Drugs Affecting Blood and Blood Formation Practice Questions

Q: A pregnant mother is treated with oral anticoagulant. What is the likely congenital malformation that may result in the fetus?

Chondrodysplasia punctata. **Explanation:** The correct answer is **Chondrodysplasia punctata**. This condition is the hallmark of **Fetal Warfarin Syndrome (Warfarin Embryopathy)**, which occurs when oral anticoagulants (specifically Vitamin K antagonists like Warfarin) are administered during the first trimester (6–9 weeks of gestation). **Why it is correct:** Warfarin crosses the placenta and interferes with the γ-carboxylation of proteins required for bone and cartilage formation (such as osteocalcin). This leads to **Chondrodysplasia punctata**, characterized by "stippled epiphyses" (calcific punctate deposits in the ends of bones) on X-ray. Other classic features include **nasal hypoplasia** (depressed nasal bridge) and midface hypoplasia. **Why the other options are incorrect:** * **A. Long bones limb defect:** While Warfarin affects bone development, it typically causes stippling and shortening rather than gross limb reduction defects (which are more characteristic of Thalidomide). * **B. Cranial malformation:** Though CNS anomalies (like microcephaly or hydrocephalus) can occur if Warfarin is used in the 2nd or 3rd trimester due to fetal hemorrhage, they are not the primary "stippled" malformation associated with early exposure. * **C. Cardiovascular malformation:** These are more commonly associated with Lithium (Ebstein’s anomaly) or uncontrolled maternal diabetes, rather than oral anticoagulants. **High-Yield Clinical Pearls for NEET-PG:** * **Critical Period:** Exposure between **6–9 weeks** gestation is most teratogenic for bone defects. * **Safe Alternative:** **Heparin** (both UFH and LMWH) is the anticoagulant of choice in pregnancy because it is a large molecule and **does not cross the placenta**. * **Late Pregnancy Risk:** Warfarin in the 3rd trimester increases the risk of fetal intracranial hemorrhage during labor.

Q: Which of the following drugs does not cross the placenta?

Heparin. **Explanation:** The passage of drugs across the placental barrier is primarily determined by the drug's molecular weight, lipid solubility, and ionization state. **Why Heparin is the Correct Answer:** Heparin is a large, highly polar (negatively charged) polysaccharide molecule with a high molecular weight (approx. 15,000 Daltons). Due to its **large size and high degree of ionization**, it cannot cross the placental barrier. Consequently, heparin does not affect the fetus and is the **anticoagulant of choice during pregnancy**. **Why the Other Options are Incorrect:** * **Warfarin (Option B):** Unlike heparin, warfarin is a small, lipid-soluble molecule that easily crosses the placenta. It is highly teratogenic, especially during the first trimester, causing **Fetal Warfarin Syndrome** (characterized by nasal hypoplasia and stippled epiphyses). * **Dicoumarol (Option C) and Nicoumalone (Option D):** These are coumarin derivatives similar to warfarin. They are small molecules that cross the placenta and carry significant risks of fetal hemorrhage and teratogenicity. **NEET-PG High-Yield Pearls:** 1. **Rule of Thumb:** Drugs with a molecular weight **>1000 Daltons** generally do not cross the placenta. Heparin fits this criterion. 2. **LMWH (Low Molecular Weight Heparin):** Even though it is smaller than Unfractionated Heparin, LMWH (e.g., Enoxaparin) also **does not cross the placenta** and is frequently used in clinical practice for pregnant patients. 3. **Teratogenicity:** Warfarin is contraindicated in pregnancy (Category X), except in specific cases of high-risk mechanical heart valves, though even then, it is avoided near term due to the risk of intracranial hemorrhage during delivery.

