Analgesics and Anti-inflammatory Drugs Practice Questions

Q: In low doses, aspirin inhibits which of the following enzymes?

Cyclo-oxygenase. **Explanation:** Aspirin (Acetylsalicylic acid) is a non-steroidal anti-inflammatory drug (NSAID) that works by **irreversibly inhibiting the Cyclo-oxygenase (COX)** enzyme. It achieves this by acetylating a serine residue at the active site of the enzyme, thereby blocking the synthesis of prostaglandins and thromboxanes. **Why Option B is Correct:** Aspirin is unique among NSAIDs because of its irreversible action. In **low doses (75–150 mg/day)**, aspirin selectively inhibits **COX-1** in platelets. Since platelets are anucleated and cannot synthesize new enzymes, the inhibition lasts for the entire lifespan of the platelet (approx. 8–11 days), leading to its potent anti-platelet effect. **Why Other Options are Incorrect:** * **A. Lipoxygenase:** Aspirin does not inhibit the lipoxygenase (LOX) pathway. In fact, by blocking the COX pathway, arachidonic acid may be shunted toward the LOX pathway, potentially increasing leukotriene production (the mechanism behind aspirin-induced asthma). * **C & D. Thromboxane A2 and Prostaglandin I2:** These are **products** of the COX pathway, not enzymes themselves. While aspirin reduces the levels of TXA2 and PGI2, the question specifically asks for the *enzyme* being inhibited. **High-Yield Clinical Pearls for NEET-PG:** * **Zero-order kinetics:** Aspirin follows first-order kinetics at low doses but shifts to zero-order kinetics at high/toxic doses. * **Reye’s Syndrome:** Aspirin is contraindicated in children with viral infections (except in Kawasaki disease) due to the risk of hepatic encephalopathy. * **Aspirin Triad (Samter’s Triad):** Asthma, nasal polyposis, and aspirin hypersensitivity. * **Antidote for Salicylate poisoning:** Sodium bicarbonate (to alkalinize urine and promote excretion).

Q: What is the drug of choice for relieving pain in myocardial infarction?

Morphine. **Explanation:** **Morphine** is the drug of choice for managing the intense chest pain associated with acute myocardial infarction (MI) [2]. Its efficacy is due to a dual mechanism: 1. **Analgesia:** It is a potent opioid agonist that provides rapid relief from severe pain [2]. 2. **Hemodynamic Benefits:** Morphine acts as a **venodilator**, reducing venous return (preload) and decreasing the workload on the heart [3]. It also reduces sympathetic overactivity, which lowers myocardial oxygen demand and alleviates the patient's anxiety/apprehension. **Analysis of Incorrect Options:** * **B. Fortwin (Pentazocine):** This is a partial opioid agonist/antagonist. It is avoided in MI because it can increase systemic and pulmonary arterial pressure and heart rate, thereby **increasing myocardial oxygen demand**, which can worsen the infarct. * **C. Diazepam:** While it is a benzodiazepine used to reduce anxiety, it has no analgesic properties and cannot manage the severe pain of an MI. * **D. NSAIDs:** These are generally **contraindicated** in the acute phase of MI (except for Aspirin). NSAIDs can increase the risk of myocardial rupture, impair infarct healing, and increase the risk of re-infarction and heart failure. **High-Yield Clinical Pearls for NEET-PG:** * **M.O.N.A. Protocol:** The classic mnemonic for initial MI management is **M**orphine, **O**xygen, **N**itroglycerin, and **A**spirin [1]. * **Route:** Morphine should be administered **Intravenously (IV)**. Intramuscular (IM) injections are avoided as they can cause erratic absorption and interfere with CK-MB enzyme levels used for diagnosis. * **Antidote:** In case of morphine-induced respiratory depression, **Naloxone** is the specific antagonist. * **Caution:** Morphine should be used cautiously in **Right Ventricular MI** or inferior wall MI due to the risk of severe hypotension.

Q: A common side effect associated with all NSAID drugs is?

