Analgesics and Anti-inflammatory Drugs — MCQs

A 35-year-old woman has been taking acetylsalicylic acid (aspirin) for arthritis for several years. Her joint pain is reduced with this therapy, though the joint destruction with loss of articular cartilage still continues. The aspirin therapy temporarily alleviates her pain. This pain reduction is primarily the result of diminishing the inflammatory response characterized by:

Q109Medium

Which of the following statements regarding morphine is NOT true?

Q110Easy

Which of the following drugs is used in the treatment of acute gout?

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

Question 101: Which of the following is the most potent narcotic analgesic?

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

Explanation: **Explanation:** The correct answer is **Buprenorphine**. Potency refers to the amount of drug (dose) required to produce a specific intensity of effect. Among the given options, Buprenorphine is the most potent, being approximately **25–50 times more potent than Morphine**. **Why Buprenorphine is correct:** Buprenorphine is a **semi-synthetic thebaine derivative** that acts as a **partial $\mu$-opioid agonist** and a **$\kappa$-antagonist**. Due to its extremely high affinity for $\mu$-receptors, it produces significant analgesia at very low doses. It also exhibits a "ceiling effect" for respiratory depression, making it safer in overdose compared to full agonists. **Analysis of Incorrect Options:** * **Morphine (Option A):** The gold standard for opioid analgesia. While highly effective, it is used as the reference point (potency = 1) and is significantly less potent than Buprenorphine or Fentanyl. * **Codeine (Option C):** A natural opium alkaloid used for mild-to-moderate pain and as an antitussive. It is a weak opioid with only about **1/10th the potency** of Morphine. * **Pentazocine (Option D):** A benzomorphan derivative acting as a $\kappa$-agonist and weak $\mu$-antagonist/partial agonist. It is less potent than Morphine (approx. 1/3rd) and can precipitate withdrawal in opioid-dependent patients. **High-Yield Clinical Pearls for NEET-PG:** * **Most Potent Opioid Overall:** **Sufentanil** (approx. 500–1000x Morphine), followed by Remifentanil and Fentanyl (approx. 100x Morphine). * **Buprenorphine Kinetics:** It has a very slow dissociation from $\mu$-receptors, leading to a long duration of action and making its effects difficult to reverse with Naloxone. * **Drug of Choice:** Morphine remains the drug of choice for **Myocardial Infarction** pain due to its venodilatory properties (reducing preload).

Question 102: Which of the following opioid analgesics has an oral to parenteral activity ratio of 1:2?

A. Morphine
B. Oxymorphone
C. Methadone (Correct Answer)
D. Diacetylmorphine

Explanation: ***Methadone*** - Has excellent **oral bioavailability** of approximately **70-90%**, resulting in an oral to parenteral ratio of **1:2**. - This high bioavailability makes it ideal for **opioid maintenance therapy** and **chronic pain management**. *Morphine* - Has poor **oral bioavailability** of only **15-30%** due to extensive **first-pass metabolism**. - The oral to parenteral ratio is approximately **1:6**, requiring much higher oral doses. *Oxymorphone* - Exhibits very poor **oral bioavailability** of approximately **10%** due to significant **hepatic first-pass effect**. - The oral to parenteral ratio is approximately **1:10**, making it less suitable for oral administration. *Diacetylmorphine* - Also known as **heroin**, it is **not used clinically** in oral formulations due to rapid metabolism. - Has poor oral bioavailability and is primarily used parenterally in very limited medical contexts.

Question 103: Which of the following NSAIDs is used for Bartter syndrome?

