Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 201: Which of the following actions is ascribed to delta type of opioid receptors?

A. Supraspinal analgesia (Correct Answer)
B. Respiratory depression
C. Euphoria
D. Reduced intestinal motility

Explanation: Opioid receptors are G-protein coupled receptors (GPCRs) categorized into three main types: **Mu (μ), Kappa (κ), and Delta (δ)**. Understanding their distinct physiological effects is high-yield for NEET-PG. ### **Explanation of the Correct Option** **A. Supraspinal analgesia:** Delta (δ) receptors are primarily located in the pontine nuclei, amygdala, and deep layers of the cerebral cortex. Their activation leads to both **supraspinal and spinal analgesia**. While Mu receptors are the primary mediators of analgesia, Delta receptors play a significant modulatory role, particularly in chronic pain states. ### **Explanation of Incorrect Options** * **B. Respiratory depression:** This is a classic side effect primarily mediated by **Mu (μ₂)** receptors. Activation of Mu receptors in the brainstem respiratory centers decreases responsiveness to CO₂. * **C. Euphoria:** This is predominantly associated with **Mu (μ)** receptor activation. In contrast, Kappa (κ) receptor activation often leads to the opposite effect—dysphoria and hallucinations. * **D. Reduced intestinal motility:** Constipation is mediated by **Mu (μ₂)** receptors located in the myenteric plexus of the gastrointestinal tract. ### **High-Yield Clinical Pearls for NEET-PG** * **Mu (μ):** Responsible for most clinical effects—Supraspinal analgesia (μ₁), Respiratory depression, Constipation, Euphoria, and Physical dependence (μ₂). * **Kappa (κ):** Responsible for Spinal analgesia, Miosis (pin-point pupil), and Dysphoria. * **Delta (δ):** Responsible for Supraspinal/Spinal analgesia and potentially modulating emotional responses (Anxiolysis). * **Pure Antagonist:** **Naloxone** and **Naltrexone** antagonize all three receptor types (Mu, Kappa, and Delta). * **Endogenous Ligands:** Enkephalins have the highest affinity for **Delta** receptors, Endorphins for **Mu**, and Dynorphins for **Kappa**.

Question 202: Which of the following drugs can cause aseptic meningitis?

A. Indomethacin
B. Ibuprofen (Correct Answer)
C. Aspirin
D. Icatibant

Explanation: **Explanation:** **Drug-Induced Aseptic Meningitis (DIAM)** is a rare but well-documented hypersensitivity reaction. Among the options provided, **Ibuprofen** is the most common pharmacological trigger for this condition. 1. **Why Ibuprofen is Correct:** Ibuprofen is the leading cause of NSAID-induced aseptic meningitis. It is believed to be a **Type III or Type IV hypersensitivity reaction** rather than direct toxicity. It occurs most frequently in patients with underlying autoimmune conditions, particularly **Systemic Lupus Erythematosus (SLE)** and Mixed Connective Tissue Disease (MCTD), though it can occur in healthy individuals. Symptoms typically include fever, headache, neck stiffness, and altered mental status, resolving rapidly upon drug discontinuation. 2. **Analysis of Incorrect Options:** * **Indomethacin:** While an NSAID, it is more commonly associated with severe frontal headaches and GI disturbances rather than aseptic meningitis. * **Aspirin:** Though it can cause Reye’s syndrome in children and salicylism (tinnitus/vertigo), it is not a classic cause of aseptic meningitis. * **Icatibant:** This is a selective **Bradykinin B2 receptor antagonist** used in the treatment of acute attacks of Hereditary Angioedema (HAE). It does not cross the blood-brain barrier to cause meningeal inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Common triggers for DIAM:** NSAIDs (Ibuprofen, Naproxen), Antimicrobials (Trimethoprim-Sulfamethoxazole), and IV Immunoglobulins (IVIG). * **CSF Findings in DIAM:** Pleocytosis (predominantly neutrophils), elevated protein, and **normal glucose levels** (distinguishing it from bacterial meningitis). * **Classic Association:** Always suspect Ibuprofen-induced meningitis in a patient with **SLE** presenting with meningeal signs and negative cultures.

