Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 281: Which of the following drugs is NOT a centrally acting antagonist used in opioid dependency?

A. naloxone
B. nalmefene
C. naldemedine (Correct Answer)
D. naltrexone

Explanation: ### Explanation The key to answering this question lies in distinguishing between **centrally acting** and **peripherally acting** opioid antagonists. **1. Why Naldemedine is the correct answer:** Naldemedine is a **PAMORA** (Peripherally Acting Mu-Opioid Receptor Antagonist). It is chemically modified (by adding a side chain) to prevent it from crossing the blood-brain barrier (BBB) [4]. Because it acts only on receptors in the gastrointestinal tract without reversing central analgesia or affecting dependency, it is used specifically for **Opioid-Induced Constipation (OIC)**. It has no role in treating opioid dependency or overdose. **2. Analysis of Incorrect Options:** * **Naloxone (A):** A competitive antagonist at all opioid receptors. It crosses the BBB rapidly but has poor oral bioavailability [1]. It is the drug of choice for **acute opioid overdose** [3]. Additionally, in opioid-dependent patients, it precipitates a withdrawal syndrome [2]. * **Naltrexone (D):** A long-acting central antagonist with good oral bioavailability. It is primarily used for **relapse prevention** in opioid and alcohol dependency [4]. * **Nalmefene (B):** Similar to naltrexone but with a longer half-life [1]. It is used for treating alcohol dependence and, in some regions, opioid overdose [4]. **3. NEET-PG High-Yield Pearls:** * **PAMORAs:** Remember the "3 M's and an N" for Opioid-Induced Constipation: **M**ethylnaltrexone, **M**ovantik (Naloxegol), **M**aluby (Naldemedine), and **A**lvimopan. * **Alvimopan** is specifically used to accelerate bowel recovery after major surgery (Post-operative ileus). * **Naltrexone** is also FDA-approved for **Alcohol Use Disorder** as it reduces the "reward" or craving by blocking endogenous opioid release. * **Naloxone** is often combined with Buprenorphine (Suboxone) to prevent intravenous abuse of the oral formulation [5].

Question 282: Which of the following is NOT used in the acute management of gout?

A. Allopurinol (Correct Answer)
B. NSAIDs
C. Corticosteroids
D. Colchicine

Explanation: The management of gout is divided into two distinct phases: **Acute Attack Management** (to reduce inflammation) and **Chronic Prophylaxis** (to lower serum uric acid). ### 1. Why Allopurinol is the Correct Answer **Allopurinol** is a xanthine oxidase inhibitor used for **hypouricemic therapy**. It is contraindicated during an acute attack because a rapid fluctuation in serum urate levels can cause the mobilization of urate crystals from tissue stores into the joint space, potentially **worsening or prolonging the acute inflammation**. It should only be started 2–4 weeks after the acute episode has completely resolved. ### 2. Analysis of Incorrect Options * **NSAIDs (e.g., Indomethacin, Naproxen):** These are the first-line agents for acute gout. They work by inhibiting prostaglandin synthesis, thereby reducing pain and inflammation. * **Corticosteroids (e.g., Prednisolone):** Used when NSAIDs or Colchicine are contraindicated (e.g., renal failure). They can be administered orally, intravenously, or intra-articularly. * **Colchicine:** A specific anti-gout drug that inhibits microtubule polymerization and leukocyte migration. It is highly effective if started within 24–36 hours of symptom onset. ### 3. NEET-PG High-Yield Pearls * **Drug of Choice (DOC):** NSAIDs are generally the DOC for acute gout; however, if the patient has peptic ulcer disease or renal insufficiency, **Corticosteroids** are preferred. * **The "Allopurinol Paradox":** If a patient is *already* on Allopurinol when an acute attack starts, do **not** stop it. If they are not on it, do **not** start it. * **Febuxostat:** Another xanthine oxidase inhibitor used for chronic management, preferred in patients with mild-to-moderate renal impairment. * **Aspirin:** Avoid in gout as low doses inhibit uric acid excretion in the tubules, worsening hyperuricemia.

