Analgesics and Anti-inflammatory Drugs Practice Questions

Q: Which of the following drugs does not inhibit the COX pathway?

Betamethasone. The question asks to identify the drug that does not inhibit the **Cyclooxygenase (COX)** pathway. The COX pathway is responsible for converting arachidonic acid into prostaglandins and thromboxanes, which are key mediators of inflammation and pain. **Why Betamethasone is the correct answer:** Betamethasone is a potent **Glucocorticoid (Corticosteroid)**. Unlike Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), corticosteroids do not directly inhibit the COX enzyme [2]. Instead, they act further upstream in the inflammatory cascade by inducing the synthesis of **Lipocortin-1 (Annexin A1)**. Lipocortin-1 inhibits the enzyme **Phospholipase A2**, thereby preventing the release of arachidonic acid from the cell membrane [2]. By cutting off the supply of the precursor, corticosteroids suppress both the COX and the LOX (Lipoxygenase) pathways. **Why the other options are incorrect:** * **Aspirin:** A salicylate that irreversibly inhibits COX-1 and COX-2 by acetylating a serine residue at the active site [1]. * **Indomethacin:** A potent, non-selective reversible inhibitor of COX-1 and COX-2, commonly used in the management of PDA (Patent Ductus Arteriosus) and gout [1]. * **Diclofenac:** A phenylacetic acid derivative that is a non-selective COX inhibitor, widely used for musculoskeletal pain [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Upstream Inhibition:** Corticosteroids (like Betamethasone) inhibit **Phospholipase A2**, whereas NSAIDs inhibit **COX** [2]. * **Dual Pathway Suppression:** Because corticosteroids inhibit Phospholipase A2, they decrease both **Prostaglandins** (COX pathway) and **Leukotrienes** (LOX pathway) [2]. * **Aspirin Uniqueness:** It is the only NSAID that binds **irreversibly** to the COX enzyme; all others are reversible [1]. * **Steroid Potency:** Betamethasone and Dexamethasone have minimal mineralocorticoid activity and are long-acting glucocorticoids.

Q: Monoamine oxidase inhibitors (MAOIs) should not be used concurrently with which of the following analgesics?

Pethidine. **Explanation:** The concurrent use of **Pethidine (Meperidine)** and **Monoamine Oxidase Inhibitors (MAOIs)** is strictly contraindicated due to the risk of a life-threatening drug interaction known as **Serotonin Syndrome** (or hyperpyretic coma). **Why Pethidine is the correct answer:** Pethidine acts as a weak serotonin reuptake inhibitor. MAOIs prevent the breakdown of serotonin. When combined, they cause a massive accumulation of serotonin in the synaptic cleft, leading to two distinct types of reactions: 1. **Excitatory Reaction:** Characterized by hyperpyrexia (high fever), agitation, muscle rigidity, convulsions, and cardiovascular instability. 2. **Depressive Reaction:** Characterized by respiratory depression, hypotension, and coma. **Why other options are incorrect:** * **Morphine:** It is primarily a pure mu-opioid agonist and does not significantly affect serotonin reuptake. It is generally considered safe to use with MAOIs, though caution is advised regarding potential potentiation of sedative effects. * **Pentazocine & Buprenorphine:** These are mixed agonist-antagonists. While they have complex receptor profiles, they do not possess the potent serotonergic activity required to trigger the classic MAOI interaction seen with Pethidine. **High-Yield Clinical Pearls for NEET-PG:** * **The "P" Rule:** Remember **P**ethidine + **P**henelzine (MAOI) = **P**yrexia. * **Metabolite Fact:** Pethidine is metabolized to **Norpethidine**, which is neurotoxic and can cause seizures (especially in renal failure). * **Other Serotonergic Opioids:** Besides Pethidine, **Tramadol**, **Tapentadol**, and **Dextromethorphan** should also be avoided with MAOIs to prevent Serotonin Syndrome. * **Clinical Presentation:** Look for the triad of cognitive changes (confusion), autonomic hyperactivity (tachycardia, diaphoresis), and neuromuscular abnormalities (clonus, tremors).

Q: Which of the following is a feature of a nonselective COX inhibitor but not of a selective COX-2 inhibitor?

