Analgesics and Anti-inflammatory Drugs Practice Questions

Q: What is the most prominent toxic effect associated with acetaminophen use?

Hepatic necrosis. **Explanation:** **Acetaminophen (Paracetamol)** is primarily metabolized in the liver via glucuronidation and sulfation. However, a small fraction is metabolized by **Cytochrome P450 (CYP2E1)** into a highly reactive and toxic intermediate called **NAPQI** (*N-acetyl-p-benzoquinone imine*). In therapeutic doses, NAPQI is rapidly detoxified by conjugation with **glutathione**. In overdose, glutathione stores are depleted, leading to the accumulation of NAPQI. This reactive metabolite binds covalently to hepatic cellular proteins, causing direct cellular damage and **centrilobular hepatic necrosis**. **Analysis of Incorrect Options:** * **A. Respiratory alkalosis:** This is a characteristic early feature of **Salicylate (Aspirin)** poisoning due to direct stimulation of the respiratory center, not acetaminophen. * **B. Haemorrhage:** While severe liver failure can lead to coagulopathy, hemorrhage is not the primary toxic mechanism. Aspirin is more commonly associated with bleeding due to irreversible COX inhibition and anti-platelet effects. * **D. Gastric Ulceration:** Acetaminophen is a weak inhibitor of peripheral COX enzymes and does not significantly affect gastric mucosal prostaglandins. Therefore, it lacks the gastrointestinal toxicity common to NSAIDs like Ibuprofen or Indomethacin. **High-Yield Clinical Pearls for NEET-PG:** * **Antidote:** **N-acetylcysteine (NAC)** is the specific antidote; it replenishes glutathione stores. * **Toxicity Marker:** The **Rumack-Matthew Nomogram** is used to predict hepatotoxicity based on plasma acetaminophen levels relative to time since ingestion. * **Chronic Alcoholics:** They are at higher risk of toxicity even at lower doses because alcohol induces CYP2E1 and depletes baseline glutathione.

Q: Which of the following analgesics should not be given in acute myocardial infarction?

Pentazocine. **Explanation:** The primary goal of analgesia in Acute Myocardial Infarction (AMI) is to relieve pain and reduce myocardial oxygen demand. **Why Pentazocine is contraindicated:** Pentazocine is an opioid agonist-antagonist (κ-agonist and μ-antagonist/partial agonist). It possesses **sympathomimetic properties**, which lead to an increase in plasma catecholamines. This results in an **increase in heart rate (tachycardia) and systemic blood pressure**, which significantly increases **myocardial oxygen demand**. In the setting of an AMI, where the heart is already ischemic, this can worsen the infarct size and increase the risk of arrhythmias. Furthermore, it can increase pulmonary artery pressure, increasing the workload on the right ventricle. **Analysis of other options:** * **Morphine:** This is the **drug of choice** for pain relief in AMI. It provides potent analgesia, reduces anxiety (anxiolytic), and has beneficial hemodynamic effects, such as venodilation (reducing preload) and modest arterial dilation (reducing afterload), thereby decreasing myocardial oxygen demand. * **Methadone:** A long-acting μ-opioid agonist. While not the first line for AMI due to its long half-life and risk of QTc prolongation, it does not possess the sympathomimetic "pressor" effects seen with pentazocine. * **Buprenorphine:** A partial μ-agonist. While it can be used for severe pain, it is generally avoided in AMI because its effects are difficult to reverse with Naloxone, but it does not carry the same high risk of increasing cardiac workload as pentazocine. **High-Yield Clinical Pearls for NEET-PG:** * **MONA** mnemonic for AMI: **M**orphine, **O**xygen, **N**itroglycerin, **A**spirin. * **Pentazocine** should also be avoided in patients with heart failure for the same hemodynamic reasons. * **Naloxone** is the specific antagonist for opioid overdose, but higher doses may be required to reverse buprenorphine.

Q: Aspirin is contraindicated in which of the following conditions?