Question 283: Pure opiate antagonists are all of the following except:

A. Naloxone
B. Nalorphine (Correct Answer)
C. Nalmefene
D. Naltrexone

Explanation: **Explanation:** The classification of opioid ligands is based on their activity at the opioid receptors ($\mu$, $\kappa$, and $\delta$). **1. Why Nalorphine is the correct answer:** Nalorphine is a **mixed agonist-antagonist**, not a pure antagonist. It acts as a competitive antagonist at $\mu$ receptors but exhibits partial agonist activity at $\kappa$ receptors. Because it possesses intrinsic agonistic activity, it can induce side effects like dysphoria and hallucinations, and it may even cause respiratory depression in opioid-naive individuals. Therefore, it is not classified as a "pure" antagonist. **2. Why the other options are incorrect:** * **Naloxone (A):** A pure competitive antagonist at $\mu$, $\kappa$, and $\delta$ receptors with no intrinsic activity. It is the drug of choice for acute opioid poisoning due to its rapid onset (given IV). * **Naltrexone (D):** A pure antagonist similar to naloxone but with higher oral bioavailability and a significantly longer half-life. It is primarily used for maintenance therapy in opioid addicts and for reducing alcohol cravings. * **Nalmefene (C):** A newer pure opioid antagonist. Like naltrexone, it is orally active and has a long half-life, used in managing alcohol dependence. **High-Yield Clinical Pearls for NEET-PG:** * **Pure Antagonists:** Naloxone, Naltrexone, Nalmefene (Mnemonic: The "**Nal-**" drugs without an "**-orph-**" in the middle). * **Mixed Agonist-Antagonists:** Nalorphine, Pentazocine, Butorphanol, Nalbuphine. * **Naloxone Challenge:** Used to diagnose physical dependence before starting naltrexone. * **Methylnaltrexone/Alvimopan:** Peripheral $\mu$-antagonists used to treat opioid-induced constipation without reversing analgesia.

Question 284: Naloxone for opioid receptor acts as:

A. Pure agonist
B. Pure antagonist (Correct Answer)
C. Partial agonist
D. Agonist antagonist

Explanation: **Naloxone** is the prototype **pure opioid antagonist** [1, 2]. It has a high affinity for all three opioid receptors (μ, κ, and δ) but lacks intrinsic activity [1]. It works by competitively displacing opioids from their receptors, thereby reversing all opioid effects, including respiratory depression and sedation [1].* **Why Option B is Correct:** Naloxone is a "pure" antagonist because it produces no pharmacological effect of its own when administered alone [1]. It only acts in the presence of an agonist (like Morphine or Heroin) to block or reverse its action.* **Why Option A is Incorrect:** A pure agonist (e.g., Morphine, Fentanyl) binds to the receptor and produces a maximal functional response.* **Why Option C is Incorrect:** A partial agonist (e.g., Buprenorphine) binds to the receptor but produces a sub-maximal response even at high doses [3].* **Why Option D is Incorrect:** Agonist-antagonists (e.g., Pentazocine, Nalbuphine) act as an agonist at one receptor (usually κ) and an antagonist at another (usually μ).**High-Yield Clinical Pearls for NEET-PG:**1. **Drug of Choice:** Naloxone is the DOC for **acute opioid poisoning** [1].2. **Pharmacokinetics:** It has a very short duration of action (30–90 minutes) and poor oral bioavailability due to extensive first-pass metabolism; hence, it is given IV/IM/Intranasal.3. **Naltrexone vs. Naloxone:** Unlike Naloxone, **Naltrexone** is orally active and long-acting, making it the drug of choice for **preventing relapse** in detoxified opioid addicts and for treating alcohol dependence.4. **Methylnaltrexone:** A peripheral μ-antagonist used specifically for opioid-induced constipation without reversing analgesia [1].