Q: Eltrombopag is a

Thrombopoietin analogue. **Explanation:** **Eltrombopag** is a small-molecule, orally active **thrombopoietin (TPO) receptor agonist**. It functions as a TPO analogue by binding to the transmembrane domain of the erythropoietin/thrombopoietin (c-mpl) receptor. This interaction initiates signaling pathways (JAK/STAT and MAPK) that lead to the proliferation and differentiation of megakaryocytes, ultimately increasing platelet production. **Analysis of Options:** * **Option A & B (Erythropoietin analogue/receptor agonist):** These drugs (e.g., Epoetin alfa, Darbepoetin alfa) stimulate the production of red blood cells. They are used in anemias related to chronic kidney disease or chemotherapy, not for platelet disorders. * **Option C (Correct):** Eltrombopag mimics the action of endogenous thrombopoietin, making it a functional analogue used to treat thrombocytopenia. * **Option D (GMCSF analogue):** Granulocyte-Macrophage Colony-Stimulating Factor analogues (e.g., Sargramostim) primarily stimulate the production of neutrophils and monocytes. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Chronic immune thrombocytopenia (ITP) refractory to steroids, thrombocytopenia in Hepatitis C patients (to allow interferon therapy), and severe aplastic anemia. * **Route of Administration:** Eltrombopag is **oral**, whereas **Romiplostim** (another TPO agonist) is administered **subcutaneously**. * **Key Side Effect:** Hepatotoxicity (monitor LFTs) and potential for marrow fibrosis. * **Drug Interaction:** It chelates with polyvalent cations (calcium, iron, antacids); it must be taken on an empty stomach (1 hour before or 2 hours after meals).

Q: Which of the following is a longer-acting erythropoietin derivative?

Darbepoetin alfa. **Explanation:** **Darbepoetin alfa** is the correct answer because it is a synthetic glycosylated form of erythropoietin. The primary medical concept here is **hyperglycosylation**. While recombinant human erythropoietin (Epoetin alfa) has three N-linked carbohydrate chains, Darbepoetin alfa contains **five**. These additional chains significantly increase its molecular weight and decrease its affinity for the erythropoietin receptor, which paradoxically results in a much **longer half-life** (approximately 24–26 hours compared to 4–8 hours for Epoetin). This allows for less frequent dosing (once weekly or every two weeks) in patients with chronic kidney disease or chemotherapy-induced anemia. **Analysis of Incorrect Options:** * **A. Sargramostim:** This is a recombinant **GM-CSF** (Granulocyte-Macrophage Colony-Stimulating Factor) used to stimulate the production of neutrophils and monocytes, not red blood cells. * **C. Dornase alfa:** This is a recombinant **DNase enzyme** used via inhalation in Cystic Fibrosis to decrease the viscosity of mucus by breaking down extracellular DNA. * **D. Oprelvekin:** This is a recombinant **Interleukin-11 (IL-11)** used to stimulate megakaryocytopoiesis and prevent severe thrombocytopenia. **High-Yield Clinical Pearls for NEET-PG:** * **Methoxy polyethylene glycol-epoetin beta:** This is the longest-acting erythropoietin (Continuous Erythropoietin Receptor Activator - CERA), administered once a month. * **Adverse Effect:** The most common side effect of erythropoiesis-stimulating agents (ESAs) is **hypertension** and an increased risk of thromboembolism. * **Black Box Warning:** ESAs can increase the risk of tumor progression or recurrence in certain cancers.

Q: Which drug does not cause hemolysis in G6PD deficiency?

