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Medical Pharmacology — MCQ ও উত্তর

মেডিকেল ভর্তি · । এই অধ্যায়ে মোট 75টি প্রশ্ন আছে। নিচে প্রথম 10টি প্রশ্ন ও সঠিক উত্তর দেওয়া হলো।

এই অধ্যায়ে সব প্রশ্নে অনুশীলন করুন

  1. The primary cause of lactic acidosis in patients taking metformin is:

    1. Mitochondrial dysfunction
    2. Increased insulin secretion
    3. Enhanced gluconeogenesis
    4. Decreased renal excretion

    সঠিক উত্তর: Mitochondrial dysfunction

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A Metformin primarily inhibits mitochondrial respiratory chain complex I, leading to reduced oxidative phosphorylation. This results in decreased cellular ATP production and promotes anaerobic metabolism, causing accumulation of lactic acid. The impaired mitochondrial function diminishes the conversion of lactate to glucose via gluconeogenesis, further increasing lactate levels. This mechanism underlies metformin-associated lactic acidosis, especially in conditions predisposing to hypoxia or impaired drug clearance. Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson, 20th Edition.

  2. Long-term use of proton pump inhibitors (PPIs) is associated with which adverse effect?

    1. Increased risk of fractures
    2. Hypokalemia
    3. Hyperglycemia
    4. Renal failure

    সঠিক উত্তর: Increased risk of fractures

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A Long-term use of proton pump inhibitors (PPIs) can lead to decreased calcium absorption due to reduced gastric acidity, which is essential for calcium solubility and absorption in the intestine. This chronic hypochlorhydria may result in impaired bone mineralization, increasing the risk of osteoporotic fractures, particularly in the hip, wrist, and spine. Patients on prolonged PPI therapy should be monitored for bone health and advised on calcium and vitamin D intake to mitigate fracture risk. Reference: Harrison's Principles of Internal Medicine, Jameson et al., 20th Edition.

  3. Which parameter determines the rate at which a drug is eliminated from the body?

    1. Clearance
    2. Bioavailability
    3. Volume of distribution
    4. Half-life

    সঠিক উত্তর: Clearance

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A The clearance of a drug is the primary parameter that quantifies the body's efficiency in eliminating the drug per unit time, reflecting the volume of plasma completely cleared of the drug. It directly determines the rate at which the drug is removed, impacting dosing and steady-state concentrations. Unlike half-life, which depends on both clearance and volume of distribution, clearance alone solely governs elimination rate. Understanding clearance is crucial for optimizing drug therapy, especially in impaired organ function. Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  4. Which factor most significantly affects drug absorption in the gastrointestinal tract?

    1. pH of the environment
    2. Drug color
    3. Patient age
    4. Route of administration

    সঠিক উত্তর: pH of the environment

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A The pH of the gastrointestinal environment significantly affects drug absorption because it influences the ionization state of the drug. Only the non-ionized form of a drug can readily cross cell membranes by passive diffusion. Since different areas of the GI tract vary in pH, drugs may be absorbed optimally in specific regions. For example, weakly acidic drugs are better absorbed in the acidic stomach, while weak bases absorb better in the more alkaline intestines. This factor directly impacts the bioavailability and therapeutic efficacy of orally administered drugs.Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  5. A drug with zero-order kinetics is characterized by:

    1. Constant rate of elimination
    2. Rate proportional to concentration
    3. Variable half-life
    4. Saturable absorption

    সঠিক উত্তর: Constant rate of elimination

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A A drug with zero-order kinetics is eliminated at a constant rate regardless of its concentration, meaning the elimination process is saturated. Unlike first-order kinetics, where elimination rate is proportional to drug concentration, zero-order elimination proceeds at a fixed amount per unit time. This results in a constant rate of elimination, and the half-life becomes variable and dependent on concentration. Clinical examples include phenytoin, ethanol, and aspirin at high doses, where the elimination pathways become saturated, causing drug accumulation if dosing is not adjusted.Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  6. What is the primary action of diuretics such as furosemide?