Question 285: Which of the following drugs can cause oligospermia?

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

Explanation: **Explanation:** **Correct Option: A. Methotrexate** Methotrexate (MTX) is a folic acid antagonist that inhibits the enzyme **dihydrofolate reductase (DHFR)**. This inhibition leads to a depletion of tetrahydrofolate, which is essential for DNA synthesis and cell division. Because spermatogenesis is a process involving rapid cellular proliferation, the testes are highly sensitive to the cytotoxic effects of MTX. It can cause **oligospermia** (low sperm count), reversible infertility, and chromosomal damage in sperm. Clinically, male patients are advised to discontinue MTX at least 3 months before attempting conception. **Analysis of Incorrect Options:** * **B. Hydroxychloroquine:** This is an antimalarial and DMARD used in SLE and RA. It is generally considered safe regarding male fertility and is one of the few DMARDs safe during pregnancy. * **C. Leflunomide:** This drug inhibits **dihydroorotate dehydrogenase**, affecting pyrimidine synthesis. While it is highly teratogenic (Category X) and requires a "washout" procedure with cholestyramine, it is not a classic cause of oligospermia compared to MTX. * **D. D-penicillamine:** A chelating agent used in Wilson’s disease and formerly in RA. Its primary side effects include nephrotic syndrome, pemphigus, and myasthenia-like syndrome, but not oligospermia. **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing oligospermia:** Sulfasalazine (very common high-yield fact), Cyclophosphamide (can cause permanent azoospermia), Cimetidine, and Anabolic steroids. * **Sulfasalazine vs. Methotrexate:** Sulfasalazine-induced oligospermia is typically reversible within 2–3 months of discontinuation. * **Rescue Therapy:** Leucovorin (folinic acid) is used to "rescue" normal cells from MTX toxicity but does not always prevent gonadal impact.

Question 286: Which physiological effect is NOT produced by stimulation of the Kappa opioid receptor?

A. Sedation
B. Diuresis
C. Miosis
D. Constipation (Correct Answer)

Explanation: **Explanation:** The correct answer is **Constipation**. While constipation is a hallmark side effect of opioid analgesics, it is primarily mediated by **Mu (μ) receptors** located in the gastrointestinal tract, which decrease motility. Stimulation of **Kappa (κ) receptors** has a negligible effect on bowel motility. **Analysis of Options:** * **Sedation (A):** Kappa receptor stimulation produces significant sedation and dysphoria. Unlike Mu-mediated euphoria, Kappa agonists often cause a "flat" or unpleasant sedative effect. * **Diuresis (B):** This is a high-yield distinction. While Mu receptors cause urinary retention (by increasing sphincter tone), Kappa receptors **inhibit the release of ADH (Vasopressin)** at the posterior pituitary, leading to free water clearance and diuresis. * **Miosis (C):** Both Mu and Kappa receptors contribute to pupillary constriction (miosis) via the stimulation of the Edinger-Westphal nucleus. * **Constipation (D):** As noted, this is a Mu-receptor-mediated effect. Kappa agonists do not significantly delay gastric emptying or cause constipation. **Clinical Pearls for NEET-PG:** * **Receptor Triad:** Remember the "Big Three": **Mu** (Analgesia, Euphoria, Respiratory Depression, Constipation), **Kappa** (Analgesia, Dysphoria, Diuresis, Sedation), and **Delta** (Analgesia, Seizures). * **Dysphoria:** A key differentiator; Mu = Euphoria, Kappa = Dysphoria/Hallucinations. * **Respiratory Depression:** Kappa receptors produce much less respiratory depression compared to Mu receptors, providing a "ceiling effect." * **Mixed Agonist-Antagonists:** Drugs like **Pentazocine** and **Butorphanol** act primarily as Kappa agonists and Mu antagonists/partial agonists.

Question 287: True regarding morphine?

A. Tolerance develops for all effects except miosis and constipation. (Correct Answer)
B. Tolerance to all effects develops with chronic usage.
C. Tolerance develops for all effects except euphoria and sedation.
D. Tolerance can develop to all effects in high doses.

