Drugs Affecting Blood and Blood Formation — MCQs

Drugs Affecting Blood and Blood Formation Indian Medical PG Practice Questions and MCQs

Question 321: Filgrastim is used in treatment of:

A. Neutropenia (Correct Answer)
B. Anemia
C. Malaria
D. Filariasis

Explanation: ***Neutropenia*** - **Filgrastim** is a **granulocyte colony-stimulating factor (G-CSF)**, which stimulates the production and release of neutrophils from the bone marrow. - It is primarily used to treat or prevent **neutropenia**, a condition characterized by abnormally low levels of neutrophils, often seen in cancer patients undergoing chemotherapy. *Anemia* - **Anemia** is a condition characterized by a deficiency of red blood cells or hemoglobin. - While red blood cells are also produced in the bone marrow, G-CSFs like filgrastim do not directly stimulate **erythropoiesis** (red blood cell production). *Malaria* - **Malaria** is a parasitic disease transmitted by mosquitoes, affecting red blood cells and other organs. - Treatment for malaria involves **antimalarial drugs** that target the parasite, not bone marrow stimulants like filgrastim. *Filarial* - **Filariasis** is a parasitic disease caused by roundworms, typically transmitted by mosquitoes or black flies. - Treatment involves **anthelmintic drugs** to kill the parasites and manage symptoms, not filgrastim, which targets neutrophil production.

Question 322: Which of the following statements about vitamin K is correct?

A. All of the options are incorrect.
B. It is an anticoagulant.
C. Prolonged use of antimicrobials can lead to vitamin K deficiency. (Correct Answer)
D. The recommended dietary allowance (RDA) for adults is 500-600 micrograms.

Explanation: ***Prolonged use of antimicrobials can lead to vitamin K deficiency.*** - **Antimicrobials** can reduce the normal flora in the gut, which are responsible for synthesizing a significant portion of the body's **vitamin K**. - This reduction in gut bacteria can lead to decreased **vitamin K production** and absorption, potentially causing a deficiency. *It is an anticoagulant.* - **Vitamin K** is a crucial factor in the **coagulation** cascade, acting as a **procoagulant** by activating clotting factors. - Anticoagulants, such as **warfarin**, work by *inhibiting* vitamin K's action, thereby *reducing* clotting. *All of the options are incorrect.* - As established, one of the statements is indeed **correct**, making this option false. - There is a valid statement regarding vitamin K and antimicrobials. *The recommended dietary allowance (RDA) for adults is 500-600 micrograms.* - The **RDA** for adult men is approximately **120 micrograms (mcg)** per day, and for adult women, it is about **90 mcg** per day. - The figure of 500-600 micrograms is significantly higher than the actual recommended daily intake.

Question 323: What type of anticoagulant is Apixaban?

A. Antithrombin inhibitor
B. Direct Xa inhibitor (Correct Answer)
C. Vitamin K antagonist
D. Factor XII inhibitor

Explanation: ***Direct Xa inhibitor*** - **Apixaban** belongs to a class of anticoagulants known as **direct oral anticoagulants (DOACs)**. - It directly inhibits **Factor Xa**, preventing the conversion of **prothrombin to thrombin** and thereby blocking the coagulation cascade. *Antithrombin inhibitor* - **Antithrombin inhibitors** like unfractionated heparin and low molecular weight heparins work by enhancing the activity of the natural anticoagulant **antithrombin**. - Apixaban's mechanism of action is independent of antithrombin. *Vitamin K antagonist* - **Vitamin K antagonists** such as **warfarin** interfere with the synthesis of **vitamin K-dependent clotting factors** (II, VII, IX, X) in the liver. - Apixaban does not affect vitamin K metabolism. *Clotting Factor XII* - **Factor XII** (Hageman factor) is involved in the intrinsic pathway of coagulation. - Apixaban specifically targets **Factor Xa**, not Factor XII.

Question 324: What is the primary treatment indication of folic acid?

A. Prevention of neural tube defects in pregnancy
B. Treatment of megaloblastic anemia (Correct Answer)
C. Management of hemoglobinopathies
D. None of the above

Explanation: ***Treatment of megaloblastic anemia*** - Folic acid is essential for **DNA synthesis** and cell division, and its deficiency leads to impaired red blood cell maturation, causing **megaloblastic anemia**. - Supplementation with folic acid effectively reverses the hematological abnormalities in **folate-deficient megaloblastic anemia**. *Prevention of neural tube defects in pregnancy* - While folic acid is crucial for preventing **neural tube defects** (NTDs), this is a **prophylactic** rather than a primary therapeutic use. - The focus of this question is on the *primary therapeutic* use, implying treatment of an existing condition. *Management of hemoglobinopathies* - Hemoglobinopathies like **sickle cell anemia** or **thalassemia** are genetic disorders affecting hemoglobin structure or production, not primarily due to folic acid deficiency. - Folic acid may be given to these patients to support increased red blood cell turnover, but it does not address the underlying genetic defect. *None of the above* - This option is incorrect because folic acid has a clear primary therapeutic role in treating **megaloblastic anemia**.