Corticosteroids. **Explanation:** Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is an X-linked recessive disorder where erythrocytes lack the ability to generate sufficient NADPH. NADPH is essential for maintaining a pool of reduced glutathione, which protects red blood cells from oxidative stress. When exposed to oxidizing agents, hemoglobin denatures into **Heinz bodies**, leading to hemolysis. **Why Corticosteroids are the Correct Answer:** Corticosteroids (Option C) are anti-inflammatory and immunosuppressive agents. They do not possess oxidative properties and do not interfere with the glutathione pathway. Therefore, they do not trigger hemolytic crises in G6PD-deficient individuals. **Analysis of Incorrect Options:** * **Primaquine (Option A):** A classic "high-yield" trigger. It is an antimalarial that generates reactive oxygen species (ROS), causing severe hemolysis in G6PD deficiency. * **Dapsone (Option B):** Used for leprosy and dermatitis herpetiformis, it is a potent oxidizing agent known to cause both hemolysis and methemoglobinemia. * **Methylene Blue (Option D):** While used to treat methemoglobinemia, it requires NADPH to be converted to leukomethylene blue. In G6PD deficiency, the lack of NADPH makes it ineffective and potentially oxidative, worsening hemolysis. **NEET-PG High-Yield Pearls:** * **Other common triggers:** Nitrofurantoin, Sulfonamides, Quinolones, and Fava beans (Favism). * **Diagnosis:** Look for "Bite cells" (degmacytes) and "Heinz bodies" on a peripheral smear. * **Timing:** Hemolysis typically occurs 2–3 days after drug exposure. * **Safe Alternatives:** For analgesia, Paracetamol is generally safe in therapeutic doses; for malaria, Chloroquine is safe.

Q: Which drug is used in mild hemophilia?

DDAVP. **Explanation:** **Correct Option: B (DDAVP / Desmopressin)** DDAVP is a synthetic analogue of vasopressin (ADH) [3]. In patients with **mild Hemophilia A** and **Type 1 von Willebrand Disease (vWD)**, DDAVP acts on V2 receptors to trigger the release of stored **Factor VIII** and **von Willebrand Factor (vWF)** from the Weibel-Palade bodies of endothelial cells. This transiently increases plasma levels of these factors (usually 3–5 fold), making it the treatment of choice for minor surgical procedures or spontaneous bleeding in mild cases. It is ineffective in severe Hemophilia A (where factor stores are absent) or Hemophilia B (Factor IX deficiency). **Incorrect Options:** * **A. Corticosteroids:** These are used to manage immune-mediated complications (like inhibitors) or joint inflammation (hemophilic arthropathy) but do not increase clotting factor levels. * **C. Vitamin K:** This is essential for the synthesis of Factors II, VII, IX, and X [2]. It is used for warfarin reversal or Vitamin K deficiency but has no role in treating Hemophilia A. * **D. Tranexamic acid:** This is an antifibrinolytic agent. While often used as an **adjunct** in hemophilia (especially for mucosal bleeds) to prevent clot breakdown, it is not the primary drug used to elevate factor levels. **High-Yield Pearls for NEET-PG:** * **Route:** DDAVP can be administered IV, SC, or via a high-concentration nasal spray (Stimate). * **Side Effects:** Hyponatremia and water intoxication (due to antidiuretic effect) and facial flushing [1]. * **Tachyphylaxis:** Repeated doses lead to diminished effect as endothelial stores become exhausted. * **Contraindication:** Avoid in Type 2B vWD (may cause paradoxical thrombocytopenia).

Q: A patient is diagnosed to be having iron deficiency anemia. What agent can be used to improve the absorption of iron?

Ascorbic acid. ### Explanation **Correct Answer: D. Ascorbic acid** **Mechanism of Action:** Iron is primarily absorbed in the duodenum and proximal jejunum. Dietary iron exists in two forms: Heme and Non-heme (ferric, $Fe^{3+}$). However, the human body can only absorb iron in its **ferrous ($Fe^{2+}$) state** via the divalent metal transporter 1 (DMT1). **Ascorbic acid (Vitamin C)** enhances iron absorption through two mechanisms: 1. It acts as a reducing agent, converting ferric iron ($Fe^{3+}$) to the more soluble ferrous iron ($Fe^{2+}$). 2. It forms a soluble iron-ascorbate complex that prevents the precipitation of iron in the alkaline environment of the small intestine. **Analysis of Incorrect Options:** * **A. Antacids:** These increase gastric pH. An acidic environment is essential for the ionization and solubilization of iron; therefore, antacids significantly **decrease** iron absorption. * **B. Tetracyclines:** These drugs form insoluble **chelates** with divalent and trivalent cations like iron, preventing the absorption of both the drug and the mineral. * **C. Phosphates:** Found in foods like eggs and cereals, phosphates (along with phytates and oxalates) form **insoluble complexes** with iron in the gut, hindering its uptake. **NEET-PG High-Yield Pearls:** * **Oral Iron:** Ferrous salts (Sulfate, Fumarate, Gluconate) are preferred over ferric salts due to better bioavailability. * **Hepcidin:** This liver-derived peptide is the **master regulator** of iron homeostasis; it inhibits iron absorption by degrading ferroportin. * **Drug Interactions:** Iron should be taken on an empty stomach for maximal absorption, but if GI distress occurs, it is taken with food (though this reduces absorption by 40-50%). * **Toxicity:** Acute iron poisoning is treated with **Desferrioxamine** (IV) or **Deferiprone/Deferasirox** (Oral).