A. Paracetamol
B. Sulindac
C. Mefenamic acid
D. Indomethacin (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Indomethacin** **Mechanism and Rationale:** Bartter syndrome is a rare genetic renal tubular disorder characterized by defective salt reabsorption in the thick ascending limb of the loop of Henle. This leads to salt wasting, hypokalemia, metabolic alkalosis, and, crucially, **increased renal prostaglandin (PGE2) production**. Elevated PGE2 stimulates the renin-angiotensin-aldosterone system (RAAS), worsening the electrolyte imbalance. **Indomethacin** is the drug of choice because it is a potent non-selective COX inhibitor that effectively reduces renal prostaglandin synthesis. By inhibiting PGE2, Indomethacin helps decrease renin secretion, improves potassium levels, and mitigates polyuria and growth retardation in affected children. **Analysis of Incorrect Options:** * **A. Paracetamol:** It has weak peripheral anti-inflammatory and prostaglandin-inhibiting activity. It is ineffective in reducing the high renal prostaglandin levels seen in Bartter syndrome. * **B. Sulindac:** While an NSAID, it is a prodrug known for its "renal-sparing" effect (it inhibits systemic COX but has less effect on renal prostaglandins). This makes it unsuitable for a condition where renal prostaglandin inhibition is the primary goal. * **C. Mefenamic acid:** Primarily used for dysmenorrhea and mild-to-moderate pain; it lacks the clinical evidence and potency required for managing Bartter syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Indomethacin** is also the drug of choice for **Patent Ductus Arteriosus (PDA)** and **Ankylosing Spondylitis**. * **Side Effects:** Indomethacin is notorious for GI toxicity (peptic ulcers) and frontal headaches. * **Gitelman Syndrome:** Often confused with Bartter; it mimics thiazide diuretic use (hypocalciuria), whereas Bartter mimics loop diuretic use (hypercalciuria). Indomethacin is less central to Gitelman treatment than Bartter.

Question 104: Prolonged use of aspirin causes:

A. Hypoprothrombinemia (Correct Answer)
B. Hyperprothrombinemia
C. Hypophosphatasia
D. Hypercalcemia

Explanation: **Explanation:** **Why Hypoprothrombinemia is correct:** Prolonged use of high-dose aspirin (salicylates) can lead to **hypoprothrombinemia** (deficiency of Factor II). This occurs because salicylates interfere with the utilization of Vitamin K by the liver, similar to the mechanism of warfarin [2]. By inhibiting the synthesis of Vitamin K-dependent clotting factors (II, VII, IX, and X), aspirin prolongs the Prothrombin Time (PT) [2]. This effect is distinct from aspirin’s more common antiplatelet action, which involves the irreversible inhibition of COX-1 and thromboxane A2. **Why the other options are incorrect:** * **B. Hyperprothrombinemia:** This refers to an excess of prothrombin, which would increase clotting tendency. Aspirin acts as an anticoagulant/antiplatelet agent, making this physiologically opposite to its effect. * **C. Hypophosphatasia:** This is a rare genetic disorder characterized by low levels of alkaline phosphatase. Aspirin has no known clinical link to the inhibition of this enzyme. * **D. Hypercalcemia:** Aspirin does not significantly affect systemic calcium homeostasis [3]. Hypercalcemia is more commonly associated with thiazide diuretics or Vitamin D toxicity. **High-Yield Clinical Pearls for NEET-PG:** 1. **Dual Hemostatic Defect:** Aspirin causes bleeding via two mechanisms: **Platelet dysfunction** (low doses) and **Hypoprothrombinemia** (prolonged high doses) [2]. 2. **Reversibility:** Aspirin-induced hypoprothrombinemia can be reversed by administering **Vitamin K** [1]. 3. **Acid-Base Balance:** In salicylate poisoning, the classic pattern is **Respiratory Alkalosis** followed by **Metabolic Acidosis** (with a high anion gap). 4. **Reye’s Syndrome:** Avoid aspirin in children with viral infections (flu/chickenpox) due to the risk of fulminant hepatic failure and encephalopathy.

Question 105: Which of the following is given at intervals as a pulsatile therapy?