Question 203: Which among the following anti-gout drugs can precipitate an attack of acute gouty arthritis?

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

Explanation: ### Explanation **Correct Answer: C. Allopurinol** **Mechanism of Precipitation:** Allopurinol is a **Xanthine Oxidase Inhibitor** used for the chronic management of gout [1,2]. When initiated, it causes a rapid reduction in serum uric acid levels. This sudden drop leads to the **mobilization of urate crystals** from tissue stores (tophi) into the joint space. These "shed" crystals trigger an inflammatory response, paradoxically precipitating an acute gouty flare. To prevent this, Allopurinol should never be started during an acute attack and should always be co-administered with low-dose Colchicine or NSAIDs for the first 3–6 months [2,3]. **Analysis of Incorrect Options:** * **A. Colchicine:** This is the drug of choice for **terminating** an acute attack. It works by binding to tubulin, inhibiting neutrophil migration and phagocytosis. It does not lower serum uric acid and therefore does not cause crystal mobilization. * **B. Probenecid & D. Sulfinpyrazone:** These are **Uricosuric agents** that inhibit the URAT-1 transporter in the proximal tubule to increase uric acid excretion. While they can theoretically cause flares, **Allopurinol** is the classic and most common culprit cited in exams due to its potent effect on total body urate stores. **High-Yield Clinical Pearls for NEET-PG:** * **The "Wait" Rule:** Never start Allopurinol during an acute attack; wait 2–4 weeks after the inflammation has subsided [2]. * **HLA-B*5801:** Screening for this allele is recommended in certain populations (e.g., Han Chinese, Thai) before starting Allopurinol to prevent **Stevens-Johnson Syndrome (SJS)/Toxic Epidermal Necrolysis (TEN).** * **Drug Interaction:** Allopurinol inhibits the metabolism of **6-Mercaptopurine and Azathioprine**, necessitating a dose reduction of these drugs by 75%.

Question 204: Which analgesic can itself cause headache as a side effect?

A. Indomethacin (Correct Answer)
B. Mefenamic acid
C. Piroxicam
D. Aspirin

Explanation: **Explanation:** **Indomethacin** is a potent, non-selective COX inhibitor known for its high incidence of adverse effects, occurring in approximately 35–50% of patients. The most characteristic side effect is a **frontal headache**, which occurs in up to 25% of chronic users. 1. **Why Indomethacin is correct:** The mechanism behind the "Indomethacin headache" is thought to be related to its chemical structure (an indole derivative) which is similar to serotonin. It can cause cerebral vasoconstriction or direct CNS toxicity. This headache is often accompanied by dizziness, vertigo, and confusion, a cluster of symptoms sometimes referred to as "Indomethacin-induced CNS toxicity." 2. **Why other options are incorrect:** * **Mefenamic acid:** Primarily used for dysmenorrhea; its most notable side effects are diarrhea and hemolytic anemia, not headaches. * **Piroxicam:** An oxicam derivative with a long half-life. Its main toxicity is a high risk of GI ulceration and skin reactions (Stevens-Johnson Syndrome). * **Aspirin:** While aspirin overdose causes **Salicylism** (tinnitus, dizziness, hyperventilation), it is actually a primary treatment for headaches rather than a common cause of them. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Indomethacin is the DOC for **Ankylosing Spondylitis**, **Bartter Syndrome**, and **Acute Gout**. * **PDA:** It is used to medically close a Patent Ductus Arteriosus in neonates. * **Contraindication:** Due to its high CNS side effect profile, it should be avoided in patients with epilepsy, psychosis, or Parkinsonism. * **Memory Aid:** Remember "Indo-**meth**-acin" affects the "**head**" (CNS).

Question 205: Leflunomide acts on which of the following pathways?

