4; co-administration with Clarithromycin can lead to fatal colchicine toxicity.

Question 83: Morphine when used for cancer palliative therapy is least likely to cause which of the following side effects?

A. Nausea and vomiting
B. Constipation
C. Dry mouth (Correct Answer)
D. Respiratory depression

Explanation: **Explanation:** The question asks for the side effect **least likely** to occur with morphine use in cancer palliative care. **Why "Dry Mouth" is the correct answer:** While opioids can occasionally cause xerostomia (dry mouth), it is not a hallmark pharmacological side effect of morphine. In the context of palliative care, dry mouth is more frequently attributed to concurrent medications like anticholinergics (e.g., hyoscine), tricyclic antidepressants, or the underlying disease state (dehydration). **Analysis of Incorrect Options:** * **Constipation:** This is the most common and persistent side effect. Unlike other effects, **tolerance never develops** to opioid-induced constipation. It occurs due to $\mu$-receptors in the myenteric plexus decreasing GI motility. * **Nausea and Vomiting:** Morphine stimulates the **Chemoreceptor Trigger Zone (CTZ)** in the area postrema. While tolerance usually develops within days, it is a very common initial side effect in palliative settings. * **Respiratory Depression:** This is the most serious adverse effect. While tolerance develops to this effect over time in chronic cancer pain management, it remains a primary pharmacological action of morphine via $\mu_2$ receptors. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mnemonic for Morphine Side Effects:** **MORPHINE** (Miosis, Out of it/Sedation, Respiratory depression, Pneumonia/Aspiration, Hypotension, Infrequency/Constipation, Nausea, Emesis). 2. **No Tolerance:** Tolerance develops to most effects of morphine **EXCEPT** Miosis (pinpoint pupils) and Constipation. 3. **Triad of Morphine Poisoning:** Coma, Pinpoint pupil, and Depressed respiration. 4. **Drug of Choice:** Morphine is the gold standard for severe cancer pain (Step 3 of the WHO Analgesic Ladder).

Question 84: Baricitinib was approved by the FDA for which condition?

A. Osteoarthritis
B. Rheumatoid arthritis (Correct Answer)
C. Clostridium difficile infection
D. Gout

Explanation: **Explanation:** **Baricitinib** is a potent, selective, and reversible inhibitor of **Janus Kinases (JAK1 and JAK2)**. It belongs to the class of Targeted Synthetic Disease-Modifying Antirheumatic Drugs (tsDMARDs). **1. Why Rheumatoid Arthritis (RA) is correct:** In RA, the signaling of various pro-inflammatory cytokines (like IL-6, IL-12, and IFN-γ) is mediated through the JAK-STAT pathway. By inhibiting JAK1 and JAK2, Baricitinib prevents the phosphorylation and activation of STATs (Signal Transducers and Activators of Transcription), thereby modulating the gene expression of inflammatory mediators. It was FDA-approved for adults with moderately to severely active RA who have had an inadequate response to TNF antagonists. **2. Why other options are incorrect:** * **Osteoarthritis:** This is primarily a degenerative joint disease, not an autoimmune inflammatory condition mediated by the JAK-STAT pathway. Treatment focuses on NSAIDs and intra-articular steroids. * **Clostridium difficile infection:** This is a bacterial gastrointestinal infection treated with antibiotics like Vancomycin or Fidaxomicin. * **Gout:** Acute gout is managed with NSAIDs, Colchicine, or Corticosteroids; chronic gout is managed with Xanthine Oxidase inhibitors (Allopurinol). **3. High-Yield Clinical Pearls for NEET-PG:** * **Other JAK Inhibitors:** Tofacitinib (JAK1/3), Upadacitinib (JAK1), and Ruxolitinib (JAK1/2 - used in Myelofibrosis). * **COVID-19 Connection:** Baricitinib received an Emergency Use Authorization (EUA) for hospitalized COVID-19 patients requiring supplemental oxygen due to its anti-inflammatory properties. * **Adverse Effects:** Increased risk of serious infections (URTI, Herpes Zoster), malignancy, and **thromboembolism** (DVT/PE). * **Monitoring:** Always screen for Latent Tuberculosis before starting any JAK inhibitor.

