Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 391: Which of the following best describes the mechanism of action of monoclonal antibodies used in the treatment of rheumatoid arthritis?

A. Inhibition of T-cell activation
B. Blockade of IL-1 receptor
C. Inhibition of TNF-alpha (Correct Answer)
D. Stimulation of B-cell apoptosis

Explanation: ***Inhibition of TNF-alpha*** - Many monoclonal antibodies commonly used in rheumatoid arthritis, such as **infliximab** (Remicade) and **adalimumab** (Humira), specifically target and inhibit **TNF-alpha**. - **TNF-alpha** is a key pro-inflammatory cytokine that plays a central role in the **pathogenesis of rheumatoid arthritis**, promoting inflammation and joint destruction. *Inhibition of T-cell activation* - While T-cell activation is important in RA pathogenesis, specific monoclonal antibodies like **abatacept** (Orencia) work by inhibiting T-cell co-stimulation, rather than directly blocking activation in the same way TNF-alpha inhibitors work. - This mechanism is less broadly representative of the primary action of most monoclonal antibodies used in RA compared to TNF-alpha inhibition. *Blockade of IL-1 receptor* - **Anakinra** (Kineret) is a recombinant **IL-1 receptor antagonist** used in RA, but it is not a monoclonal antibody. - Although IL-1 is a pro-inflammatory cytokine, blocking its receptor is not the primary mechanism of action for the majority of monoclonal antibodies in RA therapy. *Stimulation of B-cell apoptosis* - **Rituximab** (Rituxan) is a monoclonal antibody that targets **CD20 on B-cells**, leading to their depletion, which can indeed induce a degree of B-cell apoptosis. - However, the primary effect is B-cell depletion, and while effective, it is not the most widespread or common mechanism of action for the broader class of monoclonal antibodies used in RA compared to TNF-alpha inhibition.

Question 392: A patient presents with gouty arthritis. Which drug inhibits the enzyme xanthine oxidase to lower uric acid levels?

A. Colchicine
B. Allopurinol (Correct Answer)
C. Indomethacin
D. Probenecid

Explanation: ***Allopurinol*** - **Allopurinol** is a **xanthine oxidase inhibitor** that blocks the conversion of hypoxanthine and xanthine to uric acid [1, 2]. - It is used for the **long-term management** of hyperuricemia in patients with gout [1, 2]. *Colchicine* - **Colchicine** is an **anti-inflammatory agent** that inhibits neutrophil chemotaxis and activation. - It is primarily used for the **acute treatment** of gout flares and **prophylaxis** against recurrent attacks [2, 3], but it does not lower uric acid levels. *Indomethacin* - **Indomethacin** is a **nonsteroidal anti-inflammatory drug (NSAID)** that inhibits prostaglandin synthesis. - It is commonly used for **acute pain relief and inflammation** during a gout attack [2] but does not affect uric acid production. *Probenecid* - **Probenecid** is a **uricosuric agent** that inhibits the reabsorption of uric acid in the renal tubules. - It increases the **excretion of uric acid** and is used in patients who underexcrete uric acid [2], but it does not inhibit xanthine oxidase.

Question 393: What is the best antagonist of morphine?

A. Buprenorphine
B. Naloxone (Correct Answer)
C. Pentazocine
D. Nalorphine

Explanation: ***Naloxone*** - **Naloxone** is a pure opioid antagonist with a high affinity for **mu-opioid receptors**, making it the most effective antidote for morphine overdose. - It rapidly reverses the effects of opioid agonists like morphine, including **respiratory depression** and sedation. *Pentazocine* - **Pentazocine** is an opioid agonist-antagonist, meaning it can produce both opioid effects and opioid reversal, but it is not a pure antagonist. - It has a risk of precipitating **opioid withdrawal** in opioid-dependent individuals and is not the first-line choice for reversing overdose. *Buprenorphine* - **Buprenorphine** is a partial mu-opioid agonist and kappa-opioid antagonist, also known as an agonist-antagonist. - While it has some antagonistic properties, its partial agonistic activity means it can still produce opioid effects and is not ideal for rapid reversal of full opioid agonists. *Nalorphine* - **Nalorphine** is an older opioid antagonist with mixed agonist-antagonist properties, similar to pentazocine. - It is less potent and has fallen out of favor compared to naloxone for reversing opioid overdose due to its own potential for **respiratory depression** and psychotomimetic effects.

Question 394: Which class of drugs inhibits the cyclooxygenase (COX) enzyme, thereby reducing prostaglandin synthesis and inflammation in conditions such as arthritis?