A. Purine synthesis
B. Pyrimidine synthesis (Correct Answer)
C. Cell membrane synthesis
D. None of the above

Explanation: **Explanation:** **Leflunomide** is a Disease-Modifying Antirheumatic Drug (DMARD) primarily used in the treatment of Rheumatoid Arthritis. **Why Option B is Correct:** Leflunomide is a prodrug that is converted into its active metabolite, **A77 1726 (Teriflunomide)**. This metabolite acts by inhibiting the mitochondrial enzyme **Dihydroorotate Dehydrogenase (DHODH)**. This enzyme is critical for the **de novo synthesis of pyrimidines** (specifically UMP). By depleting intracellular pyrimidine pools, Leflunomide causes G1 cell cycle arrest in rapidly proliferating T-cells, thereby suppressing the autoimmune response. **Why Other Options are Incorrect:** * **Option A (Purine Synthesis):** Drugs like **Methotrexate** (inhibits dihydrofolate reductase), **Azathioprine**, and **Mycophenolate Mofetil** (inhibits IMPDH) primarily interfere with purine synthesis. Leflunomide specifically targets the pyrimidine pathway. * **Option C (Cell Membrane Synthesis):** This is the mechanism of action for various antibiotics (like Beta-lactams) or antifungals (like Polyenes/Azoles), but it is not relevant to the mechanism of DMARDs. **High-Yield Clinical Pearls for NEET-PG:** * **Loading Dose:** Leflunomide has a very long half-life (~2 weeks); hence, a loading dose is often used to achieve steady-state levels quickly. * **Enterohepatic Circulation:** It undergoes significant enterohepatic circulation. * **Washout Procedure:** In cases of toxicity or planned pregnancy, **Cholestyramine** is administered to enhance drug elimination by interrupting enterohepatic recycling. * **Contraindication:** It is highly **teratogenic** (Category X) and contraindicated in pregnancy. * **Side Effects:** Hepatotoxicity (monitor LFTs) and alopecia are common.

Question 206: All of the following are opioid agonist-antagonist compounds EXCEPT?

A. Buprenorphine
B. Nalbuphine
C. Pentazocine
D. Papaverine (Correct Answer)

Explanation: ### Explanation The question asks to identify the drug that is **not** an opioid agonist-antagonist. **1. Why Papaverine is the Correct Answer:** Papaverine is a **benzylisoquinoline alkaloid** derived from the opium poppy, but it is **not** an opioid analgesic. It does not act on opioid receptors ($\mu, \kappa, \delta$). Instead, it is a direct-acting **smooth muscle relaxant** and a non-selective **phosphodiesterase (PDE) inhibitor**. * **Mechanism:** It increases intracellular cAMP/cGMP levels, leading to vasodilation. * **Clinical Use:** Historically used for erectile dysfunction (intracavernosal injection) and to treat vasospasm (e.g., during neurosurgery). **2. Why the Other Options are Incorrect:** Options A, B, and C are classic examples of **Mixed Agonist-Antagonists** (or partial agonists): * **Buprenorphine:** A **Partial $\mu$-agonist** and $\kappa$-antagonist. It has a high affinity for $\mu$-receptors but low intrinsic activity, leading to a "ceiling effect" for respiratory depression. * **Nalbuphine:** A **$\kappa$-agonist** and **$\mu$-antagonist**. It is often used for obstetric analgesia and to treat opioid-induced pruritus. * **Pentazocine:** A **$\kappa$-agonist** and **weak $\mu$-antagonist/partial agonist**. It is known for causing dysphoria and psychotomimetic effects (due to $\kappa$ and $\sigma$ receptor activation). **3. High-Yield Clinical Pearls for NEET-PG:** * **Ceiling Effect:** Mixed agonist-antagonists (like Buprenorphine) exhibit a ceiling effect, where increasing the dose beyond a point does not increase the clinical effect but may increase side effects. * **Precipitated Withdrawal:** If a mixed agonist-antagonist is given to a patient already dependent on a pure $\mu$-agonist (like Morphine), it can displace the morphine and precipitate **acute withdrawal symptoms**. * **Papaverine vs. Papaveretum:** Do not confuse Papaverine (vasodilator) with Papaveretum (a mixture of opium alkaloids containing morphine, codeine, and papaverine).