Gastric irritation. **Explanation:** The primary mechanism of action for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) is the inhibition of the enzyme **Cyclooxygenase (COX)**. This prevents the conversion of arachidonic acid into prostaglandins (PGs). **Gastric irritation** is the most common side effect because NSAIDs inhibit **COX-1**, which is responsible for synthesizing "housekeeping" prostaglandins (**PGE2 and PGI2**) in the gastric mucosa. These prostaglandins are cytoprotective; they increase bicarbonate secretion, enhance mucosal blood flow, and promote mucus production. By inhibiting their synthesis, NSAIDs increase gastric acid secretion and weaken the mucosal barrier, leading to dyspepsia, erosions, and peptic ulcers. **Analysis of Incorrect Options:** * **Drowsiness:** This is not a characteristic side effect of NSAIDs. It is more commonly associated with opioid analgesics or first-generation antihistamines. * **Xerostomia (Dry mouth):** This is a classic anticholinergic side effect (e.g., Atropine, TCAs) and is not typically caused by NSAIDs. * **Constipation:** This is the most common gastrointestinal side effect of **Opioids** (due to decreased intestinal motility). In contrast, some NSAIDs (like Mefenamic acid) may actually cause diarrhea. **High-Yield Clinical Pearls for NEET-PG:** * **Selective COX-2 Inhibitors (e.g., Celecoxib):** Developed to reduce gastric irritation, but carry a higher risk of cardiovascular thrombotic events. * **Misoprostol:** A PGE1 analogue used to prevent NSAID-induced gastric ulcers. * **Aspirin Sensitivity:** Inhibition of COX can shift arachidonic acid metabolism toward the lipoxygenase (LOX) pathway, increasing leukotrienes and potentially triggering **aspirin-exacerbated respiratory disease (AERD)** or "Aspirin Asthma."

Q: Gum hypertrophy is an adverse effect of which of the following drugs when used at therapeutic levels?

Phenytoin. **Explanation:** **Phenytoin** is a classic cause of **Gingival Hyperplasia (Gum Hypertrophy)**, occurring in approximately 30–50% of patients. The underlying mechanism involves the drug’s effect on calcium metabolism and the stimulation of **platelet-derived growth factor (PDGF)**. This leads to the over-proliferation of gingival fibroblasts and increased collagen synthesis. Poor oral hygiene is a significant risk factor, and the condition often regresses upon drug discontinuation. **Analysis of Incorrect Options:** * **Phenobarbitone:** Primarily causes sedation, cognitive impairment, and skin rashes. It does not typically affect the gums. * **Carbamazepine:** Common side effects include diplopia, ataxia, and hyponatremia (SIADH). It is notably "gingival-neutral." * **Sodium Valproate:** Known for causing weight gain, alopecia (curly hair regrowth), hepatotoxicity, and pancreatitis. While it can cause transient thrombocytopenia, it does not cause gum hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Other Drugs causing Gingival Hyperplasia:** Remember the mnemonic **"PNC"** — **P**henytoin, **N**ifedipine (and other Calcium Channel Blockers like Verapamil/Amlodipine), and **C**yclosporine. * **Phenytoin Side Effects Mnemonic (HOT MALAYALAM):** **H**irsutism, **O**steomalacia, **T**eratogenicity (Fetal Hydantoin Syndrome), **M**egaloblastic anemia, **A**taxia, **L**ymphadenopathy, **A**rrhythmias, **Y**ellow-brown skin, **A**denopathy, **L**eukopenia, **A**nd **M**outh (Gingival Hyperplasia). * **Zero-Order Kinetics:** Phenytoin follows capacity-limited elimination at therapeutic/high doses, making its plasma concentration unpredictable.