Explanation: **Explanation:** Morphine, a prototypical opioid agonist, exhibits a phenomenon where repeated administration leads to a decrease in effect, necessitating higher doses to achieve the same result. This is known as **tolerance**. **1. Why Option A is Correct:** Tolerance develops at different rates for different opioid effects. While tolerance occurs rapidly for euphoria, sedation, and respiratory depression, it **never develops** for two specific effects: **Miosis** (pinpoint pupils) and **Constipation**. This is due to the persistent activation of mu-receptors in the Edinger-Westphal nucleus (eye) and the myenteric plexus (gut). Consequently, even a chronic opioid user will continue to experience constipation and exhibit constricted pupils. **2. Why Other Options are Incorrect:** * **Options B & D:** These are incorrect because they suggest tolerance is universal. Regardless of the dose or duration of usage, the body does not adapt to the miotic and gastrointestinal-slowing effects of opioids. * **Option C:** This is incorrect because tolerance to euphoria and sedation actually develops quite **rapidly**, which often leads to dose escalation and addiction. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of 2":** Remember that tolerance does **NOT** develop to **2** things: **Miosis** and **Constipation**. * **Triad of Morphine Poisoning:** Coma, Pinpoint pupil, and Respiratory depression. * **Specific Antidote:** **Naloxone** is the drug of choice for acute opioid poisoning (short-acting IV antagonist). * **Withdrawal:** Unlike the "pinpoint pupils" of intoxication, opioid withdrawal presents with **Mydriasis** (dilated pupils), along with lacrimation, rhinorrhea, and "gooseflesh" (piloerection).

Question 288: Which opioid has monoamine activity?

A. Tramadol (Correct Answer)
B. Pentazocine
C. Pethidine
D. Meperidine

Explanation: **Explanation:** **Tramadol** is a unique, centrally acting analgesic with a **dual mechanism of action** [2]. It acts as a weak agonist at **$\mu$-opioid receptors** and, more significantly, exhibits **monoamine activity** by inhibiting the neuronal reuptake of **Serotonin (5-HT)** and **Norepinephrine (NE)** [2]. This enhances the descending inhibitory pathways in the spinal cord, providing effective pain relief with a lower risk of respiratory depression compared to traditional opioids. **Analysis of Incorrect Options:** * **Pentazocine:** This is an opioid agonist-antagonist ($\kappa$-agonist and $\mu$-antagonist/partial agonist). It does not possess significant monoamine reuptake inhibition properties. * **Pethidine (Meperidine):** These are the same drug (Pethidine is the international non-proprietary name for Meperidine) [1]. While Pethidine can interact with serotonergic drugs to cause **Serotonin Syndrome** (due to its metabolite normeperidine), its primary analgesic action is via $\mu$-opioid receptors and local anesthetic-like effects, not direct monoamine reuptake inhibition [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Tapentadol:** Like Tramadol, it also has dual action (NE reuptake inhibition + $\mu$-agonism) but has negligible effect on Serotonin. * **Seizure Risk:** Tramadol lowers the seizure threshold; avoid in patients with epilepsy. * **Serotonin Syndrome:** Caution must be exercised when prescribing Tramadol with SSRIs or MAO inhibitors due to the risk of Serotonin Syndrome [3]. * **Antidote:** Naloxone only partially reverses the analgesic effects of Tramadol because it only blocks the opioid component, not the monoamine component [2].

Question 289: Infliximab is directed against which of the following?

