Analgesics and Anti-inflammatory Drugs — MCQs

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

Question 61: Tolerance develops to the following effects of Morphine, except:

A. Euphoria
B. Miosis (Correct Answer)
C. Nausea and vomiting
D. Analgesia

Explanation: In the clinical use of Morphine and other opioids, **tolerance** refers to the need for increasing doses to achieve the same pharmacological effect. However, tolerance does not develop uniformly across all organ systems [1]. **Why Miosis is the correct answer:** Tolerance develops to most of the central nervous system effects of Morphine, but there are two notable exceptions: **Miosis (pinpoint pupils)** and **Constipation** [2]. The miotic effect is mediated through the Edinger-Westphal nucleus (parasympathetic pathway). Because tolerance does not develop to this effect, miosis remains a reliable diagnostic sign of opioid overdose even in chronic addicts [1]. **Analysis of Incorrect Options:** * **A. Euphoria:** Tolerance develops rapidly to the mood-elevating effects of opioids, which often drives the cycle of dose escalation in substance abuse [2]. * **C. Nausea and vomiting:** These effects occur due to the stimulation of the Chemoreceptor Trigger Zone (CTZ). With repeated administration, patients typically become "tolerant" to these emetic effects [2]. * **D. Analgesia:** This is the most clinically significant area where tolerance occurs. Over time, higher doses are required to maintain the same level of pain relief [2]. **NEET-PG High-Yield Pearls:** 1. **"The Rule of Two":** Remember that tolerance **DOES NOT** develop to **Miosis** and **Constipation** [2]. 2. **Mechanism of Miosis:** Morphine stimulates the **Edinger-Westphal nucleus** of the 3rd cranial nerve. 3. **Lethal Effect:** Tolerance develops to **Respiratory Depression**, allowing addicts to survive doses that would be fatal to non-users [2]. 4. **Antidote:** Naloxone is the specific antagonist used for opioid overdose; it will reverse miosis and respiratory depression.

Question 62: Morphine can be administered via which of the following routes, except?

A. Intravenous
B. Intramuscular
C. Subcutaneous
D. Sublingual (Correct Answer)

Explanation: **Explanation:** Morphine is a potent opioid analgesic primarily used for moderate to severe pain. The correct answer is **Sublingual** because Morphine has very poor and erratic absorption through the oral mucosa. Additionally, it undergoes significant **first-pass metabolism** in the liver, making the sublingual route clinically ineffective compared to other opioids like Buprenorphine or Fentanyl. **Analysis of Options:** * **Intravenous (IV):** This is the preferred route in emergency settings (e.g., Myocardial Infarction or acute pulmonary edema) as it provides rapid onset of action and 100% bioavailability. * **Intramuscular (IM) & Subcutaneous (SC):** These are standard parenteral routes for Morphine. While effective, absorption is slower than IV but much more reliable than oral/sublingual administration. * **Sublingual:** As mentioned, Morphine is highly ionized at physiological pH and has low lipid solubility, preventing efficient transmucosal absorption. **High-Yield NEET-PG Pearls:** 1. **Metabolism:** Morphine is conjugated in the liver to **Morphine-6-glucuronide (M6G)**, which is an active metabolite (more potent than morphine), and **Morphine-3-glucuronide (M3G)**, which is inactive but can cause neurotoxicity (seizures). 2. **Excretion:** Both metabolites are renally excreted; therefore, Morphine is **contraindicated in renal failure** to avoid toxicity. 3. **Specific Contraindications:** Head injury (increases intracranial pressure), Bronchial asthma, and Biliary colic (causes spasm of the Sphincter of Oddi). 4. **Oral Route:** Morphine *can* be given orally (tablets/syrup), but the dose must be significantly higher (3:1 ratio) than the parenteral dose due to high first-pass metabolism.

Question 63: Which of the following patient histories permits the use of celecoxib in patients with arthritis?