    1. Stimulate potassium channels
    2. Inhibit sodium reabsorption
    3. Increase aldosterone secretion
    4. Block calcium channels

    সঠিক উত্তর: Stimulate potassium channels

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A The primary action of diuretics such as furosemide is to inhibit sodium reabsorption in the thick ascending limb of the loop of Henle. This inhibition decreases sodium and chloride reabsorption, leading to increased excretion of sodium, water, and potassium. Furosemide blocks the Na⁺-K⁺-2Cl⁻ symporter, which results in a potent diuretic effect. It does not stimulate potassium channels; instead, it may cause potassium loss due to increased distal sodium delivery. Therefore, the correct primary mechanism is the inhibition of sodium reabsorption. Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  7. How does tamoxifen exert its therapeutic effect in breast cancer?

    1. Inhibits estrogen receptors
    2. Blocks androgen receptors
    3. Stimulates progesterone receptors
    4. Inhibits aromatase enzyme

    সঠিক উত্তর: Inhibits estrogen receptors

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A Tamoxifen exerts its therapeutic effect in breast cancer primarily by inhibiting estrogen receptors on breast cancer cells. It acts as a selective estrogen receptor modulator (SERM), binding to estrogen receptors and blocking estrogen from stimulating tumor growth. This inhibition reduces cell proliferation in estrogen receptor-positive breast cancers, thereby slowing disease progression. Tamoxifen’s targeted action makes it effective in both treatment and risk reduction for hormone-responsive breast cancer. Reference: DeVita, Hellman, and Rosenberg's Cancer: Principles & Practice of Oncology, DeVita et al., 11th Edition.

  8. Sildenafil treats erectile dysfunction by:

    1. Inhibiting phosphodiesterase-5
    2. Blocking alpha-adrenergic receptors
    3. Stimulating nitric oxide synthase
    4. Inhibiting testosterone synthesis

    সঠিক উত্তর: Inhibiting phosphodiesterase-5

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A Sildenafil treats erectile dysfunction by selectively inhibiting phosphodiesterase-5 (PDE5), an enzyme that breaks down cyclic guanosine monophosphate (cGMP) in the corpus cavernosum. Increased cGMP levels lead to relaxation of smooth muscle and vasodilation, allowing enhanced blood flow into the penis and facilitating erection. This mechanism is dependent on nitric oxide release during sexual stimulation but does not initiate it directly. Therefore, sildenafil enhances the natural erectile response rather than causing spontaneous erections. Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  9. The half-life of a drug is defined as:

    1. Time for plasma concentration to reduce by half
    2. Time to reach maximum effect
    3. Time for absorption
    4. Time for elimination from the body

    সঠিক উত্তর: Time for plasma concentration to reduce by half

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A The half-life of a drug is the time required for its plasma concentration to decrease by 50%. This parameter is crucial because it reflects the rate of drug elimination from the bloodstream, impacting dosing intervals and steady-state levels. It does not indicate the time to reach maximum effect or absorption but specifically measures the decline in plasma levels. Understanding half-life helps clinicians optimize therapy by predicting how long a drug stays active in the body and when the next dose should be administered to maintain therapeutic levels without toxicity.Reference: Goodman & Gilman’s The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

  10. Which method of drug administration achieves steady state most rapidly?

    1. Intravenous bolus
    2. Oral tablet
    3. Transdermal patch
    4. Intramuscular injection

    সঠিক উত্তর: Intravenous bolus

    ব্যাখ্যা: সমাধান সঠিক উত্তর: Option A Intravenous bolus administration achieves steady state most rapidly because the entire drug dose is delivered directly into the bloodstream instantaneously, resulting in an immediate peak plasma concentration. This bypasses absorption and first-pass metabolism phases that delay the onset of action in other routes like oral, transdermal, or intramuscular. Oral tablets require gastrointestinal absorption, transdermal patches rely on skin permeation, and intramuscular injections involve gradual release from muscle tissue, all prolonging the time to reach steady state. Therefore, IV bolus provides the fastest systemic availability and steady-state attainment. Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.

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