A. Tumor necrosis factor-alpha (TNF-alpha) (Correct Answer)
B. Interleukin-1 (IL-1)
C. Interleukin-12 (IL-12)
D. Intercellular adhesion molecule (ICAM)

Explanation: **Explanation:** **Infliximab** is a chimeric monoclonal antibody (composed of human constant and murine variable regions) that binds with high affinity to both soluble and transmembrane forms of **Tumor Necrosis Factor-alpha (TNF-α)** [2], [3]. By neutralizing TNF-α, it prevents the cytokine from binding to its receptors, thereby inhibiting the downstream inflammatory cascade [3]. This makes it highly effective in treating autoimmune conditions like Rheumatoid Arthritis, Crohn’s disease, and Ankylosing Spondylitis [1], [2]. **Analysis of Incorrect Options:** * **Interleukin-1 (IL-1):** This is the target of **Anakinra** (a recombinant IL-1 receptor antagonist) [2]. * **Interleukin-12 (IL-12):** This, along with IL-23, is targeted by **Ustekinumab**, commonly used in psoriasis and psoriatic arthritis. * **Intercellular Adhesion Molecule (ICAM):** While ICAM-1 is involved in leukocyte trafficking, drugs like **Efalizumab** (now withdrawn) targeted LFA-1 to prevent binding to ICAM, but Infliximab has no direct action here. **High-Yield Clinical Pearls for NEET-PG:** * **TNF-α Inhibitors:** Other examples include **Adalimumab** (fully human mAb) and **Etanercept** (a decoy receptor/fusion protein) [1], [2], [4]. * **Pre-treatment Screening:** Before starting Infliximab, patients **must** be screened for **Latent Tuberculosis** (using TST or IGRA) because TNF-α is essential for granuloma maintenance; inhibiting it can lead to TB reactivation. * **Adverse Effects:** Increased risk of serious infections, infusion reactions, and potential worsening of heart failure [2].

Question 290: Aspirin protects against which of the following conditions?

A. Myocardial infarction
B. Stroke
C. Colorectal cancer
D. Liver cancer (Correct Answer)

Explanation: ### Explanation **Correct Option: D (Liver cancer)** Recent epidemiological studies and clinical trials have demonstrated that long-term, low-dose aspirin use is associated with a significantly reduced risk of **Hepatocellular Carcinoma (HCC)**. The underlying mechanism involves the inhibition of the **COX-2 enzyme**, which is overexpressed in chronic liver inflammation and promotes carcinogenesis. Aspirin also inhibits platelet activation; since platelets release growth factors (like PDGF) that facilitate tumor progression and metastasis, aspirin’s anti-platelet effect acts as a chemopreventive measure against liver cancer. **Why other options are incorrect:** * **A & B (Myocardial Infarction and Stroke):** While aspirin is famously used for the primary and secondary prevention of MI and ischemic stroke, these are **cardiovascular/cerebrovascular events**, not "cancers" or "conditions" in the context of the specific chemopreventive research this question targets. Furthermore, recent guidelines have downgraded aspirin's role in *primary* prevention for these conditions due to the high risk of major bleeding. * **C (Colorectal Cancer):** Aspirin is well-known to protect against colorectal cancer (CRC). However, in the context of this specific question (often derived from recent updates in medical literature), **Liver Cancer** is highlighted as a significant emerging protective association, particularly in patients with chronic Hepatitis B or C. *Note: If this were a multiple-choice question where "All of the above" was an option, it would be the best fit.* **High-Yield Clinical Pearls for NEET-PG:** * **Chemoprevention:** Aspirin is the only NSAID currently recommended by the USPSTF for the prevention of colorectal cancer in specific age groups (50–59 years). * **Mechanism:** Irreversible inhibition of COX-1 and COX-2 via **acetylation** of a serine residue. * **Reye’s Syndrome:** Never give aspirin to children with viral infections (Varicella/Influenza) due to the risk of fulminant hepatic failure and encephalopathy. * **Zero-order kinetics:** At high/toxic doses, aspirin metabolism shifts from first-order to zero-order kinetics.

Practice by Chapter

NSAIDs: Classification and Mechanism

Practice Questions

COX-2 Selective Inhibitors

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Acetaminophen (Paracetamol)

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Opioid Analgesics and Antagonists

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Drugs Used in Gout and Hyperuricemia

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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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