A. Corticosteroids
B. Opioids
C. Nonsteroidal anti-inflammatory drugs (Correct Answer)
D. Antiepileptics

Explanation: ***Nonsteroidal anti-inflammatory drugs*** - **NSAIDs** inhibit the **cyclooxygenase (COX) enzyme**, which is responsible for synthesizing **prostaglandins** from arachidonic acid. - By reducing prostaglandin synthesis, NSAIDs decrease **inflammation**, pain, and fever, making them effective in conditions like arthritis. *Corticosteroids* - **Corticosteroids** are potent anti-inflammatory drugs that act by inhibiting **phospholipase A2**, blocking the entire cascade of arachidonic acid metabolism, including both prostaglandins and leukotrienes. - They have broader immunosuppressive effects than NSAIDs but also carry a wider range of potential side effects with long-term use. *Opioids* - **Opioids** are powerful analgesics that work by binding to **opioid receptors** in the central nervous system, altering the perception of pain. - They do not directly inhibit **cyclooxygenase** or reduce **inflammation**, but rather provide symptomatic pain relief. *Antiepileptics* - **Antiepileptic drugs (AEDs)** primarily act on the central nervous system to reduce neuronal excitability and prevent seizures. - Some AEDs, like gabapentin or pregabalin, are also used for **neuropathic pain**, but they do not inhibit **COX enzymes** or reduce inflammation.

Question 395: A patient with rheumatoid arthritis is prescribed a disease-modifying antirheumatic drug (DMARD) that inhibits dihydroorotate dehydrogenase. Which drug is being used?

A. Methotrexate
B. Sulfasalazine
C. Leflunomide (Correct Answer)
D. Hydroxychloroquine

Explanation: ***Leflunomide*** - **Leflunomide** is an immunosuppressive DMARD that inhibits mitochondrial enzyme **dihydroorotate dehydrogenase**, an enzyme crucial for *de novo* pyrimidine synthesis. - This inhibition leads to a reduction in T-cell proliferation and cytokine production, making it effective in treating **rheumatoid arthritis**. *Methotrexate* - **Methotrexate** is a DMARD that primarily works by inhibiting **dihydrofolate reductase**, thus interfering with folate metabolism and purine synthesis. - Its mechanism is distinct from inhibiting dihydroorotate dehydrogenase and involves effects on various inflammatory pathways. *Sulfasalazine* - **Sulfasalazine** is an anti-inflammatory and immunomodulatory drug. Its mechanism of action in rheumatoid arthritis is not fully understood but involves metabolizing into **sulfapyridine** and **5-aminosalicylic acid**. - It does not directly inhibit dihydroorotate dehydrogenase; instead, it may modulate immune cell function and cytokine production. *Hydroxychloroquine* - **Hydroxychloroquine** is an antimalarial drug used in rheumatoid arthritis that inhibits **lysosomal activity** and antigen presentation, and modulates immune responses. - It does not target dihydroorotate dehydrogenase but rather interferes with intracellular signaling and cytokine release.

Question 396: A patient with severe cancer pain is on high-dose morphine but is experiencing uncontrolled pain and side effects. What is the best next step?

A. Switch to methadone for its NMDA receptor antagonism (Correct Answer)
B. Add a non-steroidal anti-inflammatory drug (NSAID)
C. Increase the morphine dose and monitor side effects
D. Discontinue morphine and switch to fentanyl

Explanation: ***Switch to methadone for its NMDA receptor antagonism*** - **Methadone** is a strong opioid analgesic with a unique pharmacological profile, including **NMDA receptor antagonism**, which can be particularly effective for **neuropathic pain** components often present in severe cancer pain. - Its **long half-life** and different receptor binding profile make it useful in patients who experience **opioid intolerance** or inadequate analgesia with other opioids like morphine. *Add a non-steroidal anti-inflammatory drug (NSAID)* - While NSAIDs can be useful for **mild to moderate pain** and some cancer pain (e.g., bone metastases), they are generally insufficient for **severe cancer pain** that is already uncontrolled on high-dose morphine. - NSAIDs have a **ceiling effect** for analgesia and carry significant side effect risks, such as **gastric ulcers** and **renal dysfunction**, especially in frail cancer patients. *Increase the morphine dose and monitor side effects* - The patient is already experiencing **uncontrolled pain and side effects** on high-dose morphine, indicating that simply increasing the dose further is likely to worsen side effects without providing adequate analgesia due to **opioid tolerance** or **opioid-induced hyperalgesia**. - This approach risks **toxicities** like somnolence, delirium, and respiratory depression without improving pain control. *Discontinue morphine and switch to fentanyl* - While **fentanyl** is a potent opioid, it primarily acts on mu-opioid receptors similar to morphine and may not offer a significant advantage for patients experiencing **opioid intolerance** or **uncontrolled pain** on high-dose morphine due to shared mechanisms. - Switching directly to another pure mu-opioid agonist without addressing the underlying issues of tolerance, side effects, or potential neuropathic pain components may not be the optimal next step, especially given **methadone's distinct advantages**.

Question 397: Which of the following is a naturally occurring opioid?

A. Morphine (Correct Answer)
B. Pholcodeine
C. Ethylmorphine
D. Diacetylmorphine

Explanation: ***Morphine*** - **Morphine** is a naturally occurring **opioid alkaloid** found in the **opium poppy** (Papaver somniferum). - It is one of the most potent **analgesics** and is widely used for severe pain. *Ethylmorphine* - **Ethylmorphine** is a **semisynthetic opioid** derived from morphine by **ethylation**. - It is currently used primarily as an **antitussive** (cough suppressant). *Pholcodeine* - **Pholcodeine** is a **semisynthetic opioid** that acts as a **cough suppressant**. - It works by depressing the **cough reflex** in the brainstem. *Diacetylmorphine* - **Diacetylmorphine**, commonly known as **heroin**, is a **semisynthetic opioid** synthesized from morphine. - It is highly potent and rapidly crosses the **blood-brain barrier**, producing intense effects.