Peptic ulcer. **Explanation:** Aspirin (Acetylsalicylic acid) is a non-selective, irreversible inhibitor of the **Cyclooxygenase (COX)** enzymes. Its contraindication in peptic ulcer disease is rooted in its mechanism of action: 1. **Why Peptic Ulcer is Correct:** Aspirin inhibits **COX-1**, the constitutive enzyme responsible for synthesizing "housekeeping" prostaglandins (PGE2 and PGI2) in the gastric mucosa. These prostaglandins are vital for cytoprotection as they increase bicarbonate secretion, enhance mucosal blood flow, and stimulate mucus production. By inhibiting COX-1, Aspirin reduces these protective factors. Furthermore, as an organic acid, Aspirin exerts a direct irritant effect on the gastric lining, significantly increasing the risk of gastric erosions, ulceration, and GI bleeding. 2. **Why Other Options are Incorrect:** * **Fever & Myalgia:** Aspirin is an effective antipyretic and analgesic. It reduces fever by inhibiting PGE2 synthesis in the hypothalamus and relieves pain by blocking peripheral pain sensitization. (Note: It is avoided in children with viral fever to prevent Reye’s syndrome). * **Unstable Angina:** Aspirin is actually a **standard of care** here. At low doses (75–150 mg), it irreversibly inhibits thromboxane A2 (TXA2) in platelets, providing an anti-aggregatory effect that prevents coronary thrombosis. **High-Yield Clinical Pearls for NEET-PG:** * **Aspirin Triad (Samter’s Triad):** Asthma, Nasal polyposis, and Aspirin hypersensitivity. * **Zero-order Kinetics:** Aspirin follows zero-order elimination at high/toxic doses. * **Reye’s Syndrome:** Characterized by encephalopathy and fatty liver; occurs when Aspirin is given to children with viral infections (Varicella/Influenza). * **Toxicity:** Salicylism presents with **tinnitus** (earliest sign), respiratory alkalosis, and metabolic acidosis.

Q: Acute gouty arthritis is seen early in treatment following which medication?

All of the above. **Explanation:** The paradoxical precipitation of an **acute gouty attack** during the initiation of urate-lowering therapy (ULT) is a classic pharmacological phenomenon. This occurs due to the rapid fluctuation in serum uric acid levels, which leads to the mobilization and "shedding" of urate crystals from tissue stores (tophi) into the joint space, triggering an inflammatory response. **Breakdown of Options:** * **Allopurinol (Option B):** As a Xanthine Oxidase inhibitor, it lowers uric acid production. Rapid reduction in serum levels causes existing crystals to dissolve and fragment, precipitating acute inflammation. * **Probenecid (Option A):** This is a uricosuric agent that increases renal excretion of uric acid. Like Allopurinol, the sudden drop in serum urate can trigger a flare. * **Rasburicase (Option C):** This is a recombinant urate oxidase enzyme that rapidly converts uric acid into the highly soluble allantoin. Because it lowers uric acid levels much more aggressively than oral drugs, the risk of a flare is significant. **Why "All of the Above" is Correct:** Any drug that significantly alters the concentration of uric acid in the blood—whether by decreasing production (Allopurinol), increasing excretion (Probenecid), or direct metabolism (Rasburicase)—can destabilize intra-articular crystals and cause an acute attack early in treatment. **NEET-PG High-Yield Pearls:** * **Prophylaxis:** To prevent these early flares, ULT should always be co-administered with low-dose **Colchicine** or **NSAIDs** for the first 3–6 months. * **Timing:** Never start ULT during an ongoing acute attack; wait 2 weeks after the attack resolves. However, if a patient is already on ULT and an attack occurs, do **not** stop the medication. * **Drug of Choice:** Allopurinol is the first-line ULT for chronic gout, but **Febuxostat** is an alternative for those with renal impairment.

Q: Which of the following is an uricosuric drug?

