Drugs Affecting Blood and Blood Formation Practice Questions

Q: Eculizumab, an anti-C5 monoclonal antibody, is used in the treatment of which condition?

Paroxysmal nocturnal hemoglobinuria. **Explanation:** **Eculizumab** is a humanized monoclonal antibody that targets the **C5 complement protein**. By binding to C5, it inhibits its cleavage into C5a and C5b, thereby preventing the formation of the **Membrane Attack Complex (MAC/C5b-9)**. 1. **Why Option D is Correct:** **Paroxysmal Nocturnal Hemoglobinuria (PNH)** is caused by an acquired mutation in the *PIGA* gene, leading to a deficiency of GPI-anchored proteins like **CD55 and CD59** on red blood cells. These proteins normally protect cells from complement-mediated lysis. In their absence, the alternative complement pathway causes chronic intravascular hemolysis. Eculizumab prevents this hemolysis by blocking the terminal complement cascade. 2. **Why Other Options are Incorrect:** * **Options A & B (Lymphomas):** Non-Hodgkin’s Lymphoma is typically treated with **Rituximab** (anti-CD20), while Hodgkin’s Lymphoma may involve **Brentuximab vedotin** (anti-CD30). Eculizumab has no role in treating lymphoid malignancies. * **Option C (Multiple Myeloma):** This is treated with proteasome inhibitors (Bortezomib), immunomodulators (Lenalidomide), or monoclonal antibodies like **Daratumumab** (anti-CD38). **High-Yield Clinical Pearls for NEET-PG:** * **Black Box Warning:** Eculizumab significantly increases the risk of **Meningococcal infections** (*Neisseria meningitidis*). Patients **must** be vaccinated with meningococcal vaccines at least 2 weeks prior to starting therapy. * **Other Indications:** It is also FDA-approved for **Atypical Hemolytic Uremic Syndrome (aHUS)**, Myasthenia Gravis (AChR-antibody positive), and Neuromyelitis Optica Spectrum Disorder (NMOSD). * **Ravulizumab** is a newer, longer-acting C5 inhibitor used for similar indications.

Q: Eculizumab is used in the treatment of which condition?

Paroxysmal nocturnal hemoglobinuria. ### Explanation **Correct Answer: C. Paroxysmal nocturnal hemoglobinuria (PNH) [1]** **Mechanism of Action:** Eculizumab is a **humanized monoclonal antibody** that binds to the **C5 complement protein** [1]. By inhibiting the cleavage of C5 into C5a and C5b, it prevents the formation of the **Membrane Attack Complex (MAC)**. In PNH, red blood cells lack protective proteins (CD55 and CD59) due to a PIGA gene mutation, making them vulnerable to complement-mediated lysis. Eculizumab halts this intravascular hemolysis, reducing the need for transfusions and the risk of thrombosis. **Analysis of Incorrect Options:** * **A. Acne vulgaris:** Treated with retinoids (Isotretinoin), antibiotics (Doxycycline), or benzoyl peroxide. Monoclonal antibodies are not used here. * **B. Asthma:** Biological therapies for severe asthma include Omalizumab (anti-IgE), Mepolizumab (anti-IL-5), or Dupilumab (anti-IL-4/13), but not complement inhibitors. * **D. Autoimmune hemolytic anemia (AIHA):** While it involves hemolysis, the primary treatment involves corticosteroids, Rituximab (anti-CD20), or immunosuppressants. Eculizumab is specifically indicated for complement-mediated disorders like PNH and Atypical Hemolytic Uremic Syndrome (aHUS). **High-Yield Clinical Pearls for NEET-PG:** 1. **Black Box Warning:** Eculizumab significantly increases the risk of **Meningococcal infections** (Neisseria meningitidis) because the MAC is essential for killing encapsulated bacteria. 2. **Mandatory Pre-requisite:** Patients must receive the **Meningococcal vaccine** at least 2 weeks before starting therapy. 3. **Other Indications:** Atypical Hemolytic Uremic Syndrome (aHUS), Generalized Myasthenia Gravis (gMG), and Neuromyelitis Optica Spectrum Disorder (NMOSD). 4. **Ravulizumab:** A long-acting derivative of Eculizumab with a longer half-life, allowing for less frequent dosing.

Q: A patient is started on oral warfarin therapy. Which of the following coagulation factors shows the most rapid decline in blood levels after initiation of warfarin therapy?

