Drugs Affecting Blood and Blood Formation Practice Questions

Q: All of the following are false regarding prasugrel, except?

Contraindicated in cerebrovascular accident. **Explanation:** Prasugrel is a third-generation **thienopyridine** derivative and a potent P2Y12 receptor antagonist used to inhibit platelet aggregation. **Why Option D is Correct:** Prasugrel is associated with a significantly higher risk of major bleeding compared to clopidogrel. It is strictly **contraindicated** in patients with a history of **Cerebrovascular Accident (CVA)** or **Transient Ischemic Attack (TIA)** because it markedly increases the risk of intracranial hemorrhage in these individuals. **Analysis of Incorrect Options:** * **Option A:** Prasugrel is a **prodrug**. Unlike clopidogrel, which requires a complex two-step hepatic activation, prasugrel undergoes rapid hydrolysis by intestinal esterases followed by a single CYP-dependent step. It undergoes extensive metabolism, not minimal. * **Option B:** Because its metabolic activation is more efficient and less dependent on genetic polymorphisms (like CYP2C19), prasugrel has a **faster onset of action** and provides more consistent platelet inhibition than clopidogrel. * **Option C:** Like all thienopyridines (clopidogrel, ticlopidine), prasugrel binds **irreversibly** to the P2Y12 ADP receptor for the lifespan of the platelet. Only non-thienopyridines like Ticagrelor and Cangrelor are reversible inhibitors. **High-Yield Clinical Pearls for NEET-PG:** * **TRITON-TIMI 38 Trial:** Demonstrated prasugrel's superiority over clopidogrel in reducing MI but highlighted the increased bleeding risk. * **Dosing Caution:** Use with caution or reduced dose in patients weighing ** 75 years** due to bleeding risk. * **Drug Interactions:** Unlike clopidogrel, prasugrel's efficacy is not significantly affected by Proton Pump Inhibitors (PPIs) like omeprazole.

Q: Laboratory monitoring of which of the following is desirable with low molecular weight heparin therapy in a patient with renal failure?

Anti-factor Xa activity. ### Explanation **Correct Answer: D. Anti-factor Xa activity** **Mechanism and Rationale:** Low Molecular Weight Heparin (LMWH), such as Enoxaparin, primarily acts by inhibiting **Factor Xa** rather than Thrombin (Factor IIa) [1]. Unlike Unfractionated Heparin (UFH), LMWH has a predictable pharmacokinetic profile and is primarily excreted by the **kidneys**. In patients with **renal failure** (specifically CrCl <30 ml/min), LMWH can accumulate, significantly increasing the risk of major hemorrhage. Because LMWH does not significantly prolong the aPTT, standard coagulation tests are ineffective for monitoring. Therefore, **Anti-factor Xa activity** is the gold standard for monitoring LMWH when dosing safety is a concern (e.g., renal insufficiency, obesity, or pregnancy) [1]. **Why other options are incorrect:** * **A. aPTT (Activated Partial Thromboplastin Time):** This is used to monitor **Unfractionated Heparin (UFH)** [1]. LMWH has a high anti-Xa to anti-IIa ratio (approx. 3:1), meaning it does not prolong aPTT enough to be used for therapeutic monitoring. * **B. CT (Clotting Time):** This is an obsolete, non-specific bedside test (e.g., Lee-White method) with no role in monitoring modern anticoagulant therapy. * **C. PT (Prothrombin Time):** This measures the extrinsic pathway [3] and is used to monitor **Warfarin** (Vitamin K antagonists), not heparin products [2]. **NEET-PG High-Yield Pearls:** * **Monitoring LMWH:** Usually not required. Indications for monitoring Anti-Xa levels include **Renal failure**, **Pregnancy**, and **Extreme obesity** [1]. * **Antidote:** Protamine sulfate completely neutralizes UFH but only **partially** neutralizes LMWH (approx. 60-70%). * **Drug of Choice in Renal Failure:** If anticoagulation is needed in severe ESRD, **Unfractionated Heparin** is generally preferred over LMWH because it is cleared by the reticuloendothelial system, not the kidneys.