Probenecid. **Explanation:** **Probenecid** is the correct answer because it is a classic **uricosuric agent**. Its primary mechanism of action involves the inhibition of the **URAT1 transporter** in the proximal convoluted tubule of the kidney. By blocking the reabsorption of filtered uric acid back into the blood, it increases the renal excretion of uric acid, thereby lowering serum urate levels. It is used in the chronic management of gout in patients who are "underexcretors." **Analysis of Incorrect Options:** * **Allopurinol (Option A):** 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 not classified as uricosuric. * **Indomethacin (Option B):** This is a potent **NSAID**. It is used to treat the *inflammation and pain* during an acute gouty attack but has no direct effect on uric acid levels or excretion. * **Aspirin (Option D):** At standard analgesic doses, aspirin actually **inhibits** uric acid excretion (hyperuricemic) and can worsen gout. While very high doses (>5g/day) are uricosuric, it is never used for this purpose due to toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **The "Aspirin Paradox":** Low-dose aspirin (1-2g/day) causes urate retention; high-dose aspirin (>5g/day) is uricosuric. * **Drug Interaction:** Probenecid inhibits the renal secretion of **Penicillin**, prolonging its half-life—a fact historically used to conserve penicillin supplies. * **Contraindication:** Uricosurics should be avoided in patients with a history of **renal stones** (nephrolithiasis) to prevent stone formation in the urinary tract. * **Other Uricosurics:** Sulfinpyrazone and Lesinurad. Benzbromarone is another potent uricosuric often mentioned in exams.

Q: A patient with a history of peptic ulcer disease presents with arthritis and develops carditis. Which of the following is the most appropriate anti-inflammatory drug?

Celecoxib. ***Celecoxib***- Celecoxib is a **selective COX-2 inhibitor**, meaning it primarily blocks the enzyme responsible for inflammation while largely preserving **COX-1** activity, which is crucial for gastric mucosal protection [2].- This selectivity significantly reduces the risk of **peptic ulcers** and gastrointestinal bleeding, making it the safest NSAID choice for patients with a history of **Peptic Ulcer Disease** (PUD) requiring treatment for arthritis and carditis [1].- **Note**: While COX-2 inhibitors carry cardiovascular risk warnings, in this clinical scenario (likely **rheumatic carditis** requiring anti-inflammatory therapy), celecoxib offers the best **risk-benefit profile** among NSAIDs by minimizing GI complications in a PUD patient [3]. Close cardiac monitoring is advised.*Ibuprofen*- Ibuprofen is a **non-selective NSAID** that inhibits both COX-1 and COX-2, leading to effective anti-inflammatory effects but also significant risk of **gastrointestinal (GI) toxicity**.- Inhibition of **COX-1** impairs the synthesis of protective mucosal prostaglandins, posing a high risk of ulcer recurrence or bleeding in patients with a PUD history [4].*Diclofenac*- Diclofenac is also a **non-selective NSAID** which carries a considerable risk of GI side effects by inhibiting **COX-1**, making it generally unsuitable for patients with pre-existing PUD.- Although sometimes exhibiting relative COX-2 preference compared to agents like naproxen, the GI risk remains high enough to warrant the use of a true COX-2 selective inhibitor like celecoxib in this high-risk patient [2].*Naloxone*- Naloxone is an **opioid receptor antagonist** used primarily to reverse the effects of opioid overdose; it has no **anti-inflammatory** properties.- This medication is completely irrelevant to the underlying inflammatory condition (arthritis and carditis) and the need for **pain and inflammation control**.

Q: A patient with osteoarthritis, for the last 3 months, has been taking ibuprofen and has developed occult GI bleeding. Which is correct about the cause?

PGE-2 and prostacyclin production were reduced. ***PGE-2 and prostacyclin production were reduced***- NSAIDs like **ibuprofen** inhibit cyclooxygenase-1 (**COX-1**), which is responsible for synthesizing protective prostaglandins like **PGE2** and **prostacyclin (PGI2)** in the GI mucosa.- The loss of these protective factors impairs the mucosal barrier's ability to withstand acid, leading to ulceration, erosion, and subsequent **occult GI bleeding**. *Increased acid production*- NSAIDs primarily cause mucosal injury by reducing protective factors, not by significantly increasing **basal acid production**.- Although excess acid facilitates damage, the core mechanism of NSAID injury is the loss of **prostaglandin-mediated cytoprotection**. *PGE-1 and prostacyclin production were reduced*- While **prostacyclin (PGI2)** reduction is key, **PGE2** (not PGE1) is the major endogenous prostaglandin responsible for maintaining gastric mucosal integrity in humans.- Misrepresenting the primary protective prostaglandin (PGE2 vs PGE1) makes this option medically less precise than the former. *Mucosal injury due to inhibition of COX-2*- The severe gastrointestinal side effects, including bleeding and ulceration, are predominantly due to the inhibition of the constitutive **COX-1 isoenzyme**.- Selective **COX-2 inhibitors** (coxibs) were specifically designed to minimize GI toxicity by sparing the protective functions of COX-1.