A. History of diabetes
B. History of peptic ulcer
C. History of gout (Correct Answer)
D. History of severe rash

Explanation: **Explanation:** The correct answer is **History of gout**. Celecoxib is a selective COX-2 inhibitor. Unlike non-selective NSAIDs (like Indomethacin or Naproxen), selective COX-2 inhibitors do not interfere with the renal excretion of uric acid to the same extent and are frequently used to manage pain in patients with gouty arthritis. There is no contraindication for its use in gout; in fact, it is a therapeutic option. **Analysis of Options:** * **A. History of diabetes:** While not an absolute contraindication, diabetic patients often have underlying renal impairment or cardiovascular risks. Since COX-2 inhibitors are associated with an increased risk of thrombotic cardiovascular events (MI/Stroke) and can worsen renal function, they are used with extreme caution in diabetics. * **B. History of peptic ulcer:** Although COX-2 inhibitors are "gastric-sparing" compared to traditional NSAIDs, a *history* of peptic ulcer disease still warrants caution. They are safer than aspirin but not entirely risk-free for the GI mucosa. * **D. History of severe rash:** This is the most critical contraindication. Celecoxib contains a **sulfonamide moiety**. Patients with a history of "sulfa" allergies or severe rashes (like Stevens-Johnson Syndrome) must avoid celecoxib due to the risk of cross-reactivity and life-threatening dermatological reactions. **High-Yield NEET-PG Pearls:** 1. **Sulfonamide Group:** Celecoxib is unique among NSAIDs for containing a sulfonamide side chain. 2. **Cardiovascular Risk:** The "Coxib" class is notorious for increasing the risk of myocardial infarction because they inhibit PGI2 (vasodilator/anti-aggregatory) without affecting TXA2 (vasoconstrictor/pro-aggregatory). 3. **Platelet Sparing:** Unlike aspirin, celecoxib does not inhibit platelet aggregation (COX-1 mediated) and does not increase bleeding time.

Question 64: Which of the following is not an acetic acid derivative?

A. Ketorolac
B. Ketoprofen (Correct Answer)
C. Indomethacin
D. Nabumetone

Explanation: **Explanation:** The classification of Non-Steroidal Anti-inflammatory Drugs (NSAIDs) based on chemical structure is a high-yield topic for NEET-PG. NSAIDs are primarily categorized into derivatives of carboxylic acids or enolic acids. **Why Ketoprofen is the correct answer:** Ketoprofen belongs to the **Propionic acid derivative** group, not the acetic acid group. This class also includes commonly used drugs like Ibuprofen, Naproxen, and Flurbiprofen. A helpful mnemonic for propionic acid derivatives is **"Profens"** (Ibuprofen, Ketoprofen, Flurbiprofen). **Analysis of incorrect options (Acetic Acid Derivatives):** * **Ketorolac:** A potent analgesic often used post-operatively; it is a pyrrolo-pyrrole derivative classified under the acetic acid group. * **Indomethacin:** An indole-acetic acid derivative. It is the drug of choice for closing a Patent Ductus Arteriosus (PDA) and treating Acute Gout. * **Nabumetone:** A non-acidic prodrug that is metabolized in the liver to an active **naphthyl-acetic acid** derivative. It is unique because it is the only non-acidic NSAID in clinical use, leading to lower gastric toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Diclofenac and Aceclofenac** are also important members of the phenylacetic acid group. * **Nabumetone** is a "neutral" prodrug; it carries a lower risk of GI ulcers compared to other NSAIDs. * **Ketorolac** should not be used for more than 5 days due to its high risk of renal and GI toxicity. * **Indomethacin** is notorious for causing frontal headaches and psychiatric disturbances as side effects.

Question 65: Triptans in migraine act on which receptor?