Antiplatelet aggregatory effect. The correct answer is **B. Antiplatelet aggregatory effect**. ### **Explanation of the Correct Answer** The fundamental difference between nonselective NSAIDs and selective COX-2 inhibitors lies in their effect on **Thromboxane A2 (TXA2)**. * **Nonselective COX inhibitors** (e.g., Aspirin, Ibuprofen) inhibit **COX-1** in platelets. Since platelets lack a nucleus, they cannot synthesize new enzymes; thus, TXA2 production is inhibited for the life of the platelet (7–10 days). This leads to a potent antiplatelet effect. * **Selective COX-2 inhibitors** (e.g., Celecoxib, Etoricoxib) do not inhibit COX-1. Therefore, they do not affect platelet aggregation. In fact, by inhibiting PGI2 (prostacyclin) in the vascular endothelium without affecting TXA2, they may shift the balance toward a **pro-thrombotic state**, increasing cardiovascular risk. ### **Why Other Options are Incorrect** * **A. Analgesic effect:** Both classes are effective analgesics. Pain and inflammation are primarily mediated by COX-2 at the site of injury. * **C. Renal salt and water retention:** Both COX-1 and COX-2 are constitutively expressed in the kidneys. Inhibiting either can lead to decreased renal blood flow, sodium retention, and edema. * **D. Prolongation of labor:** Prostaglandins (PGE2 and PGF2α) are essential for uterine contractions. Both nonselective and selective inhibitors can delay the onset of labor. ### **High-Yield NEET-PG Pearls** * **Aspirin** is the only NSAID that binds **irreversibly** to the COX enzyme. * **Selective COX-2 inhibitors** are preferred in patients with a high risk of GI ulcers (as they spare the protective COX-1 in the gastric mucosa) but are **contraindicated** in patients with ischemic heart disease. * **Paracetamol (Acetaminophen)** is a poor anti-inflammatory because it is inactivated by peroxides at the site of inflammation.

Q: Tolerance develops to all of the following effects of opioids except?

All of the above. **Explanation:** The development of tolerance is a hallmark of chronic opioid use, but it does not occur uniformly across all physiological systems. Tolerance refers to the need for increasing doses to achieve the same pharmacological effect. **Why "All of the above" is correct:** In pharmacology, opioids follow a specific pattern regarding tolerance. While tolerance develops rapidly to effects like euphoria, sedation, and respiratory depression, there are certain effects to which the body **never** (or very minimally) develops tolerance. These are often referred to as the "Exceptions to Opioid Tolerance." 1. **Constipation (Option A):** Opioids act on $\mu$-receptors in the myenteric plexus, decreasing GI motility. This effect persists indefinitely regardless of the dose or duration of use. 2. **Miosis (Option B):** Pinpoint pupils (due to stimulation of the Edinger-Westphal nucleus) remain a consistent sign of opioid use/overdose because tolerance does not develop to the miotic effect. 3. **Convulsions (Option C):** At high doses (especially with Pethidine due to its metabolite norpethidine), opioids can induce seizures. Tolerance does not develop to this excitatory effect. **Clinical Pearls & High-Yield Facts for NEET-PG:** * **Mnemonic for No Tolerance:** "**M-C-C**" (**M**iosis, **C**onstipation, **C**onvulsions). * **Highest Tolerance:** Develops to Euphoria, Analgesia, Sedation, and Respiratory depression. * **Clinical Significance:** Because tolerance does *not* develop to constipation, patients on long-term opioids (e.g., palliative care) must be started on a prophylactic stimulant laxative. * **Diagnostic Sign:** Miosis is a diagnostic "tell" in the ER for opioid overdose, as it persists even in chronic addicts.

Q: Which of the following is a common side effect of colchicine?