Question 85: Which of the following selective 5-HT1B/1D receptor agonists is useful in the acute management of migraine?

A. Buspirone
B. Ondansetron
C. Frovatriptan (Correct Answer)
D. Ketanserin

Explanation: **Explanation:** **Correct Option: C. Frovatriptan** Triptans (like Sumatriptan, Rizatriptan, and Frovatriptan) are the drugs of choice for the **acute management of moderate-to-severe migraine**. They act as selective agonists at **5-HT1B and 5-HT1D** receptors. * **5-HT1B activation:** Causes vasoconstriction of dilated intracranial extracerebral blood vessels. * **5-HT1D activation:** Inhibits the release of pro-inflammatory neuropeptides (like CGRP and Substance P) from trigeminal nerve endings (pre-junctional inhibition). **Analysis of Incorrect Options:** * **A. Buspirone:** A selective **5-HT1A partial agonist** used primarily as a non-benzodiazepine anxiolytic. It has no role in migraine management. * **B. Ondansetron:** A selective **5-HT3 antagonist** used as a potent anti-emetic, particularly for chemotherapy-induced nausea and vomiting (CINV). * **D. Ketanserin:** A **5-HT2 receptor antagonist** (with α1-blocking properties) used occasionally as an antihypertensive; it is not used for migraine. **NEET-PG High-Yield Pearls:** * **Longest Half-life:** Frovatriptan has the longest half-life (~26 hours) among triptans, making it useful for preventing **menstrual migraine** and reducing headache recurrence. * **Fastest Onset:** Rizatriptan and Eletriptan generally have a faster onset of action than others. * **Contraindications:** Triptans should be avoided in patients with **Ischemic Heart Disease (IHD)**, Prinzmetal angina, or uncontrolled hypertension due to their vasoconstrictive potential. * **First Triptan:** Sumatriptan was the first drug in this class but has low oral bioavailability.

Question 86: Ziconotide acts by blocking which type of channel?

A. Voltage-gated Na+ channel
B. Voltage-gated Ca2+ channel (Correct Answer)
C. Ligand-gated Na+ channel
D. Ligand-gated Ca2+ channel

Explanation: **Explanation:**Ziconotide is a synthetic analogue of omega-conotoxin MVIIA, a peptide derived from the venom of the marine snail *Conus magus*.1. Why the Correct Answer is Right:Ziconotide acts as a potent and selective blocker of N-type voltage-gated calcium channels (VGCCs). These channels are primarily located on the pre-synaptic terminals of primary nociceptive (pain-sensing) afferent nerves in the dorsal horn of the spinal cord [1]. By blocking these channels, Ziconotide inhibits the influx of calcium, which prevents the release of excitatory neurotransmitters like glutamate, calcitonin gene-related peptide (CGRP), and substance P. This effectively interrupts the transmission of pain signals to the brain.2. Why the Other Options are Incorrect:* Options A & C (Na+ channels): While local anesthetics (e.g., Lidocaine) block voltage-gated Na+ channels to stop nerve conduction, Ziconotide specifically targets calcium influx.* Option D (Ligand-gated Ca2+ channel): Ziconotide does not require a ligand (like a neurotransmitter) to bind to a receptor to open the channel; it acts on channels that respond to changes in membrane potential (voltage-gated).3. High-Yield Clinical Pearls for NEET-PG:* Route of Administration: It must be administered intrathecally (via an infusion pump) because it does not cross the blood-brain barrier [1].* Indication: Used for refractory chronic pain (e.g., cancer pain or failed back surgery syndrome) in patients who are intolerant or refractory to other treatments like morphine.* Black Box Warning: It is associated with severe psychiatric symptoms and neurological impairment (e.g., psychosis, cognitive impairment, and hallucinations).* Advantage: Unlike opioids, it does not cause respiratory depression or physical dependence/addiction.