A. 5-HT 1A
B. 5-HT 1B/1D (Correct Answer)
C. 5-HT 1F
D. 5-HT 3

Explanation: **Explanation:** Triptans (e.g., Sumatriptan) are the drugs of choice for the acute management of moderate-to-severe migraine. They act as selective agonists at the **5-HT 1B and 5-HT 1D** receptors. * **Mechanism of Action:** 1. **5-HT 1B activation:** Causes **vasoconstriction** of the dilated intracranial extracerebral blood vessels, reversing the vasodilation associated with migraine pain. 2. **5-HT 1D activation:** Acts on presynaptic receptors on trigeminal nerve endings to **inhibit the release of pro-inflammatory neuropeptides** (like CGRP and Substance P), thereby blocking neurogenic inflammation. **Analysis of Incorrect Options:** * **5-HT 1A:** These receptors are primarily located in the CNS and are involved in mood and anxiety. **Buspirone** is a partial agonist at this site used for Generalized Anxiety Disorder. * **5-HT 1F:** While **Lasmiditan** (a "Ditan") is a selective 5-HT 1F agonist used for migraine, Triptans are primarily defined by their 1B/1D activity. 1F agonists are unique because they do not cause vasoconstriction. * **5-HT 3:** These are ligand-gated ion channels. Antagonists like **Ondansetron** are used as anti-emetics. **High-Yield Clinical Pearls for NEET-PG:** * **Sumatriptan** is the only triptan available for subcutaneous administration (fastest onset). * **Frovatriptan** has the longest half-life (~26 hours), making it useful for menstrual migraine prophylaxis. * **Contraindications:** Due to 5-HT 1B mediated vasoconstriction, triptans are strictly contraindicated in patients with **Ischemic Heart Disease (CAD)**, Prinzmetal angina, and uncontrolled hypertension.

Question 66: Dysphoria is mediated by which opioid receptor?

A. Mu
B. Kappa (Correct Answer)
C. Delta
D. None

Explanation: ### Explanation Opioid receptors are G-protein coupled receptors (GPCRs) categorized into three main types: Mu ($\mu$), Kappa ($\kappa$), and Delta ($\delta$). Each receptor mediates distinct physiological and psychological effects. **1. Why Kappa ($\kappa$) is correct:** The **Kappa receptor** is uniquely associated with **dysphoria**, hallucinations, and psychotomimetic effects (such as disorientation or depersonalization). This occurs because $\kappa$-agonists inhibit dopamine release in the mesolimbic pathway, contrasting with the "reward" sensation of other opioids. It also mediates spinal analgesia, miosis, and sedation. **2. Why the other options are incorrect:** * **Mu ($\mu$):** This is the primary receptor for most clinical opioids (like Morphine). It mediates **euphoria** (the opposite of dysphoria), supraspinal analgesia, respiratory depression, constipation, and physical dependence. * **Delta ($\delta$):** These receptors are primarily involved in spinal/supraspinal analgesia and may have antidepressant-like effects. They are not associated with dysphoria. * **Sigma ($\sigma$):** (Though not an option, often confused) Formerly considered an opioid receptor, it is now known to be the site where drugs like Phencyclidine (PCP) act, causing hallucinations. **3. High-Yield NEET-PG Pearls:** * **Pure Antagonist:** Naloxone and Naltrexone act as antagonists at all three receptors ($\mu, \kappa, \delta$). * **Mixed Agonist-Antagonist:** Pentazocine and Butorphanol act as **$\kappa$-agonists** (providing analgesia) but **$\mu$-antagonists**. This explains why Pentazocine can precipitate withdrawal in a morphine addict and why it frequently causes dysphoria as a side effect. * **Mnemonic:** **M**u = **M**iss (Euphoria/Happiness), **K**appa = **K**illing the mood (Dysphoria).

Question 67: What is the analgesic of choice in a patient with hemophilia and rheumatoid arthritis?