A. GnRH (Correct Answer)
B. GH
C. PSH
D. Estrogen

Explanation: **Explanation:** The correct answer is **GnRH (Gonadotropin-Releasing Hormone)**. **1. Why GnRH is the correct answer:** The physiological secretion of GnRH from the hypothalamus is naturally **pulsatile**. In clinical practice, the therapeutic effect of GnRH depends entirely on its mode of administration: * **Pulsatile administration:** Mimics physiological release and is used to **stimulate** the pituitary to release FSH and LH. This is used to treat infertility and delayed puberty (e.g., Kallmann syndrome). * **Continuous (Continuous/Non-pulsatile) administration:** Leads to **downregulation** and desensitization of GnRH receptors on pituitary gonadotropes, causing a "medical castration" effect. This is used in treating prostate cancer, endometriosis, and precocious puberty. **2. Why other options are incorrect:** * **GH (Growth Hormone):** While GH is naturally secreted in pulses (mainly at night), therapeutic GH is typically administered as a once-daily subcutaneous injection to maintain steady levels for growth stimulation. * **FSH (Follicle-Stimulating Hormone):** In ovulation induction protocols, FSH is given in a steady daily dose to promote follicular recruitment rather than in a pulsatile manner. * **Estrogen:** Estrogen is administered continuously (or cyclically in HRT/OCPs) to maintain systemic levels; it does not require pulsatile delivery to exert its biological effects. **High-Yield Clinical Pearls for NEET-PG:** * **GnRH Agonists (e.g., Leuprolide, Goserelin):** Initially cause a "flare-up" of symptoms due to a transient rise in LH/FSH before downregulation occurs. * **GnRH Antagonists (e.g., Cetrorelix, Degarelix):** Provide immediate suppression without the initial flare-up. * **Diagnostic Use:** Pulsatile GnRH can be used to differentiate between hypothalamic (responds to GnRH) and pituitary (does not respond) causes of hypogonadism.

Question 106: Which of the following is a uricosuric drug?

A. Probenecid (Correct Answer)
B. Colchicine
C. Allopurinol
D. All of these

Explanation: **Explanation:** **1. Why Probenecid is Correct:** Probenecid is a classic **uricosuric agent**. Its primary mechanism of action involves the inhibition of the **URAT-1 transporter** in the proximal convoluted tubule of the kidney. By blocking this transporter, it prevents the reabsorption of filtered uric acid back into the blood, thereby increasing its excretion in the urine. It is used in the chronic management of gout to lower serum urate levels. **2. Why the Other Options are Incorrect:** * **Colchicine:** This is an anti-inflammatory drug used for **acute gouty attacks**. It works by binding to tubulin, inhibiting microtubule polymerization, and preventing neutrophil chemotaxis and degranulation. It does not affect uric acid levels or excretion. * **Allopurinol:** This is a **xanthine oxidase inhibitor**. It reduces the *production* of uric acid rather than increasing its excretion. It is the first-line drug for chronic gout but is classified as a hypouricemic agent, not a uricosuric. **3. NEET-PG High-Yield Clinical Pearls:** * **Uricosuric Contraindication:** Do not start uricosurics if the patient has a history of **renal stones (nephrolithiasis)** or high urinary uric acid levels, as they increase the risk of stone formation. * **Drug Interaction:** Probenecid inhibits the renal tubular secretion of **Penicillin** and **Methotrexate**, increasing their plasma concentrations (this was historically used to prolong penicillin action). * **Salicylate Interaction:** Low-dose Aspirin interferes with the uricosuric action of Probenecid and should be avoided. * **Other Uricosurics:** Sulfinpyrazone and **Lesinurad** (a newer URAT-1 inhibitor). Note that **Losartan** (an ARB) also possesses mild uricosuric properties.

Question 107: Ibuprofen acts on which pathway?