Q: Which of the following drugs increases uric acid in urine?

Probenecid. ***Probenecid***- This drug is a **uricosuric agent** that works by inhibiting the reabsorption of urate at the **proximal convoluted tubule** of the kidney.- By blocking reabsorption, **probenecid** promotes the excretion of uric acid into the urine, thereby reducing serum uric acid levels.*Colchicine*- *Colchicine* is primarily used for the management of **acute gout flares** and works by inhibiting neutrophil migration and subsequent inflammatory responses.- It does **not** significantly alter the renal handling of uric acid; therefore, it does not increase uric acid excretion in the urine.*Febuxostat*- *Febuxostat* is a **non-purine selective inhibitor of xanthine oxidase**, an enzyme required for uric acid synthesis.- Its mechanism is to **decrease the production** of uric acid by the body, thus lowering serum levels, rather than promoting its excretion in the urine.*Allopurinol*- *Allopurinol* is a **purine analog and a xanthine oxidase inhibitor** used for the prophylactic management of chronic gout.- Like Febuxostat, it acts to **decrease the synthesis** (production) of uric acid, contrasting with uricosuric agents which increase excretion.

Question 1

What is the most prominent toxic effect associated with acetaminophen use?

Accepted Answer

Hepatic necrosis

Answer

Respiratory alkalosis

Answer

Haemorrhage

Answer

Gastric Ulceration

Question 2

Which of the following analgesics should not be given in acute myocardial infarction?

Accepted Answer

Pentazocine

Answer

Methadone

Answer

Morphine

Answer

Buprenorphine

Question 3

A 44-year-old businessman presents with a markedly inflamed and painful right great toe. He reports increasing pain in his right foot during a recent flight home after a convention. Physical examination reveals swelling and erythema of the right great toe, along with small nodules on the external ears. Aspiration of the metatarsophalangeal joint of the affected toe shows needle-shaped, negatively birefringent crystals. Which of the following agents would provide the most immediate relief for this patient?

Accepted Answer

Colchicine

Answer

Allopurinol

Answer

Aspirin

Answer

Probenecid

Question 4

Aspirin is contraindicated in which of the following conditions?

Accepted Answer

Peptic ulcer

Answer

Fever

Answer

Unstable angina

Answer

Myalgia

Question 5

Gastric irritation is least with which of the following NSAIDs?

Accepted Answer

Acetaminophen

Answer

Diclofenac

Answer

Ibuprofen

Answer

Naproxen

Question 6

Acute gouty arthritis is seen early in treatment following which medication?

Accepted Answer

All of the above

Answer

Probenecid

Answer

Allopurinol

Answer

Rasburicase

Question 7

Which of the following is an uricosuric drug?

Accepted Answer

Probenecid

Answer

Allopurinol

Answer

Indomethacin

Answer

Aspirin

Question 8

A patient with a history of peptic ulcer disease presents with arthritis and develops carditis. Which of the following is the most appropriate anti-inflammatory drug?

Accepted Answer

Celecoxib

Answer

Diclofenac

Answer

Naloxone

Answer

Ibuprofen

Question 9

A patient with osteoarthritis, for the last 3 months, has been taking ibuprofen and has developed occult GI bleeding. Which is correct about the cause?

Accepted Answer

PGE-2 and prostacyclin production were reduced

Answer

PGE-1 and prostacyclin production were reduced

Answer

Increased acid production

Answer

Mucosal injury due to inhibition of COX-2

Question 10

Which of the following drugs increases uric acid in urine?

Accepted Answer

Probenecid

Answer

Allopurinol

Answer

Colchicine

Answer

Febuxostat

Analgesics and Anti-inflammatory Drugs — MCQs

Analgesics and Anti-inflammatory Drugs — MCQs

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