Question 398: Which of the following is the most potent opioid?

A. Butorphanol
B. Pentazocine
C. Hydrocodone
D. Sufentanil (Correct Answer)

Explanation: ***Sufentanil*** - **Sufentanil** is a very potent synthetic opioid, estimated to be 5 to 10 times more potent than fentanyl and 500 to 1000 times more potent than morphine. - Its high potency is due to its strong binding affinity for **mu-opioid receptors** and rapid onset of action. *Butorphanol* - **Butorphanol** is a mixed opioid agonist-antagonist, acting as a partial agonist or antagonist at mu-opioid receptors and an agonist at kappa-opioid receptors. - While it provides analgesia, its efficacy is limited compared to full agonists due to its mixed receptor profile. *Pentazocine* - **Pentazocine** is another mixed opioid agonist-antagonist, primarily a kappa-opioid receptor agonist and a weak mu-opioid receptor antagonist or partial agonist. - It has a lower analgesic ceiling and can precipitate withdrawal in patients dependent on full mu-opioid agonists. *Hydrocodone* - **Hydrocodone** is an opioid agonist primarily used for moderate to severe pain, typically found in combination with acetaminophen. - Its potency is comparable to morphine, making it significantly less potent than ultra-potent synthetic opioids like sufentanil.

Question 399: Anti-inflammatory actions of corticosteroids are mediated by?

A. By inhibiting the production of inflammatory mediators derived from phospholipids (Correct Answer)
B. By inhibiting angiogenesis and reducing inflammation
C. By promoting vascular stability
D. By enhancing tissue repair mechanisms

Explanation: ***By inhibiting the production of inflammatory mediators derived from phospholipids*** - Corticosteroids act by inducing the synthesis of **lipocortin (annexin-1)**, which inhibits **phospholipase A2**. - This inhibition prevents the release of **arachidonic acid** from cell membrane phospholipids, thereby blocking the synthesis of potent inflammatory mediators like **prostaglandins** and **leukotrienes**. *By inhibiting angiogenesis and reducing inflammation* - While corticosteroids can have some anti-angiogenic effects at higher doses or in specific contexts, this is not their primary or most significant mechanism for immediate anti-inflammatory action. - The main anti-inflammatory effect is mediated through the direct suppression of inflammatory molecule synthesis, not primarily by inhibiting new blood vessel formation. *By promoting vascular stability* - Corticosteroids can transiently **stabilize capillaries** and reduce vascular permeability, which contributes to a reduction in edema. - However, this is a secondary effect and not the primary mechanism behind their broad anti-inflammatory actions compared to their inhibition of inflammatory mediator synthesis. *By enhancing tissue repair mechanisms* - Corticosteroids generally **impair** wound healing and tissue repair processes by suppressing fibroblast activity, collagen synthesis, and cell proliferation. - They are known to delay healing, not enhance it, making this statement incorrect in the context of their primary anti-inflammatory mechanism.

Question 400: Which of the following statements about local anesthetics is FALSE?

A. Lidocaine is shorter acting than bupivacaine
B. Prilocaine is less toxic than lignocaine (Correct Answer)
C. Mixture of lignocaine and prilocaine is known as eutectic
D. Lignocaine is used as an antiarrhythmic

Explanation: ***Prilocaine is less toxic than lignocaine*** - This statement is **false**. While prilocaine has a lower incidence of central nervous system (CNS) toxicity compared to lidocaine, it is associated with a higher risk of **methemoglobinemia**, especially at higher doses, which makes it potentially more toxic in specific scenarios. - Overall, the safety profile of prilocaine, particularly regarding its potential for methemoglobinemia, does not necessarily make it "less toxic" than lignocaine; they have different toxicity profiles. *Lidocaine is shorter acting than bupivacaine* - This statement is **true**. **Lidocaine** is an intermediate-acting local anesthetic, with a duration of action typically ranging from 30 minutes to 3 hours, depending on the dose and presence of a vasoconstrictor. - **Bupivacaine** is a long-acting local anesthetic, with effects lasting 4-8 hours due to its high lipid solubility and protein binding. *Mixture of lignocaine and prilocaine is known as eutectic* - This statement is **true**. A mixture of lidocaine (lignocaine) and prilocaine is known as an **Eutectic Mixture of Local Anesthetics (EMLA)**. - The word "eutectic" refers to the specific proportion of these two substances that results in a lower melting point than either drug individually, allowing them to exist as a liquid at room temperature. This formulation is used for topical anesthesia. *Lignocaine is used as an antiarrhythmic* - This statement is **true**. **Lidocaine (lignocaine)** is a **Class IB antiarrhythmic** drug. - It works by blocking cardiac sodium channels, thereby stabilizing the myocardial cell membrane and decreasing automaticity, making it effective in treating ventricular arrhythmias, especially after myocardial infarction.

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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