A. Lipoxygenase pathway
B. Cyclooxygenase pathway (Correct Answer)
C. Kinin system
D. Serotonin system

Explanation: **Explanation:** **Ibuprofen** is a classic example of a **Non-Selective Non-Steroidal Anti-Inflammatory Drug (NSAID)**. Its primary mechanism of action is the reversible inhibition of the **Cyclooxygenase (COX) pathway**. 1. **Why Option B is Correct:** Ibuprofen inhibits both **COX-1 and COX-2** enzymes. These enzymes are responsible for converting arachidonic acid into cyclic endoperoxides, which then form **prostaglandins (PGs)**, prostacyclin, and thromboxane. By reducing PG synthesis (specifically PGE2), ibuprofen exerts its analgesic, antipyretic, and anti-inflammatory effects. 2. **Why Other Options are Incorrect:** * **Option A (Lipoxygenase pathway):** This pathway leads to the production of **Leukotrienes**. While drugs like *Zileuton* inhibit this pathway, standard NSAIDs like Ibuprofen do not. In fact, inhibiting COX can sometimes "shunt" arachidonic acid toward the LOX pathway, potentially worsening asthma (NSAID-exacerbated respiratory disease). * **Option C (Kinin system):** This involves Bradykinin, a potent pain mediator. While NSAIDs reduce the sensitization of receptors to bradykinin, they do not act directly on the kinin system. * **Option D (Serotonin system):** This system is primarily involved in mood and central pain modulation (targeted by antidepressants or Triptans), not the peripheral anti-inflammatory mechanism of Ibuprofen. **High-Yield Clinical Pearls for NEET-PG:** * **Propionic Acid Derivative:** Ibuprofen belongs to this chemical class (along with Naproxen and Ketoprofen). * **Closure of PDA:** Ibuprofen is a drug of choice for the pharmacological closure of a **Patent Ductus Arteriosus (PDA)** in neonates. * **Ceiling Effect:** Like most NSAIDs, Ibuprofen has a "therapeutic ceiling" where increasing the dose beyond a certain point provides no additional analgesia but increases side effects.

Question 108: A 35-year-old woman has been taking acetylsalicylic acid (aspirin) for arthritis for several years. Her joint pain is reduced with this therapy, though the joint destruction with loss of articular cartilage still continues. The aspirin therapy temporarily alleviates her pain. This pain reduction is primarily the result of diminishing the inflammatory response characterized by:

A. Neutrophil chemotaxis by leukotriene B4
B. Fever resulting from interleukin-1 release
C. Prostaglandin mediated vasodilation (Correct Answer)
D. Pain resulting from bradykinin generation

Explanation: **Explanation:** The primary mechanism of action of Aspirin (Acetylsalicylic acid) is the **irreversible inhibition of Cyclooxygenase (COX-1 and COX-2) enzymes**. This inhibition prevents the conversion of arachidonic acid into prostaglandins (PGs), specifically PGE2 and PGI2. **1. Why Option C is Correct:** In the inflammatory process, prostaglandins (especially PGE2) act as potent vasodilators and sensitize peripheral nociceptors to pain-producing mediators like bradykinin and histamine. By inhibiting PG synthesis, aspirin reduces **prostaglandin-mediated vasodilation**, edema, and the sensitization of pain receptors. This alleviates the "rubor" (redness), "calor" (heat), and "dolor" (pain) associated with inflammation. **2. Why Other Options are Incorrect:** * **Option A:** Aspirin does not inhibit the Lipoxygenase (LOX) pathway. In fact, by blocking the COX pathway, arachidonic acid may be shunted toward the LOX pathway, potentially increasing **Leukotriene B4** (a potent neutrophil chemotactic agent). * **Option B:** While aspirin is an antipyretic, the question asks specifically about the reduction of the **inflammatory response** in the joints. Fever is a systemic response, not the primary local inflammatory mechanism being treated in arthritis. * **Option D:** Aspirin does not prevent the **generation of bradykinin** (which is derived from the kinin system). It only prevents prostaglandins from *sensitizing* nerve endings to the effects of bradykinin. **High-Yield NEET-PG Pearls:** * **Disease Modification:** Aspirin and NSAIDs are **Symptomatic Treatments** only. They do not prevent joint destruction or disease progression in Rheumatoid Arthritis (unlike DMARDs). * **Zero-Order Kinetics:** At high anti-inflammatory doses, Aspirin follows zero-order elimination. * **Aspirin Triad (Samter’s):** Asthma, Nasal polyposis, and Aspirin sensitivity (due to leukotriene shift).

Question 109: Which of the following statements regarding morphine is NOT true?

A. It is used in the management of bone fractures.
B. It is used in the management of angina pectoris. (Correct Answer)
C. It is used in the management of myocardial infarction.
D. It is not used in head injuries.