Q: Megaloblastic anemia is caused by which of the following?

Phenytoin. **Explanation:** **Megaloblastic anemia** is a common side effect of certain drugs that interfere with folate or Vitamin B12 metabolism. **1. Why Phenytoin is correct:** Phenytoin (an antiepileptic) causes megaloblastic anemia primarily by **inhibiting the intestinal enzyme pteroylpolyglutamate hydrolase**, which is necessary for the absorption of dietary folate. It may also interfere with folate uptake by cells or increase its metabolism. This leads to a functional folate deficiency, resulting in macrocytic RBCs and hypersegmented neutrophils. **2. Why the other options are incorrect:** * **Lithium:** Primarily associated with **leukocytosis** (increased WBC count) and nephrogenic diabetes insipidus. It does not typically cause anemia. * **Lead:** Causes **sideroblastic anemia** and microcytic hypochromic anemia by inhibiting enzymes in the heme synthesis pathway (ALA dehydratase and ferrochelatase). A classic finding is **basophilic stippling**. * **Chloroquine:** Generally associated with **hemolysis** in patients with G6PD deficiency, but not megaloblastic changes. **Clinical Pearls for NEET-PG:** * **Other drugs causing Megaloblastic Anemia:** Methotrexate, Trimethoprim, Pyrimethamine (DHFR inhibitors), Zidovudine (AZT), and Valproate. * **Phenytoin Side Effects (Mnemonic: HOT MALAR):** **H**irsutism, **O**steomalacia, **T**eratogenicity (Fetal Hydantoin Syndrome), **M**egaloblastic anemia, **A**taxia, **L**ymphadenopathy, **A**rrhythmias, **R**igidity (Gingival Hyperplasia). * **Management:** Megaloblastic anemia due to phenytoin can be reversed by supplementing with **Folic acid**.

Q: Which of the following is an anticoagulant drug?

All of these. **Explanation:** Anticoagulants are drugs that prevent the formation of fibrin clots by interfering with the coagulation cascade [3]. The correct answer is **All of these** because each drug listed acts on different steps of the clotting pathway to achieve anticoagulation. * **Heparin (Option A):** An indirect thrombin inhibitor. It acts by binding to **Antithrombin III (AT-III)**, which then inactivates Factor Xa and Thrombin (Factor IIa) [2]. It is the drug of choice for rapid anticoagulation (e.g., in PE or DVT) [3]. * **Ximelagatran (Option B):** A prodrug of melagatran, which is a **Direct Thrombin Inhibitor (DTI)** [3]. While it was the first oral DTI, it was largely withdrawn due to hepatotoxicity and replaced by Dabigatran. However, it remains classified as an anticoagulant. * **Fondaparinux (Option C):** A synthetic pentasaccharide that acts as a **selective Factor Xa inhibitor** [1]. Like heparin, it requires AT-III to function, but it is too short to bridge AT-III to thrombin, making it specific for Factor Xa [2]. **High-Yield Clinical Pearls for NEET-PG:** 1. **Antidotes:** The antidote for Heparin is **Protamine Sulfate** [4]. There is no specific antidote for Fondaparinux. 2. **Monitoring:** Heparin is monitored using **aPTT**, whereas Fondaparinux and Direct Oral Anticoagulants (DOACs) generally do not require routine monitoring. 3. **HIT:** Fondaparinux does not cause Heparin-Induced Thrombocytopenia (HIT) and can be used as an alternative treatment for it [4]. 4. **LMWH vs. Heparin:** LMWH (e.g., Enoxaparin) has a higher ratio of Anti-Xa to Anti-IIa activity compared to Unfractionated Heparin (1:1).