Q: Which antiplatelet drug acts via purinergic receptors and is not largely impacted by CYP2C19 polymorphism?

Prasugrel. **Explanation:** **Prasugrel** is the correct answer because it is a third-generation thienopyridine that acts as a prodrug, irreversibly inhibiting the **P2Y12 purinergic receptor**. Unlike Clopidogrel, Prasugrel undergoes a more efficient, single-step metabolic activation by CYP3A4 and CYP2B6. It is **not significantly impacted by CYP2C19 polymorphisms**, leading to more predictable antiplatelet effects and faster onset of action. **Analysis of Options:** * **Clopidogrel (Option C):** This is a second-generation thienopyridine. Its activation is heavily dependent on the **CYP2C19** enzyme. Patients who are "poor metabolizers" due to CYP2C19 genetic polymorphism have reduced active metabolite levels, leading to a higher risk of cardiovascular events (e.g., stent thrombosis). * **Ticlopidine (Option A):** A first-generation thienopyridine. While it acts on P2Y12 receptors, it is rarely used today due to severe side effects like **neutropenia** and TTP. It is also a prodrug but is not the preferred answer regarding the specific CYP2C19 clinical context. * **Abciximab (Option D):** This is a monoclonal antibody that acts as a **GP IIb/IIIa receptor antagonist**. It does not act on purinergic (P2Y12) receptors and is administered intravenously. **High-Yield NEET-PG Pearls:** * **Ticagrelor:** A cyclopentyl-triazolo-pyrimidine that is **directly acting** (not a prodrug) and **reversible**. Like Prasugrel, it is not affected by CYP2C19. * **Prasugrel Contraindication:** It is strictly contraindicated in patients with a **history of stroke or TIA** due to a high risk of intracranial hemorrhage. * **Monitoring:** Platelet function is generally not monitored, but the gold standard for research is Light Transmission Aggregometry (LTA).

Q: Capillary leak syndrome is caused by which of the following drugs?

Sargramostim. **Sargramostim** is a recombinant **Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF)** [1]. Unlike G-CSF, which acts specifically on neutrophil precursors, GM-CSF stimulates multiple lineages (neutrophils, monocytes, macrophages, and eosinophils) and activates mature myeloid cells [1]. This broader activation leads to the release of pro-inflammatory cytokines (like TNF-α and IL-1), which increase vascular permeability. At higher doses, this manifests clinically as **Capillary Leak Syndrome**, characterized by peripheral edema, pleural/pericardial effusions, and respiratory distress. **Analysis of Incorrect Options:** * **Filgrastim & Pegfilgrastim (Options A & C):** These are recombinant **G-CSF** (Granulocyte Colony-Stimulating Factor) preparations. Their action is more lineage-specific. The most common side effect is **bone pain** (due to marrow expansion). While they can rarely cause splenic rupture, they are not typically associated with capillary leak syndrome. * **Darbepoetin (Option D):** This is a long-acting erythropoiesis-stimulating agent (ESA). Its primary adverse effects include **hypertension** and an increased risk of thromboembolic events (stroke, MI), especially if hemoglobin is raised too rapidly. **NEET-PG High-Yield Pearls:** * **Sargramostim "First-Dose Effect":** The initial dose can cause a transient syndrome of hypotension, tachycardia, and arterial oxygen desaturation. * **GM-CSF vs. G-CSF:** GM-CSF (Sargramostim) has more systemic toxicity (fever, malaise, capillary leak) compared to G-CSF (Filgrastim). * **Other drugs causing Capillary Leak Syndrome:** Interleukin-2 (Aldesleukin) is the most classic culprit mentioned in exams alongside Sargramostim. * **Clinical Use:** Sargramostim is primarily used to accelerate myeloid recovery after bone marrow transplantation or in intensive chemotherapy [2].

Q: A patient with anterior wall myocardial infarction was thrombolysed within 6 hours of presentation. On day 3, the patient developed fever with chills and a platelet count of 60,000. Which of the following is responsible for this presentation?