Q: Methotrexate is used for the management of all of 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 the enzyme **dihydrofolate reductase (DHFR)**, leading to a decrease in DNA synthesis and cell proliferation [1]. It has no role in the management of Sickle Cell Anemia. The drug of choice for reducing the frequency of painful crises in Sickle Cell Anemia is **Hydroxyurea** [3], which acts by increasing the levels of Fetal Hemoglobin (HbF) [3]. **2. Analysis of Incorrect Options:** * **Rheumatoid Arthritis (RA):** MTX is the **"Anchor Drug"** and the first-line Disease-Modifying Anti-Rheumatic Drug (DMARD) for RA [2]. It acts by increasing adenosine levels, which exerts a potent anti-inflammatory effect. * **Psoriasis:** MTX is highly effective for severe, recalcitrant psoriasis and psoriatic arthritis due to its ability to inhibit the rapid proliferation of epidermal keratinocytes [2]. * **Organ Transplantation:** In low doses, MTX acts as an immunosuppressant used to prevent Graft-versus-Host Disease (GVHD) and organ rejection by inhibiting T-cell activation and proliferation [2]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Competitive inhibition of DHFR; cell cycle-specific for the **S-phase** [1]. * **Toxicity:** Bone marrow suppression (most common), hepatotoxicity (cirrhosis), and pulmonary fibrosis [4]. * **Rescue Therapy:** **Leucovorin (Folinic acid)** is used to "rescue" normal cells from MTX toxicity by bypassing the inhibited DHFR enzyme [1], [4]. * **Contraindication:** It is highly **teratogenic** (causes neural tube defects and fetal death) [4]. * **Other Uses:** Choriocarcinoma (Drug of choice), Ectopic pregnancy, and Osteosarcoma.

Q: All drugs are used in the management of psoriatic arthritis except?

Chloroquine. **Explanation:** The correct answer is **Chloroquine**. **Why Chloroquine is the correct answer:** Chloroquine and Hydroxychloroquine are Antimalarial drugs commonly used as DMARDs (Disease-Modifying Antirheumatic Drugs) for Rheumatoid Arthritis and SLE. However, they are **contraindicated or avoided in Psoriatic Arthritis** because they can trigger or significantly exacerbate skin lesions, leading to severe exfoliative dermatitis or "psoriasis flare-ups." Therefore, they are not used in the management of this condition. **Analysis of other options:** * **A. Methotrexate:** This is the first-line conventional synthetic DMARD for psoriatic arthritis. It effectively treats both the joint inflammation and the underlying skin psoriasis. * **B. Leflunomide:** An alternative conventional DMARD used in patients who cannot tolerate methotrexate. It inhibits dihydroorotate dehydrogenase and is effective for peripheral joint involvement in psoriatic arthritis. * **D. Abatacept:** A biological DMARD that acts as a T-cell costimulation modulator (CTLA-4 Ig). It is FDA-approved for the treatment of active psoriatic arthritis in adults. **Clinical Pearls for NEET-PG:** * **First-line treatment:** NSAIDs for mild cases; Methotrexate for moderate-to-severe disease. * **TNF-inhibitors:** (e.g., Etanercept, Adalimumab) are highly effective for both skin and joint symptoms. * **IL-17 Inhibitors:** (e.g., Secukinumab) are specifically high-yield for psoriatic arthritis management. * **Avoid:** Systemic corticosteroids are generally avoided in psoriasis due to the risk of life-threatening **pustular psoriasis** upon withdrawal.

Q: What is the loading dose of leflunomide in rheumatoid arthritis?

100 mg. **Explanation:** **Leflunomide** is a Disease-Modifying Antirheumatic Drug (DMARD) that acts by inhibiting the enzyme **dihydroorotate dehydrogenase (DHODH)**. This inhibition leads to the depletion of intracellular pyrimidine pools, thereby arresting the proliferation of activated T-cells. **Why 100 mg is correct:** Leflunomide has a very long half-life (approximately **2 weeks**) due to extensive enterohepatic circulation. To achieve therapeutic steady-state plasma concentrations rapidly, a **loading dose of 100 mg once daily for 3 consecutive days** is administered. Without this loading dose, it would take several weeks to reach effective levels. **Analysis of incorrect options:** * **10 mg & 20 mg:** These represent the standard **maintenance doses**. After the initial 3-day loading period, patients are typically transitioned to 20 mg daily (or 10 mg if the higher dose is not tolerated). * **400 mg:** This is an excessively high dose and is not used in standard rheumatological practice; it would significantly increase the risk of hepatotoxicity and gastrointestinal distress. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Pyrimidine synthesis inhibitor (DHODH inhibitor). * **Active Metabolite:** Malononitrilamide (MNA) / A77 1726. * **Washout Procedure:** Due to its long half-life, if a patient experiences toxicity or wishes to become pregnant, **Cholestyramine** is used to interrupt enterohepatic circulation and accelerate drug elimination. * **Contraindication:** It is highly **teratogenic** (Category X) and contraindicated in pregnancy. * **Monitoring:** Baseline and periodic Liver Function Tests (LFTs) are mandatory due to the risk of hepatotoxicity.