Explanation: The correct answer is **B**, as Morphine is **not** typically used in the management of stable or unstable angina pectoris. **1. Why Option B is the correct (False) statement:** While Morphine is a potent analgesic, it is not a first-line or standard treatment for **Angina Pectoris**. Angina is primarily managed with nitrates, beta-blockers, and calcium channel blockers to improve oxygen supply-demand balance. Morphine is reserved for pain that is unresponsive to nitrates, specifically in the context of an acute **Myocardial Infarction (MI)**. **2. Analysis of other options:** * **Option A (True):** Morphine is highly effective for **severe traumatic pain**, such as bone fractures, due to its potent action on $\mu$-opioid receptors in the CNS [1]. * **Option C (True):** Morphine is a cornerstone in **MI management** (MONA protocol: Morphine, Oxygen, Nitrates, Aspirin). It provides analgesia, reduces anxiety (anxiolysis), and acts as a venodilator, which decreases preload and myocardial oxygen demand [1]. * **Option D (True):** Morphine is **contraindicated in head injuries**. It causes respiratory depression, leading to $CO_2$ retention. $CO_2$ is a potent cerebral vasodilator, which increases cerebral blood flow and further elevates **Intracranial Pressure (ICP)**. It also causes miosis, which interferes with pupillary monitoring. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Morphine is the DOC for **Acute Left Ventricular Failure (Cardiac Asthma)** because it relieves air hunger and reduces preload [1]. * **Biliary Colic:** Morphine can aggravate biliary colic by causing spasm of the **Sphincter of Oddi** (Pethidine is often preferred here as it has less biliary spasm effect). * **Triad of Opioid Poisoning:** Pinpoint pupil, Respiratory depression, and Coma. * **Antidote:** Naloxone (Pure antagonist) [1].

Question 110: Which of the following drugs is used in the treatment of acute gout?

A. Allopurinol
B. Colchicine (Correct Answer)
C. Pamidronate
D. Methotrexate

Explanation: **Explanation:** The management of gout is divided into two phases: treatment of acute attacks and long-term prophylaxis (urate-lowering therapy) [1, 2]. **1. Why Colchicine is Correct:** Colchicine is a first-line agent for **acute gout** [3]. Its primary mechanism involves binding to tubulin, inhibiting microtubule polymerization [2]. This disrupts the migration and phagocytic activity of neutrophils into the inflamed joint, thereby reducing the release of inflammatory mediators (like LTB4) and lactic acid [1, 2]. By inhibiting the "inflammasome" complex, it effectively halts the acute inflammatory cascade [2]. **2. Why the Other Options are Incorrect:** * **Allopurinol (Option A):** This is a Xanthine Oxidase inhibitor used for **chronic prophylaxis** [3]. It should **never** be started during an acute attack because a rapid drop in serum uric acid can cause the mobilization of urate crystals from tissues, potentially worsening or prolonging the acute episode [3]. * **Pamidronate (Option C):** This is a Bisphosphonate used to treat osteoporosis, Paget’s disease, and hypercalcemia of malignancy. It has no role in gout management. * **Methotrexate (Option D):** This is a DMARD (Disease-Modifying Anti-Rheumatic Drug) used primarily for Rheumatoid Arthritis and psoriasis. It is not used for gout. **High-Yield Clinical Pearls for NEET-PG:** * **First-line for Acute Gout:** NSAIDs (e.g., Indomethacin, Naproxen) are generally preferred over colchicine due to better tolerability [3]. * **Colchicine Toxicity:** The dose-limiting side effect is **diarrhea** [4]. * **Uricosuric Drugs:** Probenecid and Lesinurad increase uric acid excretion but are contraindicated in patients with renal stones [1]. * **Febuxostat:** A non-purine selective inhibitor of xanthine oxidase, used if Allopurinol is not tolerated.

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

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Disease-Modifying Antirheumatic Drugs

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Glucocorticoids as Anti-inflammatory Agents

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Migraine Therapeutics

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Neuropathic Pain Management

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