Question 87: All NSAIDs block cyclooxygenase and?

A. Prostaglandin synthesis (Correct Answer)
B. Ectoglandin synthesis
C. Preglandin synthesis
D. Costaglandin synthesis

Explanation: The core mechanism of action for Non-Steroidal Anti-inflammatory Drugs (NSAIDs) is the inhibition of the enzyme **Cyclooxygenase (COX)** [1]. Under normal physiological conditions, the enzyme COX (specifically COX-1 and COX-2) acts on arachidonic acid—a fatty acid released from cell membrane phospholipids—to convert it into **Prostaglandins (PGs)**, prostacyclin, and thromboxane [2]. By blocking the COX enzyme, NSAIDs directly prevent the synthesis of Prostaglandins [3]. Since PGs are the primary mediators of pain, fever, and inflammation, their reduction results in the analgesic, antipyretic, and anti-inflammatory effects characteristic of these drugs. **Analysis of Options:** * **Option A (Correct):** Prostaglandins are the direct downstream products of the cyclooxygenase pathway. * **Options B, C, and D (Incorrect):** "Ectoglandin," "Preglandin," and "Costaglandin" are not recognized biological molecules or medical terms. These are distractor options designed to test the student's familiarity with the specific nomenclature of arachidonic acid metabolites. **High-Yield Clinical Pearls for NEET-PG:** * **COX-1 vs. COX-2:** COX-1 is "constitutive" (housekeeping functions like gastric protection and platelet aggregation), while COX-2 is "inducible" (expressed during inflammation). * **Aspirin:** It is the only NSAID that causes **irreversible** inhibition of COX via acetylation [4]. * **Triple Whammy:** Be cautious of the "Triple Whammy" effect on the kidneys when combining NSAIDs, ACE inhibitors/ARBs, and Diuretics, which can lead to acute kidney injury. * **Ductus Arteriosus:** NSAIDs (like Indomethacin) are used to close a Patent Ductus Arteriosus (PDA) by inhibiting PGE2, which normally keeps the ductus open.

Question 88: Which of the following features differentiates pethidine from morphine?

A. Local anaesthetic action (Correct Answer)
B. More analgesic action
C. More respiratory depression
D. Suppresses cough effectively

Explanation: **Explanation:** **Pethidine (Meperidine)** is a synthetic opioid agonist that, while sharing the same primary mechanism of action as morphine (µ-opioid receptor agonism), possesses distinct pharmacological properties due to its unique chemical structure. 1. **Why Option A is Correct:** Unlike morphine, pethidine possesses significant **local anaesthetic properties**. It can block sodium channels, a feature not seen with morphine. Clinically, this is relevant because pethidine can be used for spinal anesthesia, providing both sensory and motor blockade, although it is rarely used this way due to the availability of better agents. 2. **Why Incorrect Options are Wrong:** * **Option B:** Pethidine is **less potent** than morphine. Approximately 75–100 mg of pethidine is required to produce the same analgesic effect as 10 mg of morphine. * **Option C:** Pethidine causes **less respiratory depression** in the newborn compared to morphine when used during labor, making it a preferred choice in obstetric analgesia (though it is not entirely risk-free). * **Option D:** Pethidine has **negligible antitussive (cough suppressant) action**. Morphine and its derivatives (like codeine) are potent cough suppressants. **High-Yield Clinical Pearls for NEET-PG:** * **Anticholinergic Activity:** Pethidine has atropine-like effects, leading to **mydriasis** (unlike morphine's miosis) and tachycardia. * **Toxic Metabolite:** It is metabolized to **norpethidine**, which is a CNS stimulant. Accumulation (especially in renal failure) can lead to **seizures**. * **Drug Interaction:** Pethidine is contraindicated with **MAO inhibitors**, as it can precipitate a life-threatening "Serotonin Syndrome" (hyperpyrexia, coma, and convulsions). * **Smooth Muscle:** It causes less spasm of the Sphincter of Oddi compared to morphine, making it historically preferred for biliary colic.