Clopidogrel. ### Explanation The patient’s presentation of **fever, chills, and thrombocytopenia** (platelet count 60,000) following an acute myocardial infarction is highly suggestive of **Thrombotic Thrombocytopenic Purpura (TTP)**, a rare but serious side effect associated with thienopyridines. **1. Why Clopidogrel is correct:** Clopidogrel is a P2Y12 receptor inhibitor commonly used in post-MI management. It is known to cause **drug-induced TTP**, typically occurring within the first 2 weeks of starting therapy. The classic pentad of TTP includes fever, thrombocytopenia, microangiopathic hemolytic anemia (MAHA), neurological symptoms, and renal failure. In NEET-PG scenarios, the combination of fever and sudden drop in platelets after starting antiplatelets points toward Clopidogrel-induced TTP. **2. Why other options are incorrect:** * **Aspirin:** While it causes platelet dysfunction (irreversible inhibition of COX-1), it does not typically cause a significant drop in platelet count or fever. * **Ranolazine:** Used for chronic stable angina, its primary side effects are QT prolongation, dizziness, and constipation; it is not associated with acute thrombocytopenia. * **Streptokinase (STK):** Though STK can cause fever and chills due to its antigenic nature (derived from *Streptococcus*), it causes bleeding due to systemic fibrinolysis, not isolated thrombocytopenia or TTP. **3. Clinical Pearls for NEET-PG:** * **Ticlopidine vs. Clopidogrel:** Ticlopidine (an older thienopyridine) has a much higher incidence of TTP and neutropenia compared to Clopidogrel. * **Mechanism of TTP:** Often involves the formation of autoantibodies against **ADAMTS13**, a von Willebrand factor-cleaving protease. * **Treatment:** The treatment of choice for drug-induced TTP is **Plasmapheresis (Plasma exchange)**. Platelet transfusion is generally contraindicated as it may "fuel the fire" of microthrombi formation.

Q: Plasma expanders are used in which of the following conditions?

Severe trauma. **Explanation:** **Plasma expanders** are intravenous fluids (colloids or crystalloids) used to restore circulating blood volume and maintain hemodynamic stability. **Why Severe Trauma is correct:** In severe trauma, the primary concern is **hypovolemic shock** due to acute blood loss or fluid shifts. Plasma expanders (like Hydroxyethyl starch, Dextran, or Gelatins) increase the oncotic pressure of the blood, drawing fluid into the vascular compartment and expanding the volume more effectively than crystalloids alone. This maintains cardiac output and organ perfusion until definitive blood transfusion or surgery can occur. **Why other options are incorrect:** * **Severe Anemia:** The primary deficit is oxygen-carrying capacity (Hemoglobin), not necessarily volume. Treatment requires Packed Red Blood Cells (PRBCs). Giving plasma expanders would further dilute the existing hemoglobin (hemodilution), worsening tissue hypoxia. * **Pulmonary Edema:** This condition is characterized by fluid overload in the lungs. Adding plasma expanders would increase hydrostatic pressure and worsen the edema. Treatment involves diuretics and fluid restriction. * **Cardiac Failure:** The heart is unable to pump the existing volume effectively. Increasing the preload with plasma expanders can lead to acute decompensation and congestive heart failure. **Clinical Pearls for NEET-PG:** * **Ideal Plasma Expander:** Should be iso-oncotic with plasma, pharmacologically inert, non-pyrogenic, and have a long shelf life. * **Dextran Warning:** Dextran-40 can cause "Dextran-induced Anaphylactoid Reaction" (DIAR) and may interfere with blood grouping/cross-matching. * **Gelatins:** These are the plasma expanders of choice in renal failure as they are excreted by the kidneys without causing significant damage. * **Albumin:** The only natural colloid; used in cirrhosis with ascites and severe burns.

Q: Heparin-induced thrombocytopenia is due to antibodies against which of the following?