Question 325: All of the following are medical uses of erythropoietin except?

A. Treatment of anaemia associated with renal disease
B. Chemotherapy induced anemia
C. Megaloblastic Anemia (Correct Answer)
D. Specific cases of anemia associated with Crohn's disease.

Explanation: ***Megaloblastic Anemia*** - Megaloblastic anemia is caused by **vitamin B12 or folate deficiency**, which impairs DNA synthesis and leads to the production of large, immature red blood cells. - Treatment involves supplementing the deficient vitamin (B12 or folate), as erythropoietin does not address the underlying cause of impaired red blood cell maturation. *Treatment of anaemia associated with renal disease* - **Erythropoietin** is primarily produced by the kidneys, and chronic kidney disease often leads to decreased erythropoietin production, resulting in anemia. - Administering exogenous erythropoietin stimulates red blood cell production, making it a critical treatment for **anemia of chronic kidney disease**. *Chemotherapy induced anemia* - Chemotherapy can suppress bone marrow function, leading to **decreased red blood cell production** and subsequent anemia. - Erythropoietin-stimulating agents can be used to mitigate this side effect by **stimulating erythropoiesis** in the bone marrow. *Specific cases of anemia associated with Crohn's disease.* - Anemia in Crohn's disease can have multiple causes, including iron deficiency from blood loss, malabsorption of vitamins, and **anemia of chronic disease**. - Erythropoietin may be considered in cases where the anemia is primarily due to **inflammation-induced suppression of erythropoiesis** or decreased erythropoietin response, particularly if other treatments are ineffective.

Question 326: All of the following are characteristic features of treatment of iron deficiency anemia with oral iron supplements, except which of the following?

A. Bioavailability is enhanced with vitamin C
B. The proportion of iron absorbed reduces as hemoglobin improves
C. The reticulocyte count should begin to increase within 7-10 days and peak at 2-4 weeks; this suggests good response to treatment
D. The treatment should be discontinued immediately once hemoglobin normalizes to prevent side effects of iron (Correct Answer)

Explanation: ***The treatment should be discontinued immediately once hemoglobin normalizes to prevent side effects of iron*** - Treatment of **iron deficiency anemia** with oral iron supplements should continue for at least **3-6 months** after hemoglobin normalizes to replenish **iron stores**. - Premature cessation can lead to a rapid **recurrence of anemia** due to depleted iron reserves, despite normal hemoglobin levels. *Bioavailability is enhanced with vitamin C* - **Ascorbic acid (vitamin C)** creates an acidic environment in the stomach and reduces ferric iron (Fe3+) to ferrous iron (Fe2+), which is more readily absorbed. - This enhancement of **ferrous iron absorption** is a common practice to improve the efficacy of oral iron supplements. *The proportion of iron absorbed reduces as hemoglobin improves* - The body's **iron absorption mechanism** is tightly regulated by **hepcidin**, a hormone that increases when iron stores are sufficient. - As hemoglobin levels improve and iron stores are replenished, hepcidin levels rise, leading to a **decrease in iron absorption** to prevent iron overload. *The reticulocyte count should begin to increase in two weeks and peak in 4 weeks this suggests good response to treatment* - An increase in **reticulocyte count** by approximately **7-10 days** and peaking around **2-4 weeks** after starting iron therapy indicates that the bone marrow is effectively responding to the increased iron availability by producing new red blood cells. - This **reticulocytosis** is an early and reliable sign of a positive treatment response before a significant rise in hemoglobin is observed.

Question 327: What is the recommended therapeutic supplementation of iron and folic acid for adults with deficiency?

A. 20 mg iron, 500 mcg folic acid
B. 40 mg iron, 250 mcg folic acid
C. 100 mg iron, 500 mcg folic acid (Correct Answer)
D. 100 mg iron, 100 mcg folic acid

Explanation: ***100 mg iron, 500 mcg folic acid*** - For adults with **iron deficiency anemia**, the therapeutic dose of elemental iron is typically **100-200 mg daily**, commonly given as ferrous sulfate 325 mg (containing ~65 mg elemental iron) 2-3 times daily. **100 mg is an appropriate therapeutic dose**. - For **folic acid deficiency**, the standard therapeutic dose is **1-5 mg (1000-5000 mcg) daily** for treating established deficiency. However, **500 mcg (0.5 mg)** represents a minimal therapeutic/high prophylactic dose that may be used in milder deficiencies or as initial supplementation. Among the given options, this is the most appropriate combination. *20 mg iron, 500 mcg folic acid* - **20 mg of iron** is grossly insufficient for therapeutic supplementation in iron deficiency anemia and would fail to correct the anemia adequately. - While 500 mcg folic acid has some therapeutic value, the **iron dose is far too low** for treatment. *40 mg iron, 250 mcg folic acid* - **40 mg of iron** is a prophylactic dose (used in pregnancy or prevention) but is **insufficient for therapeutic correction** of established iron deficiency anemia. - **250 mcg of folic acid** is also a prophylactic dose and inadequate for treating established deficiency. *100 mg iron, 100 mcg folic acid* - **100 mg of iron** is an appropriate therapeutic dose for treating **iron deficiency anemia**. - However, **100 mcg of folic acid** is purely a maintenance/prophylactic dose found in multivitamins and is **grossly insufficient** for treating established folic acid deficiency.