Diarrhea. **Explanation:** **Colchicine** is a unique anti-inflammatory agent primarily used for the management of acute gouty arthritis and prophylaxis. Its mechanism of action involves binding to tubulin, which inhibits microtubule polymerization [1]. This disrupts leukocyte migration, chemotaxis, and phagocytosis. **Why Diarrhea is the Correct Answer:** The most common and dose-limiting side effect of colchicine is **gastrointestinal distress**, specifically **diarrhea**, nausea, and vomiting [2]. This occurs because colchicine inhibits the rapid turnover of intestinal mucosal cells (which are highly dependent on microtubule-mediated mitosis). Diarrhea often serves as a clinical "stop signal," indicating that the maximum tolerated dose has been reached [2]. **Analysis of Incorrect Options:** * **A. Neutropenia:** While chronic high-dose colchicine can cause bone marrow suppression (leading to agranulocytosis or aplastic anemia), it is a rare, toxic effect rather than a "common" side effect. * **B. Asthma:** Colchicine does not cause bronchospasm or asthma. In fact, drugs like NSAIDs (via leukotriene shunting) are more commonly associated with drug-induced asthma. * **C. Fever:** Fever is not a side effect of colchicine; rather, colchicine is sometimes used to treat Familial Mediterranean Fever (FMF) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Binds to tubulin $\rightarrow$ inhibits microtubule assembly $\rightarrow$ arrests mitosis in metaphase [1]. * **Drug of Choice:** Colchicine is the drug of choice for **prophylaxis** of gout and for **Familial Mediterranean Fever** [1]. * **Toxicity:** Acute overdose can lead to multi-organ failure. Chronic use may cause **myopathy** and **neuropathy**, especially when combined with statins. * **Contraindication:** It should be avoided in patients with severe renal or hepatic impairment [2].

Q: Methotrexate is used in all the following conditions except?

Sickle cell anemia. ### Explanation **1. Why Sickle Cell Anemia is the Correct Answer:** Methotrexate (MTX) is a folate antagonist that inhibits **dihydrofolate reductase (DHFR)**, leading to a decrease in DNA synthesis. It is primarily used as a Disease-Modifying Anti-Rheumatic Drug (DMARD) and a chemotherapeutic agent. It has **no role** in the management of Sickle Cell Anemia. The drug of choice for reducing the frequency of vaso-occlusive crises in Sickle Cell Anemia is **Hydroxyurea**, which works by increasing the levels of Fetal Hemoglobin (HbF). **2. Why the other options are incorrect:** * **Psoriasis:** MTX is a standard systemic treatment for severe, recalcitrant psoriasis. It works by inhibiting the rapid proliferation of epidermal cells (keratinocytes) and providing systemic anti-inflammatory effects. * **Rheumatoid Arthritis (RA):** MTX is the **"Anchor Drug"** and the first-line DMARD for RA. It reduces joint destruction and slows disease progression by inhibiting cytokine production and increasing extracellular adenosine. * **Ankylosing Spondylitis:** While TNF-inhibitors are preferred for axial disease, MTX is frequently used as a DMARD to manage peripheral joint involvement in patients with Ankylosing Spondylitis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Competitive inhibition of DHFR; at low doses (for RA), it also increases **Adenosine**, which acts as a potent anti-inflammatory mediator. * **Toxicity:** The most common side effect is mucosal ulceration (stomatitis). The most serious are **hepatotoxicity** (cirrhosis) and **pulmonary fibrosis**. * **Rescue Therapy:** **Leucovorin (Folinic acid)** is used to "rescue" normal cells from MTX toxicity by bypassing the inhibited DHFR enzyme. * **Contraindication:** It is highly **teratogenic** (causes neural tube defects) and must be stopped at least 3 months before conception in both men and women.

Q: Which of the following drugs causes the least sedation?

Loratadine. **Explanation:** The question tests the classification of antihistamines based on their ability to cross the blood-brain barrier (BBB) and their sedative potential. **1. Why Loratadine is the correct answer:** Loratadine is a **Second-generation H1-antihistamine**. These drugs are characterized by high molecular weight and low lipid solubility, which prevents them from crossing the BBB effectively. Furthermore, they are substrates for the P-glycoprotein efflux pump, which actively removes them from the CNS. Consequently, they lack central sedative effects and are often referred to as "non-sedating antihistamines." **2. Why the other options are incorrect:** * **Hydroxyzine, Promethazine, and Chlorpheniramine** are all **First-generation H1-antihistamines**. * These agents are highly lipid-soluble and easily cross the BBB. * Once in the CNS, they block H1 receptors in the tuberomammillary nucleus (the arousal center), leading to significant sedation. * **Promethazine** and **Hydroxyzine** are particularly potent sedatives, often used clinically for their hypnotic or anti-anxiety properties. **3. High-Yield Clinical Pearls for NEET-PG:** * **Second-generation H1 blockers:** Loratadine, Cetirizine, Fexofenadine, Desloratadine. * **Fexofenadine** is considered the "least sedating" of all, as it has virtually zero CNS penetration. * **Cetirizine** is a second-generation drug but is unique because it can cause mild sedation in a small percentage of patients (it is the most sedating of the non-sedating group). * **First-generation drugs** also possess significant **anti-cholinergic** side effects (dry mouth, urinary retention, blurred vision), which are largely absent in second-generation agents.