Platelet factor 4. **Explanation:** **Heparin-Induced Thrombocytopenia (HIT)** is a life-threatening clinico-pathological syndrome caused by an immune-mediated reaction to heparin therapy. **Why Option D is Correct:** The pathogenesis of HIT (specifically Type II) involves the formation of IgG antibodies against the **Heparin-Platelet Factor 4 (PF4) complex**. 1. PF4 is a cationic protein stored in the alpha-granules of platelets. 2. When heparin (anionic) binds to PF4, it causes a conformational change, creating a neoantigen. 3. IgG antibodies bind to this Heparin-PF4 complex, forming immune complexes. 4. These complexes then bind to the **FcγRIIa receptors** on the surface of other platelets, leading to massive platelet activation, prothrombotic state, and subsequent consumption (thrombocytopenia). **Why Other Options are Incorrect:** * **Platelet Factor 1:** This is actually Factor V (proaccelerin) adsorbed onto the platelet surface; it is not involved in HIT. * **Platelet Factor 2:** Also known as thrombin-accelerator, it sensitizes fibrinogen to thrombin; it has no role in heparin-related immune reactions. * **Platelet Factor 3:** This refers to the platelet membrane phospholipids (like phosphatidylserine) that provide a surface for the assembly of coagulation complexes (tenase and prothrombinase). **High-Yield Clinical Pearls for NEET-PG:** * **Type II HIT** is the clinically significant form, typically occurring **5–10 days** after starting heparin. * **Paradoxical Thrombosis:** Despite low platelet counts, HIT is a **hypercoagulable state**. Patients are at high risk for venous and arterial thrombosis. * **Management:** Immediately stop all heparin products (including LMWH). Switch to direct thrombin inhibitors like **Argatroban** (drug of choice in renal failure) or **Lepirudin/Bivalirudin**. * **Gold Standard Test:** Serotonin Release Assay (SRA). The most common screening test is the ELISA for PF4 antibodies.

Q: Which of the following drugs does not cause thrombocytopenia?

Aspirin. **Explanation:** The correct answer is **Aspirin (Option B)**. The core concept here is the distinction between **platelet dysfunction** and **thrombocytopenia** (a decrease in the absolute number of platelets). 1. **Why Aspirin is correct:** Aspirin is an irreversible inhibitor of the enzyme Cyclooxygenase-1 (COX-1). This action prevents the synthesis of Thromboxane A2 (TXA2), which is essential for platelet aggregation. While Aspirin significantly impairs **platelet function** (increasing bleeding time), it does **not** reduce the actual platelet count. Therefore, it does not cause thrombocytopenia. 2. **Why the other options are incorrect:** * **Methotrexate (Option A):** As a cytotoxic antimetabolite (folic acid antagonist), it causes generalized **bone marrow suppression**. This leads to a decrease in all cell lines, including megakaryocytes, resulting in thrombocytopenia. * **Ticlopidine (Option C):** This P2Y12 receptor blocker is notorious for hematological toxicities, including **neutropenia** and **Thrombotic Thrombocytopenic Purpura (TTP)**, which presents with severe thrombocytopenia. * **Heparin (Option D):** Heparin can cause **Heparin-Induced Thrombocytopenia (HIT)**. This is an immune-mediated reaction where antibodies form against the Heparin-Platelet Factor 4 (PF4) complex, leading to platelet activation and subsequent consumption (low count). **High-Yield Clinical Pearls for NEET-PG:** * **Aspirin:** Affects *quality*, not *quantity* of platelets. * **HIT Type II:** Is an IgG-mediated "white clot syndrome" that paradoxically increases the risk of thrombosis despite low platelet counts. * **Clopidogrel vs. Ticlopidine:** Clopidogrel is preferred over Ticlopidine because it has a much lower risk of causing TTP and neutropenia.

Q: Which of the following drugs is administered orally?