Question 328: Ximelagatran is used as ?

A. Anticoagulant (Correct Answer)
B. Fibrinolytic
C. Platelet inhibitor
D. Clot buster

Explanation: ***Anticoagulant*** - Ximelagatran is a **direct thrombin inhibitor**, meaning it directly blocks the action of thrombin, a key enzyme in the coagulation cascade. - By inhibiting thrombin, it prevents the formation of **fibrin clots**, thus acting as an anticoagulant. *Platelet inhibitor* - **Platelet inhibitors** prevent platelets from clumping together to form a clot, often by targeting pathways like ADP receptors or COX-1 enzyme. - Examples include **aspirin** and **clopidogrel**, which have different mechanisms of action than Ximelagatran. *Clot buster* - **Clot busters** are also known as thrombolytic agents, which actively dissolve existing blood clots. - They work by activating **plasminogen** to produce plasmin, an enzyme that breaks down fibrin. *Fibrinolytic* - **Fibrinolytics** are a class of drugs that enhance **fibrinolysis**, the natural process of breaking down blood clots. - **Thrombolytics** are a subset of fibrinolytic drugs used therapeutically to dissolve clots.

Question 329: Which of the following statements best describes the underlying mechanism of heparin-induced thrombocytopenia?

A. Low molecular weight heparin can also cause heparin-induced thrombocytopenia.
B. Vitamin K is not an antidote for heparin-induced thrombocytopenia.
C. Heparin-induced thrombocytopenia can occur after several days of heparin therapy.
D. Antibodies are formed against heparin-platelet factor 4 complexes. (Correct Answer)

Explanation: **_Antibodies are formed against platelet factor 4._** - The underlying mechanism of **heparin-induced thrombocytopenia (HIT)** involves the formation of antibodies against complexes of **heparin and platelet factor 4 (PF4)** [2]. - These antibodies bind to the **heparin-PF4 complexes** on the surface of platelets, leading to platelet activation, aggregation, and consumption, which results in thrombocytopenia and a prothrombotic state [2]. *Low molecular weight heparin can also cause heparin-induced thrombocytopenia.* - While **low molecular weight heparin (LMWH)** has a lower incidence of causing HIT compared to unfractionated heparin, it can still trigger the condition [1], [2]. - This is because LMWH, like unfractionated heparin, can form complexes with PF4, leading to the same immune response in susceptible individuals [2]. *Vitamin K is not an antidote for heparin-induced thrombocytopenia.* - **Vitamin K** is the antidote for warfarin overdose, which works by reversing its anticoagulant effects [3]. - It has no role as an antidote for HIT because HIT is an **immune-mediated reaction** involving platelet activation, not a direct anticoagulant effect that can be reversed by Vitamin K [2]. *Heparin-induced thrombocytopenia can occur after several days of heparin therapy.* - HIT typically manifests after **5 to 10 days of heparin exposure**, as it takes time for the immune system to produce antibodies against the heparin-PF4 complexes [2]. - However, in patients with prior exposure to heparin, HIT can occur much sooner, even within **24 hours**, due to pre-existing antibodies.

Question 330: Which of the following is a parenteral direct thrombin inhibitor?

A. Ximelagatran
B. Dabigatran
C. Argatroban (Correct Answer)
D. Heparin

Explanation: ***Argatroban*** - **Argatroban** is a **synthetic direct thrombin inhibitor** administered exclusively via **intravenous infusion**, making it a parenteral drug. - It does not require antithrombin for its action and is primarily used in patients with **heparin-induced thrombocytopenia (HIT)**. *Ximelagatran* - **Ximelagatran** was an **oral direct thrombin inhibitor** but was withdrawn from the market due to concerns about severe **liver toxicity**. - As an oral drug, it is not a parenteral medication. *Dabigatran* - **Dabigatran** is a **direct thrombin inhibitor** that is administered **orally** in capsule form (as dabigatran etexilate, a prodrug). - Therefore, it is not a parenteral medication. *Heparin* - **Heparin** is an **indirect thrombin inhibitor** because it requires binding to **antithrombin** to exert its anticoagulant effect. - Although administered parenterally, its mechanism of action is indirect.

Practice by Chapter

Hematopoietic Growth Factors

Practice Questions

Iron Preparations and Management of Iron Deficiency

Practice Questions

Vitamin B12 and Folic Acid

Practice Questions

Anticoagulants: Heparins and Direct Inhibitors

Practice Questions

Oral Anticoagulants

Practice Questions

Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

Practice Questions

Hemostatic Drugs

Practice Questions

Plasma Expanders

Practice Questions

Blood Transfusion and Alternatives

Practice Questions

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