Q: All are effects of morphine EXCEPT:

Hyperalgesia. **Explanation:** Morphine is the prototype opioid agonist acting primarily on **$\mu$-opioid receptors**. The correct answer is **Hyperalgesia** because morphine is an **analgesic** (relieves pain); it does not typically cause increased sensitivity to pain (hyperalgesia) as a primary pharmacological effect. While "Opioid-Induced Hyperalgesia" (OIH) can occur with chronic high-dose use or rapid titration, it is considered a paradoxical side effect rather than a standard physiological effect of the drug. **Analysis of Options:** * **Miosis (A):** Morphine stimulates the **Edinger-Westphal nucleus** of the 3rd cranial nerve, leading to "pin-point pupils." This is a diagnostic sign of opioid overdose as tolerance does not develop to this effect. * **Delayed gastric emptying (B):** Opioids increase smooth muscle tone but decrease propulsive rhythmic contractions in the GI tract. This leads to delayed gastric emptying and constipation (via $\mu$-receptors in the myenteric plexus). * **Respiratory depression (C):** This is the most dangerous side effect. Morphine reduces the sensitivity of the brainstem respiratory centers to carbon dioxide ($CO_2$). **High-Yield Clinical Pearls for NEET-PG:** 1. **Mnemonic for Morphine Effects:** **"MORPHINE"** – **M**iosis, **O**ut of it (sedation), **R**espiratory depression, **P**neumonia (aspiration), **H**ypotension, **I**nfrequent stools (constipation), **N**ausea, **E**mesis. 2. **Tolerance:** Tolerance develops to most effects **EXCEPT** Miosis and Constipation. 3. **Contraindication:** Morphine is contraindicated in **Head Injury** because it causes $CO_2$ retention, leading to cerebral vasodilation and increased intracranial pressure. 4. **Biliary Colic:** Morphine can aggravate biliary colic by causing spasm of the **Sphincter of Oddi**.

Q: Tacrolimus acts by inhibiting which of the following?

T–Cell proliferation. **Explanation:** **Tacrolimus** is a potent immunosuppressant belonging to the class of **calcineurin inhibitors**. **Mechanism of Action (Why C is correct):** Tacrolimus binds to an intracellular protein called **FK-binding protein (FKBP-12)**. This complex inhibits **calcineurin**, a phosphatase enzyme required for the dephosphorylation of the **Nuclear Factor of Activated T-cells (NFAT)**. Without dephosphorylation, NFAT cannot enter the nucleus to promote the transcription of **Interleukin-2 (IL-2)**. Since IL-2 is the primary cytokine responsible for the growth and differentiation of T-lymphocytes, its suppression directly leads to the inhibition of **T-cell proliferation**. **Analysis of Incorrect Options:** * **Option A:** Drugs like Azathioprine and Mycophenolate Mofetil (antimetabolites) inhibit DNA/RNA synthesis, not Tacrolimus. * **Option B:** Tacrolimus inhibits cytokine production (cell-mediated immunity) rather than directly blocking the formation of anti-lymphocyte antibodies. * **Option D:** Since A and B are incorrect, this option is invalid. **High-Yield Clinical Pearls for NEET-PG:** * **Potency:** Tacrolimus is roughly 100 times more potent than Cyclosporine. * **Side Effects:** While similar to Cyclosporine, Tacrolimus has a **higher incidence of Nephrotoxicity and Neurotoxicity** (tremors, seizures) and is more likely to cause **Post-transplant Diabetes Mellitus (PTDM)**. * **Cosmetic Advantage:** Unlike Cyclosporine, Tacrolimus **does not** cause hirsutism or gum hyperplasia. * **Drug of Choice:** It is the preferred agent for preventing rejection in liver and kidney transplants.