Protein C. **Explanation:** Warfarin acts as a Vitamin K antagonist, inhibiting the enzyme **Vitamin K Epoxide Reductase (VKOR)**. This prevents the γ-carboxylation of Vitamin K-dependent clotting factors (II, VII, IX, X) and endogenous anticoagulant proteins (Protein C and Protein S). The rate at which these factors decline in the blood depends entirely on their individual **half-lives**. * **Protein C** has the shortest half-life (approx. **6–8 hours**) among all the factors affected by warfarin. Because it disappears first, there is a transient period where the patient is actually in a "pro-thrombotic" state (hypercoagulable) because the natural anticoagulant (Protein C) is gone while the pro-coagulant factors (especially II and X) are still circulating. **Analysis of Incorrect Options:** * **Factor VII:** While Factor VII has the shortest half-life among the *clotting* factors (approx. 4–6 hours), **Protein C** is often cited as having a similarly rapid or slightly more clinically significant initial decline in the context of the "warfarin skin necrosis" phenomenon. In most competitive exams, if both are listed, Protein C is the preferred answer for the "most rapid decline." * **Factor X:** Has a moderate half-life of approximately 36–48 hours. * **Prothrombin (Factor II):** Has the longest half-life (approx. 60–72 hours) and is the last to decline. **Clinical Pearls for NEET-PG:** 1. **Warfarin-Induced Skin Necrosis:** Occurs due to the rapid depletion of Protein C, leading to microvascular thrombosis before the full anticoagulant effect is achieved. 2. **Heparin Bridge:** To prevent the above, heparin is always co-administered with warfarin ("bridging") until the INR reaches the therapeutic range. 3. **Monitoring:** Warfarin is monitored using **PT/INR** (Extrinsic pathway), primarily reflecting the decline in Factor VII initially.

Q: Which of the following is NOT an adverse effect of heparin?

Hypokalemia. The correct answer is **C. Hypokalemia**. Heparin actually causes **Hyperkalemia**, not hypokalemia. **1. Why Hypokalemia is the correct answer (The Mechanism):** Heparin inhibits the synthesis of **aldosterone** in the adrenal cortex by reducing the number and affinity of angiotensin II receptors in the zona glomerulosa. Since aldosterone is responsible for excreting potassium and retaining sodium, its suppression leads to potassium retention, resulting in **hyperkalemia**. This effect can occur even with low-dose prophylactic heparin and is more pronounced in patients with diabetes or renal insufficiency. **2. Analysis of Incorrect Options:** * **A. Bleeding:** This is the most common adverse effect of heparin [2]. It is managed by stopping the drug or, in severe cases, administering the specific antidote, **Protamine sulfate** [1]. * **B. Thrombocytopenia:** Heparin-Induced Thrombocytopenia (HIT) is a serious immune-mediated reaction (Type II hypersensitivity) where IgG antibodies form against the Heparin-Platelet Factor 4 complex, leading to paradoxical thrombosis [3]. * **D. Osteoporosis:** Long-term heparin therapy (usually >3 months) can lead to bone loss and spontaneous fractures [2]. It occurs because heparin increases osteoclast activity and decreases osteoblast formation. **Clinical Pearls for NEET-PG:** * **Monitoring:** Unfractionated Heparin (UFH) is monitored using **aPTT** (target 1.5–2.5 times control). Low Molecular Weight Heparin (LMWH) usually does not require monitoring but can be checked using **Factor Xa assay** [2]. * **Antidote:** 1 mg of Protamine sulfate neutralizes 100 units of UFH [1]. It only partially neutralizes LMWH. * **Safe in Pregnancy:** Heparin does not cross the placenta and is the anticoagulant of choice during pregnancy (unlike Warfarin, which is teratogenic) [2].

Q: Which of the following is an indication for parenteral iron therapy?

Intolerance to oral iron. **Explanation:** Iron deficiency anemia is primarily managed with oral iron. However, **parenteral iron therapy** is reserved for specific clinical scenarios where oral administration is either impossible, ineffective, or unsafe. **Why Option B is Correct:** **Intolerance to oral iron** is the most common indication for parenteral therapy. Many patients experience significant gastrointestinal side effects (nausea, abdominal cramps, constipation, or metallic taste) that prevent them from completing the course. Other indications include malabsorption syndromes (e.g., Celiac disease, H. pylori gastritis), inflammatory bowel disease (where oral iron can exacerbate inflammation), and chronic kidney disease (CKD) patients on erythropoietin. **Analysis of Incorrect Options:** * **Option A & D:** While parenteral iron bypasses compliance issues and reduces the duration of treatment, these are not standard medical indications. Oral iron remains the first-line choice due to its safety profile and low cost. * **Option C:** This is a common misconception. Parenteral iron **does not** raise hemoglobin levels faster than oral iron; it only replenishes iron stores more rapidly. If an immediate rise in hemoglobin is required (e.g., a patient in labor or severe acute hemorrhage), **blood transfusion** is the treatment of choice. **High-Yield NEET-PG Pearls:** * **Rate of Response:** The rate of hemoglobin rise is the same for both oral and parenteral iron (approx. 0.7–1 g/dL per week). * **Dose Calculation:** The total dose of parenteral iron is calculated using the **Ganzoni Formula**: * *Total Iron Deficit (mg) = Body weight (kg) × (Target Hb - Actual Hb) × 2.4 + Iron stores (500 mg).* * **Safety:** Iron Dextran carries a risk of anaphylaxis; a **test dose** is mandatory. Newer preparations like Iron Sucrose and Ferric Carboxymaltose have a lower risk of hypersensitivity.