Q: Hydroxyethyl starch is used as:

Plasma expander. **Explanation:** **Hydroxyethyl starch (HES)** is a synthetic colloid derived from amylopectin. It is primarily used as a **plasma expander** to restore circulating blood volume in patients with hypovolemia, such as those suffering from acute hemorrhage, trauma, or major surgery. * **Why Option A is correct:** As a large molecular weight colloid, HES remains within the intravascular compartment for an extended period. It exerts **oncotic pressure**, drawing fluid from the interstitial space into the blood vessels, thereby increasing plasma volume more effectively and for a longer duration than crystalloids. * **Why Option B is incorrect:** Inotropic agents (e.g., Dobutamine, Digoxin) increase the force of myocardial contraction. HES increases preload via volume expansion but has no direct effect on cardiac contractility. * **Why Option C is incorrect:** Vasodilators (e.g., Nitroglycerin, Hydralazine) reduce peripheral resistance. HES does not act on vascular smooth muscle. * **Why Option D is incorrect:** While both are colloids, Dextran is a glucose polymer produced by bacteria (*Leuconostoc mesenteroides*), whereas HES is a modified starch. They have different chemical structures and side-effect profiles. **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effects:** The most significant side effects of HES include **nephrotoxicity** (acute kidney injury) and **coagulopathy** (by diluting clotting factors and interfering with von Willebrand factor/Factor VIII). * **Black Box Warning:** Due to the risk of kidney injury and mortality, HES is contraindicated in critically ill patients, including those with sepsis or pre-existing renal dysfunction. * **Pruritus:** Chronic use or high doses can lead to intractable itching due to starch deposition in the skin.

Question 1

A pregnant mother is treated with oral anticoagulant. What is the likely congenital malformation that may result in the fetus?

Accepted Answer

Chondrodysplasia punctata

Answer

Long bones limb defect

Answer

Cranial malformation

Answer

Cardiovascular malformation

Question 2

Which of the following drugs does not cross the placenta?

Accepted Answer

Heparin

Answer

Warfarin

Answer

Dicoumarol

Answer

Nicoumalone

Question 3

Eltrombopag is a

Accepted Answer

Thrombopoietin analogue

Answer

Erythropoietin analogue

Answer

Erythropoietin receptor agonist

Answer

GMCSF analogue

Question 4

Which of the following is a longer-acting erythropoietin derivative?

Accepted Answer

Darbepoetin alfa

Answer

Sargramostim

Answer

Dornase alfa

Answer

Oprelvekin

Question 5

Which drug does not cause hemolysis in G6PD deficiency?

Accepted Answer

Corticosteroids

Answer

Primaquine

Answer

Dapsone

Answer

Methylene Blue

Question 6

Which drug is used in mild hemophilia?

Accepted Answer

DDAVP

Answer

Corticosteroids

Answer

Vitamin K

Answer

Tranexamic acid

Question 7

A patient is diagnosed to be having iron deficiency anemia. What agent can be used to improve the absorption of iron?

Accepted Answer

Ascorbic acid

Answer

Antacids

Answer

Tetracyclines

Answer

Phosphates

Question 8

Megaloblastic anemia is caused by which of the following?

Accepted Answer

Phenytoin

Answer

Lithium

Answer

Lead

Answer

Chloroquine

Question 9

Which of the following is an anticoagulant drug?

Accepted Answer

All of these

Answer

Heparin

Answer

Ximelagatran

Answer

Fondaparinux

Question 10

Hydroxyethyl starch is used as:

Accepted Answer

Plasma expander

Answer

Inotropic agent

Answer

Vasodilator

Answer

Type of dextran

Drugs Affecting Blood and Blood Formation — MCQs

Drugs Affecting Blood and Blood Formation — MCQs

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