Rivaroxaban. **Explanation:** The correct answer is **Rivaroxaban**. This question tests your knowledge of the routes of administration for various anticoagulants, a high-yield topic for NEET-PG. **1. Why Rivaroxaban is correct:** Rivaroxaban belongs to the class of **Direct Oral Anticoagulants (DOACs)**. It is a potent, competitive, and highly selective **Direct Factor Xa inhibitor**. Unlike traditional anticoagulants like Heparin, it has high oral bioavailability, a rapid onset of action, and does not require routine laboratory monitoring (like PT/INR), making it a preferred choice for long-term outpatient management of DVT and Atrial Fibrillation. **2. Why the other options are incorrect:** * **Dalteparin:** This is a **Low Molecular Weight Heparin (LMWH)**. Due to its large molecular size and polar nature, it is not absorbed through the gastrointestinal tract and must be administered **subcutaneously**. * **Lepirudin:** This is a recombinant hirudin derivative that acts as a **Direct Thrombin Inhibitor (DTI)**. It is administered **intravenously**, primarily used in patients with Heparin-Induced Thrombocytopenia (HIT). **Clinical Pearls for NEET-PG:** * **Mnemonic for Factor Xa Inhibitors:** Drugs with **"xa"** in their name (Rivaroxaban, Apixaban, Edoxaban) inhibit Factor **Xa**. * **Antidote:** The specific reversal agent for Rivaroxaban and Apixaban is **Andexanet alfa**. * **Direct Thrombin Inhibitors (DTIs):** While Lepirudin and Argatroban are parenteral, **Dabigatran** is the only commonly used **oral** DTI. * **Monitoring:** While DOACs don't require routine monitoring, if necessary, Rivaroxaban effect is measured by anti-Xa assays.

Question 1

All of the following are false regarding prasugrel, except?

Accepted Answer

Contraindicated in cerebrovascular accident

Answer

Minimal metabolism in the body

Answer

Slower onset of action than clopidogrel

Answer

Reversible inhibitors of ADP

Question 2

Laboratory monitoring of which of the following is desirable with low molecular weight heparin therapy in a patient with renal failure?

Accepted Answer

Anti-factor Xa activity

Answer

aPTT

Answer

CT

Answer

PT

Question 3

Which antiplatelet drug acts via purinergic receptors and is not largely impacted by CYP2C19 polymorphism?

Accepted Answer

Prasugrel

Answer

Ticlopidine

Answer

Clopidogrel

Answer

Abciximab

Question 4

Which of the following is NOT a true statement about heparin?

Accepted Answer

Hyperkalemia is not seen.

Answer

It prolongs aPTT.

Answer

It can result in alopecia.

Answer

It can cause thrombocytopenia.

Question 5

Capillary leak syndrome is caused by which of the following drugs?

Accepted Answer

Sargramostim

Answer

Filgrastim

Answer

Pegfilgrastim

Answer

Darbepoetin

Question 6

A patient with anterior wall myocardial infarction was thrombolysed within 6 hours of presentation. On day 3, the patient developed fever with chills and a platelet count of 60,000. Which of the following is responsible for this presentation?

Accepted Answer

Clopidogrel

Answer

Aspirin

Answer

Ranolazine

Answer

Streptokinase (STK)

Question 7

Plasma expanders are used in which of the following conditions?

Accepted Answer

Severe trauma

Answer

Severe anemia

Answer

Pulmonary edema

Answer

Cardiac failure

Question 8

Heparin-induced thrombocytopenia is due to antibodies against which of the following?

Accepted Answer

Platelet factor 4

Answer

Platelet factor 1

Answer

Platelet factor 2

Answer

Platelet factor 3

Question 9

Which of the following drugs does not cause thrombocytopenia?

Accepted Answer

Aspirin

Answer

Methotrexate

Answer

Ticlopidine

Answer

Heparin

Question 10

Which of the following drugs is administered orally?

Accepted Answer

Rivaroxaban

Answer

Dalteparin

Answer

Lepirudin

Answer

None of the above

Drugs Affecting Blood and Blood Formation — MCQs

Drugs Affecting Blood and Blood Formation — MCQs

On this page

Practice by Chapter

Want unlimited practice?