Q: Iron dextran is indicated for which condition?

Macrocytic anemia. **Explanation:** **Correct Option: A (Macrocytic anemia)** While Iron Dextran is primarily an iron supplement, this question tests a specific clinical scenario often encountered in NEET-PG: **Dimorphic Anemia**. In patients with macrocytic anemia (due to Vitamin B12 or Folic acid deficiency) [1, 3], the initiation of treatment leads to a rapid surge in erythropoiesis. This sudden demand for hemoglobin synthesis can deplete existing iron stores, leading to a secondary iron deficiency [3]. In such cases, parenteral iron like **Iron Dextran** is indicated to support the rapid red blood cell production triggered by B12/Folate therapy. **Incorrect Options:** * **B. Severe blood loss:** The immediate treatment for severe, acute blood loss is whole blood or packed red blood cell (PRBC) transfusion to restore volume and oxygen-carrying capacity, not iron supplementation. * **C. Iron deficiency anemia:** While Iron Dextran *is* used for iron deficiency, **Oral Iron** (e.g., Ferrous sulfate) is the first-line treatment. Parenteral iron is reserved only for patients with oral intolerance, malabsorption, or non-compliance [2]. * **D. Hookworm anemia:** The primary management involves anthelmintic therapy (Albendazole) to stop the loss, followed by oral iron to replenish stores. **High-Yield Clinical Pearls for NEET-PG:** * **Route:** Iron Dextran can be given IM or IV. If given IM, use the **Z-track technique** to prevent skin staining. * **Adverse Effect:** It carries a high risk of **Type I Anaphylactic reactions**. A **test dose** is mandatory before the full dose. * **Calculation:** The total dose required is calculated using the **Haldane’s formula** (or Ganzoni equation). * **Modern Alternatives:** Iron Sucrose and Ferric Carboxymaltose are now preferred over Iron Dextran due to a lower risk of anaphylaxis [1].

Question 1

Eculizumab, an anti-C5 monoclonal antibody, is used in the treatment of which condition?

Accepted Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Non-Hodgkin's lymphoma (NHL)

Answer

Hodgkin's lymphoma

Answer

Multiple myeloma

Question 2

Eculizumab is used in the treatment of which condition?

Accepted Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Acne vulgaris

Answer

Asthma

Answer

Autoimmune hemolytic anemia

Question 3

What is the recommended level of anticoagulation for most patients, as measured by INR?

Accepted Answer

2.0-3.0

Answer

1.0-2.0

Answer

2.5-3.5

Answer

3.0-4.5

Question 4

Which of the following statements regarding ticlopidine is TRUE?

Accepted Answer

It prevents ADP mediated platelet adenylyl cyclase inhibition

Answer

It blocks GpIIb/IIIa receptors on platelet membrane

Answer

It inhibits thromboxane A2 synthesis in platelets

Answer

It does not prolong bleeding time

Question 5

A patient is started on oral warfarin therapy. Which of the following coagulation factors shows the most rapid decline in blood levels after initiation of warfarin therapy?

Accepted Answer

Protein C

Answer

Factor VII

Answer

Factor X

Answer

Prothrombin (Factor II)

Question 6

Which of the following is NOT an adverse effect of heparin?

Accepted Answer

Hypokalemia

Answer

Bleeding

Answer

Thrombocytopenia

Answer

Osteoporosis

Question 7

Which of the following is an indication for parenteral iron therapy?

Accepted Answer

Intolerance to oral iron

Answer

Patient compliance

Answer

When an immediate rise in hemoglobin is required, such as in a patient in labor

Answer

To decrease the duration of oral medication

Question 8

Erythropoietin is absolutely necessary for the treatment of:

Accepted Answer

End-stage renal failure

Answer

Liver failure

Answer

Heart failure

Answer

Lung failure

Question 9

Hypercoagulability and dermal vascular necrosis are early appearing adverse effects of:

Accepted Answer

Warfarin

Answer

Clopidogrel

Answer

Heparin

Answer

Vitamin K

Question 10

Iron dextran is indicated for which condition?

Accepted Answer

Macrocytic anemia

Answer

Severe blood loss

Answer

Iron deficiency anemia

Answer

Hookworm anemia

Drugs Affecting Blood and Blood Formation — MCQs

Drugs Affecting Blood and Blood Formation — MCQs

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