Q: Which of the following is/are cyclo-oxygenase inhibitors?

All of these. **Explanation:** The correct answer is **D (All of these)**. The underlying medical concept involves the mechanism of action of Non-Steroidal Anti-inflammatory Drugs (NSAIDs), which exert their effects by inhibiting the enzyme **Cyclo-oxygenase (COX)**. This enzyme is responsible for converting arachidonic acid into prostaglandins, prostacyclin, and thromboxane. * **Aspirin:** It is a non-selective COX inhibitor. Its unique feature is that it **irreversibly** acetylates the COX enzyme, leading to long-lasting anti-platelet effects. * **Indomethacin:** It is a potent, non-selective, reversible COX inhibitor. It is a traditional NSAID often used for acute gout and patent ductus arteriosus (PDA). * **Rofecoxib:** It belongs to the "coxib" class, which are **selective COX-2 inhibitors**. While it specifically targets the inducible COX-2 isoform (sparing the constitutive COX-1), it is still fundamentally a cyclo-oxygenase inhibitor. **High-Yield Clinical Pearls for NEET-PG:** * **COX-1 vs. COX-2:** COX-1 is "constitutive" (housekeeping functions like gastric protection), while COX-2 is "inducible" (expressed during inflammation). * **Aspirin Overdose:** Follows zero-order kinetics and can lead to Salicylism (tinnitus, respiratory alkalosis followed by metabolic acidosis). * **Selective COX-2 Inhibitors:** They have a lower risk of gastric ulcers but carry an increased risk of **cardiovascular thrombotic events** (due to the inhibition of PGI2 without affecting TXA2). * **Drug of Choice:** Indomethacin is the classic drug of choice for closing a **Patent Ductus Arteriosus (PDA)** in neonates.

Question 1

In low doses, aspirin inhibits which of the following enzymes?

Accepted Answer

Cyclo-oxygenase

Answer

Lipoxygenase

Answer

Thromboxane A2

Answer

Prostaglandin I2

Question 2

What is the drug of choice for relieving pain in myocardial infarction?

Accepted Answer

Morphine

Answer

Fortwin

Answer

Diazepam

Answer

NSAID

Question 3

A common side effect associated with all NSAID drugs is?

Accepted Answer

Gastric irritation

Answer

Drowsiness

Answer

Xerostomia

Answer

Constipation

Question 4

What is the mechanism of action of allopurinol?

Accepted Answer

Inhibits the synthesis of uric acid

Answer

Inhibits the tubular reabsorption of uric acid

Answer

Anti-inflammatory action

Answer

Increases phagocytosis of urate crystals

Question 5

Gum hypertrophy is an adverse effect of which of the following drugs when used at therapeutic levels?

Accepted Answer

Phenytoin

Answer

Phenobarbitone

Answer

Carbamazepine

Answer

Sodium valproate

Question 6

Methotrexate is used for the management of all of the following conditions except?

Accepted Answer

Sickle cell anemia

Answer

Rheumatoid arthritis

Answer

Psoriasis

Answer

Organ transplantation

Question 7

A 30-year-old male presents with sudden onset pain, swelling, and redness of the left first metatarsophalangeal joint. A needle aspirate of the joint shows needle-shaped, negatively birefringent crystals. The patient was prescribed a medication and returned the next day with nausea, vomiting, and diarrhea after taking it. Which of the following is the most likely medication that was prescribed?

Accepted Answer

Colchicine

Answer

Allopurinol

Answer

Steroids

Answer

Indomethacin

Question 8

All drugs are used in the management of psoriatic arthritis except?

Accepted Answer

Chloroquine

Answer

Methotrexate

Answer

Leflunomide

Answer

Abatacept

Question 9

What is the loading dose of leflunomide in rheumatoid arthritis?

Accepted Answer

100 mg

Answer

20 mg

Answer

10 mg

Answer

400 mg

Question 10

Which of the following is/are cyclo-oxygenase inhibitors?

Accepted Answer

All of these

Answer

Aspirin

Answer

Indomethacin

Answer

Rofecoxib

Analgesics and Anti-inflammatory Drugs — MCQs

Analgesics and Anti-inflammatory Drugs — MCQs

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