A. Ibuprofen
B. Aspirin
C. Acetaminophen (Correct Answer)
D. Phenylbutazone

Explanation: **Explanation:** The core clinical challenge in this scenario is managing pain in a patient with a pre-existing bleeding disorder (**Hemophilia**). **Why Acetaminophen is the Correct Choice:** Acetaminophen (Paracetamol) is the preferred analgesic because it is a **selective CNS prostaglandin synthesis inhibitor** with negligible effects on peripheral COX-1 and COX-2 enzymes. Unlike NSAIDs, it does not inhibit platelet aggregation or prolong bleeding time. In a hemophilic patient, maintaining intact platelet function is critical to prevent spontaneous or exacerbated bleeding episodes. **Analysis of Incorrect Options:** * **Aspirin:** It is strictly contraindicated. Aspirin causes **irreversible inhibition of COX-1**, leading to prolonged anti-platelet effects (7–10 days). In hemophilia, this significantly increases the risk of life-threatening hemorrhage. * **Ibuprofen:** As a non-selective NSAID, it causes reversible inhibition of platelet aggregation and can irritate the gastric mucosa, potentially leading to GI bleeds—a high risk for hemophiliacs. * **Phenylbutazone:** This is a potent NSAID with a high side-effect profile, including bone marrow suppression (agranulocytosis) and significant GI irritation. It is rarely used today and is unsafe in patients with bleeding tendencies. **NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** Acetaminophen is the DOC for pain/fever in patients with peptic ulcers, bleeding disorders, and children with viral infections (to avoid **Reye’s Syndrome**). * **RA Management:** While NSAIDs are typically first-line for RA inflammation, in the presence of hemophilia, systemic NSAIDs are avoided. If inflammation is severe, selective COX-2 inhibitors (like Celecoxib) may be used with caution, but Acetaminophen remains the safest initial analgesic. * **Toxicity:** The toxic metabolite of Acetaminophen is **NAPQI**, which is neutralized by **N-acetylcysteine (NAC)**.

Question 68: Which of the following patient characteristics is a possible reason for the use of celecoxib in the treatment of arthritis?

A. History of severe rash after treatment with a sulfonamide antibiotic
B. History of gout
C. History of peptic ulcer disease (Correct Answer)
D. History of type 2 DM

Explanation: **Explanation:** **Why Option C is Correct:** Celecoxib is a **selective COX-2 inhibitor**. Traditional NSAIDs (like Ibuprofen or Naproxen) inhibit both COX-1 and COX-2 enzymes. COX-1 is constitutively expressed in the gastric mucosa, where it produces cytoprotective prostaglandins ($PGE_2$ and $PGI_2$) that maintain the mucosal barrier. By sparing COX-1 and selectively inhibiting COX-2 (the enzyme induced during inflammation), celecoxib significantly reduces the risk of **gastric ulcers and GI bleeding** [1], [2]. Therefore, it is the preferred NSAID for patients with a history of peptic ulcer disease (PUD) or those at high risk for GI complications [1]. **Why Other Options are Incorrect:** * **Option A:** Celecoxib contains a **sulfonamide moiety**. It is contraindicated in patients with a known history of severe allergic reactions (like Stevens-Johnson Syndrome) to sulfonamides. * **Option B:** While NSAIDs are used to treat acute gout, celecoxib offers no specific advantage over non-selective NSAIDs for gout. In fact, traditional NSAIDs like Indomethacin are often preferred. * **Option D:** There is no specific therapeutic indication or advantage for using celecoxib in patients with Type 2 Diabetes Mellitus. **NEET-PG High-Yield Pearls:** 1. **Cardiovascular Risk:** While GI-friendly, selective COX-2 inhibitors (except perhaps Celecoxib at low doses) are associated with an increased risk of **thrombotic cardiovascular events** (MI/Stroke) because they inhibit $PGI_2$ (vasodilator/anti-aggregatory) without affecting Thromboxane $A_2$ (vasoconstrictor/pro-aggregatory) [2], [3]. 2. **Renal Effects:** Selective COX-2 inhibitors carry the **same risk of nephrotoxicity** as non-selective NSAIDs, as both enzymes play a role in renal perfusion. 3. **Sulfonamide Allergy:** Celecoxib is the only NSAID with a sulfonamide group; always screen for "sulfa" allergies before prescribing.