Question 207: All of the following drugs are used in the treatment of acute gout, EXCEPT:

A. Aspirin
B. Naproxen
C. Allopurinol (Correct Answer)
D. Colchicine

Explanation: ### Explanation The management of gout is divided into two distinct phases: **Acute management** (to reduce inflammation and pain) and **Chronic management** (to lower serum uric acid levels). **Why Allopurinol is the Correct Answer:** Allopurinol is a **Xanthine Oxidase Inhibitor** used for the long-term prophylaxis of gout. It is **contraindicated during an acute attack** for two reasons: 1. It has no analgesic or anti-inflammatory properties. 2. A rapid reduction in serum urate levels can cause the mobilization of urate crystals from joint tissues, paradoxically **precipitating or worsening** an acute flare-up. It should only be started 2–4 weeks after the acute inflammation has completely subsided. **Analysis of Incorrect Options:** * **Aspirin:** While NSAIDs are first-line for acute gout, **low-dose aspirin** is generally avoided because it inhibits uric acid excretion in the renal tubules (hyperuricemia). However, in the context of this question, Allopurinol is the "more correct" exception as it is strictly a prophylactic drug, whereas high-dose salicylates were historically used for their uricosuric effects. * **Naproxen:** NSAIDs (like Naproxen, Indomethacin, or Celecoxib) are the **first-line agents** for acute gout to inhibit prostaglandin synthesis and reduce inflammation. * **Colchicine:** This is the drug of choice for patients who cannot tolerate NSAIDs. It works by binding to tubulin, inhibiting neutrophil migration and phagocytosis within the joint. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for Acute Gout:** NSAIDs (specifically Indomethacin or Naproxen). * **DOC for Chronic Gout (Overproducers):** Allopurinol (Febuxostat is an alternative). * **Colchicine Toxicity:** Limited by GI side effects (diarrhea). It is most effective if started within 24–48 hours of symptom onset. * **HLA-B*5801:** Testing is recommended in certain ethnicities before starting Allopurinol to prevent Stevens-Johnson Syndrome (SJS).

Question 208: Morphine is used in the treatment of which one of the following conditions?

A. Asthma
B. Kyphoscoliosis
C. Chronic cor pulmonale
D. Left ventricular failure (Correct Answer)

Explanation: **Explanation:** Morphine is a cornerstone in the management of **Acute Left Ventricular Failure (LVF)** and acute pulmonary edema [1]. Its therapeutic benefit is derived from several key pharmacological actions: 1. **Venodilation:** Morphine increases peripheral venous capacitance (venodilator effect), which reduces **preload**. This decreases the workload on the failing heart and relieves pulmonary congestion. 2. **Arteriodilation:** It reduces systemic vascular resistance (**afterload**), further improving cardiac output. 3. **Anxiolysis:** By relieving the intense anxiety and "air hunger" associated with dyspnea, it reduces sympathetic overactivity [1]. 4. **Respiratory Depression:** It reduces the tachypnea and the work of breathing, making the patient’s respiratory effort more efficient [1]. **Why the other options are incorrect:** * **Asthma:** Morphine is strictly **contraindicated** in bronchial asthma because it triggers histamine release from mast cells, leading to bronchoconstriction. Furthermore, its respiratory depressant effect can be fatal during an acute attack. * **Kyphoscoliosis & Chronic Cor Pulmonale:** These conditions are characterized by a diminished respiratory reserve and chronic hypercapnia. Morphine suppresses the respiratory center and can precipitate acute respiratory failure in these patients [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Specific Antidote:** Naloxone is the drug of choice for morphine poisoning. * **Miosis:** Morphine causes "pin-point pupils" via stimulation of the Edinger-Westphal nucleus (tolerance does not develop to this effect). * **Biliary Colic:** Morphine is generally avoided in biliary colic as it causes spasm of the **Sphincter of Oddi** (Pentazocine or Buprenorphine are preferred). * **Contraindications:** Head injury (increases ICP), Undiagnosed abdominal pain, and Hypothyroidism.