Question 89: What is the antagonist of morphine?

A. Naloxone (Correct Answer)
B. Nalbuphine
C. Nalorphine
D. Methadone

Explanation: **Explanation:** **1. Why Naloxone is the Correct Answer:** Naloxone is a **pure opioid antagonist** that competes with opioids at all three receptor sites ($\mu$, $\kappa$, and $\delta$), with the highest affinity for $\mu$-receptors. It is the drug of choice for treating acute opioid overdose because it rapidly reverses respiratory depression and sedation. Due to its extensive first-pass metabolism, it is administered parenterally (IV/IM) and has a short duration of action (30–90 minutes), often requiring repeated doses. **2. Analysis of Incorrect Options:** * **Nalbuphine:** This is a **mixed agonist-antagonist** ($\kappa$-agonist and $\mu$-antagonist). While it can reverse $\mu$-mediated respiratory depression, it possesses intrinsic analgesic activity and is not used as a primary antagonist. * **Nalorphine:** This was the first opioid antagonist discovered but is also a **mixed agonist-antagonist**. It is rarely used today because it can cause unpleasant psychotomimetic side effects (dysphoria, hallucinations) via $\kappa$-receptor activation. * **Methadone:** This is a **full $\mu$-agonist** with a long half-life. It is used in the management of opioid detoxification and maintenance programs to prevent withdrawal symptoms, not to antagonize morphine. **3. High-Yield Clinical Pearls for NEET-PG:** * **Naltrexone:** Unlike Naloxone, Naltrexone is orally active and long-acting. It is used for **maintenance** in detoxified addicts and to reduce alcohol cravings. * **Methylnaltrexone/Alvimopan:** These are peripheral opioid antagonists used to treat opioid-induced constipation without reversing central analgesia. * **Diagnostic Sign:** In morphine poisoning, look for the triad of **Pinpoint pupil (miosis)**, **Respiratory depression**, and **Coma**. Naloxone will cause immediate pupillary dilation and arousal.

Question 90: Aspirin is contraindicated in children suffering from influenza or similar viral infections due to an increased risk of which condition?

A. Fanconi syndrome
B. Thrombocytopenia
C. Gastric bleeding
D. Reye's syndrome (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Reye's Syndrome** Reye’s syndrome is a rare but potentially fatal condition characterized by **acute encephalopathy** and **fatty degeneration of the liver (microvesicular steatosis)**. The pathophysiology involves mitochondrial injury, which is triggered when aspirin is administered to children or adolescents during a viral prodrome (typically Influenza A, B, or Varicella). Aspirin inhibits mitochondrial beta-oxidation, leading to hyperammonemia and cerebral edema. Therefore, **Acetaminophen (Paracetamol)** is the preferred antipyretic in the pediatric population. **Analysis of Incorrect Options:** * **A. Fanconi Syndrome:** This is a disorder of the proximal renal tubules resulting in the excretion of glucose, amino acids, and phosphates. While associated with expired tetracyclines or heavy metal poisoning, it is not linked to aspirin use in viral infections. * **B. Thrombocytopenia:** While aspirin inhibits platelet aggregation (via irreversible COX-1 inhibition), it does not typically cause a decrease in the absolute platelet count (thrombocytopenia). * **C. Gastric Bleeding:** Aspirin is a known cause of gastric mucosal injury and GI bleeding due to the inhibition of protective prostaglandins ($PGE_2$). However, this is a general side effect and not the specific reason for its contraindication in pediatric viral illnesses. **High-Yield Clinical Pearls for NEET-PG:** * **Exception to the rule:** Aspirin is still used in children for **Kawasaki Disease** (to prevent coronary artery aneurysms) and **Juvenile Idiopathic Arthritis**, despite the risk of Reye's syndrome. * **Histology:** Look for "microvesicular steatosis" in liver biopsy descriptions for Reye's syndrome. * **Salicylism:** Chronic aspirin toxicity presents with tinnitus, vertigo, and a mixed respiratory alkalosis/metabolic acidosis.

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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