Question 69: What is the most effective treatment for an acute attack of gout?

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

Explanation: In the management of an **acute attack of gout**, the primary goal is to control intense inflammation and pain. ### Why Mefenamic Acid is Correct The first-line treatment for acute gout is **Non-Steroidal Anti-inflammatory Drugs (NSAIDs)**. While Indomethacin and Naproxen are traditionally preferred, **Mefenamic acid** (an anthranilic acid derivative) is a potent NSAID that effectively inhibits prostaglandin synthesis and provides rapid symptomatic relief. In the context of this specific question, it represents the NSAID class, which is the standard of care for acute episodes. ### Analysis of Incorrect Options * **Aspirin (A):** It is **contraindicated** in gout. Low-dose aspirin inhibits the renal excretion of uric acid (via OAT transporters), leading to hyperuricemia, which can worsen or prolong an attack. * **Allopurinol (B):** This is a Xanthine Oxidase inhibitor used for **chronic gout** (prophylaxis). It should **never** be started during an acute attack, as a rapid drop in serum urate levels can mobilize urate crystals from tissues, paradoxically worsening the acute inflammation. * **Colchicine (C):** While highly effective, it is now considered **second-line** due to its narrow therapeutic index and significant gastrointestinal side effects (diarrhea, vomiting). It is used if NSAIDs are contraindicated or ineffective. ### NEET-PG High-Yield Pearls * **Drug of Choice (DOC) for Acute Gout:** NSAIDs (specifically Indomethacin). * **DOC for Chronic Gout:** Allopurinol (or Febuxostat if renal impairment is present). * **Colchicine Mechanism:** Inhibits microtubule polymerization by binding to tubulin, preventing neutrophil migration to the joint. * **Uricosuric agents:** Probenecid and Sulfinpyrazone (used in underexcretors).

Question 70: An analgesic 'X' acts through opioid as well as additional spinal monoaminergic mechanisms. Which of the following can be 'X'?

A. Tramadol (Correct Answer)
B. Etioheptazine
C. Dextropropoxyphene
D. Alfentanil

Explanation: ### Explanation **Correct Option: A (Tramadol)** Tramadol is a unique, centrally acting analgesic characterized by a **dual mechanism of action**: 1. **Opioid Mechanism:** It is a weak $\mu$-opioid receptor agonist. 2. **Non-Opioid (Monoaminergic) Mechanism:** It inhibits the neuronal reuptake of **Norepinephrine (NE)** and **Serotonin (5-HT)** in the spinal cord. This enhances the descending inhibitory pathways of pain transmission. This dual action allows for effective analgesia with a lower risk of respiratory depression and constipation compared to traditional opioids. **Analysis of Incorrect Options:** * **B. Etioheptazine:** This is an older, non-opioid analgesic structurally related to pethidine but lacks significant opioid receptor activity or monoaminergic reuptake inhibition. * **C. Dextropropoxyphene:** A weak $\mu$-opioid agonist. While it was used for mild-to-moderate pain, it does not possess the specific spinal monoaminergic reuptake inhibition seen in Tramadol. (Note: It has been banned in many regions due to cardiotoxicity). * **D. Alfentanil:** A potent, short-acting phenylpiperidine derivative that acts as a pure $\mu$-opioid agonist. It is primarily used in anesthesia and does not have a monoaminergic component. **High-Yield Clinical Pearls for NEET-PG:** * **Tapentadol:** Similar to Tramadol, it is a $\mu$-agonist and NE reuptake inhibitor (NRI), but it has negligible effect on Serotonin. * **Side Effects:** Tramadol can lower the **seizure threshold** (caution in epileptics) and may cause **Serotonin Syndrome** if combined with SSRIs or MAO inhibitors. * **Metabolism:** It is a prodrug converted to its active metabolite (O-desmethyltramadol) by **CYP2D6**.

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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