Question 209: Abatacept is a new drug approved for which of the following conditions?

A. Systemic Lupus Erythematosus (SLE)
B. Rheumatoid Arthritis (Correct Answer)
C. Sjogren Syndrome
D. Scleroderma

Explanation: **Explanation:** **Abatacept** is a selective T-cell costimulation modulator. Its mechanism of action involves binding to **CD80 and CD86** on antigen-presenting cells (APCs). By doing so, it blocks the interaction with **CD28** on T-cells, which is the "second signal" required for T-cell activation. Without this costimulatory signal, T-cells cannot become fully activated, thereby reducing the inflammatory cascade in the synovium. * **Why Rheumatoid Arthritis (RA) is correct:** Abatacept is FDA-approved for the treatment of moderate-to-severe RA in patients who have had an inadequate response to conventional DMARDs (like Methotrexate) or TNF-inhibitors. It is also used in Juvenile Idiopathic Arthritis (JIA) and Psoriatic Arthritis. * **Why other options are incorrect:** While SLE, Sjogren’s, and Scleroderma are autoimmune conditions, Abatacept is not a first-line or standard approved therapy for them. Clinical trials for Abatacept in SLE and Sjogren’s have largely failed to meet primary endpoints or remain experimental. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mechanism:** It is a fusion protein consisting of the extracellular domain of **CTLA-4** fused to the Fc portion of human IgG1. 2. **Contraindication:** It should **not** be used concurrently with TNF-alpha inhibitors (e.g., Etanercept, Infliximab) due to an increased risk of serious infections. 3. **Screening:** Patients must be screened for **Latent Tuberculosis** and Hepatitis B before starting therapy, similar to other biological DMARDs. 4. **Mnemonic:** "Abata-**C**ept blocks **C**D80/86" (The **C**TLA-4 component).

Question 210: Which organ system is adversely affected by NSAIDs?

A. Bone
B. Kidney
C. Liver
D. Stomach (Correct Answer)

Explanation: **Explanation:** The primary mechanism of action of Non-Steroidal Anti-inflammatory Drugs (NSAIDs) is the inhibition of the enzyme **Cyclooxygenase (COX)**. In the stomach, the **COX-1** isoenzyme is responsible for synthesizing "housekeeping" prostaglandins (PGE2 and PGI2). These prostaglandins are vital for gastric mucosal protection as they increase bicarbonate secretion, enhance mucus production, and maintain mucosal blood flow. By inhibiting COX-1, NSAIDs deplete these protective factors, leading to gastric erosions, peptic ulcers, and gastrointestinal bleeding. This makes the **Stomach** the most common and clinically significant organ system adversely affected. **Analysis of Incorrect Options:** * **Bone:** NSAIDs generally do not have a direct adverse effect on bone health. In fact, they are frequently used to manage pain in bony conditions like osteoarthritis. * **Kidney:** While NSAIDs can cause nephrotoxicity (e.g., acute tubular necrosis or interstitial nephritis) by reducing renal blood flow, the incidence is lower compared to gastric complications. * **Liver:** Hepatotoxicity (e.g., with Paracetamol overdose or idiosyncratic reactions with Diclofenac) occurs, but it is not the most characteristic or frequent adverse effect of the NSAID class as a whole. **NEET-PG High-Yield Pearls:** * **Misoprostol:** A PGE1 analogue used specifically to prevent NSAID-induced gastric ulcers. * **Selective COX-2 Inhibitors (Celecoxib):** Developed to reduce gastric toxicity but associated with increased cardiovascular risks (pro-thrombotic state). * **Aspirin Sensitivity:** NSAIDs can trigger "Aspirin-Exacerbated Respiratory Disease" (AERD) or Samter’s Triad (Asthma, Nasal polyps, and NSAID sensitivity) due to the shunting of arachidonic acid to the leukotriene pathway.

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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