Q: Which of the following drugs is implicated in causing urinary retention?

Meperidine. **Explanation:** **Correct Option: B. Meperidine** Meperidine (Pethidine) is a synthetic opioid analgesic. While most opioids can cause urinary retention by increasing the tone of the bladder sphincter and decreasing the detrusor muscle's excitability, Meperidine has a distinct pharmacological profile. It possesses significant **anticholinergic (atropine-like) properties**. Anticholinergic drugs inhibit the parasympathetic nervous system, leading to relaxation of the detrusor muscle and contraction of the internal urethral sphincter, which directly results in acute urinary retention. **Incorrect Options:** * **A & D (Lisinopril & Losartan):** Lisinopril (an ACE inhibitor) and Losartan (an ARB) primarily affect the Renin-Angiotensin-Aldosterone System (RAAS). Their main side effects include hyperkalemia and renal impairment, but they do not typically cause urinary retention. * **C (Terazosin):** This is an **alpha-1 blocker**. It is actually used to *treat* urinary retention associated with Benign Prostatic Hyperplasia (BPH) by relaxing the smooth muscles of the bladder neck and prostate. **High-Yield NEET-PG Pearls:** * **Meperidine Metabolism:** It is metabolized to **normeperidine**, which is neurotoxic and can cause tremors, myoclonus, and **seizures** (especially in renal failure). * **Mydriasis:** Unlike most opioids that cause miosis (pinpoint pupils), Meperidine can cause mydriasis due to its anticholinergic effect. * **Drug Interaction:** Meperidine is contraindicated with **MAO inhibitors** as it can precipitate a life-threatening **Serotonin Syndrome**. * **Other drugs causing retention:** Tricyclic antidepressants (TCAs), first-generation antihistamines, and antiparkinsonian drugs (due to anticholinergic effects).

Question 1

Which of the following drugs does not inhibit the COX pathway?

Accepted Answer

Betamethasone

Answer

Aspirin

Answer

Indomethacin

Answer

Diclofenac

Question 2

Monoamine oxidase inhibitors (MAOIs) should not be used concurrently with which of the following analgesics?

Accepted Answer

Pethidine

Answer

Pentazocine

Answer

Buprenorphine

Answer

Morphine

Question 3

Which of the following is a feature of a nonselective COX inhibitor but not of a selective COX-2 inhibitor?

Accepted Answer

Antiplatelet aggregatory effect

Answer

Analgesic effect

Answer

Renal salt and water retention

Answer

Prolongation of labor

Question 4

Tolerance develops to all of the following effects of opioids except?

Accepted Answer

All of the above

Answer

Constipation

Answer

Miosis

Answer

Convulsions

Question 5

Which of the following is a common side effect of colchicine?

Accepted Answer

Diarrhea

Answer

Neutropenia

Answer

Asthma

Answer

Fever

Question 6

Methotrexate is used in all the following conditions except?

Accepted Answer

Sickle cell anemia

Answer

Psoriasis

Answer

Rheumatoid arthritis

Answer

Ankylosing spondylitis

Question 7

Which of the following drugs causes the least sedation?

Accepted Answer

Loratadine

Answer

Hydroxyzine

Answer

Promethazine

Answer

Chlorpheniramine

Question 8

All are effects of morphine EXCEPT:

Accepted Answer

Hyperalgesia

Answer

Miosis

Answer

Delayed gastric emptying

Answer

Respiratory depression

Question 9

Tacrolimus acts by inhibiting which of the following?

Accepted Answer

T–Cell proliferation

Answer

DNA and RNA synthesis

Answer

Anti–lymphocyte antibody formation

Answer

All of the above

Question 10

Which of the following drugs is implicated in causing urinary retention?

Accepted Answer

Meperidine

Answer

Lisinopril

Answer

Terazosin

Answer

Losartan

Analgesics and Anti-inflammatory Drugs — MCQs

Analgesics and Anti-inflammatory Drugs — MCQs

On this page

Practice by Chapter

Want unlimited practice?